Rapid detection of carbapenem-resistant phenotype of Enterobacteriaceae in blood culture by modified Carba Np test
Objective To explore the application value of improved Carba NP test for rapid detection of carbapenem-resistant phenotype of Enterobacteriaceae in blood culture.Methods A total of 163 strains of carbapenem-resistant Enterobacteriaceae isolated from clinical blood culture samples in Xingtai Third Hospital in 2022 were selected,the phenotypes of the strains were detected by improved Carba NP test and mCIM/eCIM respectively.The results of carbapenem phenotype identified by PCR were used as the gold standard to compare the tests of the two imoproved methods.Results The 163 strains of carbapenem-resistant Enterobacteriaceae included 8 strains,of which 134 strains were Klebsiella pneumoniae,accounted for 82.21％,followed by Escherichia coli,17 strains,accounted for 10.41％.Among 163 strains of carbapenem-resistant Enterobacteriaceae,ICU ranked first,with 72 strains,accounted for 44.17％,followed by surgery department,20 strains,accounted for 12.27％.The drug sensitivity test showed that the drug resistance rate was 100％to ampicillin,ceftizoxime,ceftriaxone,imipenem and ertapenem,the drug resistance rate to ceftazidime,azithromycin,ciprofloxacin and levofloxacin was over 90％.Among the 16 antibacterial drugs tested,only amikacin had a drug resistance rate below 50％.The results of phenotypic test showed that 161 strains were positive for carbNP test,with a positive rate of 98.77％.154 strains were positive in mCIM/eCIM test,and the positive rate was 94.47％.Two strains were negative in phenotypic test.In this study,163 strains of carbapenem-resistant Enterobacter were screened.Among 134 strains of Klebsiella pneumoniae,101 strains carried blaKPC-2 gene,3 strains carried blaNDM,2 strains carried blaIMP,and 28 strains were negative.Among the 17 strains of Escherichia coli,5 strains carried blaKPC-2 gene and 9 strains carried blaNDM.Based on the PCR results,the improved Carba Np test mCIM/eCIM test had high sensitivity and specificity in carbapenem-resistant Enterobacter,and there was no statistical difference between the two groups(P＞0.05).Conclusion The improved CarbNP test could quickly identify carbapenem-resistant Enterobacteriaceae strains,which has great clinical application value.
Modified Carba Np testIdentification of carbapenem typeCarbapenem-resistant enterobacteriaceae
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