Abstract: Psychrotolerant probiotic lactic acid bacteria were isolated from the guts of 7 cold-water fish species in Xinjiang and were analyzed for genetic structure differences according to the sequences of their 16S rRNA gene by rep-PCR fingerprint typing technology. The results showed that 15 strains of Carnobacterium were obtained, including 4 strains of C. maltaromaticum, 10 strains of C. divergens and 1 unidentified strain of Carnobacterium spp.. By the Oxford cup method, it was found that the metabolites of 8 of these strains had different inhibitory effects on three pathogens, and the strongest antibacterial effect was observed against Listeria monocytogenes. The fermentation supernatants of the 8 strains were subjected to exclusion of organic acids and hydrogen peroxide or protease treatment. After protease treatment, all the supernatants except BS-JYC-3 completely lost their antibacterial activity, indicating that the bacteriostatic substance in the fermentation supernatants may be a bacteriocin. Drug susceptibility tests showed that all of the 8 strains were very sensitive to ampicillin, minocycline and chloramphenicol, and moderately sensitive to gentamicin, tetracycline, rifampicin and teicoplanin.

Key words: cold-water fish intestine, Carnobacterium, fingerprint, inhibitory activity, antibiotics resistance