NDT Advance Access originally published online on May 21, 2008
Nephrology Dialysis Transplantation 2008 23(8):2693-2694; doi:10.1093/ndt/gfn252
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Nocardia asteroides peritoneal dialysis-related peritonitis: a case of successful treatment and return to peritoneal dialysis
1 Department of Renal Medicine 2 Department of Clinical Microbiology, Middlemore Hospital, Manukau, New Zealand
Correspondence and offprint requests to: M. R. Marshall, Department of Renal Medicine, Middlemore Hospital, Private Bag 93311, Auckland, New Zealand. Tel: +64-9-2760000; Fax +64-9-2760034; E-mail: mrmarshall{at}middlemore.co.nz, mrmarsh{at}woosh.co.nz
Keywords: Nocardia asteroides; peritoneal dialysis; Peritonitis; CAPD; Microbiolgical resistance
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A 66-year-old male from rural Manukau, New Zealand, presented to hospital with 2 weeks of generalized abdominal pain and cloudy PD effluent. He had been on PD for 3 years, with only one previous episode of PD-related peritonitis secondary to Streptococcus oralis a year prior. Other significant co-morbidity included well-controlled Type 2 diabetes mellitus on diet therapy, hypertension, mild chronic obstructive airways disease and quiescent gout.
On initial examination, the patient was afebrile with blood pressure of 140/70mmHg. Abdominal examination showed generalized tenderness and normal bowel sounds. The PD catheter exit site was normal. Microscopy of dialysate showed 1600 leucocytes, 86% of which were neutrophils, and no organisms. After initial investigations, antibiotic treatment was commenced for PD-related peritonitis with empirical intraperitoneal cephazolin and gentamicin.
His dialysate sample was processed in our microbiology laboratory; this involved inoculation of 10 mL into both BacT/ALERT FA aerobic and FN anaerobic blood culture bottles (bioMérieux, Marcy-l’Etoile, France), with the deposit from 10 mL of centrifuged sample inoculated onto two sheep blood agar plates, incubated in 5% CO2 and anaerobically, and one chocolate agar plate incubated in 5% CO2. After 5 days incubation, the BacT/ALERT FA aerobic bottle was reported as growing a fungus. Since one of the enrichment broths had become positive, the primary agar plates were held longer than the usual 5 days, but remained culture negative after 21 days.
The patient was therefore treated as fungal peritonitis with a change in his antibiotic regimen to fluconazole 200 mg orally on alternate days and removal of his PD catheter with commencement of interim haemodialysis. He continued without clinical improvement, until the isolate initially reported as a fungus was found on subculture 3 days later to be a Nocardia species. This isolate was forwarded to the local reference laboratory, and biochemical testing and partial sequencing of the 16S rRNA gene confirmed the isolate as Nocardia asteroides. Broth microdilution minimum inhibitory concentration (MIC) tests were performed according to Clinical and Laboratory Standards Institute (CLSI) methods [1]. The MICs for trimethoprim-sulphamethoxazole were 4/76 mg/L when read at 72 h, noting that MICs 
4/76 mg/L for Nocardia are considered resistant using CLSI interpretive criteria. For comparison, an Epsilon test (E-test, AB Biodisk, Sweden) was also performed to measure the MIC for trimethoprim-sulphamethoxazole with a result of 0.12 mg/L.
Following these results, the patient's antibiotic regimen was changed to trimethoprim-sulphamethoxazole 960 mg orally daily. He responded well with steady improvement of abdominal pain, and was discharged after a total of 18 days with a plan for a further 12 months of oral trimethoprim-sulphamethoxazole as an outpatient. He subsequently made steady progress, with complete resolution of abdominal pain and normalization of his c-reactive protein by 6 months. Because of his wish to return to PD, we performed diagnostic ultrasonography and laparoscopy of his abdomen which revealed no residual fluid collections and visually normal peritoneum with minimal adhesions, respectively. A PD catheter was subsequently re-inserted a year after his Nocardia peritonitis, and PD recommenced which remains his modality until the present time.
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Discussion |
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Nocardia is an uncommon cause of PD-related peritonitis [2]. The species of the genus Nocardia are gram-positive branching bacteria belonging to the order Actinomycetales. They are ubiquitous in the environment and are found in soil, fresh and salt water and decaying vegetation. Our patient had potential environmental exposure through his rural lifestyle, and we speculate that contaminated soil or water containing Nocardia was introduced to his peritoneum via his PD catheter by touch contamination. Nocardiosis can occur in immunocompetent hosts, but the majority of cases are in the immunocompromised, particularly those with abnormalities of cell-mediated immunity. Hallmark characteristics of Nocardia are its ability to disseminate and the tendency for infection to relapse or progress in spite of appropriate treatment.
There are three teaching points from our experience. Firstly, cases of Nocardia PD-related peritonitis generally present as infection unresponsive to empirical treatment and initially an apparent ‘culture-negative’ peritonitis [4–6]. Diagnosis and management can be problematic due to the slow growth and difficult identification of Nocardia species [6,8,9]. Because of this, extending incubation of dialysate to a minimum of 10 days should always be considered when no pathogens are initially isolated in the setting of non-resolving peritonitis. The optimum recovery of any infecting organism from dialysate should involve culture of large volumes of fluid. Inoculation of blood culture bottles enables 20 mL to be cultured in addition to that plated on to solid agar. Isolation of Nocardia causing peritonitis only after inclusion of an enrichment broth has also been described by others [6].
Secondly, our experience illustrates the ill-defined relationship between in vitro susceptibilities of Nocardia species and clinical response to antibiotic treatment in nocardiosis [3]. MICs for trimethoprim-sulphamethoxazole 4/76 mg/L are rarely reported among Nocardia asteroids complex, and in our case we chose to continue with trimethoprim-sulphamethoxazole despite the microdilution broth MIC results. This situation has been reported in one other case of PD-related peritonitis with apparently resistant Nocardia nova infection, and the authors of that report also noted a slow but satisfactory improvement in clinical condition with co-trimoxazole therapy [5]. The optimal duration of treatment for Nocardia PD-related peritonitis is not known. Although 3 weeks has been previously suggested [4], it is our opinion that treatment duration needs to be titrated to the clinical response of the patient, and that longer treatment duration is advisable for more resistant organisms. The treatment duration of a year for our patient was conservative, but based upon the slow clinical response of the patient and recommendations for pulmonary and central nervous system nocardiosis of 6–12 months in immunocompromised patients [7].
Thirdly, our experience illustrates that peritoneal integrity can be maintained with aggressive and sustained therapy, and patients can return to PD successfully after Nocardia PD-related peritonitis. Such positive outcomes are uncommon with patients often remaining on haemodialysis [6,10].
Nocardia PD-related peritonitis is difficult to diagnose, and treatment with co-trimoxazole may require a protracted course if isolates are relatively resistant. A favourable return to PD is possible.
Conflict of interest statements. None declared.
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References |
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- NCCLS. Susceptibility testing of Mycobacteria, Nocardiae and other aerobic Actinomycetes. In: Approved Standards (2003) Wayne, PA: National Committee for Clinical Laboratory Standards.
- Arfania D, Everett ED, Nolph KD, et al. Uncommon causes of peritonitis in patients undergoing peritoneal dialysis. Arch Intern Med (1981) 141:61–64.[CrossRef][Web of Science][Medline]
- Brown-Elliott BA, Brown JM, Conville PS, et al. Clinical and laboratory features of the Nocardia spp. based on current molecular taxonomy. Clin Microbiol Rev (2006) 19:259–282.
[Abstract/Free Full Text] - Chan DT, Cheng IK, Chan PC, et al. Nocardia peritonitis complicating continuous ambulatory peritoneal dialysis. Perit Dial Int (1990) 10:99.[Web of Science][Medline]
- Chu KH, Fung KS, Tsang WK, et al. Nocardia peritonitis: satisfactory response to intraperitoneal trimethoprim-sulfamethoxazole. Perit Dial Int (2003) 23:197–198.
[Free Full Text] - Kaczmarski EB, Wilkie M, Thornhill C, et al. Problems encountered in diagnosis of Nocardia asteroides peritonitis complicating CAPD. Perit Dial Int (1990) 10:106.[Web of Science][Medline]
- Lerner P. Nocardia species. In: Bennett's Principles and Practice of Infectious Diseases—Mandell D, ed. (1995) 4th Edn. New York: Churchill Livingstone Inc. 2273–2278.
- Lopes JO, Alves SH, Benevenga JP, et al. Nocardia asteroides peritonitis during continuous ambulatory peritoneal dialysis. Rev Inst Med Trop Sao Paulo (1993) 35:377–379.[Medline]
- Ortiz AM, Rabagliati R, Machuca E. Successful treatment of Nocardia asteroides peritonitis in a patient undergoing automated peritoneal dialysis and receiving immunosuppressive therapy. Adv Perit Dial (2005) 21:66–68.[Medline]
- Recule C, Milongo R, Boiron P, et al. Nocardia peritonitis complicating CAPD. Perit Dial Int (1994) 14:297–298.[Web of Science][Medline]
Accepted in revised form: 14. 4.08
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