Antimicrobial Susceptibility Pattern and Characterization of integrons and Associated Cassette Genes among Acinetobacter baumannii Isolates from Namazi Hospital, Shiraz, Iran.

Background and objectives: the aims of the present study were the evaluation of antimicrobial susceptibility pattern, detection of class 1-3 integron and identification of gene cassette in class 1 integron in Acinetobacter baumannii isolates in southwest of Iran. Materials and methods: In present study, we determined the antimicrobial susceptibility of A. baumannii, isolated from different specimens in Shiraz, south of Iran during a 3-month period. Moreover, we detected different types of integrons (class 1, 2, 3) of 174clinical strains carrying OXA-51 like gene and associated gene cassettes by PCR methods. Results: The resistance rates to: imipenem (99.4%),piperacilin(98.2%),gentamycin (98.2%) meropenem (97.7%)ceftazidime(95.4%)amikacin(95.4%) and trimethoprim- sulfamethoxazole(90.8%) were obtained by Disk diffusion method, based on CLSI documents. All strains were reported as MDR.The distribution analysis of integrons genes showed that 90.2%, 72.4% and 12.1% of the isolates carried the intI 1, intI2 and intI3 genes, respectively. Two types of gene cassettes including aadA،dfrA12were detected in Class 1 integron-carrying strains with high prevalence in Iran. Conclusion: The current study showed that prevalence of A. baumannii isolates harboring integrons is high in our investigated medical center, which may propel distribution of multidrug resistance event. The different types of gene cassette arrays in the present study spotlight the remarkable role of geographical issues in MDR isolates dissemination. This subject could be attributed to the choice of appropriate profiles of drug prescription in different areas. Obtained data highlight the need for continuous surveillance to prevent distribution of multidrug resistance among A. baumannii strains in Iran.