| Objective:1.To understand the drug resistance and distribution characteristics of Enterobacteriaceae bacterial infections in Henan Province in 2019,so as to provide a scientific basis for empirical clinical drug use..2.Study on the molecular mechanism and epidemiological characteristics of colistin-resistant Enterobacteriaceae in Henan Province to prevent the spread of colistin-resistant strains of bacteria.Methods:1.Analysis of drug sensitivity,resistance characteristics and detection of Carbapenem-resistant Enterobacteriacea（CRE）bacteria in 144 hospitals in Henan Province in 2019 using WHONET 5.6software.To compare the resistance of Escherichia coli and Klebsiella pneumoniae to colistin,tigecycline and carbapenem in five regions of east and west Henan,and to compare the resistance of Escherichia coli and Klebsiella pneumoniae detected in secondary and tertiary hospitals to the above three types of antibacterial drugs;SPSS 25.0 software was used for statistical analysis,and P<0.05 indicated that the difference was statistically significant.2.Thirteen strains of non-repetitive colistin-resistant Enterobacteriaceae,including five strains of Escherichia coli and eight strains of Klebsiella pneumoniae,were collected from six hospitals in Henan Province from January 2019 to December 2019.The minimum inhibitory concentration（MIC）of colistin against clinical isolates of Escherichia coli and Klebsiella pneumoniae was determined by micro-broth dilution method,and all colistin-resistant strains were identified by polymerase chain reaction（PCR）technique.The mcr-1 gene and carbapenemase genes(bla KPC,bla NDM,bla IMP,bla VIM,bla OXA-48)were identified by PCR and Sanger sequencing to detect mutations in mgr B,pho PQ and pmr AB in colistin-resistance Klebsiella pneumoniae.Pulsed Field Gel Electrophoresis（PFGE）and Multi-Locus Sequence Typing（MLST）were performed to determine the affinities among the colistin-resistant isolates.Results:1.In 2019,the rate of emergency outpatient delivery of Enterobacteriaceae bacteria in Henan Province was only 4.4%（2728/61989）,and the main source of specimens was respiratory specimens 42.9%（26593/61989）,followed by urine specimens 17.6%（10910/61989）.The Enterobacteriaceae had high resistance rates to most antimicrobial drugs,with high susceptibility only to colistin and tigecycline,both of which were>90.0%.The detection rates of CRE,carbapenem-resistant Klebsiella pneumoniae（CRKP）and carbapenem-resistant Escherichia coli（CREC）were 12.1%（7493/61989）,26.1%（5288/20256）and 3.2%（889/27539）.The highest rate of CRKP detection was in the east of Yudong（32.0%）,and the highest rate of CREC detection was in the west of Yuxi（3.5%）,and the difference between different regions was significant（P<0.05）.There were significant regional differences in the rates of resistance of Klebsiella pneumoniae to colistin and tigecycline,and Escherichia coli to tigecycline（P<0.05）.The rate of resistance of Klebsiella pneumoniae to carbapenems was higher in tertiary hospitals than in secondary hospitals（P<0.001）,but the rate of resistance of Escherichia coli to carbapenems was higher in secondary hospitals than in tertiary hospitals（P=0.01）.2.The MICs of the 8 strains of colistin-resistant Klebsiella pneumoniae collected in 2019 were4-64μg/ml,and the MICs of the 5 strains of colistin-resistant Escherichia coli were all 4μg/ml.colistin-resistant strains have a high resistance rate to most antimicrobial drugs.Four strains carrying the mcr-1 gene were detected,and all of them were Escherichia coli,among which one strain was carbapenem-resistant and carried both bla NDMand mcr-1 genes.All eight strains of Klebsiella pneumoniae were carbapenem resistant and carried the bla KPCgene.mgr B insertion sequences were detected in seven strains（81.8%）of colistin-resistant Klebsiella pneumoniae,and ISkpn14（71.4%）was the most common insertion sequence observed in mgr B in this study.no mutations were found in pho P,pho Q or pmr B,Only one strain carried M66I in the pmr A gene.Five strains of Escherichia coli belonged to four sequence types ST2,ST132,ST632 and ST983,and all eight strains of Klebsiella pneumoniae belonged to ST11.Both Escherichia coli and Klebsiella pneumoniae belonged to different PFGE types,and the genetic similarity was less than 95%.Conclusions:1.The delivery rate of outpatient and emergency specimens in Henan Province was low,and the main types of specimens were respiratory specimens and urine.The overall resistance rate of clinically isolated Enterobacteriaceae was high,especially the detection rate of carbapenem-resistant Klebsiella pneumoniae was higher than the national level,and there were significant differences between different regions and different levels of hospitals.This suggests that hospitals at all levels should be selective in the empirical use of antimicrobial drugs according to the specific analysis of the region and the hospital.2.strains carrying the mcr-1 gene had low levels of colistin resistance,and the colistin-positive Enterobacteriaceae showed a wide range of antimicrobial drug resistance characteristics.Carrying mcr-1gene was the main cause of colistin resistance in Escherichia coli in Henan Province,and inserting ISkpn14into mgr B was the main cause of colistin resistance in Klebsiella pneumoniae.PFGE showed that the colistin-resistant strains all belonged to different clonotypes and were epidemic,but hospital infection control needs to be strengthened and continuously monitored to prevent the clonal spread of colistin-resistant strains. |
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