Characterization of extended-spectrum beta-lactamase-producing Salmonella isolates in a children's hospital in Ankara--first report of SHV-2a and SHV-9 in Salmonella spp. from Turkey.

The rate of in vitro resistance to various antimicrobials in 179 consecutive isolates of Salmonella spp., which included serogroups D (109), B (52), C1 (10) and C2 (8) isolated from children, was investigated. Production of extended-spectrum beta-lactamase (ESBL) was studied in ampicillin-resistant isolates. Antimicrobial susceptibilities were determined by disk diffusion tests and by BIOMIC video reader system. Overall resistance rates to ampicillin and amoxicillin/clavulanate were 26.3% and 10.6%, respectively. Resistance to ceftriaxone and ceftazidime was 3.3%. Resistance rates for chloramphenicol, trimethoprim-sulfamethoxazole, ciprofloxacin, amikacin and gentamicin were 40.7%, 31.3%, 2.2%, 2.2% and 6.1%, respectively. beta-lactamase production was detected in 42 isolates. Mating out experiments, isoelectric focusing, dot blot hybridization, polymerase chain reaction (PCR) and sequencing were performed on two S. paratyphi B isolates that produced ESBLs. One isolate produced SHV-2 and TEM-1 and the other produced SHV-2a, SHV-5a (SHV-9) and TEM-1. This is the first report of SHV-2a and SHV-5a (SHV-9) in S. paratyphi B in Turkey.