AZTREONAM is an excellent drug for aerobic gram-negative bacteria, including Pseudomonas, but it is ineffective against gram-positive organisms.

VANCOMYCIN is only effective against the gram-positive organisms. It is very poorly absorbed orally.

Bacitracin is a mixture of polypeptides that inhibit cell wall synthesis. It is used topically.

FOSFOMYCIN:
Fosfomycin inhbits one of the first steps in the synthesis of peptidoglycan (ie, the cell wall) by inhibiting the enzyme enolpyruvyl transferase. It is used for the treatment of uncomplicated urinary tract infections.

Aminoglycosides are poorly absorbed from the GI tract.

Aminoglycosides have ototoxicity, nephrotoxicity, and neuromuscular toxicity.

Erythromycin and it relatives are of particular use in the treatment of patients with Mycoplasma infections, pneumonia, Legionnaires disease, chlamydial infections, diphtheria, and pertussis.

The quinolones inhibit DNA synthesis through a specific action on DNA gyrase.

Methenamine is metabolized to formaldehyde and ammonia and is used in urinary tract infections.

ISONIAZID inhibits synthesis of mycolic acids.

There are fast and slow acetylators of ISONIAZID.

ISONIAZID is associated with hepatotoxicity and peripheral neuropathy.

ISONIAZID is the drug of choice for chemoprophylaxis in recent converters.

RIFAMPIN inhibits RNA synthesis by formation of a stable complex with the DNA-dependent RNA polymerase.

RIFAMPIN is metabolized in the liver and is a potent inducer of the P-450 enzymes. It can cause hepatitis and may color secretions red-orange.

PYRAZINAMIDE is only effective against M tuberculosis. It increases levels of serum uric acid.

DAPSONE is the mainstay in the treatment of leprosy.

The azoles are broad-spectrum fungistatic agents that inhibit the synthesis of ergosterol by inhibiting the 14-α-demethylase enzyme.

The polyene antifungals, AMPHOTERICIN B and nystatin, work by binding to ergosterol, the principal fungal membrane sterol.

AMPHOTERICIN B is most commonly used to treat serious disseminated yeast and fungal infections, particularly in immunocompromised patients.