Modification and evaluation of the Carba NP test by use of paper strip for simple and rapid detection of carbapenemase-producing Enterobacteriaceae

作者：Srisrattakarn Arpasiri; Lulitanond Aroonlug; Wilailuckana Chotechana; Charoensri Nicha; Wonglakorn Lumyai; Piyapatthanakul Sirikan; Supajeen Ampai; Chanawong Aroonwadee^*

来源：World Journal of Microbiology and Biotechnology, 2016, 32(7): 117.

DOI：10.1007/s11274-016-2064-x

• Carbapenem resistance
• Imipenemase
• Klebsiella pnetanoniae carbapenemase
• New Delhi metallo-beta-lactamase
• Oxacillinase-48
• Verona imipenemase

Carbapenemase-producing Enterobacteriaceae (CPE) isolates have now emerged worldwide. We therefore modified the phenotypic Carba NP test by use of a filter paper strip for easily and rapidly identifying CPE in routine laboratory. A collection of 56 CPE and carbapenemase-producing Pseudotnonas spp. isolates (including 28 NDM-1, 11 IMP-14a, 1 IMP-1, 1 IMP-4, 1 IMP-9, 1 IMP-15, 4 VIM-2, 1 VIM-1,1 IMP-14a with VIM-2, 3 OXA-48, 3 OXA-181 and 1 KPC-2 producers) and 41 non-CPE isolates (including 19 ESBL, 7 pAmpC, 3 AmpC, 9 ESBL with pAmpC and 3 nonESBL & non-AmpC producers) as confirmed by the PCR methods were tested by the paper strip method using pharmaceutical imipenem/cilastatin as a substrate. Bacterial colonies of each isolate were applied directly on filter paper strips dropped with either imipenem-phenol red (test strip) or phenol red solution alone (control strip). The reaction was read within 5 min. This test failed to detect 3 OXA-181, 2 OXA-48 and 3 IMP-14a producers (85.7 % sensitivity), whereas no false positives were seen (100 % specificity). Further evaluation of the paper strip test in 267 CPE screening-positive isolates from three hospitals by their medical technologists showed 92.0 % sensitivity (100 % for NDM producers) and 100 % specificity compared with the PCR methods. Because of its ease, rapidness and cost effective, the paper strip test has a potential for routine CPE testing in low-resource laboratories particularly in areas with high prevalence of NDM enzymes, leading to appropriate antimicrobial therapy and infection control strategy.

• 出版日期2016-7