Infection Control Measures Against Viral Infections

 

In this section, various aspects of infection control measures which are used against viral infections will be covered. The topics are as follows:

  1. Needle Stick Injuries
  2. Patients with Blood-Borne Infections
  3. Blood Products
  4. Spongiform Encephalopathies
  5. Isolation of patients
  6. Disinfection Policies
  7. Standards and Criterion of The Infection Control Standards Working Party (UK)

 

Needle Stick Injuries

 

Needle stick injury is a common occupational hazard among health care workers. Most needle stick injuries arise out of unsafe practices and are thus preventable. The greatest proportion of NSIs arise from the action of resheathing the needle after taking blood and this practice should be actively discouraged. However, it has been argued that not resheathing the needle would increase the risk for other staff such as porters and nurses and therefore, it may be a better idea to encourage resheathing using a safe method. Other injuries may result from personnel coming into contact with sharps that had not been properly disposed of, or accidents occurring in the operating theatres. Safer practices should be encouraged in the operating theatre, such as not to pass sharps hand to hand and not to use hand needles for suturing, use double gloves. In theory any infectious agents which may be present in the blood may be transmitted through NSI. In practice only a few agents are known to have been transmitted by NSI, the most important among which are hepatitis B, HIV and hepatitis C.

Hepatitis_B

Hepatitis B is the most easily parenterally-transmitted agent. The risk of transmission of hepatitis after a NSI from an eAg positive carrier had been estimated to be one third. Therefore all health personnel at risk of exposure to HBV should be vaccinated. HBIG has been shown to be successful in preventing infection by HBV or if already infected, able to attenuate the course of the illness. It is most effective if given within 24 hours of exposure after which its protective effects decline rapidly. However, it can be effective in up to 10-14 days after exposure. Its use should be supplemented by the administration of active immunization 2 weeks afterwards. The accelerated course of hepatitis B vaccination is used with injections at 0, 1, 2 months with a booster at 1 year. The actual management following an acute needle stick injury depends on whether the recipient has been vaccinated or not. HBIG should not be given until a baseline blood sample is taken but its administration should not be held up by waiting for the results of the testing of the baseline sample. If the injury occurred within 48 hours, then the testing of the donor sample could be delayed until the next morning. After that it becomes a case for on call testing as the beneficial effects of HBIG rapidly decline after 48 hours.

Vaccinated Recipient

  1. Contact from donors who are HBsAg +ve ;- Where the post-vaccination anti-HBs level is known to be protective (>100 miu/ml), either no action may be taken or a booster dose of vaccine may be given. Where the post-vaccination anti-HBs level is not sufficient or a post-vaccination result is not available, then HBIG should be given followed by a booster. The anti-HBs level is determined afterwards.
  2. Contact from donors who are HBsAg -ve ;- No action is necessary. The anti-HBs level in the recipient should be assessed.
  3. Contact from an unknown source or blood from the donor is unavailable for any reason;- This should be treated as if the donor source as if the donor is HBsAg -ve. However, discretion should be exercised especially in cases where the donor is from a high-risk group.

Unvaccinated Recipient

  1. Contact from donors who are HBsAg +ve; - Where the recipient is not naturally immune, HBIG should be prescribed immediately and an accelerated course of active immunization should begin 2 weeks afterwards.
  2. Contact from donors who are HBsAg -ve; - No HBIG is given but it is recommended that a full course of active immunization against HBV is given.
  3. Contact from an unknown source or blood from the donor is unavailable for any reason; - This should normally be treated as if the donor is HBsAg negative. Where the donor is in a high-risk group then HBIG should be given.

 

HIV

HIV is the most-feared agent that can be transmitted by NSI. To-date, there had been over 200 well-documented or highly suspected cases. The chance of transmission had been estimated to be 0.3%. It was found in a case-control study that the risk was increased for exposures involving (1) deep injury, (2) visible blood on the device causing injury, (3) a device previously placed in the source patient’s vein or artery, or (4) a source patient who died within 60 days of exposure with AIDS (therefore presumed to have a high titre of HIV). Identification of these risk factors suggests that the risk for HIV infection exceeds 0.3% for percutaneous exposures involving a larger volume of blood or a higher HIV titre in the blood. The risks after mucous membrane and skin exposures (approximately 0.1% and <0.1% respectively) probably also depend on the volume of blood and the titre of HIV. The risk is probably higher for skin contact that is prolonged, involves an area that is extensive, or in which the skin integrity is visibly compromised.

A recent case-control study showed that AZT postexposure prophylaxis was associated with a 79% reduction in risk after percutaneous exposure to HIV-infected blood in health care workers. However, there had been many examples of seroconversion to HIV in NSI victims even after zidovidine had been administered. In HIV-infected patients, combination therapy with AZT and lamivudine (3TC) has greater anti-retroviral activity that AZT alone and is active against many AZT-resistant strains without significant increase in toxicity. The addition of a protease-inhibitor provides even greater increases in antiretroviral activity. Among protease inhibitors, indinavir (IDV) is more potent than saquinavir and appears to have fewer drug interactions and short-term adverse effects than ritonavir. In currently recommended doses, AZT prophylaxis is well-tolerated with health workers; short-term toxicity associated with higher doses primarily includes GI symptoms, fatigue, and headache. In HIV-infected adults, 3TC can cause GI symptoms, and rarely pancreatitis. IDV toxicity includes GI symptoms and after prolonged use, mild hyperbilirubinaemia (10%), and kidney stones (4%). The current recommendations by the MMWR is as follows;-

  1. Chemoprophylaxis should be recommended to exposed workers after high-risk exposures. For exposures with a lower risk such as splashing of blood onto mucous membranes, chemoprophylaxis should be offered, balancing the lower risk against the use of drugs having efficacy and toxicity. For exposures with a negligible risk such as the splashing of urine onto skin or mucous membrane, chemoprophylaxis is not justified.
  2. At present AZT should be considered for all postexposure regimens because this is the only agent for which data is available to support its efficacy. 3TC should usually be added for increased anti-retroviral activity and activity against AZT-resistant strains. A protease inhibitor, preferably IDV should be added for exposures with the highest risk of HIV infection.
  3. Postexposure prophylaxis should be initiated promptly, preferably within 1-2 hours after exposure. Although animal studies suggest that postexposure prophylaxis is probably not effective when started 24-36 hours after postexposure, the interval after which there is no benefit is undefined. Initiating therapy after a longer interval e.g. 1-2 weeks, may be considered for high risk exposures, since even if infection is not prevented, early treatment of acute HIV infection may be beneficial. The optimum duration of postexposure prophylaxis is unknown, given that 4 weeks of AZT appears to be effective, postexposure prophylaxis should probably be given for at least 4 weeks if tolerated.
  4. If the source patient or the patient’s HIV is unknown, the initiation of chemoprophylaxis should be decided on a case-by-case basis, based on the exposure risk and the likelihood of HIV infection in the source patient.
  5. Workers with occupational exposures to HIV should receive follow-up counseling and medical evaluation, including HIV-antibody testing at baseline and for at least 6 month postexposure eg. 6 weeks, 3 months, 6 months.
  6. They should also be given advice on the prevention of secondary infection such as safe sex, abstention from donating blood, avoiding exposure-prone procedures on patients etc.  

HCV

HCV had been known to be transmitted through NSI, the actual risk is unknown but is thought to be considerably smaller than that of HBV but greater than HIV. The risk had been estimated to be around 3%. Since HCV infection is at present more prevalent than HIV, the risk of contracting HCV from an unknown source after a NSI is greater than that of HIV. Since hepatitis C tends to be milder than hepatitis B and the risk of transmission lower, routine testing of the NSI donor and recipient for HCV antibody is not recommended, unless the donor is known to be HCV positive, or belongs to a high risk group for hepatitis C.  

 

Patients With Blood-Borne Infections

 

A single policy should be devised to cover clinical entities which are transmitted via blood and body fluids such as HIV, HBV, HCV, syphilis, and malaria The policy should assess the risks to the staff and patients and should apply to all departments dealing with blood and blood products ie. Renal dialysis, operating theatres, labour ward, blood transfusion centre, and transplant units. There must be clear policies on screening patients, screening staff before they start work on the unit, disposal of sharps and waste, protective clothing, inoculation accidents and policy, sterilization and disinfection. Other points to consider include isolation facilities, procedures for dealing with spillage of blood and body fluids, intravenous procedures, and risk to staff. Good practices and adequate staff training should minimize the risk to staff, although extra care is needed with these patients.

General Infection Control Measures

  1. Apply good basic hygiene practices with regular hand washing
  2. Cover existing wounds or skin lesions with waterproof dressings
  3. Avoid invasive procedures if suffering from chronic skin lesions on hands
  4. Avoid contamination of person by appropriate use of protective clothing
  5. Protect mucous membrane of eyes mouth and nose from blood splashes
  6. Prevent puncture wounds, cuts and abrasions in the presence of blood
  7. Avoid sharps usage where possible
  8. Institute safe procedures for handling and disposal of needles and other sharps
  9. Institute approved procedures for sterilization and disinfect surfaces
  10. Clear up spillages of blood and other body fluids promptly and disinfect surfaces
  11. Institute a procedure for the safe disposal of contaminated waste

Protective clothing - universal precautions means that particular high-risk procedures are always dealt with using protective clothing such as gloves, aprons etc. Countries with a low incidence of blood-borne diseases sometimes practice a tow-tier system (protective clothing is only used for known high-risk patients such as HIV or HBV-positive patients). A single-tier system (where universal precautions are applied to all patients) should be practiced when the incidence is high. Gloves should be made of latex and fit well. Plastic aprons should be worn to protect staff from body fluids, as in the case with gloves, disposable aprons are preferable to reusable. Goggles or visor should be worn to avoid conjunctival splash contamination, although spectacles are acceptable. Masks are used to avoid blood or body fluids splashing into the moth and nostrils.

Isolation facilities - single cubicles should be provided only for patients who need high-dependency nursing, such as those with a poor standard of hygiene.

Spillage of blood and body fluids - spillages should be dealt with as quickly as possible with latex gloves. The spillage should be covered with hypochlorite granules (presept) or paper towels soaked with hypochlorite solution (1000 to 10000 ppm). At least 2 minutes of contact time should be allowed before the spillage is cleared and disposed of as clinical waste The surface is then washed with warm water and detergent

Sterilization and disinfection - hypochlorites are recommended for surfaces and 2% glutaraldehyde for heat-sensitive equipment and metals.

Intravenous procedures - these must be performed with great care by an experienced practitioner. Gloves and plastic aprons should be worn; eye protection is optional. A closed system (Vacutainer) is recommended but if a hypodermic needle and syringe is used, the whole unit must be discarded in a sharps container. Do not resheath needles. Devices which reduces the risk of needle stick injuries such as vacutainers, retractable needles should be considered for general use although they are expensive.

Collection and transportation of blood from patients - an absolute minimum of tests should be performed on high risk patients. If possible, specimens should be collected in a closed system (vacutainer), labelled clearly, and put in a leak-proof bag with request form and warning label. Venepuncture should only be performed by an experienced phlebotomist. Double gloves may be worn and a disposable paper towel should be placed beneath the patient’s arm to reduce contamination in the event of accidental spillage Any gauze or soiled paper towels should be discarded in the clinical waste bag. The transfer of blood to the appropriate container should be done slowly and carefully and without creating an aerosol. Needles should not be resheathed but discarded in the sharps container. However, if resheathing is absolutely necessary, use a mushroom device, which holds the cap so the needle can be introduced safely. Alternatively, lay the cap on the table with the closed end against anything that offer resistance and insert the needle carefully - never hold the cap while resheathing.

Staff protection and immunization - all staff working with category A patients (HBV, HIV) must be immunized against HBV. staff should have adequate training in the care of patients who are HIV or HBV positive. Clear policies of safety, covering inoculation accidents must be available. All inoculation accidents must be recorded and documented. Frequent lectures are essential to allay fear and promote good morale

Needle-stick injuries - if a non-immunized member of staff sustains a needle-stick injury from a e Ag positive HBV carrier, he should be offered HBIG and a course of vaccine. If the source is not eAg positive, then a course of vaccine alone would be sufficient. If the source is known to be HIV-positive, then AZT may be administered within 24 hours of exposure and counseling should be offered.
   

Operating theatres and labour wards

There has been much discussion about the protection of staff operating on HIV and HBV positive patients. Recent figures from the US show that the overall risk of acquiring a blood-borne disease is 0.3% in surgical operation. The following guidelines are advised during the operation or procedure;-

  1. The HBV and/or HIV status of the patient should be determined before the operation (with patient’s consent). The theatre or labour ward staff should be informed so that appropriate precautions can be made. It is advisable to schedule the patient at the end of the operating list.
  2. All staff should wear protective clothing - double gloves, plastic aprons and eye protection are recommended. Appropriate footwear should be worn to avoid contact with splashed blood or body fluids.
  3. Equipment and staff should be kept to a minimum. Where possible avoid using equipment which is difficult to sterilize, use as much disposable instruments as possible. Inexperienced staff should be excluded.
  4. The highest degree of discipline is essential. Sharps should not be passed hand to hand. Needles should not be guided with fingers and hand needles should not be used in the operation. For the purpose of wound drainage, closed apparatus should be used.
  5. All disposable items used during the operation eg. administration sets, IV cannulae, should be disposed of in the sharps container. The sharps container should be sealed and disposed of as soon as possible after the procedure. All instruments should be sent to the CSSD or TSSU after the operation. They should clearly be labelled as high risk. Non-disposable items should not be incinerated as they can be sterilized. Linen should be sent to the laundry marked as "infected linen". There is no need for incineration. Disposable suction tubing is preferred, where this is not available, the tubing should be autoclaved after use.
  6. There should be minimum handling of abdominal swabs. Contaminated swabs should be discarded into individual plastic bags which will facilitate weighing and counting. The swabs can then be discarded. It is not necessary to soak the swabs in disinfectant.

After the operation, all disposable, incinerable waste should be removed in clearly labelled colour-coded bags. Surfaces should be washed with warm water and detergent. Walls should be washed up to ahnd height with water and detergent. Blood and body fluid spillages should be spotted with hypochlorite. Heat-stable equipment should be sent for sterilization and labelled "high risk". Respiratory equipment should be disinfected by heat or glutaraldehyde. Larger machines should be wiped with warm water and detergent to remove organic contamination. This is sufficient unless heavy soiling has occurred. In that instance, they should be wiped with hypochlorite.

Renal dialysis unit

The same basic principles apply to the renal dialysis unit as for the theatre and delivery room. Staff should be immunized against hepatitis B before starting work in the unit. All patients should be screened and immunized against hepatitis B. Machines should be reserved for the exclusive use of HBsAg carriers. Disposable tubing and heat-labile equipment are recommended for dialysis. The outer surfaces of the dialysis machine should be cleaned with warm water and detergent. The inside of the machine should be disinfected with 1% hypochlorite and rinsed thoroughly before further use. Disposable filters should be used to prevent contamination with blood. Disposable administration lines, dialyser, and needles should be used. Re-usable equipment must be able to withstand autoclaving.   

Normal ward

Category A contact isolation is advisable for patients with HBV and HIV infection after surgery. Although not strictly necessary, it would be prudent to put the patient into a single room after the operation so that the risk to other patients in the ward is minimized. Whilst looking the patient, masks would not be necessary except for procedures such as endotracheal aspiration or changing the drainage bottle. Plastic gloves should be worn at all times and any cuts and bruises covered adequately. Any blood spilled onto the floor should be decontaminated with chlorox immediately. Extra care must be observed if blood is to be taken from this patient using venepuncture so that needle stick injuries are avoided. The same vigilance applies to the insertion of IV lines. Any waste material taken from the patient, such as wound dressings should be discarded into well-marked disposal bags and incinerated. It would not be necessary to have separate eating utensils for the patient provided that the washing machine goes up to 80oC. However disposable utensils would further minimize the risks.

 

HIV Transmission and Assisted Conception

 

Limitation of risks of transmission of any infection from donor to recipient is a major concern in overcoming infertility using donor gamates. Very specific guidelines have been issued by the RCOG.

Sperm donation

A careful history should be taken from men wishing to be sperm donors. As with blood donors, careful attention should be paid to the sexual history, recent travel to, or sexual contact with persons living in areas of the world where HIV is endemic, a history of blood transfusions, or intravenous drug use. After suitable counseling, all prospective donors are required to have HIV and HBV tests, in addition to screens for other STDs. In addition, in order to prevent transmission of infection, it is mandatory that sperm be quarantined by cryopreservation for a period before use, normally 3 to 6 months, with the sperm being released for use following a further negative HIV and HBV test on the donor. The use of fresh donated sperm for insemination is now prohibited in the UK.

Ovum donation

Ovum donation presents a particular problem as the equivalent technology for cryopreserving unfertilized oocytes has yet to be developed successfully as pregnancy success rates using frozen embryos are lower than using fresh embryos. However, most ovum donors are in stable heterosexual relationships and embark on ovum donation for altruistic reasons. Therefore they are a low risk population for HIV and fresh oocyte donation is allowed in the UK.

Intrauterine insemination where the male partner is known to be HIV positive

Many HIV-discordant couples wish to have children notwithstanding the risks associated with unprotected intercourse, estimated to be 1:100 episodes of intercourse. Although some reduction in risk may be made by decreasing the frequency of unprotected intercourse by monitoring ovulation and timing intercourse, there has been recent interest in the use of artificial insemination with semen processed to remove infectious virus. To date, no seroconversions had been seen in the 28 couples who participated in the study involving Percoll separation and "swim up". Further investigation is needed before this type of technique is declared safe.

In vitro fertilization

There is no statutory requirement for patients participating in in-vitro fertilization procedures to be screened routinely for HIV. However, some units will screen high-risk couples, while others make it a condition of acceptance, either for protection of the laboratory staff, or in the interests of the "welfare of the child", will refuse treatment for HIV-affected couples.

 

Blood Products

 

The emergence of HIV in the 1980’s provided a major driving force for the development of virus screening tests as well as virus-inactivation methods for use with plasma products. The inactivation methods that were developed also proved effective against other major plasma-transmitted viruses e.g. HBV and HCV. A number of factors contribute to the safety of both blood and plasma products. The high quality of blood donated by non-remunerated UK donors, donor selection, and the testing of each donor for various viral markers are initial contributors to virus safety. The main products derived from plasma include coagulation factors, albumin, and immunoglobulin. The use of plasma pools of 10,000 or more donations increases the risk of virus transmission. In addition to HIV, HBV and HCV screening on each donation, additional testing should be done on the plasma pool, process intermediates, and final products. The use of PCR assays requires further evaluation, especially given that PCR positivity does not necessarily equate with infectivity.

Coagulation factors

Coagulation factors are prepared from plasma by various precipitation and adsorption tests. Following the outbreak of the HIV-epidemic, virus-inactivation steps were introduced into the manufacturing process which were effective in inactivating HIV with little loss in product activity. For products of immediate purity, heat treatment was either carried out at 80oC, or pasteurization at 60oC for 10 hours. Treatment with B-propiolactone/UV has also been used in the past but this was discontinued when a single batch of factor IX was found to transmit HIV. High purity coagulation factor concentrates incorporates an in-process virus inactivation step. The most widely used method is the solvent/detergent procedure using Tri-n-butyl phosphate and a non-ionic detergent such as Triton X 100 or Tween 80. This method is currently used for about 70% of all plasma products and has an unblemished safety record for enveloped viruses. The method has no adverse effect on the product, although the chemicals must be removed after treatment. Other virus inactivation methods such as pasteurization or moist-heat treatment are also used. Dry heat-treatment and virus-removing filters are being evaluated as final virus-reducing steps in an effort to control more resistant non-enveloped viruses such as hepatitis A and parvovirus B19. Subsequent purification steps involving chromatographic processes can also contribute to virus safety of the product.

Albumin

Albumin is prepared from plasma by cold-ethanol fractionation, a process which is likely to reduce the virus load in the product. Pasteurization (60oC for 10 hours) can also be carried out on both the bulk product and on the final product. Under these conditions, HIV is rapidly inactivated within 30 minutes. Albumin has been prepared in this manner since the 1940’s and has an excellent safety record.

Intramuscular immunoglobulins

Immunoglobulins are prepared from plasma by cold-ethanol fractionation. Although there are no reports of HIV having been transmitted by immunoglobulins, there have been several reports concerning the transmission of HCV. These reports suggest that the conditions of cold-ethanol fractionation, by themselves, are not sufficient to render immunoglobulins completely safe from virus transmission.

Intravenous immunoglobulins

Further processing is required to make an immunoglobulin product suitable for intravenous use. This is simply accomplished in some products by treating the Intramuscular product with pepsin at pH4 for extended periods of time. Alternative approaches for the production of IVIG involve chromatographic processes. Although no cases of HIV had been reported following the administration of IVIG, high rates of HCV transmission had been reported. As a result, there is now increasing pressure for the incorporate of a specific inactivation step in such products eg. a solvent/detergent step with Tween 80. In addition the CM sepharose ion-exchange chromatographic step can reduce the level of enveloped viruses significantly. It is expected that these steps will contribute further to the safety of the product.

In conclusion, the safety of blood products has increased significantly over the last 10 years with the introduction of virus screening and virus reduction methods. Residual risk estimates are in the order of 1 in 3.5 X 105 per unit of blood and <1 in 106 per unit of solvent/detergent treated factor VIII. However, there has been pressure to introduce additional inactivation steps for plasma products as a result of reported rare instances of HBV and HCV transmission, and also because of the inability of current manufacturing processes to deal with small non-enveloped viruses such as HAV and parvovirus B19. Currently, many new techniques are being evaluated, such as photochemical inactivation, iodine-based chemicals, UV-C, virus filtration, and phase conversion by high pressure.

 

Spongiform Encephalopathies

 

Creutzfeldt-Jacob Disease is a transmissible spongiform encephalopathy (TME). In recent years, there has been an increase in iatrogenic cases through injections of human cadaver derived growth hormone, cornea grafts, dura mater grafts for eardrums, and contaminated neurosurgical instruments. TME agents are highly resistant to heat, radiation and chemical inactivation. The sterilization and disinfection procedures for TME agents are far more stringent than those usually applied in hospital practice for the control of conventional bacterial, viral, and other infectious disease agents. Contaminated reusable instruments should be sterilized at 134-138oC for not less than 18 minutes (hold time) or for six cycles of 3 minutes. It is thought that the downward displacement autoclave which is commonly used in laboratory work may be less effective even at these high temperatures than the surgical sterilizer operating with a pulsed vacuum cycle. Scrapie-infected tissue stored in 10% formalin has been shown to be still infectious. The application of sodium hypochlorite containing 20000 ppm appears to be effective when used in decontaminating surfaces. Phenolic disinfectants and B -propiolactone are regarded as unreliable. There is practical difficulty in disinfecting safety cabinets of TME agents because of their resistance to formaldehyde and other fumigants.

To date, there are no confirmed cases of laboratory-acquired infection. However, the long incubation period makes the cause and effect difficult to relate and two recently reported cases of CJD in ex-laboratory workers who had handled neural tissues extensively are a matter of concern. Therefore, particular caution is advised in dealing with tissue from the CNS, especially from suspected cases of CJD and GSS. Equipment used in the laboratory and post-mortem room should be subjected to stringent disinfection procedures. Work practices should be reviewed to avoid puncture wounds and cuts. Eye protection and gloves should be worn. The skull of a CJD or GSS patients should only opened in a bag. At present, level 2 containment is advised for TME agents with additional measures to guard against puncture wounds and cuts and contamination of broken skin and eyes.

Bovine Spongiform Encephalopathy

A new variant of CJD was described in the UK in 1996 characterized by a much younger age of onset (mean of 26 years as opposed to 65 years for the classical disease), a longer duration of illness, and a distinct histopathological pattern for which the only common risk factor was the consumption of beef. A WHO Consultation was carried out in April 1996 which reviewed the public health issues related to BSE and the emergence of the new variant of CJD. The group concluded that there is no definite link between BSE and the variant CJD, but the circumstantial evidence suggests that exposure to BSE is the most likely hypothesis. The recommendations made by the group was as follows;-

  1. No part of product of any animal which has shown signs of transmissible spongiform encephalopathy should enter any food, whether human or animal.
  2. All countries should establish continuous surveillance and compulsory notification for BSE.
  3. Tissues that are likely to contain the BSE agent (specified bovine offals) such as brain, spinal cord, tonsil, spleen, thymus, and intestines should not be permitted to enter any food chain, whether human or animal.
  4. The use of ruminant tissues in ruminant feed should be prohibited.
  5. Milk and milk products are considered to be safe. Gelatin and tallow are considered to be safe provided that effective rendering procedures are in place.
  6. Manufacturers of medicinal products containing bovine material should obtain the material only from countries effective surveillance and control programmes.    

The group also recommends increased surveillance and research on BSE and CJD worldwide. There is concern that specific occupational groups such as abattoir workers, butchers and vets have a higher risk of exposure to TME agents. Specific recommendations include;-

  1. Taking care to avoid injuries especially with instruments which have been in contact with specified bovine offals.
  2. Covering open cuts and grazes with waterproof dressings
  3. Wearing suitable protective equipment and clothing
  4. Minimizing direct contact with specified bovine offals  

The infectivity of the BSE agent is substantially but not completely reduced when subjected to porous load autoclave at 134-138oC for up to 60 minutes. There is no detectable infectivity after exposure to hypochlorite 16500 ppm for 120 minutes.

 

Isolation of Patients

 

Isolation for the control of infection is used to prevent infected patients from infecting others (source isolation) , and/or prevent susceptible patients from being infected (protective isolation). The methods of physical protection are:-

  1. Barrier nursing - special nursing procedures which reduce the risks of person to person transmission, especially by direct contact or by fomites.
  2. Segregation into single rooms, cubicles, or plastic isolators - which reduces airborne spread to from patients, and facilitates nursing techniques.
  3. Mechanical ventilation - which reduces the risks of airborne spread by removing bacteria from the patient’s room and by excluding bacteria present in the outside air from the room.

The transfer of infection by the airborne route can be controlled only by confining the patients in a single room, whether source or protective isolation. On the other hand, diseases spread by contact, such as enteric fever, depends primarily on barrier nursing. The term isolation is commonly used in the sense of segregation of the patient in a single room. Barrier nursing is one of the basic components of patient isolation and can be used on its own or together with the other components. There are various types of isolation offering different degrees of protection;-

  1. High security isolation units - these are usually part of an infectious diseases hospital. Total environmental control is usually achieved by the use of negative pressure plastic isolators. Theses units are designed for treating Hazard Group 4 viral pathogens such as Lassa, Marburg, and Ebola fevers.
  2. Infectious diseases hospitals - these units are usually separate from other hospitals but may be situated in the grounds of a general hospital with separate ventilation and nursing staff.
  3. General hospital isolation units - these provide source isolation facilities for hospital-acquired infections; they also provide facilities for protective isolation and for the screening of patients with suspected infections before admission to a general ward or transfer to a communicable diseases unit.
  4. Single rooms of a general ward - these provide less secure source isolation than the above because of the close proximity to other patients and sharing of nursing and domestic staff with a general ward. Their value in protective isolation depends on the type of patient in the general ward, on the thoroughness of barrier nursing, on whether the room is self-contained (with w.c.), and on the type of ventilation used.
  5. Barrier nursing in open ward - this can be effective in controlling infections transferred by contact but not by air.
  6. Isolators in open wards - plastic enclosures for individual patients have been shown to be of value as a form of protective isolation for high risk patients and of source isolation for infected patients.
  7. Ultra-clean wards - experimental units have been set up in special centres for organ transplantation, treatment of leukaemia and other diseases associated with extreme susceptibility to infection.

Categories of Isolation

The term strict isolation is used to describe the isolation procedure for highly transmissible and/or dangerous pathogens. The term standard isolation is used to describe methods used for other transmissible infections. The term protective isolation is used to describe methods of isolation for highly susceptible patients. The isolation categories vary from country to country. Most UK hospitals have adopted four categories, and special instructions are given by the Infection Control Team if variations are necessary. In general the patient should be isolated for the duration of the illness or until the infectious stage of the illness has passed.

Category A.

These infections are spread by; (1) hands, (2) contact with non-sterile equipment, faeces, blood and body fluids, and (3) bedpans/urinals. Viruses considered under this category include HIV, HAV, HBV, HCV, diarrhoeal viruses and enteroviruses. A cubicle or private room is required. All staff should wear a gown or apron and gloves when attending a patient. All persons should wash their hands on leaving the cubicle. Masks are not necessary but should be used if indicated. The discipline of the staff is of vital importance, especially in hand-washing, keeping the door closed, disinfection of toilets and bedpans etc. Enteric precautions are always necessary for diarrhoeal diseases and enteric fever. Staff should be protected against TB, polio, rubella and HBV.

Category B.

This category covers infections spread from the respiratory tract via droplets eg. chickenpox, measles, mumps. A cubicle or single room is essential. Masks, gloves, and aprons should be worn when handling the patient. A ventilation system (consisting of at least an extractor fan) is advantageous for patients with communicable respiratory infections, especially chickenpox.

The following general principles apply for category A and B isolation;-

  1. Room or cubicle - the door should be kept closed at all times. An extraction fan may be fitted. Any unnecessary furniture should be removed before admitting the patient. The room may be equipped with special items needed to nurse the patient eg. pedal bins, plastic bags etc. All equipment should be kept inside the room and the room should be kept tidy.
  2. Gowns and aprons- disposable aprons are recommended. Cotton gowns provide limited protection but are acceptable in most circumstances. Gowns made of water-repellent material give better protection. The gown or apron should be left hanging in the room and changed daily or earlier when soiled. Although disposable aprons are preferable, non-disposable plastic aprons may be used and should be disinfected by heat or alcohol.
  3. Gloves - gloves should be worn when handling infected material and sites and. Conventional disposable non-sterile plastic gloves are adequate for most purposes. Long sleeved disposable gloves may be used when protection of the arms is necessary.
  4. Masks - masks are necessary for category B and perhaps some category A infections; if used they should be of the high efficiency filter type, which should provide protection for 10-15 minutes.
  5. Hands - hand washing before and after contact with the patient is perhaps the most important measure in preventing the spread of infection. Either a non-medicated soap or a detergent antiseptic preparation should be adequate for most purposes. 70% alcohol is more effective in removing transient as well as residual flora and should be used in high risk situations.
  6. Bedpans and urinals - gloves should be worn when handling bedpans and urinals. The contents should be disposed of directly into the sluice or bedpan disinfector. The bedpan or urinal should then be heat disinfected and dried. A bedpan washer/disinfector and a high temperature washing-up machine should be available in the ward.
  7. Wastes - all clinical waste should be disposed of in a colour-coded bag for incineration.
  8. Equipment - disposable or autoclavable equipment should be used whenever possible. Essential items of patient care such as sphygmomanometers and stethoscopes should be left in the room and disinfected when the patient is discharged or before being used on another patient. Hard surfaces may be disinfected by wiping with a phenolic or hypochlorite solution. Other equipment may be disinfected by wiping with 70% alcohol. Sphygmomanometer cuffs may be disinfected by low temperature steam. Thermometers should be kept in the isolation room until the patient is discharged.
  9. Needles and syringes - these should be disposable and placed in a hardened container which is sealed before disposal.
  10. Linen - avoid vigorous bed-making - linen from infected patients should be placed in a colour-coded linen bag for transfer to the laundry. Linen which may present a hazard to the laundry staff eg. hepatitis B, should first be sealed in labelled bag.
  11. Crockery and cutlery - disposable items may be used when a dishwasher heating the items to over 80oC is not available. Food should be placed in polythene bags and discarded with ward waste.
  12. Laboratory specimens - some warning should be given to the laboratory staff. Containers should be placed in a biohazard bag.
  13. Charts - patient’s charts should be kept outside the contaminated areas.
  14. Disposal of personal clothing - clean clothing requires no special treatment. Contaminated or fouled clothing should be transferred to the hospital laundry in a sealed water-soluble or alginate-stitched bag. Clothing from patients with viral hemorrhage fever require special arrangement.    
  15. Transporting patients - patients should be sent to other departments only if it is essential to do so. The department should be notified in advance so that they may take suitable measures to prevent the spread of infection.
  16. Staff should also take the following precautions when handling secretion, excretion and exudates;-
  1. Oral - patients should be encouraged to cough or spit into paper and then discard into a plastic bag.
  2. Exudate - a "non-touch" technique using forceps or disposable gloves should be used and contaminated material should be placed in sealed paper or plastic bags.
  3. Excretion - for patients with enteric fever, dysentery, cholera and other infections spread by urine or faeces, disposable gloves should be worn to take the bedpan from the patient to the disposal area. The nurse should don a plastic gown or apron and the pan should be covered with a disposable paper bag before transport. Disposable gloves and a plastic apron or gown should be worn to handle contaminated equipment or linen, and when washing the perineal area.

Disposal of the dead - when death of a person suffering from a notifiable infectious disease takes place in a hospital, provision is made under the Public Health Act 1936 to prohibit the removal of the body from the hospital, except for the purpose of being taken direct to a mortuary or being buried or cremated. Every step should be taken to prevent persons coming unnecessarily into contact with it. A justice of the peace has the power to order the removal or the burial of the body. In practice the above powers are not generally enforced. Cremation is the safest method of disposal and relatives should be encouraged to agree to this method although it cannot be legally enforced.

Terminal disinfection of isolation rooms - all surfaces and walls must be washed thoroughly with warm water and detergent and dried (wipe over with a disinfectant if indicated) All bed linen, curtains etc. that is sent to the laundry should be clearly marked "infected" The bed mattress and pillow should be wiped with warm water and detergent and dried thoroughly. Occasionally, a disinfectant may be indicated. All heat-sensitive items of equipment that are for common ward use should be wiped with 70% alcohol mixture. All autoclavable items should be sent to the CSSD. All disposable items should be discarded in containers for clinical waste and the room should be aired and open for admission after 24 hours. If the isolation area is a bed on an open ward, then the entire surrounding area up to the next bad, including curtains, should be treated as above.

Category C. (Reverse - Protective Isolation)

This is used for diseases in which there is increased susceptibility to infection such as patients with neutropenia, on anti-cancer chemotherapy, and severely immunocompromized patients. The amount of protection required varies with the type of patient. Essentially, such patients should be isolated with a minimum of dust, dirt, and wet areas. Hands must be washed or disinfected before entering the room. Sterile gloves, gown or apron, and masks should be worn and discarded after attending patient. Maximum protection, including sterile linen, food and other supplies, may be required for immunosuppressed patients, but is not necessary for patients with eczema and burns. Maximum protective isolation requires the use of a ventilated room or positive pressure isolator. Mouth and other orifices should be decontaminated, gut and skin may also have to be decontaminated. Staff should wear sterile protective clothing. If visitors are admitted to the isolation room, they should be given detailed instructions and if suffering from any infection, they should be excluded.  

Category D. (Strict Isolation)

Category D isolation is only found in specialized units for highly contagious infections such as rabies and viral haemorrhagic fevers. A cubicle is essential (a plastic bubble that contains the patient and all essential patient-care equipment) may be used. Gowns, plastic aprons, masks, and eye goggles should be worn. Crockery and cutlery should be disposable. Disposable non-clinical articles should be used and should not be recycled. All other clinical equipment should be sterilized. Air-borne contamination and patient-handling should be kept to a minimum. Hospital staff and visitors should be made aware of the risks when tending such patients.

Suggested labels for categories of isolation

Adhesive labels are recommended to be used for patients in isolation. These should be attached to the door of the isolation room. The labels should be held by the Ward Sister and are colour-coded.

Category A or B Isolation  

Visitors Please report to sister’s office before entering room
Single Room Necessary for all infections transferred by air, and preferred for other infections, door must be kept closed
Plastic Aprons Must be worn when attending patients
Masks Not necessary, except for persons susceptible to the disease (filter type)
Hands Must be washed on leaving
Gloves Not necessary (except for contact with infected area, or when excretion or secretion precautions necessary
Articles Normal supplies. Disposed in waterproof containers
Comments  

D. Strict source isolation  

Visitors Please report to sister’s office before entering room
Single Room Necessary, door must be kept closed
Gowns, aprons Must be worn
Masks Must be worn (filter type)
Hands Must be washed on leaving
Gloves Must be worn
Articles Disposable supplies. Disposed in waterproof containers
Comments  

The "comments" line is left blank so that the ward sister may enter details pertaining to the individual patient.

Category C. Protective isolation  

Visitors Please report to sister’s office before entering room
Single Room Necessary, door must be kept closed; patient must not leave the room
Gowns 

(Impervious)

Must be worn
Masks Must be worn (filter type)
Hands Must be washed before handling the patient and his surroundings
Gloves Must be worn by those handling the patient or with objects coming in contact with the patient
Articles For immunosuppressed patient all items, including food should be sterile. No special precautions when removing from the room.

 

Isolation methods for individual viral diseases  

Chickenpox

or shingles

B in room with extractor fan, non-immune staff must be excluded. Non-immune visitors must be warned. SR may be used for shingles
Diarrhoea A enteric precautions, should be isolated for duration of illness
Hepatitis A A enteric precautions, isolation probably not required after jaundice has developed
Influenza, other

resp. infections

B isolation not necessary if acquired in hospital or if other patients with the disease are in the ward. Cohorting of patients recommended in outbreaks
Measles B secretion precautions. If outbreak occurred in paediatric ward, do not admit non-immune children until 14 days after the last contact has gone home
Meningitis

Encephalitis

A enteric precautions for enteroviruses
Mumps B exclude staff who are non-immune
Poliomyelitis A enteric precautions, non-immune staff should be excluded
Rabies D staff should be immunized immediately
Viral HF D special needs

 

Isolation Procedure Classification in the USA

Seven isolation categories are used in the US: Strict isolation, Contact isolation, Respiratory isolation, Enteric precautions, Blood/Body Fluid Precautions, Drainage/Secretion Precautions, and tuberculosis isolation.

  1. Strict Isolation - this is designed to prevent transmission of highly contagious or virulent infections that may be spread by air or contact. This is equivalent to the strict isolation protocol in the UK. However in the US, this is recommended for chickenpox as well as for viral haemorrhagic fevers. A private room is required and gowns, masks, and gloves must be worn before entry. Hands must be washed after leaving the room and contaminated articles should be discarded or bagged and labelled before being sent for decontamination and reprocessing.
  2. Contact Isolation - this is designed to prevent transmission of highly transmissible or epidemiologically important infections that do not warrant strict isolation. All diseases included in this category are spread primarily by close or direct contact such as HSV and respiratory infections in infants and young children. Private room is indicated although patients infected with the same organism may share a room. Masks are indicated for those who come close to the patient. Gowns are indicated if soiling is likely. Gloves are indicated for touching infective material. Hands must be washed after touching the patient or potentially contaminated articles and before taking care of another patient. Articles contaminated with infective material should be discarded or bagged and labelled.
  3. Respiratory Isolation - this is designed to prevent transmission of infectious diseases over short distances through the air. Direct and indirect contact transmission may occur but is infrequent. Diseases requiring respiratory isolation include measles, mumps, and rubella. Private room is indicated although patients infected with the same organism may share a room. Masks are indicated for those who come in close contact with the patient. Gowns and gloves are not indicated. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled.
  4. Enteric Precautions - enteric precautions are designed to prevent infections that are transmitted by direct or indirect contact with faeces. Diarrhoeal viruses, hepatitis A, and enteroviruses are included in this category. A private room is indicated if patient hygiene is poor and thus at risk of contaminating others. Masks are not indicated. Gowns are not indicated if soiling is likely. Gloves should be used for touching infective material. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled.
  5. Blood/body fluid precautions - blood/body fluid precautions are designed to prevent infections that are transmitted by contact with blood or other body fluids such as HIV and HBV. A private room is indicated if patient hygiene is poor because of the higher risk to others. Masks are not indicated. Gowns are only indicated f soiling is likely. Masks are not indicated but gloves should be worn. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled. Care should be taken to avoid needle-stick injuries. Used needles should not be recapped or bent; they should be placed in a prominently labelled, puncture-resistant container designated specifically for such disposal. Blood spills should be cleaned up promptly with hypochlorite.
  6. Drainage/Secretion Precautions - these are designed to prevent infections that are transmitted by direct or indirect contact with purulent material or drainage from an infected body site. A private room is not indicated. Gowns are only indicated if soiling is likely. Masks are not indicated but gloves should be worn. Hands must be washed after touching the patient or contaminated articles, and contaminated articles should be discarded or bagged and labelled.

 

 

Disinfection Policy

 

Decontamination renders an article safe for handling; disinfection is used to reduce the number of microorganisms and; sterilization means the removal of all microorganisms.

Sterilization - heat sterilization is the cheapest, safest, and the most effective method of sterilization. Cold sterilization should only be used on heat-sensitive items such as endoscopes. The only reliable method of cold sterilization is prolonged exposure to 2% glutaraldehyde, although this can become inactivated under adverse conditions.

Disinfection - disinfectants should be used according to instructions at the optimum dilution. Some disinfectants may be rapidly inactivated by organic matter, therefore any object that is to be disinfected should be cleaned thoroughly with warm water and detergent prior to disinfection. Sustained-action disinfectant should be used for hand hygiene by staff and for cleaning the skin and mucous membranes of patients. Alcohol preparations over 40% are no recommended because of the risk of fire when use in conjunction with diathermy. In general, hard surfaces do not require disinfectants - warm water with detergent is usually sufficient to remove all organic contamination. The exceptions are where persistence of potentially dangerous pathogens, such as HIV or HBV is suspected, when the surface should be wiped by a disinfectant afterwards.

Certain rules should be followed when using disinfectants. The manufacturer’s instructions should be followed. The expiry date should be checked and the optimum dilution used. Articles to be disinfected should be washed and clean before disinfection. The disinfectant container should not be refilled without sterilizing between each use and not be topped up. Disinfectants should be supplied ready for use from the pharmacy and empty containers should be returned to the pharmacy Empty containers should not be discarded or used to store any other solutions as this is potentially dangerous. Open containers of disinfectant should not be tolerated as there is a serious risk of contamination with multiple antibiotic-resistant bacteria, such as Pseudomonas species and spores. When disinfectants are indicated for use on surfaces, they should be applied by wiping rather than bathing as bathing wastes disinfectants.    

Waste disposal

All hospital waste should be disposed of so that it presents no risk of injury or contamination. Clinical waste is generated during routine patent care and surgery. It is potentially dangerous and should be clearly labelled as high risk. Examples of clinical waste include dressings, body fluids, pathology waste, iv needles and syringes, drainage bags etc. Laboratory waste should also come under the high risk category and should be autoclaved before leaving the department and labelled biohazard. Other hospital waste include non-clinical waste and kitchen waste. The latter should be disposed of properly because it is a potential source of pests and vermin and thus may pose an indirect threat to the hospital. Provision must also be made for the safe disposal of radioactive waste. A simple colour-coding system should be used to separate waste so that the different components can be treated safely. The UK has a national colour-coding system ie. clinical - yellow, non-clinical - black, soiled laundry - red, dirty laundry - white, theatre laundry - green/blue. In the kitchen, different coloured gloves are used for cooking and cleaning equipment. In general, non-clinical waste is taken to a compactor and clinical waste to an incinerator or if not possible, to a lime-pit. Under no circumstances should clinical waste, needles or syringes be sent to the municipal dump. All staff handling clinical waste should be adequately trained especially with regards for the protocol of action in case of accidents. All staff must be provided with adequate protective clothing and replacement garments. Hepatitis B immunization should be offered to all staff and proper records kept for such immunization.

It is totally unjustified to recycle needles and syringes. Broken glass should be included in the sharps category. To dispose safely of broken glass, thick gloves should be worn and the pieces collected with a newspaper. The glass is then wrapped securely in the paper and either disposed of into the sharps container or if not practicable, into a cardbox box which is then marked and sealed. Sharps containers used in the UK must comply with BS89/52770, they must be leak and puncture-proof. Have a handle that allows lifting, a non-reopenable lid, and carry a biohazard sign. They should be sealed and replaced when it is no more than two-thirds full. Sharps containers are treated as clinical waste and should be put into clinical waste bags before being incinerated. In the event of an inoculation or contamination accident, it must be documented by the senior manager and reported to the Occupational health department and the Infection Control Team so that appropriate action can be taken. In the UK, all injuries must be recorded in an accident book. There must be clearly defined policy on the action to be taken after the injury and all staff should be aware of the policy.

 

Sterile Services and Recycling

 

A sterile services department (SSD) is vital for an effective infection program. Most hospitals in developed countries have a SSD to deal to deal with hospital and community services and a Theatre Sterile Services Unit (TSSU) to deal with the operating theatres and associated departments. However, hospitals in developing countries do not have the funds to run two separate departments. Dirty, recyclable equipment should be collected from the wards and transferred to the SSD, where it is washed, inspected, sterilized, packed, and dispatched back to the wards.

Workflow of the SSD - in the ward, dirty re-usable instruments are collected and put into clearly labelled containers and delivered to the SSD. Cotton wools and dressing should be discarded as clinical waste for incineration. The dirty instruments are then received in the dirty area of the SSD. All equipment is first washed in hot water and detergent either mechanically or manually. Manual washing requires the use of appropriate protective clothing such as heavy-duty gloves, plastic aprons, and eye-protection. The equipment is then inspected for cleanliness and damage. Instruments are then packed into individual trays for ward use and autoclaved and/or disinfected as required. The packaged trays are then inspected to ensure that they are dry and then sorted for ward collection. The sterile packs should be stored in well-ventilated rooms ready for dispatch to the wards. Collections should be regular and there should be a written record of receipt and delivery.

SSD staff facilities - all staff in the SSD should be provided with adequate protective clothing (eg. heavy duty gloves, plastic aprons, and eye-protection if manual washing is undertaken). Overshoes and masks are not necessary. All SSD staff should be immunized against hepatitis B and records kept by the Occupational Health Department. All staff should receive formal training and lectures on the prevention of sharps injuries and the procedure to follow should an accident occur. There should be policies for handling sharps, inoculation accidents, spillage of body fluids, and accidental splashing with reagents used in the SSD. Adequate changing, rest, and handwash facilities should be provided.

Processing instruments

All equipment should be cleaned in the SSD. Equipment requiring sterilization must be cleaned thoroughly before the sterilization/disinfection process. For heavily contaminated equipment, it is not recommended that they be autoclaved before cleaning since it poses the problem of baked-on dirt.

1. Mechanical cleaning - most modern SSDs are automated and there is minimum handling of dirty equipment by staff. The equipment is placed in trays read for washing. The following machines are usually available;-

  1. Washing machine - this gives a cold rinse, followed by a hot wash at 71oC for 2 minutes, and a 10-second hot water-rinse at 80-90oC before drying.
  2. Washer/disinfector - this is mainly used for anaesthetic equipment. It runs a 45-minute cycle of washing and cleaning plus a 2-minute cycle with water at 80-100oC and a detergent.
  3. Ultrasonicator - this uses high-power output to dislodge all organic matter.   

2. Manual Cleaning - manual cleaning is necessary when mechanical facilities are not available or for cleaning delicate instruments or those which need to be taken apart to be cleaned. It is also used for narrow-necked jugs and bowls. Hand-cleaning must be done with extreme caution. The staff should wear heavy-duty rubber gloves, plastic apron, and eye protection. The instrument should first be soaked in hot water containing a foaming agent and detergent. The water is then drained carefully and the instruments separated. Care must be taken to ensure that the sharpends are away from the handler while handling instruments. the instruments are then washed gently; a soft brush should be used for delicate instruments and a high-pressure jet to clean the inside of hollow needles and tryphines. After washing, the instruments are replaced on a tray before autoclaving.    

Sterilization

  1. Autoclave (moist heat) - this is by far the most commonly used process and the most reliable. Moist heat penetrate and kill bacteria at temperatures lower than that required by dry heat. Steam penetrates best when air has been removed and the air is removed by (1) mechanical means, (2) downward displacement, and (3) pulse prevacuum, the latter of which is now the most commonly used method. The moisture content of the steam is very important, the optimum conditions for steam sterilization occurs when the steam is saturated (relative humidity = 100%). The packs of equipment should come out of the autoclave dry, if not, then the packs cannot be considered as non-sterile.
  2. Dry heat - dry heat sterilization is used for non-aqueous fluids, delicate instruments, hollow needles, glass, metal and waxes. It is unsuitable for rubber, plastics, combustible substances, and glycerol. Items to be sterilized should be wrapped in craft paper and aluminum foil. The oven is then heated to 160-180oC for a set period of time and then allowed to cool. The disadvantages of dry heat sterilization are (1) the sterilization cycle is long, (2) uneven heat distribution in the oven results in a marked temperature variation.
  3. Ethylene oxide - ethylene oxide can be used to sterilize most articles that can withstand temperatures of 50-60oC. However it must be used with extreme caution as it is extremely toxic and explosive. A long period of aeration is required to remove all traces of ethylene oxide
  4. Low pressure steam formaldehyde - as in the case of ethylene oxide, it is a very versatile method of sterilization.
  5. Radiation - this is only used industrially  
  6. Glutaraldehyde (2%) - this is used for disinfecting endoscopes, bronchoscopes, and other fibre-optic instruments. The COSHH regulations require its use to be controlled and the equipment rendered safe. Protective clothing must be worn which include gloves, eye goggles, masks, and impervious body covering. Either a well-ventilated room (with exhaust to the outside), a fume cabinet, or a closed system such as a fibre optic disinfection trolley must be used. The environment used should be tested from time to time by gas or HPL chromatography for the presence of aldehydes every 14 months.

 

Equipment and Patient-Care Articles

 

General Use Articles

  1. Bedpans and Urinals - gloves should be worn to empty the bedpan and its contents directly into the bedpan disinfector. Alternatively, the contents may be flushed down the sluice or toilet and then washed thoroughly with warm water and detergent to remove all signs of organic contamination and dried. The bedpan disinfector is the preferred method and it functions at no less than 80oC for 1 minute.
  2. Washing bowls - these must be washed thoroughly between each patient and stored and inverted to dry. Fresh water and towels should be used for each patient.
  3. Towels, soaps, hairbrushes, shaving brushes etc. - all these items should be for individual use only and should never be shared.
  4. Crockery and cutlery - each patient should have an individual set. the crockery and cutlery should be washed in very hot water (>60oC) and detergent. Disposable crockery is only necessary in cases of strict isolation such as rabies.
  5. Mattresses and pillows - they are a major source of cross-infection. Wet mattresses must be changed. Contaminated mattresses should be washed with warm water and detergent. Mattresses should be covered with an impervious layer so that they can be cleaned thoroughly between patients. Damaged mattresses should be discarded as they may easily trap microorganisms.
  6. Thermometers - they should be washed in warm water and dried before being wiped over with a swab soaked in 70% isopropyl alcohol. They should never be soaked in disinfectants.
  7. Trolley tops - they should be washed with warm water and detergent  

Endoscopy Unit

Fibre-optic endoscopes are usually heat-labile and therefore require chemical disinfection. 2% glutaraldehyde should be used under strict controlled conditions as required by the COSHH regulations. Protoscopes and sigmoidoscopes may be disposable or reusable. The latter must be cleaned, sterilized, or disinfected by heat or 2% glutaraldehyde.

ITUs, Operating Theatres

  1. Ventilatory circuits - multiple-use circuits must be heat-disinfected for at least 80oC for 3 minutes or sterilized by autoclave or ethylene oxide between each patient. Filters may be used between circuits and if properly maintained, a ventilated patient may use the same circuit for 4-5 days before disinfection.
  2. Humidifiers - humidifiers are a common source of viruses and Gram-negative bacilli and should be emptied daily and refilled with distilled water. They should be disinfected when contaminated or when the respiratory circuit is changed. Routine heat disinfection is essential after each patient use and if humidification is required for a prolonged period, the humidifier should be cleaned thoroughly, dried, and filled daily with distilled water.
  3. Endotracheal suction catheters - they are usually disposable but may be used up to 24 hours on the same patient.
  4. Endotracheal tubes - these may be recycled after thorough cleaning and autoclaving. Disposable endotracheal tubes are available but are more expensive.
  5. Ambu-bags - they are extremely difficult to disinfect and become contaminated very quickly. Heat is the most reliable method and 2% glutaraldehyde is a less acceptable alternative.
  6. Oxygen-delivery face masks - these can be disposable or reusable. If reused, they should be washed thoroughly and wiped over with 70% isopropyl alcohol.
  7. Suction and drainage bottles - these are usually disposable, with a self-dealing inner container held in a clear outer plastic container. The outer container should be heat-disinfected or autoclaved after each use. Non-disposable bottles must be changed every 24 hours or sooner if full. They must then be washed and autoclaved. Recyclable connector tubing should be cleaned thoroughly and sterilized. The system must be closed and risk to staff from body fluids should be minimal.
  8. Incubators in SCBU - they should be cleaned thoroughly with warm soapy water and then wiped over with 70% isopropyl alcohol.  

Disposable Equipment

  1. Syringes and needles - disposable syringes and needles should be used. Under no circumstances should fine-bore needles be recycled because they cannot be cleaned. If syringes are to be recycled, it must be well controlled. After thorough cleaning, the syringes must be autoclaved or processed in ethylene oxide.
  2. Administration sets - administration sets for IV fluids must be disposable
  3. Urinary catheters and drainage bags - these should be single-use and disposable

 

Standards and Criterion of The Infection Control Standards Working Party

 

Hospital acquired infection remains an important, with approximately 10% of patients acquiring an infection during their hospital stay. The Infection Control Standards Working Party have identified five core standards, each of which is divided into criteria.

Standard 1 - Management structure and responsibilities in infection control

1. There is an infection control structure with sufficient resources and clear lines of responsibility - there should be an infection control committee (ICC) covering each provider unit, an infection control team (ICT) responsible for day to infection control, there are designated staff in outlying hospitals or small units who Liaise with the ICT. The Trust Chief Executive or Unit General Manager is ultimately responsible for providing resources.

2. The ICC consists of a chairperson, the Infection Control Doctor (ICD), the Consultant in Communicable Disease Control (CCDC), or Medical Officer for Environmental Health, Infection Control Nurses, Occupational Health Physician, Infectious Diseases Physician, a surgeon. a physician, chief nurse advisor and the Unit General Manager. Other members may include an engineer, pharmacist, HSDU manager. The ICC is responsible to the UGM and should meet at least twice a year to provide specialist advice, formulate and to monitor the implementation of policy. The chairperson is informed during a major outbreak of infection and decides when the ICC should meet.

3. The ICT comprises the ICD (usually a Consultant Medical Microbiologist), ICNs and has direct access to a representative of the Trust Chief Executive/UGM. The ICT is responsible to the ICC and directly to the Chief Executive. The ICT functions on a daily basis supported by adequate clerical staff. There should be at least one ICN who may liaise daily with the ICD. When a serious problem arises, the Chief Executive or representative is informed. The CCDC is informed of any significant hospital outbreak. In a serious outbreak, the CCDC informs the Regional Health Authority, the Chief Medical Officer, the CDSC and PHLS. The ICT must liaise closely with the CCDC and inform him of suspected cases of notifiable diseases or food poisoning. It is expected to provide advise on and monitor policies and procedures, conduct surveillance activity and review the effectiveness of control measures. When appropriate, an outbreak control group will be called.   

Standard 2 - Policies and Procedures

1. The ICC initiates the development, evaluation, and revision of written policies and procedures at least biennially. Reference is made to the appropriate legislation or published guidance. Each hospital department or service has a current copy of the approved policies and procedures pertinent to the activities of the department or service. Areas covered include;-

  1. Medical, surgical, nursing and physiotherapy procedures
  2. Isolation policies and procedures for high risk and communicable diseases
  3. Outbreaks of infection
  4. Mortuary procedures
  5. Sterile Supplies Services and decontamination of health care equipment
  6. Housekeeping, laundry, catering
  7. Engineering and building services, in particular ventilation and water services
  8. Building works
  9. Disposal of waste products
  10. Equipment purchasing e.g. reusable or disposable equipment

 

2. These policies and procedures are made known to the personnel, and there is an on going continuing education for employees working in high risk areas.

3. There should also be a written program for the auditing of infection control policies or procedure.    

Standard 3 - Microbiological Services

  1. A document is made available to all users of the laboratory which describes the organization and overall scope of the laboratory services.
  2. The laboratory is directed professionally by a consultant medical microbiologist or clinical scientist of equivalent status.
  3. The microbiology laboratory provides information and help relating to the control of infection within the hospital.
  4. Written policies are available relating to specimen collection, handling and disposal.
  5. There is a written policy for the reporting of results on each test ie. the circumstances in which verbal reports may be transmitted, and some indication as to when the report will be available.
  6. There is appropriate data storage, retrieval and communication facilities for laboratory and clinical information.

Standard 4 - Surveillance

  1. There are agreed objectives and priorities for surveillance of infection
  2. The methods of surveillance are defined and in place.
  3. There are mechanisms for storage, analysis, and distribution of surveillance data  

Standard 5 - Education

  1. Adequate resources are available in each unit for the necessary education facilities, such as the provision for annual study leave for ICN, purchase of books and audiovisual material, and facilities for study.
  2. An infection control educational program addresses topics of relevance to different types of health staff.
  3. The ICT is involved in the initial education of other health care personnel, such as the course design.
  4. There are mechanisms for the continuing education of health care staff.