Natalia Drabińska1, Keith Hewett2, Paul White3, Matthew B Avison4, Raj Persad5, Norman M Ratcliffe2, Ben de Lacy Costello6. 1. Centre for Research in Biomedicine, University of the West of England, Frenchay, Bristol, United Kingdom; Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland. 2. Centre for Research in Biomedicine, University of the West of England, Frenchay, Bristol, United Kingdom. 3. Department of Engineering, Design and Mathematics, University of the West of England, Bristol, United Kingdom. 4. School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom. 5. Bristol Royal Infirmary and Bristol Urological Institute, Bristol, United Kingdom. 6. Centre for Research in Biomedicine, University of the West of England, Frenchay, Bristol, United Kingdom. Electronic address: Ben.DeLacyCostello@uwe.ac.uk.
Abstract
PURPOSE: Antibiotic resistance is widespread throughout the world and represents a serious health concern. There is an urgent need for the development of novel tools for rapidly distinguishing antibiotic resistant bacteria from susceptible strains. Previous work has demonstrated that differences in antimicrobial susceptibility can be reflected in differences in the profile of volatile organic compounds (VOCs) produced by dissimilar strains. The aim of this study was to investigate the effect of the presence of cephalosporin antibiotics on the VOC profile of extended spectrum beta-lactamase (ESBL) and non-ESBL producing strains of Escherichia coli. MATERIAL AND METHODS: In this study, VOCs from strains of Escherichia coli positive and negative for the most commonly encountered ESBL, CTX-M in the presence of cephalosporin antibiotics were assessed using solid-phase microextraction (SPME) coupled with a combined gas chromatography-mass spectrometry/metal oxide sensor (GC-MS/MOS) system. RESULTS: Our proof-of-concept study allowed for distinguishing CTX-M positive and negative bacteria within 2 h after the addition of antibiotics. One MOS signal (RT: 22.6) showed a statistically significant three-way interaction (p = 0.033) in addition to significant two-way interactions for culture and additive (p = 0.046) plus time and additive (p = 0.020). There were also significant effects observed for time (p = 0.009), culture (p = 0.030) and additive (p = 0.028). No effects were observed in the MS data. CONCLUSIONS: The results of our study showed the potential of VOC analysis using SPME combined with a GC-MS/MOS system for the early detection of CTX-M-producing, antibiotic-resistant E. coli, responsible for urinary tract infections (UTIs).
PURPOSE: Antibiotic resistance is widespread throughout the world and represents a serious health concern. There is an urgent need for the development of novel tools for rapidly distinguishing antibiotic resistant bacteria from susceptible strains. Previous work has demonstrated that differences in antimicrobial susceptibility can be reflected in differences in the profile of volatile organic compounds (VOCs) produced by dissimilar strains. The aim of this study was to investigate the effect of the presence of cephalosporin antibiotics on the VOC profile of extended spectrum beta-lactamase (ESBL) and non-ESBL producing strains of Escherichia coli. MATERIAL AND METHODS: In this study, VOCs from strains of Escherichia coli positive and negative for the most commonly encountered ESBL, CTX-M in the presence of cephalosporin antibiotics were assessed using solid-phase microextraction (SPME) coupled with a combined gas chromatography-mass spectrometry/metal oxide sensor (GC-MS/MOS) system. RESULTS: Our proof-of-concept study allowed for distinguishing CTX-M positive and negative bacteria within 2 h after the addition of antibiotics. One MOS signal (RT: 22.6) showed a statistically significant three-way interaction (p = 0.033) in addition to significant two-way interactions for culture and additive (p = 0.046) plus time and additive (p = 0.020). There were also significant effects observed for time (p = 0.009), culture (p = 0.030) and additive (p = 0.028). No effects were observed in the MS data. CONCLUSIONS: The results of our study showed the potential of VOC analysis using SPME combined with a GC-MS/MOS system for the early detection of CTX-M-producing, antibiotic-resistant E. coli, responsible for urinary tract infections (UTIs).