Clin Microbiol Infect 2006, 12:582–585.CrossRefPubMed 33. Vignoli R, Varela G, Mota MI, Cordeiro NF, Power P, Ingold E, Gadea P, Sirok JPH203 order A, Schelotto F, Ayala JA, Gutkind G: Enteropathogenic Escherichia coli strains carrying genes encoding the PER-2 and TEM-116 extended -spectrum β-lactamases isolated from children with diarrhea in Uruguay. J Clin Microbiol 2005, 43:2940–2943.CrossRefPubMed Authors’ contributions MJA, VOR, ASP and GS conceived the study and MJA wrote the paper. RD and AMM participated in clinical aspects of the study and specimen collection. SS performed the laboratory studies. All authors read and approved the final manuscript.”
S. aureus is one of the leading causes of nosocomial infections and is re-emerging as a major threat among hospitals due to the spread of methicillin resistant
strains (MRSA). Furthermore, the occurrence of community acquired MRSA (CA-MRSA) is on the rise in this country and many others . S. aureus has a multitude of virulence factors that allow for host immune evasion, adherence to host tissues, biofilm formation, toxin production, and dissemination during infection . As the biological functions of cellular components continue to be elucidated,  more and more virulence factors are added to this extensive list. In a study designed to elucidate potential vaccine ABT-888 price targets in S. aureus, Lorenz et al identified a protein, which they designated the immunodominant surface antigen B (IsaB), that elicited an immune response during MRSA septicemia. IsaB is a 19.5 kDa S. aureus protein with no significant Salubrinal homology to other proteins with known function . Another study demonstrated a mutation in the gene encoding IsaB in a hyper-virulent musculoskeletal isolate, leading the authors to suggest that mutation or loss of IsaB may increase immune evasion C-X-C chemokine receptor type 7 (CXCR-7) in the S. aureus isolate under investigation .
Other labs have reported microarray data showing that isaB expression is increased in response to neutrophil exposure, in biofilms, under anaerobic conditions, and following internalization into human epithelial cells [4, 7–9]. All of these phenomena suggest that in spite of its role in eliciting an immune response, IsaB expression is induced during infection. Currently, IsaB is annotated as a putative virulence factor, however its function has yet to be determined. Biofilms have been shown to be a critical component of certain S. aureus infections, as these structures confer increased survival of the bacteria under many stressful conditions such as low nutrient availability, antibiotic challenge, oxidative stress, and host immune defenses . The major intercellular adhesin in S. aureus biofilms is the polysaccharide poly-N-acetylglucosamine (PNAG), which is encoded by the intercellular adhesin locus (ica) [11, 12]. We and others have previously studied the regulation of PNAG production and ica expression at the transcriptional level [13–17].