Methicillin-resistant Staphylococcus aureus (MRSA) strains are characterized by a heterogeneous expression of resistance. We have previously shown in clinical oxacillin-susceptible, mecA-positive MRSA strains that selection from a very heterogeneous (HeR) to highly homogeneous (HoR) resistant phenotype was mediated by acquisition of mutations through an oxacillin-induced SOS response. In the pr...

The accessory gene regulator (agr) is a central system that controls the expression of Staphylococcus aureus virulence factors. In this study, the distribution of agr alleles, defined by agr restriction fragment length polymorphism within agr interference groups, among S. aureus isolates from bovine and human origin was measured with PCR-based techniques. Statistically highly significant associ...

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 production of cell surface proteins in Staphylococcus aureus is generally down-regulated in the postexponential growth phase by the global regulator agr. The effector of this regulation is the RNAIII molecule, which is encoded within the agr locus. RNAIII seems to regulate most target genes at the level of transcription, but it also has an effect on the translation of some genes. To study t...

Agr is an autoinducing, quorum-sensing system that functions in many Gram-positive species and is best characterized in the pathogen Staphylococcus aureus, in which it is a global regulator of virulence gene expression. Allelic variations in the agr genes have resulted in the emergence of four quorum-sensing specificity groups in S. aureus, which correlate with different strain pathotypes. The ...

Staphylococcus aureus contains an autoinducing quorum-sensing system encoded within the agr operon that coordinates expression of virulence genes required for invasive infection. Allelic variation within agr has generated four agr specific groups, agr I-IV, each of which secretes a distinct autoinducing peptide pheromone (AIP1-4) that drives agr signaling. Because agr signaling mediates a pheno...

We previously reported that the cvfB gene (SA1223) of Staphylococcus aureus is responsible for the virulence of this pathogenic bacterium. We show here that the cvfB gene regulates exoprotein gene expression. In a cvfB gene deletion mutant, hemolysin, DNase, and protease production were decreased, whereas protein A expression was increased. The amount of RNAIII, the transcript from the P3 promo...

We apply the “almost good reduction” (AGR) criterion, which has been introduced in our previous works, to several classes of discrete integrable equations. We verify our conjecture that AGR plays the same role for maps of the plane define over simple finite fields as the notion of the singularity confinement does. We first prove that q-discrete analogues of the Painlevé III and IV equations hav...

Introduction. Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) represents a risk for the spread of bacteria. This study characterized the S. aureus isolated from medical students, who were in their clinical rotation at a hospital in the city of Cali. Materials and Methods. 216 students participated in the study and 63 isolates of S. aureus were evaluated for susceptibility a...

This study evaluated the predictive value of the preoperative albumin/globulin ratio (AGR) in laryngeal squamous cell carcinoma (LSCC) retrospectively, which has not been reported before. The current study enrolled 241 newly diagnosed LSCC patients in the Second Affiliated Hospital of Nanchang University between January 2005 and December 2010. The optimal AGR cut-off value for overall survival ...