Antimicrobial resistance of Lactobacillus spp. from fermented foods and human gut

A total of 122 Lactobacillus strains were isolated from household-prepared or commercial yogurts and pickles in Sichuan, among which 15 representative strains, along with another 37 strains isolated from human guts, were analyzed for their antimicrobial resistance (AMR) to 17 clinically significant antimicrobials applied in China by agar dilution method. The correlation of AMRs in Lactobacillus plantarum from fermented foods and human gut was examined. The AMRs varied with Lactobacillus species. For L. plantarum, the distributions of minimum inhibitory concentration to 12 antimicrobials were correlated between food and gut source (P < 0.05), and the percentages of resistant strains from foods and gut were also similar (P > 0.05) except to norfloxacin, where the AMR was more severe in gut than in foods (P < 0.05), while all 14 high-level vancomycin-resistant strains were from gut. Illustrated by L. plantarum, the severity of resistance to most antimicrobials in lactobacilli from fermented foods and human gut gradually converged, with gut ones taking the leading role. Accordingly, AMR in human gut lactobacilli was more likely the consequence of clinical medication instead of acquired from fermented foods. Lactobacillus strains widely utilized in fermented foods would unlikely aggravate their AMR in human guts.