Staphylococcus lugdunensis Peritoneal Dialysis-Related Peritonitis: A Matched Comparative Analysis

Rationale & Objective

Staphylococcus lugdunensis (S lugdunensis) is a coagulase-negative staphylococcus species that has been increasingly recognized to cause serious infections with virulence resembling Staphylococcus aureus (S aureus). No studies have evaluated the characteristics and outcomes of patients with S lugdunensis peritoneal dialysis-related peritonitis compared with those with S aureus peritonitis. We aim to evaluate the clinical course of peritonitis as caused by these organisms.

Study Design

A retrospective matched comparative analysis involving a single tertiary center from July 2000 to July 2020.

Setting & Participants

Forty-eight episodes of S aureus peritonitis were matched to 19 cases of S lugdunensis peritonitis.

Analytical Approach

The cases were individually matched for year of peritonitis, sex, age (±10 years), and Charlson Comorbidity Index (±3). A comparative analysis was performed between the 2 organisms. The outcome includes responses at day 5 of peritonitis and the rate of complete response.

Results

There is a higher predilection of diabetes in those with S aureus peritonitis than in those with S lugdunensis (64.6% vs 31.6%; P = 0.03). Patients with S aureus peritonitis also have a much higher total cell count at presentation (4,463.9 ± 5,479.5 vs 1,807.9 ± 3,322.7; P = 0.05); a higher prevalence of poor response at day 5 (50.0% vs 15.8%; P = 0.03); a lower rate of complete response (64.6% vs 94.7%; P = 0.01) and are more prone to relapse with the same organism (29.2% vs 0%, respectively; P = 0.01) as compared to those with S lugdunensis.

Limitations

The result of this small retrospective study involving a single center may not be generalizable to other centers. There is also no data for comparative analysis on other coagulase-negative staphylococci such as Staphylococcus epidermidis, which belongs to the same family as S lugdunensis.

Conclusions

Although S aureus peritonitis is more virulent with significant morbidity, S lugdunensis can cause similarly serious peritonitis. This largest case series of S lugdunensis peritonitis enabled better characterization of clinical features and outcomes of patients with S lugdunensis peritonitis.

Recurrent peritonitis relapse in a patient with atrial septal defect undergoing peritoneal dialysis: a case report

BACKGROUND

Peritonitis is the most common complication in patients undergoing peritoneal dialysis (PD). Most patients recover with appropriate antibiotic treatment; however, when peritonitis repeatedly relapses, the cause of recurrence must be explored. The relationship between atrial septal defect (ASD), infective endocarditis (IE), and peritonitis is rarely reported. Here, we present a case of recurrent peritonitis due to Staphylococcus aureus in a patient with ASD and IE undergoing PD.

CASE PRESENTATION

A 46-year-old woman with chronic renal failure secondary to chronic glomerulonephritis experienced three episodes of peritonitis within 80 days of starting PD. The patient had a history of untreated ASD without symptoms. After undergoing PD for approximately 35 days, the patient was admitted to our hospital on April 5, 2016, due to abdominal pain and fever for 1 week (maximum temperature of 38.5 °C) accompanied by chills and shivering. The PD effluent from the time of her admission was positive for S. aureus. Thereafter, peritonitis recurred each month. When the third episode of peritonitis occurred, transthoracic echocardiography was performed, and a vegetation measuring 9.5 × 6.4 mm attached to the surface of the right ventricle around the ventricular septal membrane was identified. Finally, the patient was diagnosed with IE. Then, ASD repair surgery was successfully performed after the infection was controlled. The patient was followed up for 5 years, with no further episodes of recurrence.

CONCLUSIONS

When a patient with ASD undergoing PD develops peritonitis, especially relapsing peritonitis, the possibility of IE is significantly increased. ASD repair surgery may be an important contributing factor to prevent peritonitis recurrence.

Peritonitis-Related Mortality in Patients Undergoing Chronic Peritoneal Dialysis

Peritonitis is a well-known cause of mortality in peritoneal dialysis (PD) patients. We carried out a retrospective study to disclose the clinical spectrum and risk profile of peritonitis-related mortality. We analyzed 693 episodes of infectious peritonitis suffered by 565 patients (follow-up 1149 patient-years). Death was the final outcome in 41 cases (5.9% of episodes), peritonitis being directly implicated in 15.2% of the global mortality and 68.5% of the infectious mortality observed. In 41.5% of patients with peritonitis-related mortality, the immediate cause of death was a cardiovascular event. Highest mortality rates corresponded to fungal (27.5%), enteric (19.3%), and Staphylococcus aureus (15.2%) peritonitis. Multivariate analysis disclosed that the baseline risk of peritonitis-related mortality was significantly higher in female [relative risk (RR) 2.13, 95% confidence interval (CI) 1.24 – 4.09, p = 0.02], older (RR 1.10/year, CI 1.06 – 1.14, p < 0.0005), and malnourished patients (RR 2.51, CI 1.21 – 5.23, p = 0.01) with high serum C-reactive protein (s-CRP) levels (RR 4.04, CI 1.45 – 11.32, p = 0.008) and a low glomerular filtration rate (RR 0.75 per mL/minute, CI 0.64 – 0.87, p < 0.0005). Analysis of risk after a single episode of peritonitis and/or subanalysis restricted to peritonitis caused by more aggressive micro-organisms disclosed that overall comorbidity [odds ratio (OR) 1.21, CI 1.05 – 1.71, p = 0.005], depression (OR 2.35, CI 1.14 – 4.84, p = 0.02), and time on PD at the time of the event (OR 1.02/month, CI 1.00 – 1.03, p = 0.02) were other predictors of mortality.

In summary, the etiologic agent is a definite marker of peritonitis-related mortality but gender, age, residual renal function, inflammation (s-CRP), malnutrition, and depression are other significant correlates of this outcome. Most of these risk factors are common to cardiovascular and peritonitis-related mortality, which may explain the high incidence of cardiovascular event as the immediate cause of death in patients with peritonitis-related mortality.

Staphylococcus Aureus Prophylaxis and Trends in Gram-Negative Infections in Peritoneal Dialysis Patients

Objective

To examine gram-negative exit-site infection and peritonitis rates before and after the implementation of Staphylococcus aureus prophylaxis in peritoneal dialysis (PD) patients.

Design

Prospective data collection with periodic implementation of protocols to decrease infection rates in two PD programs.

Patients

663 incident patients on PD.

Interventions

Implementation of S. aureus prophylaxis, beginning in 1990.

Main Outcome Measures

Rates of S. aureus, gram-negative, and Pseudomonas aeruginosa exit-site infections and peritonitis.

Results

Staphylococcus aureus exit-site infection and peritonitis rates fluctuated without significant trends during the first decade (without prophylaxis), then began to decline during the 1990s subsequent to implementation of prophylaxis, reaching levels of 0.02/year at risk and zero in the year 2000. Gram-negative infections fell toward the end of the 1980s, due probably to the implementation of better connectology. However, there have been no significant changes for the past 6 years. There was little change in P. aeruginosa infections over the entire time period. Pseudomonas aeruginosa is now the most common cause of catheter infection and catheter-related peritonitis.

Conclusions

Prophylaxis against S. aureus is highly effective in reducing the rate of S. aureus infections but has no effect on gram-negative infections. Pseudomonas aeruginosa is now the most serious cause of catheter-related peritonitis.

Peritonitis in Latin America

Peritoneal dialysis has a high acceptance rate in Latin America, thus the knowledge concerning complication patterns is of great relevance. This work reviews Latin American data on peritonitis, the most serious complication of peritoneal dialysis.

The incidence of peritonitis has been reduced over time, concomitantly with the incorporation of safer exchange systems and the use of prophylactic measurements. Today, rates lower than 1 episode per 24 patient-months are commonly reported. Furthermore, changes in causative organisms have been observed, with predominance of Staphylococcus aureus up through the mid-1990s, as well as increases in coagulase-negative staphylococcus and participation of gram negatives. However, the prevalence of S. aureus is still high, due possibly to climatic conditions and the elevated prevalence of carriers. Resolution rate varies from 55% to 78%, transfer to hemodialysis from 10.9% to 15.4%, and death in 3% to 9.9% of cases. Outcome is worse in S. aureus episodes compared to those with coagulase-negative staphylococcus, despite the higher percentage of oxacillin-resistant strains among the former. In general, despite socioeconomic or climatic conditions, our results are similar to those in developed countries, perhaps as a consequence of technological improvements and/or center expertise.

IncreasingStaphylococcusSpecies Resistance in Peritoneal Dialysis-Related Peritonitis Over a 10-Year Period in a Single Taiwanese Center

Background

Peritonitis is a major complication of peritoneal dialysis (PD). Staphylococcus species are gram-positive bacteria that are most commonly associated with peritoneal peritonitis. The increasing antimicrobial resistance rate is a severe burden when considering the initial choice of antibiotics. This investigation examined the trends of staphylococcal infection as well as the resistance rate and clinical outcomes from 2006 to 2015 in southern Taiwan.

Methods

We retrospectively investigated all PD-related peritonitis episodes in southern Taiwan between January 2006 and December 2015 and evaluated the clinical characteristics of peritonitis, microbiological prevalence and resistance of Staphylococcus species, and outcomes in patients.

Results

Among 244 episodes of peritonitis, Staphylococcus species accounted for approximately 65% of the gram-positive bacteria that caused the infection. The methicillin resistance rate among Staphylococcus species substantially increased to 64% by 2015 in both Staphylococcus aureus and coagulase-negative staphylococci in southern Taiwan. Notably, patients with methicillin-resistant staphylococcal infection exhibited a significantly higher hospitalization rate than those with methicillin-sensitive staphylococcal infection. However, the catheter removal rate and transfer to hemodialysis exhibited no differences between the 2 groups.

Conclusion

Peritonitis is the most serious complication in patients on PD, and microbiological trends have changed over the past 10 years at a single center in southern Taiwan. The number of methicillin-resistant Staphylococcus species has substantially increased. Empirical initial antibiotic therapy should be adapted on the basis of the growing microbiological resistance.

Prevention of peritoneal dialysis catheter infections in Saudi peritoneal dialysis patients: the emergence of high-level mupirocin resistance

PURPOSE

Exit-site infection (ESI) and peritonitis remain the major causes of morbidity and mortality in peritoneal dialysis (PD) patients. This study compared the effectiveness of local mupirocin ointment and gentamicin cream in preventing both gram-positive and gram-negative bacterial infections in PD patients.

METHODS

Patients from two centers (n = 203) were assigned to daily mupirocin ointment or gentamicin cream application. Infections were tracked prospectively by organisms and expressed as episodes per patient-year for both ESI and peritonitis.

RESULTS

The rate of gram-positive ESI was 0.31/episode/patient-year and 0.22 episodes/patient-year (p<0.05), whereas the rate of gram-negative ESI was 0.28 episode/patient-year and 0.11 episode/patient-year (p<0.01) in the mupirocin group and gentamicin group, respectively. Gram-positive ESI occurred in 17.1% vs 10.2% of patients (p<0.05), whereas 20% of and 5.1% of patients (p<0.001) had gram-negative ESI in the 2 groups respectively. S.aureus was cultured at exit-site in the mupirocin group in 27.8% patients, 60% (16.7% of the total Gram-positive isolates) of them being with high-level mupirocin-resistance. Pseudomonas aeruginosa was cultured in 21.8% of ESI in the mupirocin group, and in only 6.7% in the gentamicin group (p<0.01). Peritonitis rates were lower using gentamicin cream, 0.17 episode/patient-year compared with mupirocin, 0.39 episode/patient-year (p<0.01). With multivariate analysis, only gentamicin exit-site use was a significant predictor for lower catheter infection rate.

CONCLUSION

Prolonged use of mupirocin for ESI-prophylaxis is associated with the emergence of mupirocin-resistant S. aureus. Gentamicin cream is superior to mupirocin ointment in the prevention of PD catheter infections.

Abscess formation and alpha-hemolysin induced toxicity in a mouse model of Staphylococcus aureus peritoneal infection

Staphylococcus aureus is a frequent cause of skin infection and sepsis in humans. Preclinical vaccine studies with S. aureus have used a mouse model with intraperitoneal challenge and survival determination as a measure for efficacy. To appreciate the selection of protective antigens in this model, we sought to characterize the pathological attributes of S. aureus infection in the peritoneal cavity. Testing C57BL/6J and BALB/c mice, >10(9) CFU of S. aureus Newman were needed to produce a lethal outcome in 90% of animals infected via intraperitoneal injection. Both necropsy and histopathology revealed the presence of intraperitoneal abscesses in the vicinity of inoculation sites. Abscesses were comprised of fibrin as well as collagen deposits and immune cells with staphylococci replicating at the center of these lesions. Animals that succumbed to challenge harbored staphylococci in abscess lesions and in blood. The establishment of lethal infections, but not the development of intraperitoneal abscesses, was dependent on S. aureus expression of alpha-hemolysin (Hla). Active immunization with nontoxigenic Hla(H35L) or passive immunization with neutralizing monoclonal antibodies protected mice against early lethal events associated with intraperitoneal S. aureus infection but did not affect the establishment of abscess lesions. These results characterize a mouse model for the study of intraperitoneal abscess formation by S. aureus, a disease that occurs frequently in humans undergoing continuous ambulatory peritoneal dialysis for end-stage renal disease.

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.

[Ecology and mechanisms of bacterial resistance to antibiotics in peritonitis]

Peritonitis remains a common complication of peritoneal dialysis. The aim of our study is to describe the mechanisms of antibiotic resistance in bacteria isolated during peritonitis in peritoneal dialysis, to determine whether antibiotic therapy proposed by the International Society for Peritoneal Dialysis (ISPD) is adapted to the mechanisms of resistance. All causative microorganisms of peritonitis, isolated in 106 dialysis patients and reported 170 episodes of peritonitis, during the study period (01/01/2005 to 31/12/2010) were reviewed. According to the usual classification, twelve groups of microorganism were created. An interpretive reading of antibiograms was performed in each group to identify resistance phenotypes. The species most frequently isolated are coagulase-negative staphylococci (n=73) of which 46 had PBP2a (penicillin-binding protein). Many Enterobacteriaceae were also isolated (n=45), they are susceptible to third generation cephalosporins with the exception of Enterobacteriaceae producing an extended spectrum β-lactamase (ESBL) or a cephalosporinase. Except for staphylococci, probabilistic antibiotic therapy recommended by the ISPD to treat peritonitis is effective. Indeed, many staphylococci producing a PBP2a, a first-generation cephalosporin cannot be administered in all cases. It is therefore necessary to identify patients with a strain of staphylococcus producing a PBP2a, it must be treated by vancomycin.

Staphylococcus Aureus Peritonitis in Australian Peritoneal Dialysis Patients: Predictors, Treatment, and Outcomes in 503 Cases

Staphylococcus aureus peritonitis is a serious complication of peritoneal dialysis (PD). Since reports of the course and treatment of S. aureus peritonitis have generally been limited to small, single-center studies, the aim of the current investigation was to examine the frequency, predictors, treatment, and clinical outcomes of this condition in all 4675 patients receiving PD in Australia between 1 October 2003 and 31 December 2006. 3594 episodes of peritonitis occurred in 1984 patients and 503 (14%) episodes of S. aureus peritonitis occurred in 355 (8%) individuals. 273 (77%) patients experienced 1 episode of S. aureus peritonitis, 52 (15%) experienced 2 episodes, 19 (5%) experienced 3 episodes, and 11 (3%) experienced 4 or more episodes. The predominant antibiotics used as initial empiric therapy were vancomycin (61%) and cephazolin (31%). Once S. aureus was isolated and identified, the prescription of vancomycin did not appreciably change for methicillin-sensitive S. aureus (MSSA) peritonitis (59%) and increased for methicillin-resistant S. aureus (MRSA) peritonitis (84%). S. aureus peritonitis was associated with a higher rate of relapse than non-S. aureus peritonitis (20% vs 13%, p < 0.001) but comparable rates of hospitalization (67% vs 70%, p = 0.2), catheter removal (23% vs 21%, p = 0.4), hemodialysis transfer (18% vs 18%, p = 0.6), and death (2.2% vs 2.3%, p = 0.9). MRSA peritonitis was independently predictive of an increased risk of permanent hemodialysis transfer [odds ratio (OR) 2.11, 95% confidence interval (CI) 1.17 – 3.82] and tended to be associated with an increased risk of hospitalization (OR 2.00, 95% CI 0.96 – 4.19). The initial empiric antibiotic choice between vancomycin and cephazolin was not significantly associated with clinical outcomes, but serious adverse outcomes were more likely if vancomycin was not used for subsequent treatment of MRSA peritonitis. In conclusion, S. aureus peritonitis is a serious complication of PD, involves a small proportion of patients, and is associated with a high rate of relapse and repeat episodes. Other adverse clinical outcomes are similar to those for peritonitis overall but are significantly worse for MRSA peritonitis. Empiric initial therapy with either vancomycin or cephazolin results in comparable outcomes, provided vancomycin is prescribed when MRSA is isolated and identified.

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

Background

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 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.

Methods

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 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.

Results

The 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.

Conclusion

Bacterial species and virulence factors rather than antibiotic resistance influence the outcome of staphylococcal peritonitis.

Determinants of Catheter Loss following Continuous Ambulatory Peritoneal Dialysis Peritonitis

Background

Few patients are able to resume peritoneal dialysis (PD) therapy after an episode of peritonitis that requires catheter removal. PD catheter loss is therefore regarded as an important index of patient morbidity. The aim of the present study was to evaluate factors influencing catheter loss in patients suffering from continuous ambulatory PD (CAPD) peritonitis.

Patients and Methods

We retrospectively reviewed 579 episodes of CAPD peritonitis from 1999 to 2006 in a tertiary-care referral hospital. Demographic, biochemical, and microbiological characteristics were recorded. Episodes resulting in PD catheter removal ( n = 68; 12%) were compared by both univariate and multivariate analyses with those in which PD catheters were preserved.

Results

The incidence of PD catheter loss increased as the number of organisms cultured increased ( p = 0.001). Also, PD catheter removal was more likely to occur after peritonitis episodes with low serum albumin level ( p = 0.004), those with long duration of PD effluent leukocyte count remaining above 100/μL ( p < 0.001), those with concomitant tunnel infection ( p < 0.001), those with concomitant exit-site infection ( p = 0.005), and those with presence of catastrophic intra-abdominal visceral events ( p < 0.001). Duration on PD preceding the peritonitis episode was of borderline significance ( p = 0.080). On the contrary, initial PD effluent leukocyte count and serum level of C-reactive protein were not predictive of PD catheter loss. Micro-organisms of the Enterobacteriaceae family were the major pathogens responsible for PD catheter loss following polymicrobial peritonitis. Furthermore, we found that there was no association between polymicrobial peritonitis and the catastrophic intra-abdominal visceral event, although both resulted in a greater incidence of PD catheter loss. Among the single-organism group in our population, the microbiological determinants of PD catheter loss included fungi ( p < 0.001), anaerobes ( p = 0.018), and Pseudomonas sp (borderline significance: p = 0.095).

Conclusion

PD catheter loss as a consequence of peritonitis is related primarily to hypoalbuminemia, longer duration of PD effluent leukocyte count remaining above 100/μL, the etiologic source of the infection, and the organism causing the infection. Peritonitis associated with concomitant tunnel or exit-site infections and abdominal catastrophes were more likely to proceed to PD catheter loss. The microbiological determinants of PD catheter loss in the present study included polymicrobial infections caused by Enterobacteriaceae as well as monomicrobial pseudomonal, anaerobic, and fungal infections.

Receptor-interacting protein-2 deficiency delays macrophage migration and increases intracellular infection during peritoneal dialysis-associated peritonitis

BACKGROUND

Early upregulation of receptor-interacting protein-2 (RIP2) expression during peritoneal dialysis (PD)-associated peritonitis correlates with a favorable clinical outcome, while failure to upregulate RIP2 correlates with a protracted course. We noticed that patients who do not upregulate RIP2 during PD-associated peritonitis have more peritoneal macrophages during the early phase of infection.

METHODS

To study the mechanism behind this observation, we examined the role of RIP2 in the immune response to bacterial challenge in a mouse model of acute peritonitis. We injected RIP2(+/+) and RIP2(-/-) mice intraperitoneally with a Staphylococcus epidermidis cell free-preparation, and peritoneal cells were isolated 3, 6 and 24 h after challenge.

RESULTS

Surprisingly, RIP2(-/-) mice had a comparable influx of inflammatory leukocytes, but had a significantly higher number of peritoneal macrophages at 3 h, indicating delayed emigration of these cells. No significant differences were seen at later times suggesting that migration was delayed but not inhibited. In addition, RIP2(-/-) macrophages were more permissive to intracellular infection by Staphylococcus aureus, indicating that, in the absence of RIP2, resident peritoneal macrophages could become reservoirs of bacteria.

CONCLUSION

These findings provide a mechanism for the observation that upregulation of RIP2 expression is required for rapid resolution of peritonitis, by decreasing intracellular infection and by regulating the migration of antigen-presenting cells in the early stages of an inflammatory response.

Staphylococcus aureusPeritonitis Complicates Peritoneal Dialysis: Review of 245 Consecutive Cases

Peritonitis that is caused by Staphylococcus aureus is a serious complication in peritoneal dialysis (PD), but the clinical course of PD-related S. aureus peritonitis remains unclear. All of the S. aureus peritonitis in a dialysis unit from 1994 to 2005 were reviewed. During this period, 2065 episodes of peritonitis were recorded; 245 (11.9%) episodes in 152 patients were caused by S. aureus and 45 (18.4%) episodes were caused by methicillin-resistant S. aureus (MRSA). Patients with a history of recent hospitalization had a higher risk for isolation of MRSA than the others (30.6 versus 14.2%; P = 0.004). The overall primary response rate was 87.8%; the complete cure rate was 74.3%. However, 21 (8.6%) episodes developed relapse and 59 (24.1%) developed repeat S. aureus peritonitis. Episodes that were caused by MRSA had a lower primary response rate (64.4 versus 93.0%; P < 0.001) and complete cure rate (60.0 versus 77.5%; P = 0.023) than the others. Episodes that were treated initially with vancomycin had better primary response rate than those that were treated with cefazolin (98.0 versus 85.2%; P = 0.001), but the complete cure rate was similar. Adjuvant rifampicin treatment was associated with a significantly lower risk for relapse or repeat S. aureus peritonitis than was treatment without rifampicin (21.4 versus 42.8%; P = 0.004). In contrast, initial antibiotic regimen (cefazolin versus vancomycin) and concomitant exit-site infection did not have any effect on the risk for relapse or repeat peritonitis. S. aureus peritonitis is a serious complication of PD. Recent hospitalization is a major risk factor of methicillin resistance in the bacterial isolate. Rifampicin is a valuable adjunct in preventing relapse and repeat S. aureus peritonitis after the index episode.

Randomized, double-blind trial of antibiotic exit site cream for prevention of exit site infection in peritoneal dialysis patients

Infection is the Achilles heel of peritoneal dialysis. Exit site mupirocin prevents Staphylococcus aureus peritoneal dialysis (PD) infections but does not reduce Pseudomonas aeruginosa or other Gram-negative infections, which are associated with considerable morbidity and sometimes death. Patients from three centers (53% incident to PD and 47% prevalent) were randomized in a double-blinded manner to daily mupirocin or gentamicin cream to the catheter exit site. Infections were tracked prospectively by organism and expressed as episodes per dialysis-year at risk. A total of 133 patients were randomized, 67 to gentamicin and 66 to mupirocin cream. Catheter infection rates were 0.23/yr with gentamicin cream versus 0.54/yr with mupirocin (P = 0.005). Time to first catheter infection was longer using gentamicin (P = 0.03). There were no P. aeruginosa catheter infections using gentamicin compared with 0.11/yr using mupirocin (P < 0.003). S. aureus exit site infections were infrequent in both groups (0.06 and 0.08/yr; P = 0.44). Peritonitis rates were 0.34/yr versus 0.52/yr (P = 0.03), with a striking decrease in Gram-negative peritonitis (0.02/yr versus 0.15/yr; P = 0.003) using gentamicin compared with mupirocin cream, respectively. Gentamicin use was a significant predictor of lower peritonitis rates (relative risk, 0.52; 95% confidence interval, 0.29 to 0.93; P < 0.03), controlling for center and incident versus prevalent patients. Gentamicin cream applied daily to the peritoneal catheter exit site reduced P. aeruginosa and other Gram-negative catheter infections and reduced peritonitis by 35%, particularly Gram-negative organisms. Gentamicin cream was as effective as mupirocin in preventing S. aureus infections. Daily gentamicin cream at the exit site should be the prophylaxis of choice for PD patients.

[Infection peritonitis in patients undergoing continuous ambulatory peritoneal dialysis: microbiological review during an four-year period]

The purpose of this study was to analyse the microbiological characteristics of infectious peritonitis in patients undergoing continuous ambulatory peritoneal dialysis. This study was conducted at the CHU Nancy from 1999 to 2002. The diagnosis of peritonitis was based on cloudy peritoneal effluent (>100 cells per mm(3)) with an elevated leukocyte count (>50%), on isolation of bacteria or fungi and on symptoms such as abdominal discomfort or pain. The majority of infections associated with continuous ambulatory peritoneal dialysis were caused by Gram-positive bacteria (68%), Gram-negative bacteria (31%), and Candida (1%). The coagulase-negative staphylococci were the most common cause of peritonitis. The antibiotic sensitivity of species corresponded to community-acquired isolation.