Phenotypic and Genotypic Characterization of Two Lactic Acid Bacterial Strains Previously Isolated from Traditional Filipino Fermented Foods for Antibiotic Resistance

Abstract

Lactic acid bacteria (LABs) are generally considered as safe (GRAS) and are being utilized in the food industry as a biopreservative and probiotic. However, the prevalence of antibiotic resistance genes in food-associated LABs has become a public health hazard due to its possible transmission through functional foods. This study aimed to screen Lactiplantibacillus plantarum BS25 and Pediococcus acidilactici 3G3 isolated from fermented rice-shrimp mixture (balao-balao) and fermented pork, respectively, for their phenotypic and genotypic antibiotic resistance profiles. Kirby-Bauer disk diffusion method was used to determine the susceptibility of strains to different antibiotics, and a conventional polymerase chain reaction was used to detect antibiotic resistance genes. L. plantarum BS25 exhibited resistance against clindamycin, norfloxacin, streptomycin, tobramycin, and trimethoprim-sulfamethoxazole. Similarly, P. acidilactici 3G3 was resistant to ceftazidime, erythromycin, streptomycin, tobramycin, and trimethoprim-sulfamethoxazole. This study screened ten antibiotic resistance genes (ARGs), namely, aphA-2, blaIMP, blaTEM, ermB, linB, mefE, parC, rrs, sul2, and tetM. Of the 10 ARGs, only aphA-2, blaIMP, and blaTEM were amplified by L. plantarum BS25, and none for P. acidilactici 3G3. Only blaIMP was successfully amplified in the plasmid DNA of L. plantarum BS25. These findings underscore the potential role of such strains in fueling the emergence and dissemination of multi-drug resistant pathogenic strains. The identification and characterization of antibiotic resistance genes emphasize the urgent need for enhanced surveillance, prudent use of antibiotics, and the implementation of effective strategies to mitigate the risk of multi-drug resistance.