Case report: Ulocladium spp. (mold) catheter-related peritoneal dialysis-associated peritonitis

Introduction

Peritoneal dialysis-associated peritonitis (PD peritonitis) is a common complication of PD. While most PD peritonitis cases are bacterial, approximately 5% are fungal. ¹ Fungal peritonitis is challenging to treat with mortality rates ranging from 5% to 53%.^2–4 Fungal peritonitis is predominately Candidal (60–90%); filamentous fungi account for the remaining cases. ⁵ Diagnosis is established by meeting at least two of the three following: (1) abdominal pain or cloudy peritoneal effluent, (2) a dialysate WBC count >100/µL with a >50% neutrophilic shift, or (3) a positive culture of peritoneal fluid. ⁶ Our patient met all three criteria. To date, this is the first known documentation of the filamentous fungus “Ulocladium” as a cause for PD peritonitis.

Ulocladium spp. are saprophytic molds found in damp, humid environments. ⁷ Ulocladium spp. have been found to cause allergic sinusitis and occasionally cutaneous infections in immunocompromised patients. ⁸ Systemic infections with Ulocladium spp. have not been reported.

Despite sparse treatment data on Ulocladium spp., management of fungal peritonitis during PD universally includes prompt removal of the peritoneal catheter and empiric treatment with systemic antifungals. Amphotericin B was chosen for this patient, as it is the preference when species identity is uncertain. ⁶ Other options could include azoles, such as voriconazole or posaconazole.

This report highlights prevention, early detection, and management principles for Ulocladium peritonitis.

Case report

A 65-year-old female with end-stage kidney disease (ESKD) secondary to hypertensive nephrosclerosis, managed for two years with automated PD, presented for evaluation after noting black spots within her PD catheter lumen. She was uncertain when they first appeared. She was otherwise asymptomatic.

PD catheter with intraluminal spot after removal.

Her social history was significant for recent extended travel to the Philippines and remote tobacco use. The patient's medications included antihypertensives (amlodipine, losartan, metoprolol succinate), diuretics (torsemide), and renal adjunct medications (cinacalcet, sevelamer, sodium bicarbonate, sodium zirconium cyclosilicate). She had never had peritonitis before.

Vitals were normal; exam showed no erythema or exudate at the PD catheter exit site, though small black intraluminal spots within the patient's PD catheter were newly observed. On the day of her presentation, peritoneal effluent was turbid without sediment. Analysis revealed 2687 WBC/µL (56% neutrophils) consistent with PD peritonitis. CT imaging on Day 9 revealed moderate ascites consistent with ESKD on PD. Preliminary effluent cultures grew a mold of uncertain taxonomy.

Empiric intravenous liposomal amphotericin B (3 mg/kg/day) was started on Day 10. On Day 12, the PD catheter was removed and a hemodialysis permcath inserted, which was cleared for immediate use. Infectious disease consultants supported a four-week amphotericin course.

Due to its uncertain taxonomy, the fungal isolate was directed to Quest Diagnostics for further identification. Identification was performed using a phenotypic method. Isolate was cultured on Potato Flake Agar. Macroscopic examination showed a fast growing, cottony, dark olive in color colony on the surface and reverse (Supplement 1). A small portion of the isolate was placed onto a slide with Lactophenol Cotton Blue. Microscopic examination showed dematiaceous mold with septate hyphae. Conidiophores were brown and geniculate. Conidia were muriform (septa both horizontal and longitudinal), oval, with smooth walls formed singly (Figure 1).

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Figure 1.

Microscopic examination of lactophenol cotton blue slide (400×).

Sensitivity was confirmed and amphotericin B was continued. During Week 3 of antifungal therapy, the patient visited the emergency department (ED) for severe new back pain. In the ED patient was prescribed hydromorphone, which did not improve the pain. Upon learning of this episode, her PD care team ordered a repeat CT due to concern for abscess formation, which showed resolution of the previous ascites and demonstrated no abscess. Amphotericin B was completed after four weeks without further adverse effects. At the time of treatment completion, patient noted spontaneous improvement in her back pain.

At Week 10, laparoscopy for PD catheter replacement showed no evidence of infection or adhesions. The patient resumed PD without recurrence. See Table 1.

Discussion

Fungal peritonitis is an uncommon but dangerous PD complication. ⁹ Biofilm formation and limited antifungal penetration decrease treatment efficacy and worsen mortality, emphasizing the need for rapid diagnosis and prompt source control. ¹⁰ Ulocladium was identified as the cause of PD peritonitis in this case.

Ulocladium spp. are common in many environments, including damp homes, within settled dust, mattresses, water-logged building materials, and soil. ⁶ Yet for their ubiquity, Ulocladium spp. are uncommon human pathogens, typically only arising in opportunistic settings such as in immuno-compromised patients. The low pathogenicity of Ulocladium spp. raises the question of why this patient may have contracted such an unusual pathogen.^10,11

Our patient lacked the typical risk factors for fungal peritonitis including broad-spectrum antibiotic exposure, overt immunocompromise, diabetes, bowel perforation, prior bacterial peritonitis, or historically poor line care. ¹² Hers was the first case of fungal peritonitis diagnosed at our dialysis center. She had recently traveled to a humid environment and based on the ecology of Ulocladium it may be conjectured this increased her environmental exposure.

While this appears to be the first case of Ulocladium peritonitis, Alternaria, a close phylogenetic relative of Ulocladium, has caused PD peritonitis in prior reports dating back to the 1980s. In those cases, treatment with amphotericin B or triazoles yielded variable outcomes; both mortality and peritoneal fibrosis secondary to inflammation preventing further PD were reported.^13–19 Inasmuch, despite the low incidence, clinicians should seek to recognize peritoneal infection by dematiaceous filamentous fungi early and to treat the infections with urgency to ward against any such extreme complications.

Current guidelines recommend catheter removal and initiation of systemic antifungals within 24 h of recognized fungal peritonitis, as research suggests this has a notable effect on mortality.^17,20 Additionally, some limited evidence has emerged supporting the use of Tamoxifen for prevention of encapsulating peritonitis in the setting of PD peritonitis. Ultimately, Tamoxifen was not initiated in this patient as its use is off-label and the current level of evidence to support its use is low. ⁶

In this patient, fungal peritonitis was recognized within nine days of presentation, amphotericin B therapy initiated on the 10th day, and the PD catheter removed on the 12th day. Though this patient's outcomes were favorable and amphotericin B initiation punctual, the removal of the PD catheter could be considered delayed and represents an area for future improvement. Empiric antibiotics are also recommended at the time of suspected peritonitis, even in clinically stable patients. ⁶ Lastly, a final effluent culture for test of cure would have been appropriate.

Conclusion

Fungal PD peritonitis is rare, yet serious by virtue of its high morbidity and mortality. To our knowledge, this case represents the first documentation of Ulocladium peritonitis, expanding the list of opportunistic filamentous fungi associated with peritoneal dialysis. This patient had none of the generally accepted risk factors for contracting fungal peritonitis; however, her recent travel to a humid clime may have contributed to her colonization.

Though the patient's final diagnosis was mildly delayed owing to its rarity, the recognition of mold peritonitis was relatively quick and appropriate antifungal therapy was initiated promptly, allowing the patient to achieve a favorable outcome. Immediate PD catheter removal after diagnosis of fungal PD and initiation of empiric antibiotics on first suspicion of PD peritonitis are both areas for improvement from this case, underscoring a need for close attention to updated practice guidelines.

This case demonstrates the need to maintain suspicion for fungal peritonitis in the setting of PD and to carefully evaluate patients’ PD catheters at each visit, especially as PD continues to expand as a management strategy for ESKD. Future research might explore the risks of environmental exposures during peritoneal dialysis or strategies for preventing biofilm growth in PD catheter lumens.

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Table 1.

Timeline of patient events.

Timeline (Day)	Event	Results
0	Initial encounter: spots on catheter reported; peritoneal effluent analysis, peritoneal effluent culture	Significant effluent leukocytosis, preliminary effluent culture growing mold later identified as Ulocladium spp.
9	CT of the abdomen and pelvis performed	Nonspecific ascites consistent with ESKD on PD
10	Liposomal amphotericin B initiated	3 mg/kg/day
12	PD catheter removed	Hemodialysis permcath placed
34	ED visit for back pain	Prescribed hydromorphone
40	Amphotericin B course completed	Symptoms resolved
41	Repeat CT performed for back pain, concern for abscess	Negative
75	Laparoscopy and PD catheter replacement	No intraabdominal evidence of mold persistence or adhesive disease, return to PD

ESKD: end-stage kidney disease; ED: emergency department; PD: peritoneal dialysis.

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