بررسي ملكولي بتالاكتامازهاي وسيع الطيف در ايزوله هاي انتروباكتر جمع آوري شده از بيمارستان هاي آموزشي شهرهاي قزوين و تهران

Molecular Study of Extended-Spectrum Beta-Lactamases among Enterobacter spp. Isolated from Teaching Hospitals in Tehran and Qazvin, Iran

Abstract Background and objective: Enterobacter spp. are members of the family Enterobacteriaceae. In recent years, there are several reports showing the high prevalence of beta-lactam resistant among these organisms. Different types of beta-lactamase enzymes have been identified in Enterobacter spp., which Extended-Spectrum Beta-Lactamases (ESBLs) are very important among them. The ESBL-producing isolates capable to hydrolyze extended spectrum penicillinʹs and cephalosporins. The aims of this study were to determine the prevalence of ESBLs and to detect of blaTEM and blaSHV genes among ESBL-producing Enterobacter spp. isolates. Materials and methods: A total of 107 Enterobacter isolates were collected from Tehran and Qazvin hospitals. Isolates were identified by standard microbiology and biochemical methods. All isolates were screened for ESBLs production by agar disk diffusion method using ceftazidime, cefotaxime, aztreonam, cefpodoxime and ceftriaxone discs and then were confirmed by combined disk method. ESBLs-positive isolates were tested for blaTEM and blaSHV-ESBLs genes. Results: Of the 107 isolates, 58 isolates (54.2%) showed the reduced susceptibility to the screening antibiotics. 51 isolates (47.6%) were ESBLs positive by combined disks method. Twenty eight isolates (54.9%) contained blaTEM genes and 2 isolates (3.9%) harbored the blaSHV genes. Conclusions: This study showed the high prevalence of ESBLs in Enterobacter spp. isolated from the clinical specimens in studied hospitals. The initial identification of ESBL-producing isolates and use of appropriate infection strategy is essential to control the more spread of these organisms in selected hospitals.