Lactic acid bacteria capable of inhibiting Campylobacter coli in vitro

BERISIVIL, A.P.; ROMERO SCHARPEN, A.; BLAJMAN, J.E.; ZIMMERMANN, J.A.; FUHR, E.M.; ROSMINI, M.R.; FRIZZO, L.S.; SIGNORINI, M.L.

Tucumán

Simposio; SIBAL 2016 - V Simposio Internacional de Bacterias Lácticas; 2016

Centro de Referencia para Lactobacilos (CERELA) - CONICET

Thermophilic Campylobacter (TC) are commensal microorganisms of birds, including poultry, and the subspecie C. coli is one of the most common bacterial causes of human intestinal diseases. The reduction of TC in poultry would decrease the risk of infection for consumers. Probiotics, including lactic acid bacteria (LAB), can help to improve the intestinal microbial balance and therefore, decrease the capability of Campylobacter to colonize and grow in the chicken caeca during primary production. The aim of this study was evaluate the anti-Campylobacter coli activity of cell-free culture supernatant (CSF) of eleven LAB of avian origin with probiotics capacities. Inhibition activity was evaluated by the well diffusion test. Lactobacillus strains (L. salivarius DSPV001P, DSPV002P, DSPV003P, DSPV006P, DSPV007P, DSPV008P, DSPV010P y DSPV011P, L. agilis DSPV004P, DSPV005P y DSPV009P) were cultured in deMan, Rogosa and Sharpe (MRS) broth at 37ºC for 24 h. Lactobacillus cultures were harvested and the supernatants were divided in CSF neutralized (CSFn, adjustment the cell-free supernatant to pH of 7.0 with 3N NaOH) and CSF unneutralized (CSFun). Suspensions of four C. coli isolated of chickens with different pulse types obtained by PFGE (pulsed-field gel electrophoresis) were used. C. coli were incubated in nutritive agar for 48 h in a microaerophilic environment. The microbial suspension with a concentration of 107 CFU/ml of Campylobacter was added to 15 ml of nutritive agar (0,8% agar) and plated. Five mm-wells were punched on the agar, and 35 µl of CSFn and CSFun of each strain of LAB was added into the holes. Lactic acid diluted ¼ was used as the positive control. Plates were incubated for 48 h at 37ºC under microaerophilic conditions and the diameter of the inhibition zone around each well was measured. The trial was replicated three times. In all the cases the antagonic effect was observed both CSFn and CSFun against four C. coli, which indicated that activity, was probably not exerted only by pH. Six BAL showed halos of inhibition equal or higher to 15 mm against at least 2 C. coli. Of these six, only L. salivarius DSPV006P and L. salivarius DSPV011P showed this behavior against the 4 C. coli. In conclusion, L. salivarius DSPV006P y L. salivarius DSPV011P showed the best inhibition capabilities against growth of C. coli in this study. Therefore, tests will be conducted to assess the presence the other inhibitory substances as the production of hydrogen peroxide and / or bacteriocins produced by LAB.