V. cholerae non-O1 non-O139 serogroups isolated from clinical and environmental sources in Córdoba, Argentina, were analyzed for the presence and expression of virulence genes. Most of the strains studied contained the genes toxR and hlyA, but lacked ctxA, zot, ace, tcpA and stn. The culture supernatants were tested for hemolytic and cytotoxic activity. The enterotoxic potential of the strains ...

Staphylococcus aureus subverts host defences by producing a collection of virulence factors including bi-component pore-forming leukotoxins. Despite extensive sequence conservation, each leukotoxin has unique properties, including disparate cellular receptors and species specificities. How these toxins collectively influence S. aureus pathogenesis is unknown. Here we demonstrate that the leukot...

The Gram-positive pathogen Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis, and meningitis in human newborns. GBS elaborates a pore-forming toxin known as CAMP factor that synergizes with Staphylococcus aureus beta-toxin, generating a co-hemolytic reaction useful in identification of GBS in the clinical laboratory. To evaluate the indirect evidence implicating CA...

The ability of motile strains of the Ogawa and Inaba serotypes of classical Vibrio cholerae and of the El Tor biotypes to kill suckling mice after oral challenge with 10-8 colony-forming units (representing at least 100 to 1,000 minimal lethal doses) was compared to that of nonmotile derivatives of the same strains. Loss of motility, in each case, resulted in a marked reduction in virulence. Th...

Candida albicans is an important etiological agent of superficial and life-threatening infections in individuals with compromised immune systems. To date, we know of several overlapping genetic networks that govern virulence attributes in this fungal pathogen. Classical use of deletion mutants has led to the discovery of numerous virulence factors over the years, and genome-wide functional anal...

Now that microbial whole genome sequencing is in reach of many researchers, it is common to infer virulent properties of a given bacterial isolate based on the presence of virulence genes. However, this may lead to inaccurate presumptions of virulence. Using the findings of a recent publication (Da Silva Santos et al. Gut Pathog 7:2, 2015) where virulence was inferred from a genome sequence and...

The encephalomyocarditis virus (EMCV) is a small non-enveloped single-strand RNA virus, the causative agent of not only myocarditis and encephalitis, but also neurological diseases, reproductive disorders and diabetes in many mammalian species. EMCV pathogenesis appears to be viral strain- and host-specific, and a better understanding of EMCV virulence factors is increasingly required. Indeed, ...

In the present study, we compared two strains of serotypes 088:H25 and 0145:H45 with an enteropathogenic Escherichia coli (EPEC) adherence factor-positive (EAF+) strain of the classic enteropathogenic E. coli serotype 0111ab:H2 for their association with HeLa cells and with biopsies of human duodenal mucosa. Both strains not belonging to the classic EPEC serotype showed virulence properties sim...

Proposed herein is a mechanism for virulence by Candida albicans based upon this organism's ability to produce high levels of pyruvate, potentially resulting in localized tissue ketosis and undermining the normal defensive function of neutrophil myeloperoxidase. Neutrophils, a key component of our innate defense against microbial infections, seem to play a particularly important role protecting...

Streptococcus pyogenes (GAS) is a human pathogen that causes multiple infections worldwide. The pathogenic properties of GAS strains are often linked to the production of virulence factors such as toxins, proteases or DNases. Detection of virulence factors produced by GAS strains can be used to either determine pathogenic potential of the strain or as a rapid screening and typing method. We rec...