Bacillus licheniformis Peritonitis in a CAPD Patient

Abstract

A 56-year-old woman was admitted to the hospital with a 2-day history of a sudden onset of persistent abdominal pain and nausea without vomiting and fever. She had had a 10-year history of hypertension treated with hypotensive agents, and chronic renal failure for 8 years. She had been treated with hemodialysis initially then continuous ambulatory peritoneal dialysis (CAPD) due to the occlusion of her arteriovenous fistula (AVF). This was her third episode of peritonitis, averaging one episode per 16 patient-weeks. The dialysis effluent showed cloudiness, with a white blood cell (WBC) count of 945 WBC/mm3 with 90% segmented neutrophils. The direct smear of the effluent showed many WBCs and occasional grampositive bacilli with central or paracentral spores. The effluent culture, on blood agar plate incubated aerobically at 37°C for 24 hours, revealed typical large blister colonies. These became opaque, wrinkled with rough surfaces, and b-hemolytic after additional incubation. The isolate was identified as 99% Bacillus licheniformis using the VITEK automated analyzer (bioMérieux, Hazelwood, MO, U.S.A.) with the ability to ferment glucose, mannitol, trehalose, maltose, and sucrose, and was positive for esculin and indole. The patient showed rapid improvement after treatment with netilmycin and cefotiam for 2 days. The dialysis effluent cell count decreased to 20 WBC/mm3 with diminished turbidity. The follow-up culture of the effluent had no growth. Bacillus peritonitis in CAPD is extremely rare; 5 cases have been counted so far in Western literature (1–4). We report a unique and, as far as we know, the first case of B. licheniformis peritonitis in a CRF patient being treated with CAPD. On the basis of this case, if the dialysis effluent shows Bacillus species, it shall not be regarded as a contaminant unless otherwise proven.