Screening for genes Encoding Virulence Factor in Salmonella serovar Typhimurium isolated from Tiger nut Juice

Abstract

Background: Tiger nut juice is a popular non-alcoholic beverage in Nigeria, but it can be contaminated with bacteria that pose a risk to consumers. A study in Ogbete market, South Eastern Nigeria, aimed to identify virulence genes in Salmonella enterica subsp. enterica serovar Typhimurium found in tiger nut juice to assess the potential health threat.

Materials and Methods: Fifty tiger nut juice with codes ATC1, MECB2, BNC3, CHA4, ERT5, TYR6, VMA7, EKA8, TMM9, and ORU10 were randomly purchased from Ogbete market vendors. Standard microbiological techniques and Polymerase Chain Reaction (PCR) were used to screen the samples for S. Typhimurium presence and its virulence genes including invA, spvB, pefA, csgA, orgA, msgA, spaN, spiA, spvC, sipB, and sefA.

Results: Our study found that 48.0% of the samples tested positive for S. Typhi. S. Typhi positive culture rates varied by sample location: ATC1 (10%), MECB2 (4.0%), BNC3 (6.0%), CHA4 (2.0%), ERT5 (8.0%), TYR6 (0.0%), VMA7 (6.0%), EKA8 (0.0%), TMM9 (8.0%), ORU10 (6.0%). PCR amplification of the virulence gene showed the presence of invA, spvB, pefA and csgA in all isolates. S. Typhimurium isolates from samples TYR6, VMA7, EKA8, TMM9, and ORU10 lacked orgA and msgA genes. Other virulence genes identified include spaN (40-100%), spiA (40-100%), spvC (25-100%), sipB (20-100%), and sefA (100%).

Conclusion: Our findings reveal that tiger nut juice contained Salmonella Typhimurium harboring numerous virulence genes. Therefore, to prevent the general public's health from being harmed by tiger nut drinks contaminated with Salmonella Typhimurium, relevant regulatory bodies should enforce strict hygienic practices during the production, handling, and distribution of tiger nut juice.