Molecular epidemiology & antimicrobial resistance of Acinetobacter baumannii isolated from Namazi Hospital, in Shiraz by modified AFLP analysis

Due to rapid resistance of Acinetobacter baumannii to broad-spectrum antibiotics and to cause nosocomial infections with high mortality rates, this bacterium has associated with many therapeutic problems. This study aimed to investigate epidemiologic strains pf Acinetobacter isolates in Sahid Namazi hospital, Shiraz- Iran, based on AFLP method and to determine their antibiotic resistance levels in order to design surveillance program and effective treatment.
This descriptive study were performed on the Acinetobacter baumannii strains isolated from seven different intensive Care Units of Sahid Namazi hospital. All isolates were identified with the API20NE kits. Drug resistances of the strains were determined based on broth microdilution methods. For purpose of the phenotypic typing by obtained results, the antibiodendrogram was designed with SPSS statistical software. Next, AFLP analysis was performed with DNA digestion by MboI and MseI restriction enzymes, ligation of synthetic adapters, Pre-amplification and sensitive amplification by specific primers.
In present research, 54% (46 cases) of Acinetobacter baumannii strains were MDR, while 43% (36 cases) belonged to XDR and only 2% (2 cases) was identified as PDR. The antibiotic susceptibility pattern show prominent presence of imipenem resistance (51%) and meropenem resistance (76%) strains. In addition, the AFLP results revealed that three main clusters (1, 3, and 4) have been associated with several outbreaks of nosocomial infections.
Based on the results, rapid growth of Acinetobacter baumannii and their cross-transmission among different wards of Sahid Namazi hospital have led to increase of antibiotic resistance rate and their prevalence in the hospital. Therefore, results of this study emphasizes surveillance programs for infection control and to eradication therapy.