The Minimum Inhibitory Concentration of Seventeen Antimicrobials for Salmonella Isolates from Septic Patients

Abstract

Herein we are reporting, for the first time in Kuwait, the minimum inhibitory concentrations (MICs) of Salmonella blood culture isolates vs. 17 clinically relevant antimicrobial agents. The screening of blood culture specimens was performed with the most advanced Bactec 9240 (Becton Dickinson). From over 20,000 blood cultures, 112 Salmonella isolates were obtained from 67 patients. Their MICs were determined using the automated Vitek microdilution technique (Biomerieux Vitek Inc.). During the whole 1991-1995 study period, the MICs for cefotaxime, ceftazidime, aztreonam, amikacin, gentamicin, ciprofloxacin and imipenem were below their respective susceptibility breakpoints. Resistance to chloramphenicol, ampicillin and cotrimoxazole varied from year to year, from 18% to 50%, except in 1991 when it was nil (1991 was the first year after the Gulf War, with very few newcomers from the Indian subcontinent). All ampicillin-susceptible S. typhi isolates had extremely low MIC values (≤0.25 μg/ml).