Mycobacterium fortuitum peritonitis associated with continuous ambulatory peritoneal dialysis

Mycobacterium fortuitum as a cause of peritoneal dialysis-associated peritonitis: case report and review of the literature

Background

Peritoneal dialysis-associated peritonitis (PD-peritonitis) due to Mycobacterium spp is uncommon. Non-tuberculous Mycobacterium (NTB) PD-peritonitis can present in a similar fashion to more common causes of bacterial PD-peritonitis. We describe the first reported case of multiresistant Mycobacterium fortuitum PD-peritonitis in an Australian patient.

Case presentation

A 38 year-old woman developed mild PD-peritonitis during an overseas holiday. Treatment was complicated by delayed diagnosis, requirement for special investigations, treatment with multiple antibiotics, and conversion to haemodialysis following removal of her Tenckhoff catheter.

Conclusion

This case demonstrates the diagnostic yield of pursuing further investigations in cases of initially culture-negative, problematic PD-peritonitis. A systematic review of the literature identified only 17 reports of M. fortuitum PD-peritonitis. Similar to our case, a delay in microbiological diagnosis was frequently noted and the Tenckhoff catheter was commonly removed at the time of diagnosis. The type and duration of antibiotic therapy also varied widely so the optimum treatment appears to be poorly defined.

Peritonitis from Mycobacterium wolinskyi in a chronic peritoneal dialysis patient

We report the case of acute peritonitis caused by a rapidly growing mycobacterium in a chronic peritoneal dialysis patient, whose renal failure had been caused by diabetic glomerulosclerosis. The organism cultured from the peritoneal dialysis fluid was Mycobacterium wolinskyi. Peritonitis caused by M. wolinskyi in a chronic peritoneal dialysis patient has never been reported before.

Peritoneal dialysis-associated nontuberculous mycobacterium peritonitis: a systematic review of reported cases

BACKGROUND

Peritonitis caused by nontuberculous mycobacterium (NTM) is an important complication in peritoneal dialysis (PD) patients.

METHODS

Cases of PD complicated by NTM peritonitis reported in the English language literature were identified in the PubMed database. The characteristics of these cases were reviewed.

RESULTS

In 41 articles, we identified 57 cases of PD-associated NTM peritonitis in patients ranging from 5 to 82 years. The prevalent clinical findings of these cases were fever, abdominal pain, cloudy fluid and an elevated leukocyte count in peritoneal fluid. These findings were non-specific and could not be differentiated from symptoms caused by Mycobacterium tuberculosis or other bacteria. The majority of these cases received empirical antibacterial therapy before diagnosis of NTM peritonitis. Isolates in more than half of the peritonitis cases were the rapidly growing Mycobacterium, Mycobacterium fortuitum (38.6%) and Mycobacterium chelonae (14.0%). In most cases, PD catheters were removed and experience with non-removal was limited.

CONCLUSION

Diagnosis of NTM infection should be considered in PD patients with peritonitis that are culture negative or refractory to empirical antibiotic therapy.

The clinical course of rapidly growing nontuberculous mycobacterial peritoneal dialysis infections in Asians: A case series and literature review

INTRODUCTION

Peritoneal dialysis (PD)-related infections due to rapidly growing nontuberculous mycobacterium (RGNTM) are rare in Asians and have variable clinical outcomes.

METHODS

We analysed retrospectively a series of RGNTM infections in a single-centre multi-ethnic Asian population over a 5-year period. Clinical features, treatment, risk factors and outcomes are discussed.

RESULTS

Ten infections are described. They constituted 3% of all culture-positive exit site infection (ESI) and PD peritonitis. Seventy percent were due to Mycobacterium abscessus (three ESI and four peritonitis). There were two Mycobacterim fortuitum and one Mycobacterium chelonei peritonitis. No specific findings differentiated RGNTM infections from those caused by traditional organisms. Six cases had received prior antibiotics, two being topical gentamicin. Initial routine culture and alcohol acid fast bacillus were negative except for one case of M. abscessus. A confirmatory diagnosis was made a median 9 days post culture. No infection responded to routine antibiotics. Antibiotic resistance was variable but M. abscessus was universally sensitive to clarithromycin. Combined antibiotics based on sensitivity profile were successfully used in 70% of the cases. PD catheter loss was 80%. Three-month mortality was 40% (vs. 8.5% and 12% in non-RGNTM ESI and peritonitis, respectively). This may be related to the cohort high mean Charlson score of 7.5.

CONCLUSION

RGNTM PD infections are commoner in Asians than previously reported. Their early diagnosis requires a high index of suspicion and appropriate treatment started promptly. They are associated with prior antibiotic use and refractory culture-negative infections, delayed diagnosis and lead to significant catheter loss and death.

A cluster of rapidly growing mycobacterial peritoneal dialysis catheter exit-site infections

In this case series, a cluster of 5 consecutive peritoneal dialysis patients with atypical mycobacterial exit-site infections in a single center within 20 months are described. Clinical features, treatment, and outcomes are discussed. Most patients had been treated with prolonged systemic antibiotic therapy for recurrent bacterial exit-site infections in the preceding months, and all had used topical gentamicin ointment for exit-site infection treatment or prophylaxis. It is postulated that this might have predisposed them to atypical mycobacterial exit-site infection as a result of selection pressure on uncommon organisms.

Murine infection model for Mycobacterium fortuitum

Mycobacterium fortuitum is an atypical, non-tubercular, pathogenic, rapidly growing mycobacteria. As very little is known about its virulence determinants, the absence of an animal infection model was always sorely felt. A reliable and reproducible murine infection model has been developed in which non-replicating persistence of 10(5) CFU/g tissue in kidney was observed when a standardised dosage inoculum of 5x10(7) CFU was injected intravenously. The tissue bacillary load was determined at regular intervals (10, 25, 45 and 60 days post-inoculation) in different organs, viz., kidney, spleen, lung and liver. Histopathology of kidney revealed tissue damage and granuloma-like formations which appear to be part of the host's effort to combat the infection. As IFN-gamma is known to trigger antimycobacterial effects of murine macrophages, IFN-gamma was assayed to determine the correlation between host protective measures and bacillary load in kidney. Fifteen days after infection, the level of IFN-gamma secreted by CD4+ and CD8+ T lymphocytes was high, concomitant with high tissue bacillary load, while the level sharply declined as the number of bacilli in kidney decreased 45 days post-inoculation. The invasion and proliferation of M. fortuitum ATCC 6841, when incubated with non-phagocytic (recombination activating genes (RAG) murine kidney) and phagocytic (murine peritoneal macrophages) cell lines, was assessed. M. fortuitum did not invade RAG murine kidney cell line, while the bacilli infected and proliferated freely inside murine macrophages. In conclusion, we present a reproducible murine infection model that sustains a persistent infection, the progression of which correlates meaningfully with host protective response.