Fungal Peritonitis in Peritoneal Dialysis Patients

Peritonitis is one of the most frequent complications of peritoneal dialysis (PD) and 1% – 15% of episodes are caused by fungal infections. The mortality rate of fungal peritonitis (FP) varies from 5% to 53%; failure to resume PD occurs in up to 40% of patients. The majority of these FP episodes are caused by Candida species. Candida albicans has historically been reported to be a more common cause than non-albicans Candida species, but in recent reports a shift has been observed and non-albicans Candida may now be more common. Unusual, often “nonpathogenic,” fungi are being increasingly reported as etiologic agents in FP. Clinical features of FP are not different from those of bacterial peritonitis. Phenotypic identification of fungi in clinical microbiology laboratories is often difficult and delayed. New molecular diagnostic techniques ( e.g., polymerase chain reaction) are being developed and evaluated, and may improve diagnosis and so facilitate early treatment of infected patients. Abdominal pain, abdominal pain with fever, and catheter left in situ are risk factors for mortality and technique failure in FP. In programs with high baseline rates of FP, nystatin prophylaxis may be beneficial. Each program must examine its own history of FP to decide whether prophylaxis would be beneficial. Catheter removal is indicated immediately after fungi are identified by Gram stain or culture in all patients with FP. Prolonged treatment with antifungal agents to determine response and attempt clearance is not encouraged. Antifungals should be continued for 10 days to 2 weeks after catheter removal. Attempts at reinsertion should be made only after waiting for 4 – 6 weeks.

Treatment of Fungal Peritonitis with a Combination of Intravenous Amphotericin B and Oral Flucytosine, and Delayed Catheter Replacement in Continuous Ambulatory Peritoneal Dialysis

Background

Fungal peritonitis (FP) is associated with significant mortality and high risk of peritoneal failure. The optimum treatment for peritoneal dialysis (PD)-associated FP remains unclear. Since January 2000 we have been treating FP with a combination of intravenous amphotericin B and oral flucytosine, together with deferred catheter replacement. We examined the clinical course and outcome of the FP patients treated with this approach (study group). An outcome comparison was also made to an alternatively treated historic cohort (control group).

Methods

This was a single-center retrospective study. The clinical course and outcome of 13 consecutive episodes of FP occurring in 13 patients treated between January 2000 and April 2005 with the study approach were examined. The patients were treated with an incremental dose of intravenous amphotericin B to a target dose of 0.75 – 1 mg/kg body weight/day, and oral flucytosine 1 g/day upon a diagnosis of FP at 3.77 ± 0.93 days from presentation. Replacement of the peritoneal catheter was intended after complete clearing of effluent, after which, antifungal chemotherapy was continued for another 1 – 2 weeks. Their outcome was compared with 14 historic controls that were treated between April 1995 and December 1999.

Results

Mean age of the study group was 58.7 ± 13.2 years; male-to-female ratio was 2:11; 6 (46.1%) were diabetic. All FP were caused by Candida species ( C. albicans, 2; C. parapsilosis, 8; C. glabrata, 3). Two (15.4%) patients died before resolution of the peritonitis. The dialysate effluent cleared in 11 patients (84.6%) after 13.2 ± 3.3 days of treatment, but 2 patients died of acute myocardial infarction before catheter replacement. Nine patients had their catheters replaced at day 26.7 ± 7.7 of treatment; all 9 returned to PD after a total of 31 ± 12.2 days of antifungal chemotherapy. Reversible liver dysfunction was common with this regimen. When compared with the 14 cases in the historic control group ( Candida species, 13; Trichosporon, 1), who were treated with amphotericin B, fluconazole, or a combination of the two, and the majority (78.6%) of whose catheters were removed before day 10 of presentation, the study group appeared to have a lower technique failure rate (30.8% vs 78.6%, p = 0.013) and similar all-cause mortality (30.7% vs 28.5%, p = NS), FP-related mortality (15.4% vs 28.5%, p = NS), and length of hospitalization (48.5 ± 30.2 vs 57.0 ± 37.7 days, p = NS). However, a significantly earlier commencement of antifungal treatment in the study group (3.8 ± 0.9 vs 5.8 ± 2.4 days, p = 0.012) could be an important confounder of outcome.

Conclusions

Combination of intravenous amphotericin B and oral flucytosine with deferred catheter replacement appears to be associated with a relatively low incidence of PD technique failure, without affecting mortality in patients suffering from FP due to yeasts in this preliminary study. Nonetheless, drug-induced hepatic dysfunction was common; close monitoring during treatment is of paramount importance. The reasons accounting for the observed distinctive outcome remain unclear and further study is required to confirm the results and to investigate for the underlying mechanism.

Successful treatment of Cryptococcus laurentii peritonitis in a patient on peritoneal dialysis

A 32-year-old man on peritoneal dialysis (PD) was hospitalized for seven days due to fever. A diagnosis of yeast-like fungal peritonitis was made by Gram staining. The patient was started on intravenous micafungin and oral fluconazole therapy following removal of the PD catheter. A fungal pathogen was isolated from the peritoneal fluid and identified as Cryptococcus species. Based on antifungal susceptibility testing, the treatment was changed to voriconazole and continued for 3 months. A genetic analysis identified the isolate as Cryptococcus laurentii (C. laurentii). This patient was diagnosed with C. laurentii PD-related peritonitis and was successfully treated with voriconazole and removal of the PD catheter.

Amphotericin B removal by plasma exchange

This case report adds pharmacokinetic knowledge regarding amphotericin B. Amphotericin B is highly protein bound. Plasma exchange removes 50-75% of a substance in plasma within 1-2 h, corresponding to an elimination half-life of 30-40 min. Amphotericin B reduction ratio by plasma exchange was 40% in this patient who had both liver and renal failure.

Update on Fungal Peritonitis and its Treatment

Fungal peritonitis (FP) is a rare but potentially fatal complication of chronic peritoneal dialysis (PD), associated with high morbidity and mortality ranging between 20% and 30%. If not leading to death, the inflammatory process usually causes irreversible damage to the peritoneal membrane with subsequent dropout from PD therapy. Fungal peritonitis accounts for 3% – 6% of all peritonitis episodes; however, in some areas, the numbers can be much higher. The most common cause of the disease is Candida, predominately C. albicans, C. parapsilosis, and—more recently— C. glabrata; other yeasts and filamentous fungi such as Aspergillus, Paecilomyces, Penicillium, and Zygomycetes are found, but much less frequently. The main factors associated with the development of FP include previous antibiotic therapy, particularly for bacterial peritonitis, when two important operative mechanisms coincide: fungal overgrowth in the gastrointestinal tract and declining peritoneal defense because of peritonitis.

The management of FP poses a difficult challenge. Prompt initiation of therapy is critical, but no typical clinical picture has emerged, and the infecting organism can be difficult to isolate. The approach to the disease has changed considerably in recent years, and the 2005 guidelines from the International Society for Peritoneal Dialysis list FP as a strong indication for immediate catheter removal with temporary hemodialysis. The conventional antifungal regimens include fluconazole, amphotericin B, and flucytosine alone or in combination, optimally based on fungal sensitivities. The newer agents such as caspofungin and voriconazole have the potential to alter treatment strategies for FP, but further studies are required to clarify the precise role of these agents in this group of patients.

Fungal peritonitis in children on peritoneal dialysis

Fungal peritonitis is a rare but serious complication in children on peritoneal dialysis (PD). In this study, risk factors were evaluated, and therapeutic measures were reviewed. A retrospective, multi-centre study was performed in 159 Dutch paediatric PD patients, between 1980 and 2005 (3,573 months). All peritonitis episodes were reviewed. Fungal peritonitis episodes were evaluated based on possible risk factors and treatment strategy. A total of 321 episodes of peritonitis occurred, with 9 cases of fungal peritonitis (2.9%). Candida peritonitis occurred most frequently (78%). Seven patients (78%) had used antibiotics in the prior month. Fungal peritonitis patients had a higher previous bacterial peritonitis rate compared to the total study population (0.13 versus 0.09 episodes/patient*month), with twice as many gram negative organisms. In all fungal peritonitis patients, the PD catheter was removed. In four patients restart on PD was possible. Fungal peritonitis is a rare complication of PD in children, but is associated with high technique failure. The most important risk factors are a high bacterial peritonitis rate, prior use of antibiotics, and previous bacterial peritonitis with gram negative organisms. The PD catheter should be removed early, but in children, peritoneal lavage with fluconazole before removal may be useful to prevent technique failure.

Candida parapsilosis peritonitis has more complications than other Candida peritonitis in peritoneal dialysis patients

Candida parapsilosis is the most prevalent pathogen of fungal peritonitis in peritoneal dialysis (PD). The difference between C. parapsilosis peritonitis and other C. species for clinical outcomes and treatment responses to fungal peritonitis remains unclear. This retrospective study of fungal peritonitis attempts to answer that question. A total 22 patients with fungal peritonitis in 762 PD patients were enrolled in this study. The mean age of the 22 patients, 9 males and 13 females, was 54.7 +/- 12.5 years with a mean PD duration of 39.7 +/- 33.4 months. Candida species accounted for 86% (19 cases) of fungal peritonitis and 41% (9 cases) were C. parapsilosis. Thirteen (59%) patients received fluconazole as monotherapy; others received either amphotericin B alone or in combination with fluconazole. Catheters were removed for all patients. The mean duration from peritonitis onset to catheter removal was 5.8 +/- 4.1 days. Eleven (50%) patients developed severe complications, with abscess formation or persistent peritonitis after catheter removal. C. parapsilosis peritonitis had a higher complication rate than other Candida species (78% versus 20%, p = 0.012). In patients who received fluconazole as monotherapy, the rate of severe complications of C. parapsilosis peritonitis was statistically higher than those of other Candida species (100% versus 29%, p = 0.013). Because of different severity and prognosis, C. parapsilosis peritonitis in PD patients should be treated more aggressively than other Candida species.

Prediction of human intestinal absorption of drug compounds from molecular structure

The absorption of a drug compound through the human intestinal cell lining is an important property for potential drug candidates. Measuring this property, however, can be costly and time-consuming. The use of quantitative structure-property relationships (QSPRs) to estimate percent human intestinal absorption (%HIA) is an attractive alternative to experimental measurements. A data set of 86 drug and drug-like compounds with measured values of %HIA taken from the literature was used to develop and test a QSPR mode. The compounds were encoded with calculated molecular structure descriptors. A nonlinear computational neural network model was developed by using the genetic algorithm with a neural network fitness evaluator. The calculated %HIA (cHIA) model performs wells, with root-mean-square (rms) errors of 9.4%HIA units for the training set, 19.7%HIA units for the cross-validation (CV) set, and 16.0%HIA units for the external prediction set.

Fatal Hormonema dematioides peritonitis in a patient on continuous ambulatory peritoneal dialysis: criteria for organism identification and review of other known fungal etiologic agents

We report a fatal case a fungal peritonitis caused by the yeast-like dematiaceous mould Hormonema dematioides in a 45-year-old woman. The woman had a 13-year history of insulin-dependent diabetes mellitus and had been on continuous ambulatory peritoneal dialysis for chronic renal failure. H. dematioides was repeatedly isolated from the dialysate culture specimens collected on days 3, 9, 16, and 20 of her hospital stay. Preliminary culture reports on day 7 of the growth of a yeast-like fungus, a probable Candida species, prompted the administration of fluconazole (FLU). Intraperitoneal and intravenous FLU failed to eliminate the mould, and the patient expired on day 21 of her hospital stay. We use this case to present what appears to be the first report of fungal peritonitis due to H. dematioides, to provide laboratorians with criteria for differentiating this organism from the similar mould Aureobasidium pullulans and from various yeast genera, and to provide a review of known fungal taxa inciting peritonitis.