InhA1, NprA, and HlyII as candidates for markers to differentiate pathogenic from nonpathogenic Bacillus cereus strains.
Bacillus cereus is found in food, soil, and plants, and the ability to cause food-borne diseases and opportunistic infection presumably varies among strains. Therefore, measuring harmful toxin production, in addition to the detection of the bacterium itself, may be key for food and hospital safety purposes. All previous studies have focused on the main known virulence factors, cereulide, Hbl, Nhe, and CytK. We examined whether other virulence factors may be specific to pathogenic strains. InhA1, NprA, and HlyII have been described as possibly contributing to B. cereus pathogenicity. We report the prevalence and expression profiles of these three new virulence factor genes among 57 B. cereus strains isolated from various sources, including isolates associated with gastrointestinal and nongastrointestinal diseases. Using PCR, quantitative reverse transcriptase PCR, and virulence in vivo assays, we unraveled these factors as potential markers to differentiate pathogenic from nonpathogenic strains. We show that the hlyII gene is carried only by strains with a pathogenic potential and that the expression levels of inhA1 and nprA are higher in the pathogenic than in the nonpathogenic group of strains studied. These data deliver useful information about the pathogenicity of various B. cereus strains.
Cadot
Céline
C
INRA, Unité MICALIS, GME, La Minière, Guyancourt, France.
Tran
Seav-Ly
SL
Vignaud
Marie-Léone
ML
De Buyser
Marie-Laure
ML
Kolstø
Anne-Brit
AB
Brisabois
Anne
A
Nguyen-Thé
Christophe
C
Lereclus
Didier
D
Guinebretière
Marie-Hélène
MH
Ramarao
Nalini
N
D000818:Animals; D001409:Bacillus cereus / Q000145:classification* / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D001431:Bacteriological Techniques / Q000379:methods*; D002460:Cell Line; D020869:Gene Expression Profiling; D006801:Humans; D007814:Larva / Q000382:microbiology; D007915:Lepidoptera / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D016133:Polymerase Chain Reaction; D015995:Prevalence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis; D037521:Virulence Factors / Q000235:genetics*
D001427:Bacterial Toxins; D037521:Virulence Factors