Lactococcus garvieae causes fatal haemorrhagic septicaemia in fish such as yellowtail. The comparative analysis of genomes of a virulent strain Lg2 and a non-virulent strain ATCC 49156 of L. garvieae revealed that the two strains shared a high degree of sequence identity, but Lg2 had a 16.5-kb capsule gene cluster that is absent in ATCC 49156. The capsule gene cluster was composed of 15 genes, ...

We propose that the 70-kDa heat shock protein (HSP70) protects virulent Toxoplasma gondii from the effects of the host by immunomodulation. This hypothesis was tested using quercetin and antisense oligonucleotides targeting the start codon of the virulent T. gondii HSP70 gene. Oligonucleotides were transiently transfected into two virulent (RH, ENT) and two avirulent (ME49, C) strains of T. gon...

The genetic diversity of 88 Streptococcus suis serotype 2 isolates which were recovered from various countries was examined by randomly amplified polymorphic DNA (RAPD) analysis with three primers. This bacterial collection included 80 isolates of porcine origin and 8 of human origin. This investigation allowed the identification of 23 RAPD types containing 1 to 30 isolates originating from one...

Streptococcus suis, an emerging infectious pathogen, is the cause of two large-scale outbreaks of human streptococcal toxic shock syndrome in China, and has attracted much attention from the scientific community. The genetic basis of its pathogenesis remains enigmatic, and no effective prevention measures have been established. To better understand the virulence differentiation of S. suis and d...

In this study, we investigated the ability of four clinical isolates of Mycobacterium tuberculosis representing a range of virulence for their capacity to grow in bone marrow-derived macrophages. The rate of growth of each of the isolates in macrophages reflected their known virulence, but the most virulent isolates strongly induced production of the cytokine tumor necrosis factor alpha. A key ...

Virulent strains of Salmonella opsonized with normal mouse plasma are never phagocytosed as well as avirulent strains. The virulent strains of Salmonella phagocytosed after opsonization with normal mouse plasma are able to multiply within normal mouse peritoneal macrophages, whereas under similar experimental conditions the avirulent strains are killed. When virulent strains of Salmonella are o...

Haemophilus parasuis is a commensal bacterium of the upper respiratory tract of healthy pigs. It is also the etiological agent of Glässer's disease, a systemic disease characterized by polyarthritis, fibrinous polyserositis and meningitis, which causes high morbidity and mortality in piglets. The aim of this study was to evaluate biofilm formation by well-characterized virulent and non-virulent...

UNLABELLED Footrot is a contagious, debilitating disease of sheep, causing major economic losses in most sheep-producing countries. The causative agent is the Gram-negative anaerobe Dichelobacter nodosus. Depending on the virulence of the infective bacterial strain, clinical signs vary from a mild interdigital dermatitis (benign footrot) to severe underrunning of the horn of the hoof (virulent ...