Proteomic analysis of exoproteins expressed by enterotoxigenic Staphylococcus aureus strains

Abstract

Pathogenic bacteria excrete a variety of virulence factors into extracellular medium and to the cell surface which have essential roles in the colonization and insurrection of the host cells, and thus reflect the degree of bacterial pathogenicity. For the exploration of virulence factors expressed in the secreted proteome fraction, different Staphylococcus aureus strains were analyzed using gel-based bottom-up proteomic approach. A total of 119 distinct proteins were identified for the enterotoxin gene cluster (egc) negative and seb gene positive S. aureus American Type Culture Collection (ATCC) 14458 strain by the use of one- and 2-DE based proteomics. Detailed analysis of enterotoxin region of the 2-D map confirmed, beside the highly expressed staphylococcal enterotoxin B (SEB), the presence of enterotoxin-like proteins SElK and SElQ previously predicted by genotyping (Sergeev et al.., J. Clin. Microbiol. 2004, 42, 2134-2143). Exoprotein patterns at the late-exponential (7 h) and stationary (24 h) phases of cellular growth show a high-level similarity in this region. Comparative analysis of enterotoxin region of five S. aureus strains including two clinical isolates (RIMD 31092 and A900322), a food derived strain (AB-8802) with highly prevalent egc positive operon and a nonenterotoxigenic reference strain (ROS) revealed the presence of different known enterotoxins and other virulence factors along with a number of core exoproteins. In addition, production of SElL (RIMD 31092) and SElP (A900322) was demonstrated for the first time at the protein level. Under the experimental conditions applied none of the enterotoxins encoded by the genes of egc operon was identified.

Biofilm Matrix Exoproteins Induce a Protective Immune Response against Staphylococcus aureus Biofilm Infection

“…Thus, a total of 33 extracellular proteins were detected with a MASCOT score higher than 50 (Table 2). Importantly, the proteins identified have been repeatedly detected in extracellular proteomes of various S. aureus isolates (34,(47)(48)(49)(50)(51)(52)(53)(54). More notably, 28 out of the 33 proteins identified in our analysis have also been found in the biofilm exoproteome of S. aureus D30 strain, isolated from a persistent nasal carrier (Table 2) (50).…”

Comparative Proteomic Analysis of Extracellular Proteins of Clostridium perfringens Type A and Type C Strains

“…The extracellular proteomes of several Gram-positive (monoderm) pathogenic bacteria have been the subject of recent proteomic studies (17,19,30,36,46,47,48). It is postulated that several extracellular proteins may potentially be involved in the adherence of the bacteria to host cells, while some may be required for the suppression of the host's defense mechanisms.…”

The formation ofStaphylococcus aureusenterotoxin in food environments and advances in risk assessment

“…In contrast, the se genes that showed a slight decrease in transcript level during growth are encoded by the egc operon and, notably, these enterotoxins could not be detected using two-dimensional gel electrophoresis. 58,91 It is still unclear whether the non-classical…”