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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, RESULTS. Meshes: Animals, Bacillus, Bacillus thuringiensis, Bacterial Proteins, DNA Fingerprinting, DNA, Bacterial, DNA, Ribosomal, Electrophoresis, Gel, Pulsed-Field, Enterotoxins, Heat-Shock Proteins, Milk, Pest Control, Biological, Polymerase Chain Reaction, RNA, Ribosomal, 16S, RNA-Binding Proteins, Soil Microbiology, Temperature.
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Do natural isolates of Bacillus thuringiensis display genetic and psychrotrophic properties characteristic of Bacillus weihenstephanensis? Context: To determine the potential of Bacillus thuringiensis, known primarily for its entomopathogenicity, to be a psychrotolerant contaminant of stored products. We determined the genetic properties and diversity of cold-adapted isolates of B. thuringiensis based on (i) the presence of cspA, a genetic determinant that confers psychrotolerance in Bacillus weihenstephanensis, (ii) 16S rRNA genes, and (iii) pulse-field gel electrophoretic (PFGE) genome profiles. We assessed the pathogenic potential of these isolates based on whether they harboured various combinations of known toxigenic-associated determinants (nheA, hblA, cytK). Of 36 nonclonal B. thuringiensis cultured from soil and milk, 21 harboured cspA, and of these, 16 (76%) were psychrotolerant and possessed genetic signatures typical of psychrotrophic Bacillus species. The majority of psychrotolerant isolates contained various combinations of nheA, hblA, and cytK.
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Our results show that natural isolates of psychrotolerant B. thuringiensis occur in soil and milk, and suggest that psychrotolerance is determined by cspA. Final Decision: yes