background and objectives: this study was designed to evaluate the activity of quercus infectoria galls extract (qifge) on virulence factor production and inhibition of quorum sensing (qs) in pseudomonas aeruginosa. materials and methods: minimum inhibitory concentration (mic) of qifge against 5 strains of p. aeruginosa was determined. the extract at sub-mic was used to determine biofilm format...

Sigma factors provide promoter recognition specificity to RNA polymerase holoenzyme, contribute to DNA strand separation, and then dissociate from the core enzyme following transcription initiation. As the regulon of a single sigma factor can be composed of hundreds of genes, sigma factors can provide effective mechanisms for simultaneously regulating expression of large numbers of prokaryotic ...

the bacterium oceanimonas sp. (o. sp.) gk1 is a member of the aeromonadaceae family and its genome represents several virulence genes involved in fish and human pathogenicity. in this original research study we aimed to identify and characterize the putative virulence factors and pathogenicity of this halotolerant marine bacterium using genome wide analysis. materials and methods: the genome da...

A virulence factor denotes a bacterial product or strategy that contributes to virulence or pathogenicity. Streptococci produce a variety of protein toxins and enzymes that are capable of killing host cells and breaking down cell constituents, presumably to provide nutrients for the bacteria or to promote their spread. Some of these secreted products are hemolysins, streptokinases, hyaluronidas...

Pertussis is still endemic and the recently resurgence of the disease caused by Bordetella pertussis has been shown in many countries. The polymorphism of the virulence genes of B. pertussis and lack of any information about the allelic variation between the Iranian isolates promotes us to analysis of the genes encoded virulence factors including ptxS1, prn, fim3 and cya to understand the diffe...

background helicobacter pylori infection is associated with gastritis and marked infiltration of the gastric mucosa by several cytokines secreting inflammatory cells that contribute to sustained local inflammation. in this study, we sought to examine il-6 expression in h. pylori-infected and uninfected gastric mucosa and elucidate the implication in the pathogenesis of h. pylori-associated gast...

The molecular mechanisms of Bordetella virulence are now well understood, and many virulence factors have been identified and characterized at the molecular level. These virulence factors can be grouped into two major categories: adhesins, such as filamentous hemagglutinin, pertactin and fimbriae, and toxins, such as pertussis toxin, adenylate cyclase, dermonecrotic toxin and tracheal cytotoxin...

The vast majority of infections involving female pelvic structures arise from organisms that are members of the normal flora. In addition, exogenous organisms that invade through the lower genital tract must interact with organisms that are part of the host's flora. In contrast to the concept that the normal flora is entirely innocuous, recent research has begun to identify what appear to be vi...

Virulence, defined as damage to the host, is a trait of pathogens that evolutionary theory suggests benefits the pathogen in the "struggle for existence". Pathogens employ virulence mechanisms that contribute to disease. Central to the evolution of virulence of the infectious agents causing an array of bacterial disease is the evolutionary acquisition of type III secretion, a macromolecular com...

Shigella is the major cause of bacillary dysentery world-wide. It is divided into four species, named S. flexneri, S. sonnei, S. dysenteriae, and S. boydii, which are distinct genomically and in their ability to cause disease. Shigellosis, the clinical presentation of Shigella infection, is characterized by watery diarrhea, abdominal cramps, and fever. Shigella's ability to cause disease has be...