Alarming Antibiotic Resistance of Lactobacilli Isolated from Probiotic Preparations and Dietary Supplements

Abstract

In this study, we screened eight commercially available brands of Lactobacillus-containing probiotic preparations and dietary supplements for resistance towards commonly administered antibiotics of different classes. According to disc diffusion results, most of the isolates were resistant to vancomycin and susceptible to penicillin-type antibiotics (ampicillin and amoxicillin), carbapenems (imipenem, meropenem, and ertapenem), and inhibitors of protein synthesis (chloramphenicol, erythromycin, tetracycline, clarithromycin, and linezolid). However, based on minimum inhibitory concentration (MIC) values, six strains were reconsidered as resistant to tetracycline. All tested lactobacilli were resistant towards amikacin, ciprofloxacin, and norfloxacin. Resistance to cephalosporins was highly variable and decreased in the following order: ceftazidime/cefepime, ceftriaxone, cefotaxime, cefazolin, and cefoperazone. PCR screening for antibiotic resistance determinants in probiotic lactobacilli revealed a wide occurrence of vancomycin resistance gene vanX, ciprofloxacin resistance gene parC, and extended-spectrum β-lactamase gene blaTEM. We also detected the tetK gene for tetracycline resistance in one isolate. Additionally, we identified discrepancies between the claims of the manufacturers and the identified species composition, as well as the enumerated amount of viable bacteria, for several products. The results of this study raise concerns about the safety of lactobacilli for human consumption as probiotics, as they may act as reservoirs of transferable antibiotic resistance genes.

Anti-oral cancer properties of potential probiotic lactobacilli isolated from traditional milk, cheese, and yogurt

“…The observation that all four isolates were resistant to azithromycin and trimethoprim-sulfamethoxazole raises concerns, as these antibiotics are widely used for various clinical indications. This resistance pattern aligns with findings reported in recent studies, such as the work by Anisimova et al 24 , where increased resistance of Lactobacillus strains to macrolides and sulfonamides was documented.…”

Immunomodulatory Activity on Human Macrophages by Cell-Free Supernatants to Explore the Probiotic and Postbiotic Potential of Lactiplantibacillus plantarum Strains of Plant Origin

“…The antibiotic susceptibility is a safety aspect that has to be considered in the evaluation of candidate probiotics. Overall, the antibiotic resistance pattern, observed here at the phenotypic level, mirrors that known for other lactobacilli [ 76 , 77 ]. Like other LAB, L. plantarum meets the criteria established by EFSA for Qualified Presumption of Safety (QPS) [ 28 ]; moreover, it is generally recognised as safe (GRAS) by the US FDA (U.S. Food and Drug Administration.…”

Gamma-Aminobutyric Acid (GABA) Producing Lactobacillus plantarum TSUB-17 and Probiotic Properties for Using as Probiotics Additive in Swine Feed

“…A previous study reported that lactobacilli isolate from commercial probiotic products showed a high resistance rate of approximately 54.83 % [43]. Consistent with studies of Lactobacillus isolated from probiotics in dietary supplements showing 100 % resistance to norfloxacin [44]. It has been reported that the resistance mechanism to norfloxacin is naturally or intrinsically resistant.…”

“…The most efficient GABA producers lactobacilli, were L. brevis [16,46], and L. plantarum [44]. This according to the previous report indicated the major source of GABA producing probiotic bacteria was lactic acid bacteria especially L. brevis and L. plantarum.…”