<i>In vitro </i>efficacy of ciprofloxacin alone and in combination with amoxicillin against <i>Salmonella typhi </i>isolates

Abstract

360-362Combined effect of cipronoxacin (Ci) and amoxycillin (Ax) has been studied in vitro against 12 clinical isolates of S.typhi  that showed Ci minimum inhibitory concentration (MIC) of ≥1μg/ml. By agar dilution method, MIC values of Ax were 10-16 μg /ml for 11 isolates and 0.5μg/ml for the remaining one isolate. The isolates, when treated with Ci and Ax in combination, showed fractional inhibitory concentration (FIC) of 0.004-0.256 μg /ml for Ci. FIC of Ax ranged from 6- 10 μg /ml, except for a single isolate that showed Ax FIC of 0.25 μg /ml. Thus Ci was more efficacious in combination with Ax against S. typhi than Ci alone. The antibiotic combination exhibited an additive effect for all the isolates showing FIC index 0.504-0.832