Aspergillus peritonitis in peritoneal dialysis patients: A systematic review

Fungal peritonitis in patients undergoing peritoneal dialysis (PD) is very difficult to treat and is associated with significant morbidity and mortality. Among fungal pathogens, Aspergillus peritonitis presents a higher mortality rate when compared to Candida peritonitis and its identification as well as appropriate treatment remains a challenge for the physicians. We critical reviewed all published cases in literature of Aspergillus peritonitis in PD patients. The results showed that a total of 55 cases (51% males) of Aspergillus peritonitis in PD patients were reported from 1968 to 2019. Mean patient age was 49.54±19.63years and mean PD duration prior to fungal infection was 33.31±32.45months. Aspergillus fumigatus was isolated in 17/55 patients, Aspergillus niger in 15, Aspergillus terreus in 9, unidentified Aspergillus spp. in 6, Aspergillus flavus in 4, whereas sporadic cases of other Aspergillus spp. were reported. As far as predisposing factors are concerned, 75% of patients suffered from prior bacterial peritonitis receiving antimicrobial therapy. Initial antifungal treatment was intravenous and/or intraperitoneal administration of amphotericin B formulations monotherapy in 47.2% of patients or in combination with fluconazole in 13.2%, or with itraconazole in 13.2%, or with caspofungin in 3.8%, or with ketoconazole or with 5-FC in 1.9%, each. Peritoneal catheter removal was performed in 85.5% of cases. Mortality rate was 38.2%, while 81.8% of the survived patients switched to hemodialysis. Conclusively, Aspergillus peritonitis diagnosis can be difficult, due to unspecific symptoms. Early treatment with appropriate antifungal agents can be determinant for patient prognosis. Despite appropriate treatment, reported mortality remains high.

Update on the challenging role of biofilms in peritoneal dialysis

Biofilms are commonly associated with an increased risk of patient infection. In peritoneal dialysis (PD), catheter associated infection, especially peritonitis, remains a clinically relevant problem. Although the presence of a biofilm is recognized in relapsing, repeat, and catheter-related peritonitis, it remains poorly characterized. In this review, an update on the role of biofilms in PD infections is presented. The emerging concept that host cells and tissue associated biofilms, in addition to the biofilms on the catheters themselves, contribute to the recalcitrance of infections is discussed. Furthermore, the evidence of biofilms on PD catheters, their developmental stages, and the possible influence of the PD environment are reviewed. The focus is given to ex vivo and in vitro studies that contribute to the elucidation of the interplay between host, microbial, and dialysis factors. The key issues that are still to be answered and the challenges to clinical practice are discussed.

Patient's cells colonize the biofilm of Tenckhoff catheters used in peritoneal dialysis

Peritoneal dialysis (PD) is a renal substitutive therapy based on the infusion of a dialysate in the peritoneum, which induces through an osmotic gradient the ultrafiltration of water and the clearance of blood stream impurities by the peritoneal membrane. The colonization of Tenckhoff catheters (TCs) used in PD by pathogenic microorganisms can lead to peritonitis, and probably catheter removal. Here, optical microscopy and scanning electron microscopy were applied to study biofilm formation in 11 TCs. Biofilms varied in their morphology and thickness. Short-term catheters (6 months) presented thinner deposits (3 μm) with granular or flat morphologies, either on the intraluminal or external surfaces. Bacterial colonies were found on catheters from infected patients. A tendency was observed for long-term catheters (6-8 years) to present thicker biofilms (30-35 μm). Surprisingly, patients' cells colonized the deep layers of the thicker biofilms, forming a complex multicelullar community. It was concluded that the presence of a biofilm is not necessarily related with peritonitis, and biofilm features may correlate to the therapy time.

Secondary sternal Aspergillus osteomyelitis in a diabetic hemodialysis patient with previous allograft rejection

A 29-year-old diabetic woman who had a previously failed renal allograft on maintenance hemodialysis developed sternal aspergillosis with Aspergillus terreus following a pericardiectomy. She was successfully treated with surgical debridement and a combination of antifungal agents including amphotericin B, caspofungin, and voriconizole. The diagnostic difficulties and management are discussed.