Rapid detection of the main carbapenemases in Brazil directly from spiked blood culture using the RESIST-3 O.K.N. immunoassay

Abstract

The emergence of carbapenem-resistant Enterobacterales (CRE) is a matter of public health concern. Carbapenemases are the main mechanism of resistance among CRE, and its rapid detection is essential. The detection of carbapenemases usually requires culture-based methods and molecular assays, which may be costly and need long turnaround times. Recently, an easy and rapid immunochromatographic assay for carbapenemases (OXA-48, KPC, and NDM) detection based in lateral flow immunoassay with specific monoclonal antibodies on a nitrocellulose membrane has been developed. We aimed to evaluate the RESIST-3 O.K.N. in colonies from pure culture as well as in spiked blood cultures with Enterobacterales. All carbapenemase producers (CP) presenting the OXA-48-like, KPC, and NDM enzymes presented positive results in both pure colonies and spiked blood cultures. None of the carbapenemase non-producers (CNP) presented positive results in the tests. A total of 97% CP isolates presented positive results in pure colonies in less than 5 min. For CP directly from blood culture, the mean time to positivity for OXA-48-like and KPC was 1 min, whereas it was 25 min for NDM. Our results indicate that this immunoassay can be used to detect carbapenemases directly from blood culture bottles in a routine diagnostic laboratory, which would reduce the turnaround time of CP detection.

Direct Detection of KPC Peak from Positive Blood Cultures Using MALDI-TOF MS: Are We There Yet?

“…Moreover, a considerable portion of clinical laboratories do not include PCR as part of their routine. Another possibility for rapid carbapenemase detection are the immunochromatographic tests, which may detect specific enzymes directly from blood cultures in around 30 min or less [ 22 , 23 ]. However, their costs may be an issue for many laboratories [ 24 ].…”