Antibiotic Treatment

Antibiotic Treatment

Summary

Macrolides

·        Effective against:

o   Staph aureus (up to 10% resistance in community strains)

o   Streptococci (not E faecalis)

o   Anaerobes (only moderately effective against B fragilis)

o   Mycoplasma pneumoniae

o   Chlamydia pneumoniae

o   Chlamydia trachomatis (but tetracycline is the drug of choice)

o   Campylobacter jejuni

·        Ineffective against:

o   H influenzae

o   No CSF penetration

·        Indications:

o   Treatment of susceptible bacteria if penicillin allergy

o   Atypical pneumonia (eg Mycoplasma, Chlamydia or Legionella)

o   Campylobacter

o   Chlamydia infection in pregnant women 

Erythromycin

·        New analogues:

o   Roxithromycin (Rulide)

o   Clarithromycin (Klaricid): Treatment of MAC, especially in AIDS patients

o   Azithromycin (Zithromax): Single dose treatment for STD‟s caused by Chlamydia trachomatis or

o   N. gonorrhoeae (especially in pregnancy)

Vancomycin

·        G+ive wonder drug – active against G+ive only

·        Indications: 

o   Systemic infections caused by MRSA or MRSE (Epidermidis), or infected Hickman lines in cancer patients 

o   Infective Endocarditis due to Strep or Staph with penicillin allergy

o   Clostridium difficile colitis (by mouth).  First line is metronidazole

·        Otto and nephrotoxic

·        Teicolpanin: similar drug, active against some Vancomycin Resistant Enterococci (VRE)

Rifampicin

·        Always used in combination (except meningitis prophylaxis)

·        Active against M. Tb, Staph aureus, Legionella

·        Indications:

o   TB (in combination)

o   Severe Staph aureus infections (eg infective endocarditis) in combination

o   Severe legionella pneumonia (in combination with erythromycin)

o   Prophylaxis against N meningitides or HIB

Aminoglycosides

·        Active against all coliform bacilli (eg E Coli), pseudomonas, staphylococci

·        Inactive against: streptococci, anaerobes

·        Indications: G- sepsis, perforated appendix

·        Drugs: 

o   Gentamicin

o   Tobramycin: more active against pseudomonas

o   Amikacin: reserved for Gentamycin resistant bugs

·        Spectinomycin: N gonorrhoeae (penicillinase producers)

·        Otto and nephrotoxic

Cotrimoxazole

·        = Trimethoprim + Sulphamethoxazole

·        Broad spectrum: Staph, Strep, many coliforms (not Pseudomonas), HIB, Pneumocystis, Brucella

·        Indications: Acute infectious exacerbations of chronic bronchitis, PCP in AIDS 

·        Trimethoprim on its own is the standard treatment against community acquired UTI (E Coli, Klebsiella, Proteus, Strep faecalis)

Quinolones

·        Broad spectrum oral antibiotic 

·        Active against: most coliforms, pseudomonas aeruginosa (main use), Staphs (including MRSE and MRSA), N gonorrhoeae, HIB, Branhamella catarrhalis (good), Salmonella, Shigella, Yersinia, Campylobacter 

·        Poor activity against Anaerobes, streptococci 

·        Can damage growth cartilage Þ not licensed for children

·        Indications:

o  Norfloxacin: resistant UTIs

o  Ciprofloxacin: Mainly pseudomonas

Tetracyclines

·        Eg doxycycline (once a day on full stomach), very common in treatment of STIs

·        Active against Staphs, Streps, Coliforms, HIB

·        Other indications:

o  Syphilis and Gonorrhoea if penicillin allergy

o  Mycoplasma pneumoniae

·        Contraindications: young children, pregnancy, renal failure (except doxycycline)

Metronidazole

·        = Flagyl

·        Active against all anaerobes (eg B fragilis) 

·        Inactive against aerobes (excl Gardnerella vaginalis, causing bacterial vaginosis, where it is drug of choice) 

·        Active against Protozoa: Trichomonas vaginalis, Giardia lamblia

Other

·        Fucidin: active against Staph Aureus, must be used in conjunction with, eg Flucloxacillin. Use in bone/joint infections 

·        Chloramphenicol: for infections caused by Burkholderia cepacia

Antifungals

·        Nystatin (topical): vaginal or oral candida

·        Miconazole (topical): Candida and dermatophytes (except scalp or nails)

·        Terbinafine (oral) Dermatophyte infections of scalp or nails (has superseded Griseofulvin) 

·        Itraconazole (oral): Dermatophyte infections of scalp or nails, prophylaxis in Candida and Aspergillus in immunocompromised 

·        Fluconazole (Oral/IV): active against yeasts (candida, cryptococcus). Good CSF penetration (eg Cryptococcal meningitis)

·        Amphotericin B (IV): Very good but side effects, including nephrotoxicity

Antivirals

·        Acyclovir: active against HSV and VZV (less active)

·        Ganciclovir: CMV in immunocompromised patients.  Bone marrow suppression ® neutropenia