background: the aim of this study was to compare the biofilm formation and the prevalence of biofilm-associated genes between the isolates of methicillin-resistant (mrsa) and methicillin-susceptible (mssa) staphylococcus aureus. methods: in total, 209 s. aureus isolates were collected. the antibiotic susceptibility test was conducted using nine antibiotics according to the guidelines of clinica...

Objective The objective of the study is to investigate biofilm forming ability, distribution of biofilm associated genes of the clinically isolated bovine mastitis Staphylococcus and the correlation of them. Methods Silver staining, SEM and crystal violet staining were conducted for the detection of biofilm forming ability in 24-well plates. Genes of bap, icaAD, icaBC, sar, agr, sigB, clfaA, cl...

Methicillin-Resistant Staphylococcus aureus (MRSA) is responsible for an increasing number of serious hospital and community acquired infections. Virulence gene expression in Staphylococcus aureus is orchestrated by regulators such as the accessory gene regulator (agr). Staphylococcal strains are divided into four major agr groups (agrI-IV) on the basis of agrD and agrC polymorphisms. The purpo...

CA-MRSA infection, driven by the emergence of the USA300 genetic background, has become epidemic in the United States. USA300 isolates are hypervirulent, compared with other CA- and HA-MRSA strains, in experimental models of necrotizing pneumonia and skin infection. Interestingly, USA300 isolates also have increased expression of core genomic global regulatory and virulence factor genes, includ...

Staphylococcus aureus is one of the most frequent mastitis causative agents in small ruminants. The expression of most virulence genes of S. aureus is controlled by an accessory gene regulator (agr) locus. This study aimed to ascertain the prevalence of the different agr groups and to evaluate the occurrence of encoding genes for cytotoxin, adhesins and toxins with superantigen activity in S. a...

The expression of Staphylococcus aureus virulence proteins is under the control of RNA III, a central pleiotropic regulator transcribed from the agr locus. RNA III is activated by at least two two-component systems, one encoded by the agr locus (AgrC-AgrA) and another encoded outside of this locus (TRAP-RAP). In this work, we developed new typing methods based on genes encoding these two system...

The quorum-sensing system of Staphylococcus aureus, the accessory gene regulator (Agr) system, is responsible for increased transcription of certain exoprotein genes and decreased transcription of certain cell wall-associated proteins during the postexponential phase of growth. This regulation is important for virulence, as evidenced by a reduction in virulence associated with a loss of the Agr...

The expression of genes involved in the pathogenesis of Staphylococcus aureus is known to be controlled by global regulatory loci, including agr, sarA, saeRS, arlRS, and sarA-like genes. As part of our continuing efforts to understand the regulatory mechanisms that involve sarA-like genes, we describe here the characterization of a novel transcriptional regulator called SarX, a member of the Sa...

Expression of the staphylococcal enterotoxin type C gene (sec) is regulated in response to both high NaCl concentrations (osmolarity) and the accessory gene regulator (agr). agr is a global regulator that alters the expression of many genes in Staphylococcus aureus. In this report, we have demonstrated that osmoregulation of sec occurs at the level of mRNA independently of an intact agr allele....