Enumeration and Identification of Lactobacillus and Bifidobacterium Species Isolated from Probiotic Food Supplements and Their Antibiotic Resistance

Abstract

This study aimed to evaluate the content of Lactobacillus spp. and Bifidobacterium spp. in ten probiotic food supplements, along with assessing the antibiotic resistance of isolated probiotic cultures. Thirteen isolates were identified to the species level using both phenotypic and molecular methods. Antibiotic resistance was determined using the disk diffusion method. Results indicated discrepancies between the labeled and actual viable bacterial counts, with two out of the ten products containing fewer viable bacteria than stated. Interestingly, none of the products labeled to contain monocultures of Bifidobacterium spp. actually contained bifidobacteria. Moreover, two products were found to be incompatible with the bacterial species claimed on their labels. Furthermore, all Lactobacillus and Bifidobacterium strains exhibited resistance to methicillin and vancomycin. Lactobacillus spp. strains showed resistance to cefazolin (37.5%) and ciprofloxacin (50%), while Bifidobacterium spp. strains were resistant to cefazolin (80%), clindamycin (20%), and ciprofloxacin (20%). These findings underscore the need for stringent quality control measures in the probiotic food supplement industry, particularly regarding bacterial content accuracy and monitoring antibiotic resistance. Further research is necessary to explore the implications of antibiotic resistance in probiotic strains and its potential impact on human health.