Value of modified Hodge test, Carba NP test, and modified carbapenem inactivation method for screening carbapenemase-producing Klebsiella pneumoniae
HE Hong1,2, HUANG Zi-yan1, LI Jun1, CHEN Li-hua2, SHEN Hui2, WU Jing-min2, ZOU Ming-xiang1
1. Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha 410008, China; 2. Department of Clinical Laboratory, The First Hospital of Changsha, Changsha 410005, China
Abstract：Objective To explore the value of modified Hodge test (MHT), Carba NP test (CNPt) and modified carbapenem inactivation test (mCIM) in detecting carbapenemase-producing Klebsiella pneumoniae(K. pneumoniae). Methods 117 clinically isolated strains of K. pneumoniae were collected from a hospital between December 2016 and November 2017, all strains were performed antimicrobial susceptibility testing, 57 strains were carbapenem -resistant and 60 strains were carbapenem-susceptible. Carbapenemase gene detected by PCR was as gold standard, value of three methods for detecting carbapenemase in K. pneumoniae was evaluated. Results Of 57 carbapenem-resistant K. pneumoniae strains, 40 were positive for PCR, including 39 KPC strains and 1 NDM-1 strain, no other resistance genes were detected. Positive rates of MHT, CNPt, and mCIM were 87.7% (50/57), 89.5% (51/57), and 91.2% (52/57) respectively. No carbapenemase gene was detected among 60 strains of susceptible bacteria by PCR, results of three phenotypic screening tests were all negative. Taking PCR as the gold standard, sensitivity of MHT, CNPt, and mCIM were 97.5% (39/40), 100% (40/40), and 100% (40/40) respectively, specificity were 85.7% (66/77), 85.7% (66/77), and 84.4% (65/77) respectively. Conclusion CNPt is a reliable phenotypic screening method, which can be used in epidemiology and healthcare-associated infection surveillance. mCIM has the advantages of simple operation, easy to make a judgment and is more suitable for clinical microbiology laboratory to carry out routinely.
Sun Y, Li M, Chen L, et al. Prevalence and molecular characterization of carbapenemase-producing gram-negative bacteria from a university hospital in China[J]. Infect Dis(Lond), 2016, 48(2):138-146.
Clinical and Laboratory Standards Institute. Performance stan-dards for antimicrobial susceptibility testing, twenty-seventh informational supplement[S]. CLSI, 2017, M100-S27.
[7]
Castanheira M, Farrell SE, Deshpande LM, et al. Prevalence of β-lactamase encoding genes among Enterobacteriaceae bacteremia isolates collected in 26 U.S. hospitals:Report from the SENTRY Antimicrobial Surveillance Program (2010)[J]. Antimicrobial Agents Chemother, 2013, 57(7):3012-3020.
[8]
Villegas MV, Lolans K, Correa A, et al. First detection of the plasmid-mediated class A carbapenemase KPC-2 in clinical isolates of Klebsiella pneumoniae from South America[J]. Antimicrob Agents Chemother, 2006, 50(8):2880-2882.
Hamzaoui Z, Ocampo-Sosa A, Fernandez Martinez M, et al. Role of association of OmpK35 and OmpK36 alteration and blaESBL and/or blaAmpC genes in conferring carbapenem resistance among non-carbapenemase-producing Klebsiella pneumoniae[J]. Int J Antimicrob Agents, 2018, 52(6):898-905.
Yamada K, Kashiwa M, Arai K, et al. Comparison of the modified-Hodge test, Carba NP test, and carbapenem inactivation method as screening methods for carbapenemase-producing Enterobacteriaceae[J]. J Microbiol Methods, 2016, 128:48-51.
[13]
Tijet N, Boyd D, Patel SN, et al. Evaluation of the Carba NP test for rapid detection of carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa[J]. Antimicrob Agents Chemother, 2013, 57(9):4578-4580.
[14]
Srisrattakarn A, Lulitanond A, Wilailuckana C, et al. Modification and evaluation of the Carba NP test by use of paper strip for simple and rapid detection of carbapenemase-producing Enterobacteriaceae[J]. World J Microbiol Biotechnol, 2016, 32(7):117.
[15]
Dortet L, Bréchard L, Poirel L, et al. Rapid detection of carbapenemase-producing Enterobacteriaceae from blood cultures[J]. Clin Microbiol Infect, 2014, 20(4):340-344.
