Study On Disinfectant Resistance And Homology Of Carbapenem-resistant Enterobacteriaceae

Objective: To analyze the clinical distribution,drug sensitivity and common drug resistance patterns of carbapenem-resistant Enterobacteriaceae(CRE),and to study its resistance to common disinfectants,the distribution of disinfectant-resistant genes and the homology among the strains,so as to formulate a reasonable disinfectant use strategy,determine whether the resistant strains exist in the hospital for dissemination,and help to control the infection and spread of CRE.Methods: A total of 70 strains of carbapenem-resistant Enterobacteriaceae strains clinically isolated from January to December 2017 were collected from the First Affiliated Hospital of Fujian Medical University.All tested strains were identified by MALDI-TOF-MS and VITEK-2 Compact susceptibility analyzer;the minimum inhibitory concentration(MIC)of the strain on the disinfectant was detected by agar dilution method;Polymerase chain reaction(PCR)was used to detect the disinfectant gene carried by the strain;Pulse field gel electrophoresis(PFGE)was used to analyze the homology of 59 carbapenem-resistant Klebsiella pneumoniae.Results:1?Among the 70 strains of CRE,59 strains of Klebsiella pneumoniae,8 strains of Escherichia coli,and 3 strains of Enterobacter cloacae were mainly used for sputum(44.28%),urine(22.86%),and secretions.(10.00%),etc.,the department is mainly concentrated in the ICU(28.57%),general surgery(25.73%),respiratory medicine(10.00%),rheumatology(8.57%)and other departments;2?70 strains of CRE strain had the lowest resistance rate to amikacin(64.29%),and the resistance to 13 common antibiotics was generally higher: the resistance rates of gentamicin and tobramycin were 82.86% and 81.43%,the quinolone resistance rate was 91.43%,and the resistance rate to piperacillin,piperacillin/tazobactam and cefepime was 98.57%,on ampicillin,ampicillin/sulbactam The resistance rate of ceftazidime,imipenem and meropenem is as high as 100%;3?There are five types of drug resistance patterns in 70 strains of CRE strains.The first model is resistant to clinically common aminoglycosides,quinolones,enzyme inhibitors,cephalosporins,and carbapenems.The main mode accounted for 62.86%;the second mode is only sensitive to aminoglycoside antibiotics,accounting for 10.00%;the third mode is only amikacin sensitive,accounting for 18.57%;the fourth mode is only sensitive to quinolone antibiotics,accounting for 1.43%;the fifth drug resistance model is sensitive to aminoglycosides and quinolone antibacterial drugs,accounting for 7.14%;4?The MIC values of 70 strains of CRE strains in chloroform disinfectant were 512mg/L,1024mg/L and >1024mg/L,respectively,accounting for 4 strains,19 strains and 47 strains;the MIC value of iodophor disinfectant was 256mg/L,512mg/L and 1024mg/L each accounted for 16 strains,32 strains and 22 strains;the MIC values of glutaraldehyde were distributed at 512mg/L,1024mg/L and >1024mg/L,respectively,accounting for 10 strains,15 strains and 45 strains;The MIC values of 70 strains of CRE strains were relatively low,and the MIC values of benzalkonium bromide against CRE strains were mainly concentrated in 64 mg/L to 256 mg./L;The MIC value of Avagard surgery washing liquid is mainly concentrated from 8 mg/L to 64 mg/L;the MIC value of Jianrui hand washing liquid is mainly concentrated from 32 mg/L to 128 mg/L.The MIC values of the above six disinfectants against 70 strains of CRE were greater than the MIC values of the standard strains;5?The amplification results of the disinfectant-resistant gene showed that 70 strains of CRE carried qacE,qac?E,CepA,qacE?1-sul 1 genes,but did not carry the qacA anti-disinfectant gene,and the positive rate of qacE gene was 81.43%(57/70),of which 50 strains of Klebsiella pneumoniae,6 strains of Escherichia coli,and 1 strain of Enterobacter cloacae.The distribution of qacE gene in Klebsiella pneumoniae and Escherichia coli was not statistically significant(P=0.609);the positive rate of qac?E gene was 82.86%(58/70),of which 51 strains of Klebsiella pneumoniae,6 strains of Escherichia coli,1 strain of Enterobacter cloacae.The distribution of qac?E gene in Klebsiella pneumoniae and Escherichia coli were not statistically significant(P=0.341);the positive rate of CepA gene was 82.86%(58/70),of which 54 strains of Klebsiella pneumoniae,2 strains of Escherichia coli,2 strains of Enterobacter cloacae,and the distribution of CepA gene in Klebsiella pneumoniae and Escherichia coli were statistically significant(P<0.001);the positive rate of qacE?1-sul 1 gene was 85.71%(60 /70),of which 56 strains of Klebsiella pneumoniae,6 strains of Escherichia coli,1 strain of Enterobacter cloacae,and the distribution of qacE?1-sul 1 gene in Klebsiella pneumoniae and Escherichia coli were not statistically significant(P=0.105);the strain carrying four genes of qacE,qac?E,CepA,qacE?1-sul 1 accounted for 71.43%(50/70),and the strain carrying three or more disinfectant-resistant genes accounted for 80%(56/70),only 3 CRE strains do not carry any of the above disinfectant genes;6?The results of PFGE showed that 59 strains of Klebsiella pneumoniae were subjected to XbaI digestion and showed different sizes.The similarity between the strains ranged from 59% to 100%,and the molecular weight ranged from 20 to 669 kb.According to the similarity of 80%,some bacteria are divided into the same cluster,59 strains of CR-KPN can be divided into 14 clusters,which are recorded as A to N,among which group A(23 strains)and group B(22 strains)as the main advantage cluster.Some strains are identical in band and distributed in different departments and are the same clone.Conclusion:1?70 strains of CRE were isolated from Klebsiella pneumoniae in sputum samples and distributed in high-risk departments such as ICU and general surgery;these strains had the lowest resistance rate to amikacin(64.29%),Other common 13 antibiotic resistance rates are higher than 75%;2?In addition to the qacA gene,the positive rates of qacE,qac?E,CepA and qacE?1-sul 1 antiseptics carried by CRE strains are relatively high and can be carried simultaneously;3?CRE strains are resistant to common disinfectants.Although the clinical concentration of benzalkonium bromide and hands-free disinfectant still have good disinfection effect,glutaraldehyde,iodophor and chlorine-containing disinfectant are three clinical commonly used high-efficiency disinfectant,which have a relatively high MIC value for the CRE strain;4?PFGE typing revealed the prevalence of carbapenem-resistant Klebsiella pneumoniae among different departments in the hospital.