Antibiotic resistance patterns and plasmid profiles of Salmonella typhimurium isolates in Turkey

To understand the resistance mechanisms present in 75 isolates of Salmonell a typhimurium derived from clinical infections in Turkey, antimicrobial res istance patterns and associated plasmids were investigated. Among the 22 st rains that produced extended-spectrum beta -lactamase (ESBL), 20 were resis tant to aminoglycosides and 12 to trimethoprim-sulfamethoxazole, Strains th at did not produce ESBL did not express aminoglycoside or trimethoprim-sulf amethoxazole resistance, although 27 of them were ampicillin resistant. Non e of the strains were resistant to imipenem or fluoroquinolones. Nineteen s trains producing ESBL carried a plasmid of >100 MDa, Seven ESBL-producing s trains conjugally transferred their ESBLs and trimethoprim-sulfamethoxazole resistance. No correlation was found between the resistance patterns and p lasmids in non-ESBL-producing strains.