A study of Salmonella in pigs from birth to carcass: Serotypes, genotypes, antibiotic resistance and virulence profiles

作者：Bolton Declan J^*; Ivory Claire; McDowell David

来源：International Journal of Food Microbiology, 2013, 160(3): 298-303.

DOI：10.1016/j.ijfoodmicro2012.11.001

• Salmonella
• Pig production
• Antimicrobial resistance
• Virulence

A study was undertaken to investigate Salmonella in pigs at each step from birth to carcass. Environmental and/or pig samples were taken at birth, farrowing, 1st weaning, 2nd weaning, finishing, transport, lairage, bleeding and chilling of carcasses and tested for Salmonella. All isolates were characterised in terms of serotype, phage type (where relevant) and subtyping with pulsed field gel electrophosesis (PFGE). Isolates were tested for antibiotic resistance, resistance (intl1, bla(CIT), bla(Tem), bla(PSE-1), bla(OXA-1), floR, catA1, aadA1, aadA2, tetA, tetB, tetG, sul1 and aphA1) and virulence (invA, rck, spvC and pefA) genes. PCR was also performed to test for the presence of the left junction, thdF-S001 and the right junction, S004-int2 or S004-yidY of Salmonella genomic island 1 (SGI1). Overall 4.3%, 27.5% and 5% of environmental, throat/rectal and carcass samples were Salmonella positive, respectively. S. Typhimurium DT193 was detected during production, while S. Typhimurium DTI 7 and U311 were present in lairage at the abattoir, where strain characterisation suggested cross contamination of the live animals occurred. The carcasses were also cross contaminated with S. Brandenburg during processing. PFGE grouped the isolates by serotype and/or phage type. The DTI 93 isolates displayed the ACSSuTTmMn/Gm resistance phenotype and carried the invA, spvC, rck, bla-tem, aadA2, tetA, strA virulence/antibiotic resistance markers; U311 showed an ASSuTMn resistance pattern and carried invA and tetB; DT17 was sensitive to all antibiotics tested but invA, spy and rck positive while S. Brandenburg displayed neither resistance nor virulence gene carriage. None of the isolates possessed class 1 integrons and all isolates were negative for the left and right junctions of SGI1. %26lt;br%26gt;It was concluded that control activities should target improved biosecurity at farm level and better sanitation in lairage. This study also provides further evidence that multiple drug resistance may be associated with non-SGI1 Salmonella strains. The continued emergence of non-DT104 S. Typhimurium isolates exhibiting multidrug resistance is a cause for concern as is the persistence of highly virulent Salmonella strains in the abattoir environment.

• 出版日期2013-1-1