What volatile organic compounds (VOCs) are produced by Escherichia coli, and how do their profiles differ between susceptible and resistant strains?

Escherichia coli (E. coli) is a widely studied bacterial species known for its metabolic diversity. The study investigates the volatile organic compounds (VOCs) produced by both carbapenem-susceptible and carbapenem-resistant strains of E. coli. VOCs are metabolic byproducts that can serve as biomarkers for bacterial identification and monitoring of infections. Understanding the differences in VOC profiles between susceptible and resistant strains can aid in the development of rapid diagnostic techniques for bacterial infections, particularly in critical care settings such as ventilator-associated pneumonia (VAP).

From: "Profiling of Volatile Metabolites of Escherichia coli Using Gas Chromatography–Mass Spectrometry", Int. J. Mol. Sci. 2025, 26(17), 8191;

The study identified a total of 57 VOCs from the susceptible strain and 41 from the resistant strain of E. coli. The VOCs were categorized based on their emission patterns during bacterial growth:
Continuous Release Proportional to Bacterial Load: Compounds like ethanol, 1-propanol, and 1-butanol were released in quantities directly proportional to the bacterial load. These compounds are likely useful for monitoring the progression of an infection.
Temporary Maximum Release: Compounds such as isoprene, 2-butenal, and dimethyl disulfide showed a temporary peak in emission during the logarithmic growth phase. These VOCs could serve as early indicators of bacterial infections.
Compound Uptake: Aldehydes like methacrolein and 3-methylbutanal were taken up by the bacteria, indicating their use as a nutrient source.