CTX-M-3 extended-spectrum beta-lactamase in a Shigella sonnei clinical isolate: first report from Turkey.

A Shigella sonnei strain resistant to cefotaxime and aztreonam (but not ceftazidime) was isolated from the stool sample of a 7-y-old outpatient. Double disk synergy test, isoelectric focusing, polymerase chain reaction and sequence analysis confirmed that the isolate produced CTX-M-3, an extended-spectrum beta-lactamase (ESBL). This is the first report from Turkey of Shigella spp. producing an ESBL, and of CTX-M type enzyme.