Bacillus cereus NVH 0500/00 Can Adhere to Mucin but Cannot Produce Enterotoxins during Gastrointestinal Simulation

Tsilia, Varvara; Kerckhof, Frederiek‐Maarten; Rajković, Andreja; Heyndrickx, Marc; Wiele, Tom Van de

doi:10.1128/aem.02940-15

Cited by 15 publications

(17 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This disagrees with prior studies in which NheB could not be detected in the supernatant of four B. cereus strains after they had been incubated in the presence of PGM (13,14). The authors concluded that Nhe was not detected due to insufficient bacterial concentrations or toxin degradation (13). In contrast to that, our studies proved that toxins accumulate in the supernatant and that this effect is not limited to a single toxin component.…”

Section: Discussioncontrasting

confidence: 99%

See 1 more Smart Citation

Porcine Gastric Mucin Triggers Toxin Production of Enteropathogenic Bacillus cereus

et al. 2019

View full text Add to dashboard Cite

Enteropathogenic Bacillus cereus causes foodborne infections due to the production of pore-forming enterotoxins in the intestine. Before that, spores have to be ingested, survive the stomach passage, and germinate. Thus, before reaching epithelial cells, B. cereus comes in contact with the intestinal mucus layer. In the present study, different aspects of this interaction were analyzed. Total RNA sequencing revealed major transcriptional changes of B. cereus strain F837/76 upon incubation with porcine gastric mucin (PGM), comprising genes encoding enterotoxins and further putative virulence factors, as well as proteins involved in adhesion to and degradation of mucin. Indeed, PGM was partially degraded by B. cereus via secreted, EDTA-sensitive proteases. The amount of enterotoxins detectable in culture media supplemented with PGM was also clearly increased. Tests of further strains revealed that enhancement of enterotoxin production upon contact with PGM is broadly distributed among B. cereus strains. Interestingly, evidence was found that PGM can also strain-specifically trigger germination of B. cereus spores and that vegetative cells actively move toward mucin. Overall, our data suggest that B. cereus is well adapted to the host environment due to massive transcriptome changes upon contact with PGM, attributing mucin an important and, thus far, neglected role in pathogenesis.M ucus is a highly complex viscous substance that covers gastrointestinal cells.Besides salts, lipids, and several proteins involved in defense mechanisms, it consists mainly of water (approximately 95%) and the glycoprotein mucin (1, 2). A large number of different mucins has been discovered. These can be divided into membranebound and secretory mucins, which form the mucus layers (3, 4). Mucins have a molecular weight of 0.5 to 20 MDa and consist of ϳ20% proteins and ϳ80% carbohydrates (1). The protein core is organized in tandem repeats of serine-, threonine-, and proline-rich regions, which are mostly O-glycosylated. At the C and N termini, large amounts of cysteine are found. The carbohydrates include N-acetylgalactosamine, N-acetylglucosamine, N-acetylneuraminic acid, fucose, galactose, and mannose. Mucin monomers dimerize and multimerize via disulfide bonds (1).Mucus functions as a lubricant in the gastrointestinal tract, facilitating the passage of food. It is also important for growth, adhesion, and protection of the intestinal microbiota (2). Furthermore, it represents a biophysical barrier between epithelial cells and the environment, including chemical and mechanical insults as well as the commensal microbiota and pathogens (2,5,6). The mucus layer is a reservoir for many antimicrobial molecules, and various mucin oligosaccharides themselves show antimicrobial activity (5). By adhesion to mucin oligosaccharides, pathogens are trapped and removed due to the constant renewal of the mucus layer (5, 6). Cell surface-bound mucins can even initiate intracellular signaling in response to bacteria (5).On the other hand, pathogens, espe...

show abstract

Section: Discussioncontrasting

confidence: 99%

“…Little is known about the interaction of Bacillus cereus with the mucus layer or mucins. In vitro assays demonstrated adhesion of nonpathogenic and pathogenic B. cereus strains to porcine gastric mucin (PGM) (12)(13)(14). Furthermore, induction of fucosidase production suggests that B. cereus degrades and assimilates PGM (15).…”

mentioning

confidence: 99%

Porcine Gastric Mucin Triggers Toxin Production of Enteropathogenic Bacillus cereus

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Nevertheless, under in vivo conditions, bacteria and potentially toxins, generally penetrate the outer, loosely adherent layer [55]. This could play a protective effect against the degradation by proteases present in the lumen.…”

Section: Discussionmentioning

confidence: 99%

Screening of Cytotoxic B. cereus on Differentiated Caco-2 Cells and in Co-Culture with Mucus-Secreting (HT29-MTX) Cells

Castiaux

Laloux

Schneider

et al. 2016

Toxins

View full text Add to dashboard Cite

B. cereus is an opportunistic foodborne pathogen able to cause diarrhoea. However, the diarrhoeal potential of a B. cereus strain remains difficult to predict, because no simple correlation has yet been identified between the symptoms and a unique or a specific combination of virulence factors. In this study, 70 B. cereus strains with different origins (food poisonings, foods and environment) have been selected to assess their enterotoxicity. The B. cereus cell-free supernatants have been tested for their toxicity in vitro, on differentiated (21 day-old) Caco-2 cells, using their ATP content, LDH release and NR accumulation. The genetic determinants of the main potential enterotoxins and virulence factors (ces, cytK, entFM, entS, hbl, nhe, nprA, piplC and sph) have also been screened by PCR. This analysis showed that none of these genes was able to fully explain the enterotoxicity of B. cereus strains. Additionally, in order to assess a possible effect of the mucus layer in vitro, a cytotoxicity comparison between a monoculture (Caco-2 cells) and a co-culture (Caco-2 and HT29-MTX mucus-secreting cells) model has been performed with selected B. cereus supernatants. It appeared that, in these conditions, the mucus layer had no notable influence on the cytotoxicity of B. cereus supernatants.

show abstract

“…During the pathogenic process of bacteria, attachment to external surfaces of a host is an important initial step in the colonization and subsequent occurrence of infection (Tsilia, Kerckhof, Rajkovic, Heyndrickx, & Van de Wiele, ). Indeed, without adhesion to its host, V. alginolyticus might not be able to persist at the initial infection focus, which would result in the absence of colonization and disease (Balebona et al., ).…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, without adhesion to its host, V. alginolyticus might not be able to persist at the initial infection focus, which would result in the absence of colonization and disease (Balebona et al., ). Although bacterial adherence is one of the most active areas of study in the field of infectious diseases (Tsilia et al., ), the molecular mechanisms of V. alginolyticus adhesion have not been widely investigated.…”

Section: Introductionmentioning

confidence: 99%

mcp, aer, cheB, and cheV contribute to the regulation of Vibrio alginolyticus (ND‐01) adhesion under gradients of environmental factors

Huang

Wang

et al. 2017

MicrobiologyOpen

View full text Add to dashboard Cite

Adhesion is a key virulence factor of pathogens and can be affected by the environment. Our previously research with RNA‐seq indicated that mcp, aer, cheB, and cheV might play roles in the regulation of adhesion in Vibrio alginolyticus (ND‐01). In order to determine whether and how environmental factors affect adhesion through these genes, gene silencing was performed followed by quantitative real‐time PCR (qRT‐PCR), RNAi, transmission electron microscopy, and adhesion, capillary, and motility assays to verify how these genes influence adhesion. Silencing these genes led to deficiencies in adhesion, chemotaxis, flagellar assembly, and motility. The expression levels of cheA, cheW, and cheY, which are important genes closely related to the functions of mcp, aer, cheV, and cheB, were significantly downregulated in all of the RNAi groups. The expression of mcp, aer, cheV, and cheB under different gradients of temperature, pH, and salinity and after starvation for various durations was also detected, which showed that these genes were sensitive to certain environmental stresses, particularly pH and starvation. Our results indicated that mcp, aer, cheB, and cheV: (1) are necessary for ND‐01 adhesion; (2) play key roles in the bacterial chemotaxis pathway by controlling the expression of downstream genes; (3) might affect adhesion by impacting motility, though motility is not the only route through which adhesion is affected; and (4) contribute to the regulation of ND‐01 adhesion in natural environments with different temperatures, pH levels, and salinities as well as after various starvation periods.

show abstract

Bacillus cereus NVH 0500/00 Can Adhere to Mucin but Cannot Produce Enterotoxins during Gastrointestinal Simulation

Cited by 15 publications

References 44 publications

Porcine Gastric Mucin Triggers Toxin Production of Enteropathogenic Bacillus cereus

Porcine Gastric Mucin Triggers Toxin Production of Enteropathogenic Bacillus cereus

Screening of Cytotoxic B. cereus on Differentiated Caco-2 Cells and in Co-Culture with Mucus-Secreting (HT29-MTX) Cells

mcp, aer, cheB, and cheV contribute to the regulation of Vibrio alginolyticus (ND‐01) adhesion under gradients of environmental factors

Contact Info

Product

Resources

About