The role of virulence factors in the outcome of staphylococcal peritonitis in CAPD patients

Abstract

BackgroundPeritonitis continues to be the most frequent cause of peritoneal dialysis (PD) failure, with an important impact on patient mortality. Gram-positive cocci such as Staphylococcus epidermidis, other coagulase-negative staphylococci (CoNS), and Staphylococcus aureus are the most frequent etiological agents of PD-associated peritonitis worldwide. The objective of the present study was to compare peritonitis caused by S. aureus and CoNS and to evaluate the factors influencing outcome.MethodsRecords of 86 new episodes of staphylococcal peritonitis that occurred between 1996 and 2000 in the Dialysis unit of a single university hospital were studied (35 due to S. aureus, 24 to S. epidermidis and 27 to other CoNS). The production of slime, lipase, lecithinase, nuclease (DNAse), thermonuclease (TNAse), α- and β-hemolysin, enterotoxins (SEA, SEB, SEC, SED) and toxic shock syndrome toxin-1 (TSST-1) was studied in S. aureus and CoNS. Antimicrobial susceptibility was evaluated based on the minimal inhibitory concentration determined by the E-test. Outcome predictors were evaluated by two logistic regression models.ResultsThe oxacillin susceptibility rate was 85.7% for S. aureus, 41.6% for S. epidermidis, and 51.8% for other CoNS (p = 0.001). Production of toxins and enzymes, except for enterotoxin A and α-hemolysin, was associated with S. aureus episodes (p < 0.001), whereas slime production was positive in 23.5% of CoNS and 8.6% of S. aureus strains (p = 0.0047). The first model did not include enzymes and toxins due to their association with S. aureus. The odds of resolution were 9.5 times higher for S. epidermidis than for S. aureus (p = 0.02) episodes, and were similar for S. epidermidis and other CoNS (p = 0.8). The resolution odds were 68 times higher for non-slime producers (p = 0.001) and were not influenced by oxacillin resistance among vancomycin-treated cases (p = 0.89). In the second model, the resolution rate was similar for S. aureus and S. epidermidis (p = 0.70), and slime (p = 0.001) and α-hemolysin (p = 0.04) production were independent predictors of non-resolution.ConclusionBacterial species and virulence factors rather than antibiotic resistance influence the outcome of staphylococcal peritonitis.

Staphylococcus aureus α-Toxin: Nearly a Century of Intrigue

“…Consistent with these findings, current epidemic USA300 isolates of S. aureus that cause a significant disease burden in healthy human hosts display both increased Hla expression and virulence in experimental models, dependent on the Agr and Sae regulatory systems that govern toxin expression [114,115,116]. In addition, α-toxin expression was associated with non-resolution of bacterial peritonitis in individuals receiving peritoneal dialysis [117]. Together, these studies are most consistent with the conclusion that α-toxin expression may be required for the pathogenesis of invasive disease in healthy individuals, while of lesser relevance in individuals that are already predisposed to invasive bacterial infection on account of underlying illness, hospitalization, or tissue barrier compromise in the setting of indwelling medical devices [113].…”

Inactivation of enterotoxic and non-enterotoxic Staphylococcus aureus strains by high pressure treatments and evaluation of its impact on virulence factors

“…These proteins include hemolysins (alpha, beta, gamma and delta), thermonuclease, proteases, lipases, hyaluronidase, and collagenase (Barretti, Montelli, Batalha, Caramori, & Cunha, 2009;Ortega et al, 2010). They also produce carotenoids (mainly staphyloxanthin) that are able to absorb excess energy from reactive oxygen species (ROS), protecting them against hydrogen peroxide, superoxide radical, hydroxyl radical, hypochloride and singulet oxygen and are also responsible to regulate membrane fluidity (Chamberlain et al, 1991;Clauditz, Resch, Wieland, Peschel, & G€ otz, 2006;Liu & Nizet, 2009).…”

Toll/IL-1 domain-containing adaptor inducing IFN-β (TRIF) mediates innate immune responses in murine peritoneal mesothelial cells through TLR3 and TLR4 stimulation

“…Peritonitis is an inflammation of the peritoneum which lines the inner wall of the abdomen and covers and supports most of abdominal organs. The two major types of life-threatening peritonitis are: (i) primary spontaneous peritonitis, an infection that develops in the peritoneum [1]; and (ii) secondary peritonitis, which usually develops when an injury or infection in the abdominal cavity allows infectious organisms into the peritoneum [2,3].…”