| ObjectiveWe studied the distribution characteristics and drug resistance of the main pathogenic bacteria and multidrug-resistant organisms(MDRO)isolated in a hospital over the past five years,then we further studied the Carbapenem-resistant nii(CRAB)drug resistance gene and its correlation with drug resistance phenotype to explore the drug resistance mechanism of CRAB,aiming to provide a scientific basis for nosocomial infection prevention and the rational drug use.MethodsPathogenic bacteria were collected from January 2017 to December 2021.We studied the main pathogenic bacteria and MDRO to analyse their detection,clinical distribution and drug resistance.Bacteria identification and drug susceptibility test were carried out by using the Vitek2-compact automatic microbial identification system and the matching drug susceptibility identification card and paper diffusion method.The results were judged according to the 2017 version of the American Clinical Laboratory Standards Institute standards.While the 13 CRAB strains genomic DNA was extracted,and sequencing was performed using MGISEQ-200RS gene sequencer,the sequence was uploaded to the CARD gene database for drug resistance gene analysis.The drug-resistant genes were compared with their drug-resistant phenotypes,and the correlation between drug-resistant genes and drug-resistant phenotypes was analyzed.Results1.Detection and clinical distribution of main pathogenic bacteriaFrom 2017 to 2021,a total of 3,847 pathogenic bacteria were detected,and the top five major pathogenic bacteria were 2,638 strains,followed by Escherichia coli(25.45%),Klebsiella pneumoniae(22.17%),and Pseudomonas aeruginosa(7.56%)),Staphylococcus aureus(6.94%)and Acinetobacter baumannii(6.45%).The clinical distribution was mostly middle-aged and elderly male patients,and the departments were mainly distributed in the intensive care unit(25.29%),which was significantly higher than that of general surgery(17.97%)and neurology(17.40%)(P<0.05).The samples mainly came from sputum(52.12%),which was significantly higher than that of urine(19.71%)and pus(9.78%)(P<0.05).2 Mainly monitor the detection and clinical distribution of MDROA total of 236 main monitored MDRO strains were detected from 2017 to 2021,and the detection rate showed an increasing trend during the 5 years(P<0.05).The clinical distribution was mostly middle-aged and elderly male patients,and the departments were mainly distributed in ICU(43.22%),which was significantly higher than neurosurgery(19.92%)and general surgery(14.41%)(P<0.05).The samples were mainly from sputum(73.31%),which was significantly higher than urine(9.32%)and secretions(6.78%)(P<0.05).3 Drug resistance of main pathogenic bacteria and MDRO mainly monitoredThe results of drug susceptibility tests of major pathogenic bacteria from 2017 to 2021 show that:Escherichia coli is sensitive to carbapenems and aminoglycosides,the resistance rate to quinolones is higher than 50%,and the resistance rate to ampicillin is higher than 75%.Klebsiella pneumoniae were sensitive to carbapenems,aminoglycosides and quinolones,and moderately resistant to other antimicrobials.Pseudomonas aeruginosa was sensitive to carbapenems,aminoglycosides and quinolones,and the resistance rate to cefotetan and cefazolin was higher than 75%.The overall drug resistance rate of Acinetobacter baumannii was relatively high,and the drug resistance rate to most antibacterial drugs was higher than 50%,and the drug resistance rate to aztreonam,cefotetan and cefazolin was higher than 75%.Staphylococcus aureus was sensitive to linezolid,vancomycin,rifampicin,tetracycline,carbapenems,aminoglycosides and quinolones,and the resistance rate to erythromycin and penicillin was higher than 75%.The drug susceptibility test results of major MDROs from 2017 to 2021 show that:Among the antibacterial drugs with MDRO resistance rate higher than 75%,there were 17 kinds of CRAB,15 kinds of carbapenem-resistant Escherichia coli,14 kinds of carbapenemresistant Klebsiella pneumoniae,6 kinds of methicillin-resistant Staphylococcus aureus,and 4 kinds of carbapenem-resistant Pseudomonas aeruginosa,which should be suspended.The drug resistance of CRAB was the most serious,followed by carbapenem-resistant Escherichia coli and carbapenem-resistant Klebsiella pneumoniae,and the drug resistance rates of methicillin-resistant Staphylococcus aureus and carbapenem-resistant Pseudomonas aeruginosa were relatively low.4 CRAB resistance gene analysisThe results of drug resistance gene analysis of 13 clinical isolated CRAB strains showed that all strains carried the following drug resistance genes:carbapenemases:OXA-23;Aminoglycosides:ANT(3")-Ⅱc;Topoisomerase Gene mutation:parC;polypeptide gene:LpsB;efflux pump:AmvA,AbaQ,adeK,adeF,adeJ,adeR,abeS,AbaF,adeL.The drug susceptibility results of 13 CRAB strains isolated in clinical showed that CRAB had a high level of drug resistance to most of the commonly used antibacterial drugs,and was almost completely resistant to β-lactams,aminoglycosides and quinolones with drug rates of 99.04%,96.15%and 92.31%,respectively,and 46.15%to sulfa.But,those CRAB strains were completely sensitive to tetracyclines and polypeptide.Among the 13 CRAB strains detected,the average detection rate of quinolone resistance genes was 92.31%,which was completely consistent with the corresponding resistance phenotype.The average detection rates of β-lactam and aminoglycoside resistance genes were 30.77%and 45.19%,which were much lower than the corresponding resistance phenotype rates of 99.04%and 96.15%.The average detection rate of sulfonamide-resistant genes was 34.62%,which was slightly lower than the corresponding resistance phenotype rate(46.15%).The average detection rates of tetracycline and peptide resistance genes were 69.23%and 100.00%,but the corresponding resistance phenotypes did not show drug resistance.ConclusionThe pathogenic bacteria detected in the past five years are mainly G-bacteria,and the hospital should continue to strengthen the monitoring and management of key departments and key populations.The drug resistance of the main clinical isolated pathogens and the main monitored MDRO to common antibiotics were great different.The antibiotics should be selected scientifically and rationally according to the types and characteristics of the pathogens in different hospital.The drug resistance mechanism of CRAB is complex,and the carrying of drug resistance gene is only one of the reasons why CRAB is resistant to antimicrobial drugs. |
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