Preferred beta-lactone synthesis can explain high rate of false-negative results in the detection of OXA-48-like carbapenemases

0566655 - MBÚ 2023 RIV DE eng J - Journal Article
Studentová, V. - Sudová, V. - Bitar, I. - Pašková, V. - Moravec, J. - Pompach, Petr - Volný, Michael - Novák, Petr - Hrabák, J.
Preferred beta-lactone synthesis can explain high rate of false-negative results in the detection of OXA-48-like carbapenemases.
Scientific Reports. Roč. 12, č. 1 (2022), č. článku 22235. ISSN 2045-2322. E-ISSN 2045-2322
R&D Projects: GA MZd(CZ) NV19-05-00541; GA MŠMT(CZ) LX22NPO5103
Institutional support: RVO:61388971
Keywords : antibiotic resistance * beta lactone * carbapenems * gram-negative bacteria * mass spectrometry
OECD category: Microbiology
Impact factor: 4.6, year: 2022
Method of publishing: Open access
https://www.nature.com/articles/s41598-022-26735-5

The resistance to carbapenems is usually mediated by enzymes hydrolyzing β-lactam ring. Recently, an alternative way of the modification of the antibiotic, a β-lactone formation by OXA-48-like enzymes, in some carbapenems was identified. We focused our study on a deep analysis of OXA-48-like-producing Enterobacterales, especially strains showing poor hydrolytic activity. In this study, well characterized 74 isolates of Enterobacterales resistant to carbapenems were used. Carbapenemase activity was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), liquid chromatography/mass spectrometry (LC–MS), Carba-NP test and modified Carbapenem Inactivation Method (mCIM). As meropenem-derived β-lactone possesses the same molecular weight as native meropenem (MW 383.46 g/mol), β-lactonization cannot be directly detected by MALDI-TOF MS. In the spectra, however, the peaks of m/z = 340.5 and 362.5 representing decarboxylated β-lactone and its sodium adduct were detected in 25 out of 35 OXA-48-like producers. In the rest 10 isolates, decarboxylated hydrolytic product (m/z = 358.5) and its sodium adduct (m/z = 380.5) have been detected. The peak of m/z = 362.5 was detected in 3 strains co-producing OXA-48-like and NDM-1 carbapenemases. The respective signal was identified in no strain producing class A or class B carbapenemase alone showing its specificity for OXA-48-like carbapenemases. Using LC–MS, we were able to identify meropenem-derived β-lactone directly according to the different retention time. All strains with a predominant β-lactone production showed negative results of Carba NP test. In this study, we have demonstrated that the strains producing OXA-48-like carbapenemases showing false-negative results using Carba NP test and MALDI-TOF MS preferentially produced meropenem-derived β-lactone. We also identified β-lactone-specific peak in MALDI-TOF MS spectra and demonstrated the ability of LC–MS to detect meropenem-derived β-lactone.
Permanent Link: https://hdl.handle.net/11104/0337973