Search of antimicrobial lactic acid bacteria from Salmonella-negative dogs.

Abstract

BACKGROUND: Salmonellosis is one of the most important food-borne zoonotic disease affecting both animals and humans. The objective of the present study was to identify gastrointestinal (GI) lactic acid bacteria (LAB) of canine-origin from Salmonella-negative dogs' faeces able to inhibit monophasic Salmonella&#xa0;Typhimurium previously isolated from dogs' faeces, in order to be used as a potential probiotic in pet nutrition. RESULTS: Accordingly, 37 LAB were isolated from Salmonella-negative dogs' faeces and tested against monophasic S. Typhimurium using the spot on lawn method out of which 7 strains showed an inhibition halo higher than 2.5&#x2009;cm. These 7 strains were also tested with the co-culture method and one showed the greatest inhibition value (p&#xa0;<&#x2009;0.05). Subsequently, the isolate was identified through 16S rRNA sequencing and sequence homology and designated as Ligilactobacillus salivarius (L. salivarius). LAB from Salmonella-positive dogs were also identified and none was the selected strain. Finally, to identify the mechanism of inhibition of L. salivarius, the supernatant was analyzed, and a dose response effect was observed. CONCLUSIONS: It is concluded that the canine-origin L. salivarius, could possess some in vitro functional attributes of a candidate probiotic and could prevent monophasic&#xa0;S. Typhimurium colonization or inhibit its activity if the infection occurs.