Editor:
Peritonitis because of Rhizobium radiobacter in patients on continuous ambulatory peritoneal dialysis (CAPD) is rare. Earlier, Minguela et al. (1) and Rothe and Rothenpieler (2) reported 5 cases pertaining to this species, and nearly all patients required catheter removal. However, with an updated database search (1-3), we found a total of 14 cases, among which 5 patients, including ours, achieved catheter rescue. In other words, 5 of 14 patients (35.7%) were able to keep their catheter. Here, we present the case involving our patient.
CASE DESCRIPTION
A 42-year-old man receiving CAPD because of immunoglobulin A nephropathy presented with fever and chills after 1 month of treatment. He also had cloudy effluent and diffuse abdominal pain. His effluent analysis revealed a white blood cell count of 5700/mm3, with 95% neutrophils. His plasma white cell count was 7500/mm3 with 75% neutrophils. Plasma C-reactive protein was just 1.1 mg/dL.
Empiric intraperitoneal cefazolin 250 mg and ceftazidime 250 mg were started in each 2-L exchange. The next day, the patient’s white blood cell counts had dropped to 540/mm3 and 121/mm3 respectively. The effluent culture yielded R. radiobacter, with resistance to multiple antibiotics (gentamicin, trimethoprim-sulfamethoxazole). We maintained intraperitoneal ceftazidime 250 mg in each 2-L exchange, completing a 3-week course, with successful preservation of the catheter. The patient has been free from peritonitis for the 2 years since the incident, and a history of soil contact before the CAPD peritonitis was later revealed.
R. radiobacter is a motile gram-negative oxidase-positive phytopathogenic bacillus. It is a rare opportunistic organism in human infection, being even rarer in CAPD peritonitis. Previous reports (1-2) had described only 5 cases; however, our full literature review (1-3) located 9 additional cases (including the present case). Levitski-Heikkila and Ullian (3) summarized all 11 cases occurring before 2005.
The susceptibility of R. radiobacter to antibiotics is variable (4). The first choice is probably ciprofloxacin (5), and empiric antibiotics should provide combination coverage. However, owing to the capacity of this organism to adhere to silicone tubes, Rothe and Rothenpieler (2) and Lui and Lo (6) both suggested early removal of the catheter in addition to antibiotic treatment. However, after pooling the patients from the Levitski-Heikkila and Ullian report (3) with our patient, 5 of 14 the patients infected with this organism (37.5%) had a preserved CAPD catheter after adequate antibiotics.
Even without a consensus concerning catheter removal in this kind of infection, our result was quite different from previous reports. We believe that, with early and adequate antibiotic therapy, PD catheter removal may not be required.
DISCLOSURES
I have no relationships that could be perceived to represent a financial conflict of interest.
References
- 1. Minguela JI, de-Pablos M, Castellanos T, Ruiz-de-Gauna R. Peritonitis by Rhizobium radiobacter. Perit Dial Int 2006; 26:112 [PubMed] [Google Scholar]
- 2. Rothe H, Rothenpieler U. Peritonitis due to multiresistant Rhizobium radiobacter. Perit Dial Int 2007; 27:214–15 [PubMed] [Google Scholar]
- 3. Levitski-Heikkila TV, Ullian ME. Peritonitis with multiple rare environmental bacteria in a patient receiving long-term peritoneal dialysis. Am J Kidney Dis 2005; 46:e119–24 [DOI] [PubMed] [Google Scholar]
- 4. Edmond MB, Riddler SA, Baxter CM, Wicklund BM, Pasculle AW. Agrobacterium radiobacter: a recently recognized opportunistic pathogen. Clin Infect Dis 1993; 16:388–91 [DOI] [PubMed] [Google Scholar]
- 5. Alnor D, Frimodt-Møller N, Espersen F, Frederiksen W. Infections with the unusual human pathogens Agrobacterium species and Ochrobactrum anthropi. Clin Infect Dis 1994; 18:914–20 [DOI] [PubMed] [Google Scholar]
- 6. Lui SL, Lo WK. Agrobacterium radiobacter peritonitis in a Chinese patient on CAPD. Perit Dial Int 2005; 25:95 [PubMed] [Google Scholar]