Document Type : New and original researches in the field of Microbiology.
Authors
Department of Biology, College of Science, University of Babylon, Babylon, Iraq
Abstract
Background: Bacillus spp., including pathogenic strains such as B. cereus, produce enterotoxins (e.g., non-hemolytic enterotoxin (NHE) and EntFM) associated with food poisoning and diarrheal diseases in humans. These bacteria are ubiquitous in the soil, water, food, and hospital environments. Objective: This study aims to determine the prevalence of virulence genes (nheA, nheB, nheC, entFM) in Bacillus spp. isolated from environmental and food sources in Babylon, Iraq. Methodology: From October 2024 to March 2025, 125 samples (soil, water, vegetables, and hospital environments) were collected from Babylon. Sixteen Bacillus isolates were identified using microbiological methods and 16S rRNA sequencing. DNA was extracted using (FavorPrep kit), and virulence genes were detected by PCR. Results: Genes encoding nonhemolytic enterotoxin (NHE) nheA, nheB, and nheC were identified in six (37. 5%),7 (43.75%), and 5 (31.25%) of Bacillus spp isolates, respectively, and 7 (43.75%) Bacillus spp. isolates tested were positive for entFM gene. Additionally, three (19%) of isolates did not contain any of the included genes. gene clusters were identified: nheBC (19%) and nheAB (13%). None of the isolates harbored nheABC or nheAC. Species distribution: B. cereus (56.25%, 9/16), B. subtilis (18.75%, 3/16), B. tropicus (6.25%, 1/16), B. arachidis (6.25%, 1/16), and unclassified Bacillus spp. (12.5%, 2/16). Conclusion: Bacillus spp. isolates from vegetables, soil, water, and hospital sources in Babylon harbor diarrheagenic toxin genes (nheA, nheB, nheC, entFM), with B. cereus being predominant. The presence of these virulence genes, particularly in food-related isolates, poses a significant risk for foodborne illnesses. Enhanced surveillance of vegetable and hospital environments is warranted to mitigate public health hazards.
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