Abstract
A total of 259 clinical isolates of nonrepetitive non-typhi salmonellae (NTS) were examined for antibiotic resistance patterns and plasmid content. The antibiotics used were amoxicillin-clavulanic acid (AMC), ampicillin (AM), aztreonam (ATM), carbenicillin (CB), cefixime (CFM), cefotaxime (CTX), cefoxitin (FOX), ceftazidime (CAZ), ceftriaxone (CRO), chloramphenicol (C), ciprofloxacin (CIP), gentamicin (GM), imipenem (IPM), ofloxacin (OFX), tetracycline (TE), trimethoprim-sulfomethoxazole (SXT). Multi-drug resistant (MDR) strains comprised 19.3% of the total isolates (50/259) and almost all were S. typhimurium (49/50). Fifteen different patterns of resistance was observed, AM/CB/C/AMC/TE and AM/CB/C/AMC/SXT/GM/CTX/CRO/CAZ/CFM/ATM being the most frequent patterns. Twenty-eight out of 50 multiresistant isolates were found to contain at least one plasmid (mean five) and the size of the plasmids ranged between 1.7 and 158 kb. Plasmid profiles of multiresistant NTS strains were heterogenous as 21 different profiles were detected in a total of 28 plasmid-bearing isolates. No direct correlation was established between antibiotic resistance patterns and plasmid profiles.