| Objective:Carbapenem antibiotics are considered to be the last line of defense against multi-drug-resistant bacterial infections.However,with the extensive use of carbapenem antibiotics,carbapenem-resistant Klebsiella pneumoniae are increasing,and new mutation subtypes are constantly found.It poses a serious threat to human health worldwide and poses a great challenge to clinical antibiotic treatment.A retrospective analysis of carbapenem-resistant Klebsiella pneumoniae from January 2016 to June 2019 in Lianyungang City was carried out.The carrying status of carbapenem-resistant genes,distribution characteristics of virulence-related genes and molecular epidemiological characteristics in this area were clarified,which provided scientific basis for surveillance of drug-resistant bacteria and control of nosocomial infection.The outbreak and epidemic of drug-resistant bacteria play a guiding role.Methods:1.Collect 26 non-repetitive CRKP strains from January 2016 to June 2019 in Lianyungang City.All strains were identified by VITEK2 automatic microbial identification and drug sensitivity analyzer,and re-identified by Bruker mass spectrometer before the experiment.Drug resistance and sample information of all strains were analyzed.2.ESBLs resistance gene(blaCTX-M、blaSHV、blaTEM),Carbapenemase resistance genes(blaKPC、blaNDM、bla VIM.blaIMP、blaOXA-23、blaOXA-48),polymyxin resistance gene(blaMcr-1)were detected by PCR.3.The genes of Khe、Kphp、pilv、pill.ST23、ST65 and ST86 were detected by multiplex PCR,ST typing was performed.4.Detection of serotypes of K1、K2、K47、K64 and other common ST11 by multiplex PCR,Capsule synthesis site of the strain.5.Detection of virulent plasmid-related genes(rmpA、rmpA2、iroN、iutA)by multiplex PCR.6.PFGE was used to detect all strains and analyze whether clonal transmission existed.Results:1.26 strains of bacteria were all from hospitalized patients,of which 58%were from rehabilitation department.From 2017 to June 2019,the average detection rate of CRKP was 13.1%.The main types of specimens were sputum specimens and urine specimens.Drug susceptibility results indicated that all strains had high level of drug resistance and multiple drug resistance.2.Carbapenem resistance genes of experimental strains:blaKPC gene 73%,blaNDM gene 8%,blaIMP gene 4%,blaVIM、blaOXA48、blaOXA23、blaMcr-1 four genes were not detected.The proportion of ESBLs resistant genes carrying blaCTX-M,blaTEM and bla SHV was 65.4%,88.5%and 100%respectively,and the proportion of ESBLs resistant genes carrying these three genes was 65.4%.3.The results of ST typing in the first system showed that ST11 accounted for 73.1%and ST65 for 15.4%,while ST23、ST86 and ST258 were not detected.4.The results of the second system typing:wzyKl serotype was detected by capsular serotyping 7.7%,wzyK2 was not detected.The positive rate of wzyKL64 and wzyKL47 was 84%and 16%in all ST11 strains5.The results of virulence genes of the third system showed that the positive rates of virulence genes such as rmpA、rmpA2、iroN and iutA were 30.8%、30.8%、7.7%and 38.5%,respectively.The positive rates of iutA were the highest.Eight strains of ST11 CRKP carrying virulent plasmid-related genes were detected,7 strains were concentrated in the rehabilitation department,6 of which were KL64.6.PFGE results:Clonal transmission of CRKP strain was observed.Conclusion:Carbapenemase is the main resistance mechanism of CRKP in Lianyungang City.The main resistance gene carried by this hospital is blaKPC,and the main ST typing is ST11.The highest detection rate of CRKP was found in rehabilitation department,and the highest detection rate of ESBLs resistance gene was blaTEM.PFGE results showed that there was clonal transmission of CRKP.Eight cases of CRKP carrying virulent plasmid-related genes were detected.Seven of them were concentrated in rehabilitation department.The main KL typing was KL64,which should be paid attention to by relevant departments and nosocomial departments. |
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