An investigation of the autochthonous lactic acid bacteria susceptibility to different antibiotics

Bakterije mliječne kiseline (BMK) su važne starter kulture u prehrambenoj industriji, a pojedini predstavnici su definirani i kao probiotici. Povećana primjena antibiotika utjecala je na širenje antibiotičke rezistencije, stoga su istraživanja osjetljivosti potencijalnih probiotičkih sojeva na antibiotike dio općih izbornih kriterija u okviru strogo definiranog probiotičkog koncepta. U ovom radu je provedena karakterizacija pojedinih sojeva autohtone populacije bakterija mliječne kiseline (BMK), izoliranih iz tradicionalno proizvedenog sira, kao probiotičkih starter kultura. Iz svježeg sira odabrano je 19 različitih autohtonih izolata koji su identificirani kao predstavnici BMK, te je ispitana njihova osjetljivost na različite antibiotike metodom difuzije u agaru s filter diskovima. Svi ispitivani sojevi su osjetljivi na ampicilin, bacitracin, kloramfenikol, klindamicin, eritromicin, gentamicin, novobiocin i penicilin G. Kod autohtonih izolata označenih kao BGGO7 i BGG011 nije bila prisutna zona inhibicije rasta nakon primjene vankomicina i streptomicina. U konačnici se može zaključiti da se osjetljivost pojedinog autohtonog izolata na određeni antibiotik razlikuje ovisno o soju mikroorganizma, te je potrebno provesti detaljnije analize.Lactic acid bacteria are important starter cultures in food industry and some representatives are also defined as probiotics. The uncontrolled use of antibiotics had influenced on a spreading of antibiotic resistance, hence the testing of the susceptibility of potential probiotic strains to antibiotics is an important general selective criterion inside the probiotic concept investigations. In this study the characterization of the several autochthonous lactic acid bacteria (LAB) isolates was undertaken in order to select potential probiotic starter cultures isolated from traditionally made cheese. 19 different autochthonous isolates identified as representatives of LAB were selected and their susceptibility to different antibiotics was tested by filter disc assay method. All tested strains were susceptible to ampicillin, bacitracin, chlorampheniol, clindamycin, erytromycin, novobiocin and penicillin G. The zone diameter indicating the inhibition of bacteria growth was absent for the all autochthonous isolated from group BGGO7 and BGG011 when vancomycin and streptomycin were tested. Finally, the susceptibility to the specific antibiotic was variable and depending on the species, hence more detailed analysis would be undertaken