1000. Clinical significance and antimicrobial susceptibilities of Roseomonas species infections

Abstract

Abstract Background Roseomonas species are slow-growing Gram-negative cocobacillus, and were first reported in 1993. Roseomonas have been isolated from environmental sources and can cause bacteremia in humans, especially in immunocompromised patients. Since these species were difficult to isolate and infections with these species are not common, there are only a few studies on their characteristics. Therefore, we aim to expand our knowledge of clinical features, antimicrobial susceptibility patterns, and treatment outcomes for Roseomonas human infections. Methods From January 2006 to March 2022, patients with Roseomonas isolated from blood and other aseptic sources were extracted from three tertiary hospitals in South Korea. Underlying conditions, clinical manifestations, antimicrobial susceptibility patterns, and outcomes were reviewed through the medical records. Results During the study period, a total of 39 patients (46.2% were male) with Roseomonas infections were included. The median age was 50 (interquartile range, 33.5-62.5) years old, and seven patients (17.9%) were under age 18. Of the 39 patients, 13 patients (33.3%) had malignancies, five patients (12.8%) had neutropenia with an absolute neutrophil count of fewer than 1000 cells/mm3. Blood isolates were the most common (26 cases), followed by catheter blood (3 cases), and soft tissue (3 cases). Twenty-one cases (53.8%) were cultured after 48 hours of incubation, and co-infection with other bacteria was identified in nine cases (23.1%). Twenty-eight patients (71.8%) were symptomatic, with fever (30.8%) being the most common symptom. Amikacin showed a high susceptible rate (95.7%) to isolated Roseomonas. Tigecycline also showed high susceptible rates (92.9% , respectively). The susceptible rate of levofloxacin was 85.0%. On the other hand, the susceptible rate of piperacillin-tazobactam (5.9%) and meropenem (47.6%) were below 50%. There were two cases (5.1%) of in-hospital mortality. Conclusion Although not common, Roseomonas species can cause bacteremia and even death, especially in immunocompromised individuals. Since Roseomonas are challenging to isolate and generally show resistance to antibiotics commonly used for Gram-negative bacterial infections, careful attention is warranted in selecting antibiotics. Disclosures All Authors: No reported disclosures.