Bacillus species bloodstream infections among pediatric oncology patients: When is line removal really necessary?

Background: Bacillus species are biofilm-producing organisms. They are sometimes detected as contaminants in blood cultures. However, they can cause severe infections in immunocompromised patients. Central line removal is generally recommended, though data examining when line removal is necessary are limited. Our objective was to characterize the clinical epidemiology and outcomes of Bacillusbloodstream infections in pediatric oncology patients with febrile neutropenia, including the outcomes of line retention.

Methods: We performed a retrospective chart review of febrile neutropenic pediatric oncology patients hospitalized at our institution between 5/3/2004 and 12/14/14 who had at least one blood culture positive for Bacillus spp. Demographic, clinical, microbiologic and outcome data were collected including: disseminated infection (microbiologic or radiologic evidence of metastatic focus), line removal, recurrence within 6 months, and mortality during the index hospitalization.

Results: We identified 2823 admissions for febrile neutropenia in 941 patients over the study period; 868 (30%) were associated with bloodstream infection and 27/868 (3%) had cultures positive for Bacillus spp. (9 B. cereus, 18 other Bacillus spp.). The primary oncologic diagnoses included ALL (52%), CNS tumor (15%) and neuroblastoma (11%); median age was 3 years. Four patients (15%) had disseminated Bacillus spp. infection and four required intensive care; there were no deaths. Twelve (44%), had more than one positive blood culture and 2 of these patients had evidence of dissemination. Central line was removed in 19 (70%) patients; all 12 with more than one positive blood culture and in seven of 15 patients with one positive blood culture. Mean time to line removal was 5.7 days after first positive culture. Central line was retained in eight patients (30%), including two with B. cereus infection. These eight all had a single positive culture and three grew CONS in addition to Bacillus. There were no recurrent Bacillus infections.

Conclusion: Bacillus spp. are important bloodstream pathogens in pediatric oncology patients and can disseminate. Although central line removal is recommended, line maintenance may be considered in the absence of sustained bacteremia.