Bacteremia caused by Brevundimonas species at a tertiary care hospital in Taiwan, 2000–2010

Abstract

We investigated clinical and microbiological characteristics of 30 patients with Brevundimonas bacteremia treated at a tertiary care hospital in Taiwan during 2000-2010. All the 30 bacteria isolates were confirmed to the species level by 16S rRNA sequencing analysis. Minimum inhibitory concentrations (MICs) of 11 antimicrobial agents against these isolates were determined by the agar dilution method. Seventeen (57%) patients had underlying malignancy, 12 (40%) had undergone central catheter placement, and 13 (43%) had received chemotherapy within the previous three months. Eight (27%) patients had community-acquired bacteremia and the remaining 22 patients (73%) had healthcare-associated bacteremia. The overall 14-day and 30-day mortality rates were 13% and 17%, respectively. Among the 30 isolates, B. vesicularis constituted most commonly (n = 22, 63%), followed by B. nasdae (n = 5) and B. diminuta (n = 3). All isolates were susceptible to piperacillin-tazobactam and amikacin, while all were resistant to ciprofloxacin and colistin. Tigecycline (MICs at which 90% of isolates are inhibited [MIC(90)] was 0.12 mg/L) and doripenem (MIC(90) of 1 mg/L) both possessed good in vitro activities. In conclusions, Brevundimonas should be considered a pathogen that can cause bacteremia in immunocompromised hosts. Piperacillin-tazobactam, amikacin, doripenem, and tigecycline exhibit good in vitro activities against these ciprofloxacin- and colistin-resistant Brevundimonas species.