Erythromycin

Erythromycin is a macrolide antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma and Legionellosis. In a study of in-vitro and in-vivo susceptibility of Borrelia burgdorferito, erythromycin possessed low activity, having an ED50 of 122.2 (±51.9) mg/kg. For erythromycin, an IC50 of 1.5 μg/ml was observed, indicating a fourfold lower sensitivity of the organisms to this compound.