Multilocus sequence typing of 87 strains of multidrug-resistant Acinetobacter baumannii / 安徽医科大学学报

ABSTRACT

Objective To obtain knowledge of microbial colonial structures and epidemic strains of clinically isolated multidrug-resistant Acinetobacter baumannii in Anhui in recent years.To analyze gene homologies and phylogenetic relationships of multidrug-resistant Acinetobacter baumannii.To provide some laboratory data for clinical antimicrobial application.Methods Eighty-seven strains of clinically isolate dmultidrug-resistant Acinetobacter baumannii were collected in this study,and the minimal inhibitory concentrations of these strains to 11 common antimicrobials were measured by agar dilution.Evolutionary relationships between the strains were revealed with employment of multilocus sequence typing,and clustering figures were constructed with the aid of the BioNumerics software,thus enabling genotyping.Results The drug-resistance rates of 87 strains of Acinetobacter baumannii to imipenem and meropenem were 74.7％ and 66.7％,respectively,while the drug-resistance rates to other antimicrobials were considerably high.All the 87 strains were sub-divided into 42 ST-types,6 of which were already involved in the database while 36 (temporarily named STnew01 ～STnew36) were newly established.Thirty-seven strains were proved dominant types and sub-listed in the ST2 category.The ST2 Acinetobacter baumannii belongs to the clone complex CC1.Conclusion All multidrug-resistant Acinetobacter baumannii in research show high drug-resistance rates when treated with 11 common antimicrobials.The ST2 category is the principal epidemic clones of multidrug-resistant Acinetobacter baumannii in Anhui province,and a highly recogonizable homology is observed between the principal epidemic strains(ST2) in Anhui and those in the world.