Prevalence of genes encoding extracellular virulence factors among meticillin-resistant Staphylococcus aureus isolates from the University Hospital, Olomouc, Czech Republic

Abstract

A rather fast and complicated progression of an infection caused by some strains of Staphylococcus aureus could be associated with the expression and co-action of virulence factor complexes in these strains. This study screened the antibiotic susceptibility and prevalence of virulence markers in isolates of meticillin-resistant S. aureus (MRSA) obtained from patients hospitalized at the University Hospital in Olomouc, Czech Republic. A total of 100 isolates was screened for 13 genes encoding extracellular virulence determinants (tst, pvl, eta, etb, sea, seb, sec, sed, see, seg, seh, sei and sej) and for their distribution in sample types. Eighty-nine isolates were positive for at least one of the genes. Genes for etb, pvl, see and seh were not detected in any of the MRSA isolates. No statistically significant differences in the occurrence of the determinants studied among sample types were found. INTRODUCTIONStaphylococcus aureus is one of the major nosocomial pathogens. Particular attention should be paid to meticillin-resistant S. aureus (MRSA). Resistance to meticillin is determined by the presence of the mecA gene encoding penicillin-binding protein with very low affinity to blactam antibiotics (Chambers, 1997). S. aureus produces a broad spectrum of extracellular and cell wall-associated virulence determinants (Foster, 2002). Among them, a wide variety of surface adhesins known as microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) has been described (Patti et al., 1994).The most common staphylococcal proteins anchored in the cell wall are proteins with affinity to fibrinogen (i.e. clumping factors A and B, encoded by the clfA and clfB genes, respectively), fibronectin (fnbA), collagen (cna), sialoprotein (bbp), elastin (ebpS) and adhesins with unknown function (sdrC and sdrE) (Jonsson et al., 1991;Josefsson et al., 1998; McDevitt et al., 1997;Ní Eidhin et al., 1998; Park et al., 1996;Speziale et al., 1986;Tung et al., 2000). The second group of virulence factors is represented by a family of bacterial proteins with superantigen activity: enterotoxins A-E, G-R and U (encoded by the genes seasee, seg-ser and seu), toxic shock syndrome toxin-1 (TSST-1, encoded by tst), exfoliative toxins A and B (eta and etb) and other toxins such as a-, b-, c-and d-toxin and the Panton-Valentine leukocidin (pvl) (Arbuthnott et al., 1982;Bhakdi & Tranum-Jensen, 1991;Bohach et al., 1990;Prevost et al., 1995).Apart from syndromes caused by toxin production, S. aureus pathogenesis results from synergistic interactions of a variety of the above-mentioned factors. Exfoliative toxin and pyrogenic toxin superantigen production enables S. aureus to cause staphylococcal scalded skin syndrome (SSSS), staphylococcal toxic shock syndrome and staphylococcal food poisoning. Experimental models indicate that the expression of receptors for fibrinogen and fibronectin is associated with endocarditis, whereas the presence of adhesins for sialoprotein, collagen and fibronectin is associated with arthritis and osteomyel...

Prevalence, Antimicrobial Susceptibility, and Enterotoxin Gene Detection of Staphylococcus aureus Isolates in Ready-to-Eat Foods in Shaanxi, People's Republic of China

“…The enterotoxin genes in S. aureus have been reported by many studies (7,15,19), and the prevalence of strains bearing enterotoxin genes varied in these reports. We found that 55.5% of S. aureus isolates were positive for one or more SE genes, which was higher than the rate (49.8%) of the isolates with toxigenic properties in Korea but lower than the 85.0% rate reported in the United States (6,13).…”

Species diversity and antibiotic resistance properties of Staphylococcus of farm animal origin in Nkonkobe Municipality, South Africa

“…Table 2 summarized the list of primers used for the PCR detection of ermA , ermB , ermC , msrA , and mphC genes following the protocol of Sauer et al (2008) with slight modifications. The genomic DNA was extracted using PrepMan Ultra DNA extraction kit (Applied Biosystem).…”

Frecuencia de genes que codifican factores de virulencia en Staphylococcus aureus aislados de niños que concurrieron al Hospital General Pediátrico Niños de Acosta Ñú, durante el año 2010

“…En 1932, sus descubridores (Panton y Valentine) sugirieron que era responsable de infecciones estafilocóccicas severas en humanos. Las hemolisinas también son reconocidas como potenciales factores de virulencia de S. aureus que actúan atacando la membrana celular y producen destrucción plaquetaria, destrucción lisosomal, isquemia y necrosis, por lo que son importantes en el desarrollo de patologías graves (4)(5)(6)(7)(8)(9)(10).…”