ORIGINAL RESEARCH article
Front. Vet. Sci.
Sec. Veterinary Pharmacology and Toxicology
Volume 12 - 2025 | doi: 10.3389/fvets.2025.1684650
Phenotypic and Genotypic Characterization of Probiotic Strains in the Context of Antimicrobial Resistance
Provisionally accepted
- 1Department of Pharmacology and Toxicology, University of Veterinary Medicine, Budapest, Hungary
- 2National Laboratory of Infectious Animal Diseases, Antimicrobial Resistance, Veterinary Public Health and Food Chain Safety, University of Veterinary Medicine Budapest, Budapest, Hungary
- 3One Health Institute, Faculty of Health Sciences, University of Debrecen, Debrecen, Hungary
- 4Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Budapest, Hungary
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Antimicrobial resistance (AMR) has emerged as a critical global public health concern, particularly with regard to microorganisms used as probiotics in both veterinary and human healthcare. The aim of this study was to characterize the phenotypic and genotypic resistance profiles of several industrially applied probiotic bacterial strains, with special emphasis on the presence of antimicrobial resistance genes (ARGs). Five strains, Enterococcus faecium, Bacillus licheniformis, Bacillus subtilis, Lactobacillus rhamnosus, and Pediococcus acidilactici were analyzed. Minimum inhibitory concentration (MIC) testing revealed resistance in multiple strains to clinically relevant antibiotics such as gentamicin, amoxicillin, tylosin, and florfenicol. Whole-genome sequencing identified 27 distinct ARGs, primarily associated with efflux pumps and target protection or modification mechanisms. The Bacillus licheniformis strain harbored the most diverse ARG profile, whereas no resistance genes were detected in Pediococcus acidilactici. These findings highlight the necessity of integrating phenotypic and genotypic assessments for the safe application of probiotic strains in animals and potentially human use.
Keywords: Probiotics1, Enterococcus2, Bacillus3, Lactobacillus4, Pediococcus5, antimicrobial resistance6, ARG7, Next-generation sequencing8
Received: 12 Aug 2025; Accepted: 17 Sep 2025.
Copyright: © 2025 Kerek, Palkovicsne Pezsa, Kaszab, Jerzsele and Farkas. 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: Adam Kerek, kerek.adam@univet.hu
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