Outbreak of Cutaneous Rhizopus arrhizus Infection Associated with Karaya Ostomy Bags

Abstract

We investigated an outbreak involving 2 patients hospitalized at hospital A with cutaneous Rhizopus arrhizus (oryzae) infections of surgically created stomas. A cohort study involving all patients having ileostomy or colostomy surgery during the outbreak period (January-April 2005) was performed. Environmental samples, including samples obtained from nonsterile karaya (a plant-derived adhesive) ostomy bags and from select hospital areas, were collected. A point prevalence survey was conducted at 5 unrelated hospitals to assess stoma care practices and mold contamination of karaya ostomy bags outside of hospital A. Zygomycete isolates were identified by standard methods. Infections occurred 7 and 10 days after operations for the 2 patients; 1 patient died. In a 21-patient cohort, receiving the equivalent of > or =0.5 mg/kg per day of prednisone during the week prior to the index date was associated with infection (infection rate, 33% for patients receiving > or =0.5 mg/kg per day of prednisone vs. 0% for patients receiving <0.5 mg/kg per day of prednisone; P=.07). The time to first ostomy bag change was longer for patients with infection (median duration, 8.5 days; range, 7-10 days) than for the 19 patients without infection (median duration, 1.5 days; range, 1-17 days; P=.08). At unrelated hospitals, the median time to first ostomy bag change was 2 days (range, 1-6 days) for 18 patients after ostomy. R. arrhizus was recovered from 10 of 18 karaya ostomy bags from hospital A and from karaya ostomy bags donated from 3 of 5 other hospitals, but it was not recovered from the hospital A environment. The initial karaya ostomy bag was likely to be the source of Rhizopus infection, and prolonged exposure before the first ostomy bag change might have precipitated infection in these susceptible individuals. Karaya might contain opportunistic molds that can pose an infectious risk among susceptible persons.