Understanding virulence is vital for the development of novel therapeutics to target infections with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), which cause an ongoing epidemic in the United States and are on a global rise. However, what defines virulence particularly of global CA-MRSA lineages is poorly understood. Threatening a vast population, the predominant ...

OBJECTIVES To assess the molecular epidemiology and prevalence of antibiotic resistance in Escherichia coli causing urinary tract infections of elderly patients from community and hospital settings. Also, to determine whether the possession of antibiotic resistance and virulence-associated genes can be linked to patient location or the clonal group of the organisms in question. METHODS E. col...

We present a general host-parasite model that unifies previous theory by investigating the coevolution of virulence, resistance, and tolerance, with respect to multiple physiological, epidemiological, and environmental parameters. Four sets of new predictions emerge. First, compared to virulence coevolving with resistance or tolerance, three-trait coevolution promotes more virulence and less to...

Candida albicans is a dimorphic opportunistic pathogenic yeast that is commonly isolated from different anatomical sites and clinical samples. It possesses several virulence factors, including secretion of hydrolytic enzymes, the ability to adhere to abiotic surfaces and cells, and the ability to penetrate tissues. We determined the level of in vitro expression of virulence factors by South Afr...

The evolution of higher virulence during disease emergence has been predicted by theoretical models, but empirical studies of short-term virulence evolution following pathogen emergence remain rare. Here we examine patterns of short-term virulence evolution using archived isolates of the bacterium Mycoplasma gallisepticum collected during sequential emergence events in two geographically distin...

The virulence plasmids of Salmonella typhimurium and other invasive Salmonella serovars have long been associated with the ability of these bacteria to cause systemic infection beyond the intestines in orally inoculated animals. Genetic analysis of virulence genes on the high-molecular-weight plasmids has revealed that no more than five genes spanning a 6.2-kb region are sufficient to replace t...

results the frequency of the baba2, icea1 and icea2 genes in the total isolates were 34 (54%), 14 (22.2%) and 34 (54%), respectively. the association of these virulence factors based on sex and age groups were not statistically significant (p > 0.05). there was a borderline significant association between icea1 and the clinical outcomes (p = 0.094). patients and methods in this study, 63 positi...

The phytopathogenic fungus Gibberella jujikuroi mating population A (anamorph, Fusarium mOlliliforme) produces fumonisins, which are toxic to a wide range of plant and animal species. Previous studies of field strains have identified a genetic locus, designatedjiulll, that can determine whether fumonisins are produced. To test the relationship between fumonisin production and virulence on maize...

Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in e...

Populations of Puccinia triticina, one of the casual agents of wheat leaf rust disease, in the pacific (British Columbia and Alberta), prairie (Manitoba and Saskatchewan), and eastern regions (Quebec and Ontario) of Canada from 1997 to 2007 were analyzed for virulence and genetic diversity by revealing expressed sequence tag derived simple sequence repeat (EST-SSR) polymorphisms. Since 1997, a ...