Penicillin – used as the drug of choice for S. pyognes, S. Pneumoniae, N. Meningitidis, N. gonorrhoea, B. anthracis, C. diptheriae, T. pallidum, P. multicoda, and certain anaerobes.

Methicillin group (Penicillinase-resistant) – used for S. Aureus

Ampicllin/amoxycillin – for haemophillus and other gram-negative organisms

2. Cephalosporins

1^st generation e.g. cephalexin – very active against gram-positive cocci

2^nd generation e.g. cefuroxime – additional activity against H. influenza, M. catarrhalis, N. menigitidis and Gonorrhoea.

3^rd generation – active against gram-negative bacilli. Some e.g. ceftazadime are active against pseudomonads as well.

3. Imipenam

(another B lactam antibiotic) – active against a wide range of bacteria

Its is most useful against ESBL organisms

4. Aminoglycosides

Streptomycin, gentamycin, kanamycin, amikacin

Used against gram-negative bacilli including pseudomonads

5. Rifamycins

6. Metronidazole

Used against anaerobes and certain parasitic infections

7. Erthromycin and other macrolides

Used mainly as a second line drug for penicillin. Used first line for legionella and sometimes for chlamydial and mycoplasmal infections

Clindamycin is mainly used in the treatment of anaerobic infections.

8. Vancomycin

For MRSA infections

9. Tetracyclines

Tetracycline and doxyclyine are used for a wide variety of bacterial, chlamydial, and rickettsial infections

10. Sulphonamides

Sulphonamides are often used in conjunction with trimethroprim. It is used for treating UTI and respiratory infections

11. Quinolones

Ciprofloxacin and Ofloxacin are active against a large umber of gram-negative bacilli including P. aeruginosa.