Early release of 1-pyrroline by Pseudomonas aeruginosa cultures discovered using ambient corona discharge ionization mass spectrometry

摘要

Pseudomonas aeruginosa (PA) is a leading cause of nosocomial infections in humans with an increasing number of health-threatening implications, which urges faster clinical detection of this pathogen. In the present study, we discovered for the first time the early release of 1-pyrroline vapor by PA cultures using direct ambient mass spectrometry (AMS) analysis of the bacterial culture headspace based on corona discharge ionization. Importantly, the concentration of 1-pyrroline in PA cultures was found to greatly increase during the lag phase and early log phase of bacterial growth (3–6 h, 200–800 ppb), enabling early detection. Typically, 1-pyrroline produced by PA cultures could already be detected in our experiments after 0.5–4 h of incubation at the clinically relevant initial bacterial counts. A reference AMS screen of common infectious microbes from other genera, including Staphylococcus aureus , Staphylococcus epidermidis , Staphylococcus haemolyticus , Escherichia coli , Klebsiella pneumonia , Acinetobacter baumannii , Enterococcus faecalis , Klebsiella oxytoca , Candida albicans , Candida tropicalis , Candida parapsilosis , Enterococcus faecalis , Enterobacter cloacae , did not reveal a notable release of 1-pyrroline. Our results indicate the high suitability of volatile 1-pyrroline for the early and reliable diagnosis of Pseudomonas infections using commonly available MS instrumentation.