STUDY OF ANTIBIOTIC RESISTANCE IN LACTIC ACID BACTERIA OF TECHNOLOGICAL IMPORTANCE

PETRELLI MARIA LUCIA; RAYA RAUL RICARDO; CECILIA RODRÍGUEZ

Tucumán, Argentina

Simposio; V Simposio internacional de Bacterias Lácticas; 2016

CERELA-CONICET

Although over several decades, studies on the emergence and spread of antibiotic resistance were mainly focused on clinically important bacteria, in recent years attention has been placed on bacteria associated with foods, because they may act as a reservoir of the antibiotic resistance determinants found in bacteria of clinical origin. Lactic acid bacteria (LAB) have technological properties that are widely used in the production and conservation of various fermented foods; also, the LAB are commonly found in the resident microbiota of the gastrointestinal tract of humans and animals. Furthermore, certain LAB species have potential probiotic properties. However, it has been described recently the presence and expression of antibiotic resistance genes in certain LAB associated with foods. The emergence of antibiotic resistance at global level and clinical impact representing its spread through the food chain, determine that the selection of microorganisms for use as a food additive should be pointing towards those without acquired genetic determinants of antibiotic resistance. Thus, the aim of this study was to characterize the antibiotic resistance of different Lactobacillus species, belonging to the Cerela culture collection (CRL), that were selected for their excellent technological properties and potential biotechnological use. A screening of sensitivity against seven antibiotics of clinically and veterinary importance was performed using 30 selected strains (10 LAB species) in LSM broth (MH 90% and MRS 10%, v/v). The antibiotic concentrations were employed according to the breakpoints for each bacterial species established by EFSA. Among the resistant strains, the presence and nature of the antibiotic resistance genes was confirmed by PCR amplification and sequencing of the amplicons. Tetracycline (83%), chloramphenicol (90%) and kanamycin (93%) were the most frequently antibiotic resistance detected at high levels of resistance. Also, resistance to ampicillin (70%), erythromycin (73%), streptomycin (88%), kanamycin (93%) and gentamicin (96.6%) were detected, but at low levels. The analysis in 2 out of 25 tetracycline resistant strains (L. casei CRL 706 and L. sakei CRL 1469) indicated that the resistance mechanisms were mediated by tet(M). Our results strength the need to evaluate strategies for a better control of LAB strains in probiotic products and for the rational use of antibiotics.