Peritoneal Dialysis-Related Peritonitis Due to Staphylococcus aureus: A Single-Center Experience over 15 Years

Peritonitis caused by Staphylococcus aureus is a serious complication of peritoneal dialysis (PD), which is associated with poor outcome and high PD failure rates. We reviewed the records of 62 S. aureus peritonitis episodes that occurred between 1996 and 2010 in the dialysis unit of a single university hospital and evaluated the host and bacterial factors influencing peritonitis outcome. Peritonitis incidence was calculated for three subsequent 5-year periods and compared using a Poisson regression model. The production of biofilm, enzymes, and toxins was evaluated. Oxacillin resistance was evaluated based on minimum inhibitory concentration and presence of the mecA gene. Logistic regression was used for the analysis of demographic, clinical, and microbiological factors influencing peritonitis outcome. Resolution and death rates were compared with 117 contemporary coagulase-negative staphylococcus (CoNS) episodes. The incidence of S. aureus peritonitis declined significantly over time from 0.13 in 1996–2000 to 0.04 episodes/patient/year in 2006–2010 (p = 0.03). The oxacillin resistance rate was 11.3%. Toxin and enzyme production was expressive, except for enterotoxin D. Biofilm production was positive in 88.7% of strains. The presence of the mecA gene was associated with a higher frequency of fever and abdominal pain. The logistic regression model showed that diabetes mellitus (p = 0.009) and β-hemolysin production (p = 0.006) were independent predictors of non-resolution of infection. The probability of resolution was higher among patients aged 41 to 60 years than among those >60 years (p = 0.02). A trend to higher death rate was observed for S. aureus episodes (9.7%) compared to CoNS episodes (2.5%), (p = 0.08), whereas resolution rates were similar. Despite the decline in incidence, S. aureus peritonitis remains a serious complication of PD that is associated with a high death rate. The outcome of this infection is negatively influenced by host factors such as age and diabetes mellitus. In addition, β-hemolysin production is predictive of non-resolution of infection, suggesting a pathogenic role of this factor in PD-related S. aureus peritonitis

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

<p>Abstract</p> <p>Background</p> <p>Peritonitis continues to be the most frequent cause of peritoneal dialysis (PD) failure, with an important impact on patient mortality. Gram-positive cocci such as <it>Staphylococcus epidermidis</it>, other coagulase-negative staphylococci (CoNS), and <it>Staphylococcus aureus </it>are the most frequent etiological agents of PD-associated peritonitis worldwide. The objective of the present study was to compare peritonitis caused by <it>S. aureus </it>and CoNS and to evaluate the factors influencing outcome.</p> <p>Methods</p> <p>Records 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 <it>S. aureus</it>, 24 to <it>S. epidermidis </it>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 <it>S. aureus </it>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.</p> <p>Results</p> <p>The oxacillin susceptibility rate was 85.7% for <it>S. aureus</it>, 41.6% for <it>S. epidermidis</it>, and 51.8% for other CoNS (p = 0.001). Production of toxins and enzymes, except for enterotoxin A and α-hemolysin, was associated with <it>S. aureus </it>episodes (p < 0.001), whereas slime production was positive in 23.5% of CoNS and 8.6% of <it>S. aureus </it>strains (p = 0.0047). The first model did not include enzymes and toxins due to their association with <it>S. aureus</it>. The odds of resolution were 9.5 times higher for <it>S. epidermidis </it>than for <it>S. aureus </it>(p = 0.02) episodes, and were similar for <it>S. epidermidis </it>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 <it>S. aureus </it>and <it>S. epidermidis </it>(p = 0.70), and slime (p = 0.001) and α-hemolysin (p = 0.04) production were independent predictors of non-resolution.</p> <p>Conclusion</p> <p>Bacterial species and virulence factors rather than antibiotic resistance influence the outcome of staphylococcal peritonitis.</p

Peritonitis in recent years: clinical findings and predictors of treatment response of 170 episodes at a single Brazilian center

Peritonitis continues to be a major cause of dropout in peritoneal dialysis (PD) patients. Changes in the prevalence of peritonitis etiologies and an increase in the frequency of methicillin-resistant coagulase-negative staphylococci (CoNS) and Gram-negative species resistant to commonly used antibiotics have been reported. As a consequence, the current clinical presentation and patient outcome may differ from classical descriptions. The objectives of this study were to describe the clinical and microbiological characteristics of PD-related peritonitis episodes that occurred over a period of 6 years at a single Brazilian dialysis center and to identify predictors of outcome.A total of 170 peritonitis episodes that occurred in 92 PD patients between January 2004 and December 2009 were reviewed. Multivariate analysis was used to identify demographic, clinical, and microbiological factors predicting endpoints (resolution and peritonitis-related death). Patients' characteristics and peritonitis incidence, etiology and outcomes were compared with a series of 232 episodes that occurred in the first 6 years (1995-2000) of the PD program at the same center.The overall peritonitis rate was 0.65 episodes/patient-year. Gram-positive cocci were identified in 79 (46.5%) episodes, whereas Gram-negative bacilli were isolated from 48 (28.2%). CoNS were the main Gram-positive species identified in 48 episodes. of these, 56.3% were resistant to methicillin. Among Gram-negative species, amikacin resistance was observed in 60% of non-fermentative Gram-negative bacilli (NFGNB) and in only 3.6% of Enterobacteriaceae. The overall resolution rate was 44.1%. Oxacillin resistance and NFGNB etiology were strong predictors of non-resolution, whereas older age was the only predictor of death. Antibiotic protocols did not influence outcome. Comparison with the results obtained for the 1990-1995 period showed a lower peritonitis rate, a strong decline in the proportion of Staphylococcus aureus episodes, a significant increase in the frequency of oxacillin-resistant CoNS and amikacin-resistant NFGNB, and a significantly lower resolution and higher death rate.The current clinical characteristics and outcome suggest a greater severity of peritonitis episodes and higher risk of death, possibly due to bacterial resistance. Older age is a risk factor for death.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Summary of Patient Characteristics at Baseline (<i>n</i> = 56).

<p>PD, peritoneal dialysis; APD, automated peritoneal dialysis; CAPD, continuous ambulatory peritoneal dialysis.</p

Vancomycin Minimum Inhibitory Concentration (MIC50) and Proportion of Oxacillin-Resistant <i>Staphylococcus aureus</i> Strains Isolated from Peritoneal Dialysis Patients with Peritonitis between 1996 and 2010.

<p>Vancomycin Minimum Inhibitory Concentration (MIC50) and Proportion of Oxacillin-Resistant <i>Staphylococcus aureus</i> Strains Isolated from Peritoneal Dialysis Patients with Peritonitis between 1996 and 2010.</p

Annual Rate (episodes/patient/year) of <i>Staphylococcus aureus</i> Peritonitis from January 1996 to December 2010.

<p>Annual Rate (episodes/patient/year) of <i>Staphylococcus aureus</i> Peritonitis from January 1996 to December 2010.</p