Abstract

One hundred and fifty five of Gram-negative-lactose fermented bacteria grown on MacConkey agar were collected from two main hospitals in Al- Najaf province. The isolates were identified according to cultural characteristics, biochemical activities and Vitick -2 system. 43(27.7%) isolates were identified as Klebsiella spp. Isolates, represented by 35(81.3%) isolates K. pneumoniae subsp. aerogenes, 4(9.3%) isolates Klebsiella pneumoniae subsp. pneumoniae, 2 (4.6%) isolates Klebsiella oxytoca, as well as one isolate for each of K. pneumoniae subsp. ozaenae and K. pneumoniae subsp. rhinoscleromatis. The susceptibility of Klebsiellae isolates to 20 antibiotics were tested, using disc diffusion method; the results have revealed that Klebsiellae isolates were highly resistant to most common antibiotics. The ability of Klebsiellae isolates to produces extended β-lactamase were tested, the results have revealed that 26 (60.4%) isolates produce ESBLs. The ability of Klebsiellae isolates to have CTX-M gene was tested; PCR amplification results have shown that 15 of Klebsiellae isolates were possess CTX-M lactamase gene.