Clinical characteristics of infections caused by Roseomonas species and antimicrobial susceptibilities of the isolates

Human infections due to Roseomonas species are uncommon and the vast majority of reported infections are opportunistic and easy to treat. We retrospectively reviewed the computerized database of the Bacteriology Laboratory at the National Taiwan University Hospital to identify patients with infections caused by Roseomonas species during the period January 2000 to December 2010. Isolates of Roseomonas species were confirmed by 16S rRNA gene sequencing analysis. During the study period, 20 patients had cultures positive for Roseomonas species. R. mucosa was the most prevalent isolate (n = 18), followed by 1 each of R. gilardii and Roseomonas genomospecies 5. True infection caused by Roseomonas species was confirmed in 17 (85%) patients. Most (n = 12, 71%) of these infections were health care-associated infection. The majority of the patients (n = 12, 71%) had underlying diseases. Malignancy was the most common underlying disease, and catheter-related bloodstream infection was the most common type of infection. The antimicrobial susceptibility patterns varied among the different Roseomonas species. In conclusion, Roseomonas species can cause infection in children and adults regardless of immune status. Because different Roseomonas species may have different clinical features and susceptibility profiles, molecular studies are necessary to identify Roseomonas isolates to the species level.