ORIGINAL RESEARCH article
Front. Cell. Infect. Microbiol.
Sec. Antibiotic Resistance and New Antimicrobial drugs
This article is part of the Research TopicPerspectives in Antibiotic Resistance and New Antimicrobial Drugs: 2025View all 8 articles
Correlation of OXA-1 and TEM-1 Genes with Antibiotic Resistance to Piperacillin/Tazobactam in ESBL-Producing Enterobacterales: Insights from a Multi-Center Analysis
Provisionally accepted
- 1Tripler Army Medical Center, Tripler Army Medical Center, United States
- 2Cepheid, Sunnyvale, United States
- 3United States Military Academy at West Point, West Point, United States
- 4William Beaumont Army Medical Center, El Paso, United States
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Background The emergence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae presents significant challenges in treating infections caused by these pathogens. This multi-center retrospective study investigated the prevalence of OXA-1 and TEM-1 genes in ESBL-producing E. coli and K. pneumoniae, along with their association with piperacillin/tazobactam susceptibility and additional antimicrobial resistance genes. Methods Clinical isolates were collected from three institutions as part of routine patient care: Tripler Army Medical Center (TAMC) in Hawaii, Madigan Army Medical Center (MAMC) in Washington, and Brooke Army Medical Center (BAMC) in Southern Texas. A total of 416 isolates were analyzed through genome sequencing and CLSI-guided susceptibility testing. Results OXA-1 and TEM-1 β-lactamase enzymes were present in 20.9% (73/349) and 38.7% (135/349) of the E. coli isolates, respectively. Relative risk analysis of non-susceptibility to piperacillin/tazobactam across isolates from the three study sites revealed a highly significant association for OXA-1 (P < 0.001), whereas no significant associations were observed for TEM-1 (P = 0.424) or the combination of OXA-1 and TEM-1 (P = 0.082). When analyzed by institution, the relative risk of non-susceptibility to piperacillin/tazobactam remained highly significant for OXA-1 at TAMC and MAMC (P < 0.001 for both) but was not significant at BAMC (P = 0.21). OXA-1 and TEM-1-positive variants showed a significant association with genes conferring resistance to other antibiotics. Conclusions The OXA-1 gene plays a key role in resistance to piperacillin/tazobactam in ESBL-producing organisms, with geographic differences in non-susceptibility observed. Genetic profiling and localized data are crucial for optimizing antibiotic therapy and improving treatment outcomes.
Keywords: ESBL - Extended-spectrum beta-lactamase, OXA-1, TEM-1, Enterobacterales , antimicrobial resist ance
Received: 12 Sep 2025; Accepted: 18 Dec 2025.
Copyright: © 2025 Kamau, Wong, MacArthur and Dombach. 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:
Edwin Kamau
Jamie L Dombach
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