English 
Italian CONTRIBUTI SCIENTIFICI – Scientific Papers
Volume:
Biochimica Clinica 2019; 43(4) 394-398
Pubblicato on-line:
July 4, 2019
DOI:
10.19186/BC_2019.033
Evaluation of a multiplex immunochromatographic assay for the rapid detection of carbapenemase-producing Enterobacteriaceaefrom culture colonies
AUTORI
1Medicina di Laboratorio, Ospedale di San Bassiano, AULSS 7 Pedemontana, Bassano del Grappa
2Medicina di Laboratorio, Ospedale San Camillo, Treviso
3Medicina di Laboratorio, IRCCS Ospedale Policlinico San Martino, Genova
ABSTRACT
Introduction: the increasing worldwide spread of multidrug resistant bacteria, in particular of carbapenemase-producing Enterobacteriaceae(CPE), represents a serious clinical and public health concern. An accurate and fast detection of infected patients or colonized carriers is thus mandatory.
Aim of this study was to assess the performance of a multiplex immunochromatographic assay (NG-Test CARBA 5, NG Biotech, Guipry, France) for the rapid detection of carbapenemases directly from pure bacterial colonies.
Methods: seventy-five non-replicated Enterobacteralesisolates with decreased susceptibility to carbapenems, including 71 Klebsiella pneumoniae, 3Escherichia coli and1Enterobacter cloacae, were analysed with NG-Test CARBA 5. At the same time the combination disk test (CDT) was performed according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) indications, while confirmation of carbapenemase production was achieved by polymerase chain reaction (PCR).
Results: PCR assay could find 66 CPE strains, including 64 Klebsiella pneumoniae[53 producing Klebsiella pneumoniae carbapenemase (KPC), 5 New Delhi metallo-β-lactamase (NDM), 2 class D oxacillinases (OXA-48), 1 Verona integron-encoded metallo-β-lactamase (VIM) and 3 co-producing NDM and OXA-48] and 2 Escherichia coli (2 NDM+OXA-48) while 9 isolates were found as non-carbapenemase producing: 7 Klebsiella pneumoniae, 1 Escherichia coli, 1 Enterobacter cloacae. CDT allowed us to consider those 9 strains as extended spectrum β-lactamase (ESBL) or AmpC β-lactamase producers. NG-Test CARBA 5 successfully identified 66/66 CPE showing 100% sensitivity and 100% specificity. Unlike NG-Test CARBA 5, CDT was not able to correctly identify 5 strains co-producing NDM and OXA-48 carbapenemases.
Conclusion: NG-Test CARBA 5 is a reliable assay that can be useful in settings requiring a rapid identification of CPE directly from culture colonies. Moreover, this test is an easy-to-use option that could avoid misidentification of carbapenemases co-producers strains.