AUTHOR=Deforet Francis , Jehanne Quentin , Bénéjat Lucie , Aptel Johanna , Prat Roxane , Desbiolles Chloé , Ducournau Astrid , Jauvain Marine , Bonnet Richard , Vandenesch François , Lemoine Jérôme , Lehours Philippe 

TITLE=Combined genomic-proteomic approach in the identification of Campylobacter coli amoxicillin-clavulanic acid resistance mechanism in clinical isolates

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1285236

DOI=10.3389/fmicb.2023.1285236

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>Aminopenicillins resistance among <italic>Campylobacter jejuni</italic> and <italic>Campylobacter coli</italic> strains is associated with a single mutation in the promoting region of a chromosomal beta-lactamase <italic>bla<sub>OXA61</sub></italic>, allowing its expression. Clavulanic acid is used to restore aminopenicillins activity in case of <italic>bla<sub>OXA61</sub></italic> expression and has also an inherent antimicrobial activity over <italic>Campylobacter</italic> spp. Resistance to amoxicillin-clavulanic acid is therefore extremely rare among these species: only 0.1% of all <italic>Campylobacter</italic> spp. analyzed in the French National Reference Center these last years (2017–2022).</p></sec><sec><title>Material and methods</title><p>Whole genome sequencing with bioinformatic resistance identification combined with mass spectrometry (MS) was used to identify amoxicillin-acid clavulanic resistance mechanism in Campylobacters.</p></sec><sec><title>Results</title><p>A G57T mutation in <italic>bla<sub>OXA61</sub></italic> promoting region was identified in all <italic>C. jejuni</italic> and <italic>C. coli</italic> ampicillin resistant isolates and no mutation in ampicillin susceptible isolates. Interestingly, three <italic>C. coli</italic> resistant to both ampicillin and amoxicillin-clavulanic acid displayed a supplemental deletion in the promoting region of <italic>bla<sub>OXA61</sub></italic> beta-lactamase, at position A69. Using MS, a significant difference in the expression of Bla<sub>OXA61</sub> was observed between these three isolates and amoxicillin-clavulanic acid susceptible <italic>C. coli</italic>.</p></sec><sec><title>Conclusion</title><p>A combined genomics/proteomics approach allowed here to identify a rare putative resistance mechanism associated with amoxicillin-clavulanic acid resistance for <italic>C. coli.</italic></p></sec>