The Molecular Epidemiology And And Antibiotic Resistance Of Acinetobacter Baumannii Isolated From Intensive Care Unit In Hunan Province

Objective:To investigate the Genetic background, Genotype distribution,antibiotic resistance and antibiotic resistance genes distribution of Acinetobacter baumannii which widespreaded in Intensive Care Unit (ICU) in Hunan province, and provide the theoretical basis of ICU Acinetobacter baumannii infection controlling in Hunan province.Methods:We collected138non-repeated Acinetobacter baumannii strains isolated from the ICU in-patients’sputum/bronchial secretion samples during December2010and December2011, these patients were from6hospitals in different places of Hunan province and their hospitalization time was more than48hours. We used Repetitive Extragenic Palindrome-Polymerase Chain Reaction (REP-PCR) and Multilocus sequence typing (MLST) to analyse Genotyping and homology. We detected blaOXA-51, blaOxA-23,blaOXA-24, blaOXA-58and blaNDM-1by PCR. All the drug-susceptibility test results and patients’ clinical datas were also collected at the same time. Results:All of the138Acinetobacter baumannii strains were divided into6gene types by REP-PCR, the mayor type was type A(120). MLST divided the A1subtype(101strains) of the type A into8distinct sequence types,the main sequence types was ST191(60/101),we also discovered the ST381for the first time in China. The Carbapenemases gene-positive Acinetobacter baumannii widely distributed, all the138strains contained OXA-51but were negative for OXA-24, OXA-58and NDM-1gene,80.43%isolates were positive for OXA-23gene. Compared Clone A with B, their positive rates of OXA-23gene were statistal different(P<0.01), as the same as Clone A and C. The drug-susceptibility test result showed a high antibiotic resistance rate to many antibiotics. The differences of Multi-drug-resistance(MDR) rate and Pan-drug-resistance(PDR) rate between different Clones were not statistically significant(P>0.05).Conclusions:The mayor type Acinetobacter baumannii of ICU in Hunan province was type A; and was the ST191of MLST. It had a high antibiotic resistance rate to many antibiotics; the Carbapenemases gene-positive Acinetobacter baumannii widely distributed,carry the OXA-51gene and OXA-23gene was an important reason for antibiotic resistant phenomenon of Acinetobacter baumannii of ICU in Hunan province.