Streptococcus suis infection is considered to be a major problem in the swine industry worldwide. Most virulent Canadian isolates of S. suis serotype 2 do not produce the known virulence markers for this pathogen. PCR-based subtraction hybridization was adapted to isolate unique DNA sequences which were specific to virulent strains of S. suis isolated in Canada. Analysis of some subtracted DNA ...

Strains from a subgroup of Salmonella enterica serovar Typhimurium frequently associated with pigeon infections were tested for genomic anomalies and virulence in mice. Some strains have a genomic inversion between rrn operons. Two prophages found in the common laboratory strain LT2 were absent. Pigeon-associated strains are still virulent in mice.

Virulence of the human pathogen, V. vulnificus, is associated with encapsulation, serum complement resistance, and genotype. The C-genotype of this bacterium is correlated (>90%) with virulence and with isolation source (clinical settings). E-genotype strains are highly correlated with environmental isolation (93%) but appear less virulent. In this study, we characterized the importance of geno...

We investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 69 sporadic cases (60 men, 8 women, and 1 patient of unknown sex) in Chiang Mai, Thailand, between 1993 and 2001. Fifty were human immunodeficiency virus (HIV) positive, 3 were HIV negative, and HIV status was unknown for 16. Fifty-two (75%) of 69 isolates were strains of intermediate virulence that contained ...

It has been proposed that Mycobacterium tuberculosis virulent strains inhibit apoptosis and trigger cell death by necrosis of host macrophages to evade innate immunity, while non-virulent strains induce typical apoptosis activating a protective host response. As part of the characterization of a novel tuberculosis vaccine candidate, the M. tuberculosis phoP mutant SO2, we sought to evaluate its...

Chemotaxis of porcine spirochetes towards a variety of mucins was measured quantitatively by a capillary method. A chemotaxis buffer consisting of 0.01 M potassium phosphate buffer (pH 7.0) and 0.2 mM L-cysteine hydrochloride was necessary for chemotaxis of spirochetes. The optimum incubation time and incubation temperature were 1 h and 40 degrees C, respectively. The mucin concentration also a...

ABSTRACT Twenty-one strains of Botrytis cinerea isolated from 13 species of plants grown in China were compared for pathogenicity on Brassica napus, mycelial growth on potato dextrose agar, and presence of double-stranded (ds)RNA. The results showed that the strain CanBc-1 was severely debilitated in pathogenicity and mycelial growth, compared with the 20 virulent strains. A dsRNA of approximat...

Rapp, Fred (Baylor University College of Medicine, Houston, Tex.). Plaque differentiation and replication of virulent and attenuated strains of measles virus. J. Bacteriol. 88:1448-1458. 1964.-Plaque formation by strains of measles virus in a stable line of African green monkey kidney cells (BSC-1) is characterized by development of large plaques (>1 mm) within 4 days after inoculation of the c...

Staphylococcus aureus is a commensal inhabitant of skin and mucous membranes in nose vestibule but also an important opportunistic pathogen of humans and livestock. The extracellular proteome as a whole constitutes its major virulence determinant; however, the involvement of particular proteins is still relatively poorly understood. In this study, we compared the extracellular proteomes of poul...

Listeria monocytogenes mutants defective in the actA gene, the plcB gene, and the inlA and inlB genes were less virulent when injected intravenously into BALB/c mice. The growth of these strains as well as of the virulent wild-type strains was increased by treating mice with a neutrophil-specific depleting monoclonal antibody, RB6-8C5. Histologic examination of the livers of the treated animals...