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Putative virulence factor expression by clinical and food isolates of Bacillus spp. after growth in reconstituted

N J Rowan1, K Deans, J G Anderson

  • 1Department of Bioscience, University of Strathclyde, Glasgow, Scotland. n.j.rowan@strath.ac.uk

Applied and Environmental Microbiology
|August 30, 2001
PubMed

Insights

Certain Bacillus species from clinical and food samples exhibit virulence factors like cytotoxicity and invasion, particularly after growth in infant milk formula (IMF). This highlights their potential medical significance.

Area of Science:

  • Microbiology
  • Food Safety
  • Clinical Science

Background:

  • Bacillus species are found in clinical and food environments.
  • Virulence factors in Bacillus species can pose health risks.
  • Infant milk formula (IMF) is a potential growth medium for these bacteria.

Purpose of the Study:

  • To assess the virulence potential of Bacillus species isolated from clinical and food samples.
  • To investigate the impact of infant milk formula (IMF) on bacterial virulence.
  • To identify the expression of specific enterotoxins in Bacillus isolates.

Main Methods:

  • Culturing 47 Bacillus strains (14 species) in reconstituted IMF.
  • Assessing bacterial adherence, invasion, and cytotoxicity on HEp-2 and Caco-2 cell lines.
  • Utilizing PCR and reversed passive latex agglutination (RPLA) for enterotoxin detection.

Main Results:

  • 81% of strains were cytotoxic, 91% adhered to cells, and 49% invaded cells.
  • Clinically derived Bacillus species showed higher invasion rates than food-derived ones.
  • Some Bacillus species expressed hemolysin BL (HBL) enterotoxin after growth in IMF.

Conclusions:

  • Several Bacillus species from clinical and food sources possess virulence factors.
  • Growth in IMF can enhance bacterial invasion.
  • These findings indicate potential medical significance for these Bacillus species.

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