Leucine degradation metabolite ratio as a measure of meropenem susceptibility in carbapenem-resistant Klebsiella pneumoniae

ABSTRACT:

Rapid detection of carbapenem-resistant Klebsiella pneumoniae (CRKP) is essential for effective clinical management and surveillance. This study investigated volatile organic compounds (VOCs) as phenotypic biomarkers of carbapenem resistance, with the goal of developing a translationally viable diagnostic metric. Sixteen clinical K. pneumoniae isolates comprising both CRKP and susceptible (CSKP) strains, were cultured for six hours in headspace vials and VOCs extracted using PDMS-coated probes, with and without meropenem. Volatiles were analysed by thermal desorption-gas chromatography-mass spectrometry. Under meropenem stress, CRKP and CSKP exhibited distinct VOC profiles, with two leucine-derived metabolites, 3-methyl-1-butanol (syn. isoamyl alcohol) and 3-methylbutanal (syn. isovaleraldehyde), emerging as key discriminatory features. The ratio of these two metabolites accurately classified resistance phenotype, achieving 100% sensitivity and 94.1% specificity. The ratio also correlated significantly with minimum inhibitory concentration and zone of inhibition values. Stable isotope tracing confirmed their origin from leucine catabolism, and metabolic supplementation experiments suggested a functional role for 3-methyl-1-butanol in promoting growth under antibiotic stress. These findings show that antimicrobial resistance is accompanied by detectable shifts in volatile metabolism and that VOCs can serve as reliable indicators of resistance phenotype. The 3-methyl-1-butanol/3-methylbutanal ratio presents a robust biomarker of meropenem resistance, detectable within six hours of culture growth, and supports the further development of volatilome-based diagnostics for clinical microbiology.

INSTRUMENT(S): Gas Chromatography MS - positive

PROVIDER: MTBLS13539 | MetaboLights | 2026-06-09

REPOSITORIES: MetaboLights