Antibiotic Resistance of Beneficial Lactic Acid Bacteria Isolated from Smoked Salmon

Introduction: Lactobacillus spp., Pediococcus spp. and Enterococcus spp. are wide spread lactic acid bacteria (LAB) in fermented foods. Their potential as probiotic brings an interesting opportunity to explore them as tools for novel functional food products. However, before using beneficial strains in foods, it is necessary to verify their safety including their resistance to antimicrobials, a current concern in public health.

Purpose: This study aimed to investigate the antimicrobial resistance profile of LAB strains isolated from smoked salmon, previously characterized as potential probiotics.

Methods: Lb. curvatus ET06, ET30 and ET31, Lb. fermentum ET35, Lb. delbrueckii ET32, P. acidilactici ET34 and E. faeciumET05, ET12 and ET88 were isolated from smoked salmon, identified based on their biochemical and genetic characteristics (including 16s rRNA sequencing), and characterized as possessing probiotic characteristics. The strains were subjected to PCR to verify the presence of 23 genes related to antibiotic resistance, and also to resistance/sensitivity to 31 antibiotics.

Results: All tested LAB were sensitive to amikacin, metronidasole, oxacillin and vancomycin. Strains ET05, ET12, ET31, ET35 and ET34 were resistant to ciprofloxacin; ET05 to furazolidone; ET05, ET12, ET30, ET31, ET35, ET32 and ET34 to kanamycin; ET06 to nitrofurantion; ET05, ET31, ET32 and ET34 to tobramycin; ET05, ET30, ET31, ET35, ET32 and ET34 to trimethoprim. All tested LAB contained antibiotic resistance genes: 5 genes in ET06 and ET35; 6 genes in ET30, ET05 and ET34; 8 genes in ET31 and 9 genes in ET12, ET88 and ET32.

Significance: Despite the beneficial properties of the tested LAB, presence of antibiotic resistance genes are of concern as horizontal gene transfer to pathogenic bacteria hampers their application as probiotics cultures. Acknowledgments: CNPq, CAPES, FAPESP, FAPEMIG