| Objective To analysis the distribution and antimicrobial resistance of Acinetobacter baumannii infection which separated from Anhui province.it may provide theoretical basis for controlling nosocomial infection.To detect carbapenemase resistance genes in carbapenem-resistant A.baumannii(CRAB)by PCR amplification.To identify genotype by the multilocus sequence typing technique and generate evolutionary diagram.Materials and Methods Isolates A total of 312 non-repeat A.baumannii strains were isolated from patients at 43 different hospitals located in Anhui Province,from 2015 to 2016.Pseudomonas aeruginosa ATCC27853,Escherichia coli ATCC35218 and Escherichia coli ATCC25922,and were used as quality control strains for antimicrobial susceptibility testing.All control strains were stored in Anhui Center of Surveillance of Bacterial Resistance.Methods1.A total of 312 CRAB non-repeated strains were collected from 43 tier 3 level hospitals in Anhui province from September 2015 to 2016.All strains were confirmed by Clin-To F-II Mass Spectrometer of Anhui Center of Surveillance of Bacterial Resistance and the AP120 Kit from Bio Mérieux.2.Using Agar plate dilution method to determine the Minimum inhibitory concentration(MIC)to total of 312 non-repeated CRAB strains according to Clinical and Laboratory Standards Institute guideline(CLSI).3.Our results indicated that all the 17 antibiotics showed high resistance to the 312 A.baumannii isolates which were all multidrug resistant strains.147 strains of Carbapenem-resistant A.baumannii(CRAB)were selected.4.In these 147 strains,Carbapenemase resistance genes(OXA-23,OXA-24,OXA-51,OXA-58,VIM,NDM,IMP and KPC)were detected by PCR amplification.5.The genotype was identified by the multilocus sequence typing technique.Evolutionary diagram was generated with the e BURST software.Results 1.Our results indicated that all the 17 antibiotics showed high resistance to the 147 A.baumannii isolates which were all multidrug resistant strains.Among the 17 antibiotics,POL B(0.68%)and TGC(9.27%)showed the lowest resistance.The antimicrobial resistance rates to Imipenem and Meropenem were 100%.The drug resistance rate of AMK(amikacin)was slightly lower than GEN(gentamicin).The drug resistance of four cephalosporins was similar.Among quinolone antibiotics,levofloxacin and gatifloxacin had lower resistance rates than ciprofloxacin.76.60%,79.43% and 97.16% respectively.2.134 CRAB strains were found to carry OXA-23 gene,one were found to carry OXA-24 gene,four were found to carry bla IMP gene.All the 147 CRAB strains were found to carry OXA-51 gene and other Carbapenemase genes were not found.3.The 147 strains of A.baumannii were divided into 26 ST genotypes,including 13 ST genotypes belonging to complex 92.ST195 had 48 strains,and was the main epidemiology type in Anhui province.15 new ST genotypes were found.Conclusions 1.The clinical isolation rate and drug resistance rate of Acinetobacter baumannii increased year by year.A.baumannii has become one of the most important pathogens in Anhui province.The increase of drug resistance rate has made it difficult to treat Acinetobacter baumannii infection in clinic.2.In all 147 CRAB strains,OXA-51 was detected in 100%(147/147)of strains,It was further confirmed that OXA-51 gene was an inherent gene on chromosome of Acinetobacter baumannii.3.OXA-23 gene is the most prevalent of other drug resistance genes,which is the main genotype leading to drug resistance.4.Our results indicated that CC92 was the main clone group in Anhui province,which was consistent with the world's popular cloning group.ST195 was the main epidemiology type in Anhui province.There were phylogenetic relationships among the 147 strains,suggesting that there might be a horizontal spread trend. |
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