AUTHOR=Tazehabadi Mahtab Hassanpour , Algburi Ammar , Popov Igor V. , Ermakov Alexey M. , Chistyakov Vladimir A. , Prazdnova Evgeniya V. , Weeks Richard , Chikindas Michael L. 

TITLE=Probiotic Bacilli Inhibit Salmonella Biofilm Formation Without Killing Planktonic Cells

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.615328

DOI=10.3389/fmicb.2021.615328

ISSN=1664-302X

ABSTRACT=<p>Salmonellosis is a foodborne infection caused by <italic>Salmonella.</italic> Domestic poultry species are one of the main reservoirs of <italic>Salmonella</italic>, which causes the foodborne infection salmonellosis, and are responsible for many cases of animal-to-human transmission. Keeping backyard chickens is now a growing trend, increasing the frequency of direct contact with the flock and, by consequence, the incidence of <italic>Salmonella</italic> infections. <italic>Bacillus subtilis</italic> KATMIRA1933 and <italic>Bacillus amyloliquefaciens</italic> B-1895 are probiotic bacilli that produce the bacteriocins subtilosin A and subtilin, respectively. The antimicrobial activity of the two strains was determined against the reference strain <italic>Micrococcus luteus</italic> ATCC 10420. The cell-free supernatant of <italic>B. subtilis</italic> KATMIRA1933 inhibited biofilm formation by <italic>Salmonella enterica</italic> subsp. <italic>enterica</italic> serovar Hadar, <italic>Salmonella enterica</italic> subsp. <italic>enterica</italic> serovar Enteritidis phage type 4, and <italic>Salmonella enterica</italic> subsp. <italic>enterica</italic> serovar Thompson by 51.1, 48.3, and 56.9%, respectively. The cell-free supernatant of <italic>B. amyloliquefaciens</italic> B-1895 inhibited the biofilm formation of these <italic>Salmonella</italic> strains by 30.4, 28.6, and 35.5%, respectively. These findings suggest that the bacillus strains may have the potential to be used as probiotics and antibiotic alternatives for the control of <italic>Salmonella</italic> in poultry. The number of planktonic cells was unaffected by treatment with the cell-free supernatant. A co-culture of the <italic>Salmonella</italic> strains with either bacilli showed no signs of growth inhibition, suggesting that it might have been quorum sensing that is affected by the two <italic>Bacillus</italic> strains.</p>