Skip to main content

BRIEF RESEARCH REPORT article

Front. Cell. Infect. Microbiol.
Sec. Antibiotic Resistance and New Antimicrobial drugs
Volume 14 - 2024 | doi: 10.3389/fcimb.2024.1447933

FosA3 emerging in clinical carbapenemases-producing C. freundii

Provisionally accepted
Vittoria Mattioni Marchetti Vittoria Mattioni Marchetti 1,2*Irene Venturelli Irene Venturelli 3Tiziana Cassetti Tiziana Cassetti 3Marianna Meschiari Marianna Meschiari 4Roberta Migliavacca Roberta Migliavacca 2Ibrahim Bitar Ibrahim Bitar 5
  • 1 University of Pavia, Pavia, Italy
  • 2 Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Lombardy, Italy
  • 3 Dipartimento di sanità pubblica, AUSL Modena, Modena, Lombardy, Italy
  • 4 University Hospital of Modena, Modena, Italy
  • 5 Department of Microbiology, Faculty of Medicine, University Hospital in Pilsen, Charles University, Pilsen, Czechia, Pilsen, Plzeň, Czechia

The final, formatted version of the article will be published soon.

    Fosfomycin (FOS) is an effective antibiotic against multidrug-resistant Enterobacterales, but its effectiveness against is reducing. Little is known on the current prevalence of FosA enzymes in lowrisk pathogens, as Citrobacter freundii. The aim of the study was the molecular characterization of a carbapenemases-and FosA-producing C. freundii collected in Italy. AK867, collected in 2023, showed an XDR profile, retaining susceptibility only to colistin. AK867 showed a FOS MIC>128 mg/L by ADM. Based on WGS, AK867 belonged to ST116 and owned a wide resistome, including fosA3, blaKPC-2 and blaVIM-1. The fosA3 was carried by a conjugative pKPC-CAV1312 plasmid of 320,480 bp, on a novel composite transposon (12,907 bp). FosA3 transposon shared similarities with other fosA3-harboring pKPC-CAV1312 plasmids among Citrobacter spp.. We report the first case of FosA3 production in clinical carbapenemase-producing C. freundii ST116. The incidence of FosA3 enzymes is increasing among Enterobacterales, affecting even low-virulence pathogens, as C. freundii.

    Keywords: Fosfomycin, Citrobacter freundii, carbapenemases, Fosfomycin resistance, fosA3 gene

    Received: 12 Jun 2024; Accepted: 12 Jul 2024.

    Copyright: © 2024 Mattioni Marchetti, Venturelli, Cassetti, Meschiari, Migliavacca and Bitar. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Vittoria Mattioni Marchetti, University of Pavia, Pavia, Italy

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.