Identification of Salmonella enterica serovar Kentucky genes involved in attachment to chicken skin.

Sanaz Salehi,R Hartford Bailey,Mark L Lawrence,Kevin Howe,John Brooks,Attila Karsi

doi:10.1186/s12866-016-0781-9

Sanaz Salehi, R Hartford Bailey + Show 4 more

Open Access

https://doi.org/10.1186/s12866-016-0781-9

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Journal: BMC microbiology	Publication Date: Jul 29, 2016
Citations: 11	License type: CC BY 4.0

Affiliation: Mississippi State University

Abstract

BackgroundRegardless of sanitation practices implemented to reduce Salmonella prevalence in poultry processing plants, the problem continues to be an issue. To gain an understanding of the attachment mechanism of Salmonella to broiler skin, a bioluminescent-based mutant screening assay was used. A random mutant library of a field-isolated bioluminescent strain of Salmonella enterica serovar Kentucky was constructed. Mutants’ attachment to chicken skin was assessed in 96-well plates containing uniform 6 mm diameter pieces of circular chicken skin. After washing steps, mutants with reduced attachment were selected based on reduced bioluminescence, and transposon insertion sites were identified.ResultsAttachment attenuation was detected in transposon mutants with insertion in genes encoding flagella biosynthesis, lipopolysaccharide core biosynthesis protein, tryptophan biosynthesis, amino acid catabolism pathway, shikimate pathway, tricarboxylic acid (TCA) cycle, conjugative transfer system, multidrug resistant protein, and ATP-binding cassette (ABC) transporter system. In particular, mutations in S. Kentucky flagellar biosynthesis genes (flgA, flgC, flgK, flhB, and flgJ) led to the poorest attachment of the bacterium to skin.ConclusionsThe current study indicates that attachment of Salmonella to broiler skin is a multifactorial process, in which flagella play an important role.

Highlights

Regardless of sanitation practices implemented to reduce Salmonella prevalence in poultry processing plants, the problem continues to be an issue
Bacterial concentration and inoculation time are Salehi et al BMC Microbiology (2016) 16:168 other aspects that have been suggested as contributors to the attachment of bacterium to chicken skin [7]
We identified 66 mutants with decreased bioluminescence on chicken skin compared to strain SkTn7lux

Summary

Introduction

Regardless of sanitation practices implemented to reduce Salmonella prevalence in poultry processing plants, the problem continues to be an issue. To gain an understanding of the attachment mechanism of Salmonella to broiler skin, a bioluminescent-based mutant screening assay was used. A random mutant library of a field-isolated bioluminescent strain of Salmonella enterica serovar Kentucky was constructed. Kentucky isolates from broiler chicken has elevated from 25 % in 1997 to 50 % in 2007 [2] This serovar is not considered a major source of human disease, high incidence of Salmonella Kentucky and the emergence of its recent multi-drug resistant strain outside US with high resistance level to ciprofloxacin, Salmonella contamination persists in all stages of chicken processing regardless of the hygienic steps taken. There have been numerous studies on Salmonella attachment to chicken skin, specific knowledge on the mechanism of attachment is lacking. There has been conflicting information on the role of some surface structures (e.g., fimbriae, pili, and flagella) on the attachment of the bacterium to the broiler skin surface [8,9,10]

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