Drug Resistance And The β-lactamase Gene Taken By Acinetobacter Baumannii

Objective:To investigate the resistance of multi-drug resistant Acinetobacter baumannii and its β-lactamase genes carrying in our hospital,and establish a homology analysis method based on ERIC-PCR assay for A.baumannii.To find a molecular marker for screening multidrug-resistant A.baumannii and non-multidrug-resistant A.baumannii in clinical work.Methods:A total of 131 multi-drug resistant A.baumannii strains isolated from our hospital from 2017 to 2019 were selected.The VITEK-2 Compact automatic bacterial identification and drug susceptibility analysis system was used to confirm and analyze bacterial resistance.The ERIC-PCR method was used to analyze the homology of multi-drug resistant A.baumannii strains from our hospital.Another 100non-multidrug-resistant A.baumannii strains also isolated from our hospital from2017 to 2019.The genomic DNA of above-mentioned 131 multi-drug resistant strains and 100 non-multidrug resistant strains were extracted using Bacterial Genomic DNA Extraction Kit.All of the β-lactamase genes of the two groups with different drug resistance were detected by PCR method.The β-lactamase genes detected in our study were bla OXA-23,bla OXA-24,bla OXA-51,bla OXA-58,bla TEM,bla PER,bla CARB,bla IMP,bla VIM,bla ADC and bla DHA.Results:The multi-drug resistant A.baumannii strains from our hospital was mainly originated from sputum(74.81%)and pus & secretion(22.14%).Multidrug-resistant A.baumannii in our hospital is highly resistant to common antibiotics.The resistance rate to imipenem,ceftazidime,ceftriaxone and cefepime were 100%,the resistance rate to ciprofloxacin was 87.4%,the resistance rates to sulfamethoxazole and minocycline were 85.3%,the resistance rate to levofloxacin was 55.9%,and the resistance rate to amikacin was 39.9%.The results of ERIC-PCR methods indicated that most of the multi-drug resistant A.baumannii strains had three distinct bands in ERIC-PCR product electrophoresis,and the spectral differences of amplification products of each strain were not significant,and their homology was similar.In the multi-drug resistant A.baumannii strains,the detection rate of bla TEM gene was43.51%,the detection rate of bla ADC gene was 100%,the detection rate of bla DHA gene was 1.52%,and the detection rates of bla OXA-23 gene and bla OXA-51 gene were 100%.In the non-multi-drug resistant A.baumannii strains,the detection rate of bla TEM gene was 28.00%,the detection rate of bla ADC gene was 98.00%,and the detection rate of bla OXA-51 gene was 100%.Other β-lactamase genes were not detected in both multi-drug and non-multidrug-resistant A.baumannii.Conclusion:The multi-drug resistant A.baumannii in our hospital mainly originated from ICU and respiratory department.The drug resistance was serious and the homology of the strains were similar.It might be derived from the clonal transmission of A.baumannii.It is necessary for the clinical work of the above-mentioned departments to pay close attention to the occurrence of nosocomial infections.The ERIC-PCR method was simple and convenient,and could be used for monitoring of bacterial homology and the occurrence of nosocomial infections.The multi-drug resistant A.baumannii had several kinds of β-lactamase genes,including bla TEM,bla ADC,bla DHA,bla OXA-23 and bla OXA-51.Among them,bla OXA-23 gene was only detected in multi-drug resistant A.baumannii,and non-multi-drug resistant A.baumannii was not detected.It is a potential molecular marker for multi-drug resistant A.baumannii screening,and needed for further research.