Antibiotic resistance in wild and commercial non-enterococcal Lactic Acid Bacteria and Bifidobacteria strains of dairy origin: An update

Antibiotic Resistance is a growing concern for public health and global economy. Lactic acid bacteria (LAB) involved in the production of dairy products and commonly present in the agro-zootechnical environment can act as reservoirs of antibiotic resistance genes, acquiring or transferring them to other microorganisms. The review focuses on LAB group of dairy origin (Lactobacillus, Lactococcus, Streptococcus, Leuconostoc, Pediococcus and Weissella) and Bifidobacterium genus, considering its large use in dairy industry. We have analyzed data in the last 25 years, highlighting atypical resistance, genetic traits correlated to antibiotic resistance and their ability to be transmitted to other microorganisms; comparative analysis of resistomes was also considered. Differences were observed among wild strains isolated from different regions because of authorized antibiotic use. Commercial strains belonging to Lactobacillus, Streptococcus and Bifidobacterium currently used for industrial dairy products are frequently resistant to gentamycin, kanamycin, chloramphenicol together with tetracycline. The presence of resistant wild LAB in raw milk products has been significantly reduced as a result of worldwide restrictions on the use of antibiotics in animal husbandry. Transmissible resistances are still present in industrial cultures, despite the great effort of starter industries in the process control and the safety screening of commercial cultures.