Antibiotics

Septic arthritis

• Medical emergency
• Urgent gram staining and culture are indicated
• Staphylococcus aureus is the most common infecting pathogen
• Intravenous benzylpenicillin plus flucloxacillin
• Opportunistic infection if the patient is immunocompromised (e.g. HIV positive)

Systemic MRSA infection

• Vancomycin is a glycopeptide antibiotic indicated for treatment of MRSA infection
• Should be given intravenously for systemic infection
• Teicoplanin is similar glycopeptide antibiotic with longer duration of action (so it can be given once daily)

Uncomplicated UTI

• Trimethoprim should not be given in pregnancy because it is a folic acid antagonist and teratogenic
• Quinolones and tetracycline should be avoided.
• Adverse effects of nitrofurantoin include diarrhoea, vomiting, neuropathy, and fibrosis
• Nitrofurantoin should be avoided in pregnant mothers at term and in breast feeding mothers

Antibiotic prophylaxis for cholecystectomy

• Intravenous co-amoxiclav is alternative to intravenous cefuroxime plus metronidazole

Chlamydia infection

• Tetracycline is first-line treatment for chlamydia infection
• Absolutely contraindicated in pregnancy and when breast-feeding
• Tetracyclines are deposited in growing bone and can lead to permanent staining of teeth and dental hypoplasia
• Patients treated with tetracycline are told to avoid milk products because these decrease absorption of the drug