Molecular identification of Salmonella Typhimurium from village chickens based on invA and spvC genes.

Mwanaisha Mkangara,Ernest R Mbega,Musa Chacha

doi:10.14202/vetworld.2020.764-767

Mwanaisha Mkangara, Ernest R Mbega + Show 1 more

Open Access

https://doi.org/10.14202/vetworld.2020.764-767

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Abstract

Aim:This study aimed to identify Salmonella enterica serovars by polymerase chain reaction (PCR) based on virulence genes invasion A (invA) and Salmonella plasmid virulence C (spvC).Materials and Methods:DNA extraction of eight bacteria isolates was done using the PowerSoil® DNA Isolation Kit. The amplification of invA and spvC genes was done using conventional PCR. The positive PCR products were purified using the GeneJET Purification Kit and then sequenced using ABI 3730 XL automated genetic analyzer. The sequences obtained were compared for similarities with other Salmonella serovars deposited on the NCBI GenBank using BLASTN.Results:Four out of eight samples were amplified by primers FS139/RS141 that target invA gene with products of about 284 bp, and three out of four of the same invA positive samples were also amplified by primers FSPV-1/RSPV-2 targeting spvC with a product of about 571 bp. One sample was not amplified by primers FSPV-1/RSPV-2 as it lacked virulence plasmid. Analysis of sequences indicated 100% homology with closely related serovars of S. enterica subspecies enterica serovar Typhimurium.Conclusion:Salmonella Typhimurium that contained invA and spvC genes are pathogenic and virulent strains.

Highlights

Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) is a motile Gram-negative bacterium in family Enterobacteriaceae [1]
Four out of eight samples were amplified by primers FS139/RS141 that target invasion A (invA) gene with products of about 284 bp, and three out of four of the same invA positive samples were amplified by primers FSPV-1/RSPV-2 targeting Salmonella plasmid virulence C (spvC) with a product of about 571 bp
Three out of four of the same invA positive samples were amplified by spvC gene (Table-1)

Summary

Introduction

Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) is a motile Gram-negative bacterium in family Enterobacteriaceae [1]. The bacterium is one among serovars with broad host range responsible for gastroenteritis in chickens but rarely induce systemic infection [2]. In some cases, the pathogen does not cause noticeable clinical symptoms in older chickens [4,5]. Under these circumstances, the older chickens become carriers of S. Typhimurium, which colonizes the gut with persistent shedding of bacteria that contaminate different environments [6,7,8,9]. The carrier chickens with salmonellosis are among sources of contaminated chicken products in the abattoirs with the significance of forming biofilm layers in equipment involved in the value chain [10]. The biofilm contributes to the persistence of Salmonella in different biotic

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