فراواني بتالاكتامازهاي با طيف گسترده و ژنوتيپ هاي TEM و SHV در ايزوله هاي كلبسيلا پنومونيه جدا شده از نمونه هاي باليني جمع آوري شده از بيمارستان هاي شهر قزوين

Extended Spectrum B-lactamases and TEM and SHV Genotypes in Klebsiella pneumoniae

Abstract Background and objective: Klebsiella pneumoniae is an important nosocomial pathogen. There are increasing reports of extended spectrum B-lactamases (ESBLs)-producing K. pneumonia isolates which has become a serious concern for clinicians and infection control specialists. The genes coding for ESBLs are located on transferable plasmids that can horizontally spread among different bacterial species. The TEM and SHV are the most prevalent types of acquired ESBLs. This study was conducted to assess the frequency of blaTEM and blaSHV genes among ESBLs-producing K. pneumonia isolated from teaching hospitals of Qazvin, Iran. Materials and methods: One hundred non duplicated clinical isolates were included in this study between May 2011 and May 2012. All isolates were identified using standard microbiology and laboratory methods. The collected isolates were screened for ESBL production using the standard disc diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guideline and then were confirmed by confirmatory disk combination (CD) method. PCR assay was performed for detection of ESBL-encoding blaTEM and blaSHV genes. Results: In total, 57 isolates were non-susceptible to screening antibiotics, 45 (78/94 %) of them were found to be ESBLs producers. Twenty six isolates (58%) carried blaTEM and 19 isolates (42%) carried blaSHV ESBL genes. Eleven isolates (24/4%) harbored simultaneously both of two genes. Conclusion: Considering the high prevalence of ESBL-producing Klebsiella pneumoniae isolates in the selected hospitals, the initial identification and following of resistant isolates are necessary to prevent further spread of infection by these organisms. In addition, use of appropriate infection control measures and rational antibiotics therapy leads to substantial important in managing of patients