Extensive validation of diagnostic assays using widely collected surveillance samples is critical for developing pathogen detection assays. The potentially virulent E. coli strains to the red meat industry. We previously developed two high-resolution melting (HRM) detecting and avirulent O26 O111 strains. Assays were validated enriched beef (n = 36) pork as part a U.S. federal regulatory progra...

Ovine foot rot caused by Dichelobacter nodosus is affecting sheep worldwide. The current diagnostic methods are difficult and cumbersome. Here, we present a competitive real-time PCR based on allelic discrimination of the protease genes aprV2 and aprB2. This method allows direct detection and differentiation of virulent and benign D. nodosus from interdigital skin swabs in a single test. Clinic...

Streptococcus tigurinus was recently described as a novel species, and some strains are highly virulent. We detected S. tigurinus in infected tissue sampled by necropsy. In order to characterize and confirm the virulence of this species, whole-genome sequencing of the pure cultured bacterium was performed. We found that the strain has specific and unique genetic elements contained in highly vir...

Aqueous extracts of 11-day-old chick embryos enhance the growth of tubercle bacilli in oleic acid-albumin media. These extracts also increase the tendency of virulent strains to exhibit the serpentine pattern of growth and confer this property on avirulent variants which normally grow unoriented in clumps. Growth in the presence of chick embryo extract slightly increases the virulence of the vi...

The MS character of polio-virus particles is described. Strains that produced relatively large plaques, up to 6 mm. in diameter, on a monkey stable (MS) cell line, were classified as MS(+). Such strains were found to include the highly virulent poliovirus strains. Attenuated strains appeared deficient in this gene, for they produced tiny plaques less than 1 mm. in size, or no visible plaques at...