Probiotic Bacilli Inhibit Salmonella Biofilm Formation Without Killing Planktonic Cells

Abstract

Salmonellosis is a foodborne infection caused by Salmonella. Domestic poultry species are one of the main reservoirs of Salmonella, 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 Salmonella infections. Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens 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 Micrococcus luteus ATCC 10420. The cell-free supernatant of B. subtilis KATMIRA1933 inhibited biofilm formation by Salmonella enterica subsp. enterica serovar Hadar, Salmonella enterica subsp. enterica serovar Enteritidis phage type 4, and Salmonella enterica subsp. enterica serovar Thompson by 51.1, 48.3, and 56.9%, respectively. The cell-free supernatant of B. amyloliquefaciens B-1895 inhibited the biofilm formation of these Salmonella 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 Salmonella in poultry. The number of planktonic cells was unaffected by treatment with the cell-free supernatant. A co-culture of the Salmonella strains with either bacilli showed no signs of growth inhibition, suggesting that it might have been quorum sensing that is affected by the two Bacillus strains.

Potential Probiotic Bacillus subtilis Isolated from a Novel Niche Exhibits Broad Range Antibacterial Activity and Causes Virulence and Metabolic Dysregulation in Enterotoxic E. coli

“…It has been shown that CFS of Bacillus subtilis can inhibit enteric pathogens such as ETEC and Salmonella typ. [ 43 , 44 ]. However, in our study, CP9 appeared to display an antimicrobial effect via contact-dependent inhibition and, in parts, via metabolic influence.…”

Bacillus subtilis natto Derivatives Inhibit Enterococcal Biofilm Formation via Restructuring of the Cell Envelope

“…These findings support the idea that some derivatives present in B. subtilis natto supernatant may have antibiofilm activity against E. faecalis . Consistent with this idea, some derivatives of Bacillus species have been shown to inhibit the formation of biofilms by several bacterial pathogens ( Rivardo et al, 2009 ; Yoo et al, 2019 ; Tazehabadi et al, 2021 ). Rivardo et al (2009) found that biosurfactants secreted by B. subtilis and B. licheniformis can effectively inhibit biofilm formation of Escherichia coli and S. aureus .…”

“…This trait enables them to have higher acid tolerance and better stability during heat processing and low-temperature storage than other bacteria ( Elshaghabee et al, 2017 ). In addition, previous studies ( Piewngam et al, 2018 ; Tazehabadi et al, 2021 ) have shown that some Bacillus species possess the ability to inhibit the colonization and biofilm formation of pathogens via actions, such as interference with quorum-sensing signals, or production of antimicrobial agents, such as bacteriocin proteins. Piewngam et al (2018) found that probiotic Bacillus subtilis can produce the lipopeptide fengycin for decolonization of methicillin-resistant Staphylococcus aureus (MRSA) in mouse feces and intestines via interference with S. aureus agr quorum-sensing signaling.…”

“… Piewngam et al (2018) found that probiotic Bacillus subtilis can produce the lipopeptide fengycin for decolonization of methicillin-resistant Staphylococcus aureus (MRSA) in mouse feces and intestines via interference with S. aureus agr quorum-sensing signaling. Tazehabadi et al (2021) found that two bacteriocin-producing Bacillus probiotic strains, B. subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895, can inhibit the biofilm formation of several strains of the food-borne pathogen Salmonella enterica without killing planktonic S. enterica cells. Collectively, these studies support the idea that probiotic Bacillus species and their derivatives may have the potential to inhibit the biofilm formation ability of other pathogenic bacteria, such as E. faecalis .…”

Effect of dietary direct-fed microbial and yeast cell walls on cecal digesta microbiota of layer chicks inoculated with nalidixic acid resistant Salmonella Enteritidis

“…Reduction of SE attachment to the intestinal epithelial cells by cultured medium from B. subtilis NC11 was also reported by Thirabunyanon and Thongwittaya (2012) . A recent study revealed that Bacillus strains have the potential to inhibit SE biofilm formation by producing the bacteriocin subtilosin A and subtilin ( Tazehabadi et al., 2021 ). These direct SE exclusion mechanisms may contribute to the SE at 3 dpi in this trial.…”