Molecular detection of the index case of a subclinical Salmonella Kentucky epidemic on a dairy farm

2014 ◽  
Vol 143 (4) ◽  
pp. 682-686 ◽  
Author(s):  
B. J. HALEY ◽  
M. ALLARD ◽  
E. BROWN ◽  
E. HOVINGH ◽  
J. S. KARNS ◽  
...  

SUMMARYSalmonella enterica commonly colonizes the intestinal tract of cattle and is a leading cause of foodborne illness. A previously described investigation into the prevalence of S. enterica on a dairy farm revealed an 8-year-long asymptomatic S. enterica epidemic caused by serotypes Cerro and Kentucky in the lactating herd. To investigate the source of the S. Kentucky strains, the genomes of two S. Kentucky isolates were sequenced; one collected prior to the epidemic (2004) and one collected during the epidemic (2010). Comparative genomic analysis demonstrated significant polymorphisms between the two strains. PCR primers targeting unique and strain-specific regions were developed, and screening of the archived isolates identified the index case of the asymptomatic S. Kentucky epidemic as a heifer that was raised off-site and transported onto the study farm in 2005. Analysis of isolates collected from all heifers brought onto the farm demonstrated frequent re-introduction of clones of the epidemic strain suggesting transmission of pathogens between farms might occur repeatedly.

Genes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 70 ◽  
Author(s):  
Shuo Wang ◽  
Bo Yang ◽  
R. Paul Ross ◽  
Catherine Stanton ◽  
Jianxin Zhao ◽  
...  

Lactobacillus ruminis is a commensal motile lactic acid bacterium living in the intestinal tract of humans and animals. Although a few genomes of L. ruminis were published, most of them were animal derived. To explore the genetic diversity and potential niche-specific adaptation changes of L. ruminis, in the current work, draft genomes of 81 L. ruminis strains isolated from human, bovine, piglet, and other animals were sequenced, and comparative genomic analysis was performed. The genome size and GC content of L. ruminis on average were 2.16 Mb and 43.65%, respectively. Both the origin and the sampling distance of these strains had a great influence on the phylogenetic relationship. For carbohydrate utilization, the human-derived L. ruminis strains had a higher consistency in the utilization of carbon source compared to the animal-derived strains. L. ruminis mainly increased the competitiveness of niches by producing class II bacteriocins. The type of clustered regularly interspaced short palindromic repeats /CRISPR-associated (CRISPR/Cas) system presented in L. ruminis was mainly subtype IIA. The diversity of CRISPR/Cas locus depended on the high denaturation of spacer number and sequence, although cas1 protein was relatively conservative. The genetic differences in those newly sequenced L. ruminis strains highlighted the gene gains and losses attributed to niche adaptations.


2021 ◽  
pp. 100015
Author(s):  
Eamon O. Murchu ◽  
Sinead O'Neill ◽  
Paula Byrne ◽  
Cillian De Gascun ◽  
Michelle O'Neill ◽  
...  

3 Biotech ◽  
2021 ◽  
Vol 11 (6) ◽  
Author(s):  
Kai Huang ◽  
Bo Zhang ◽  
Yu Chen ◽  
Zhe-Ming Wu ◽  
Zhi-Qiang Liu ◽  
...  

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