Antibiotic resistance of probiotic strains of lactic acid bacteria isolated from marketed foods and drugs.
OBJECTIVE
To identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probiotics.


METHODS
Antimicrobial susceptibility of 41 screened isolates was tested with disc diffusion and E-test methods after species-level identification. Resistant strains were selected and examined for the presence of resistance genes by PCR.


RESULTS
Distribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, tetracycline, ampicillin, amoxicillin/clavulanic acid, cephalothin, and imipenem. In addition, isolates resistant to vancomycin, rifampicin, streptomycin, bacitracin, and erythromycin were detected, although the incidence of resistance to these antibiotics was relatively low. In contrast, most strains were resistant to ciprofloxacin, amikacin, trimethoprim/sulphamethoxazole, and gentamycin. The genes msrC, vanX, and dfrA were detected in strains of Enterococcus faecium, Lactobacillus plantarum, Streptococcus thermophilus, and Lactococcus lactis.


CONCLUSIONS
Antibiotic resistance is present in different species of probiotic strains, which poses a threat to food safety. Evaluation of the safety of lactic acid bacteria for human consumption should be guided by established criteria, guidelines and regulations.
Liu
Chang
C
Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
Zhang
Zhuo-Yang
ZY
Dong
Ke
K
Yuan
Jian-Ping
JP
Guo
Xiao-Kui
XK
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D043302:Cultured Milk Products / Q000382:microbiology; D003611:Dairy Products; D004340:Drug Contamination; D024901:Drug Resistance, Multiple, Bacterial; D005516:Food Microbiology; D006801:Humans; D007777:Lactobacillaceae / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D004364:Pharmaceutical Preparations; D019936:Probiotics
D000900:Anti-Bacterial Agents; D004364:Pharmaceutical Preparations