First Korean case of Robinsoniella peoriensis bacteremia in a patient with aspiration pneumonia

Abstract

Robinsoniella peoriensis has recently been identifed as a Gram-positive, spore-forming, anaerobic rod originally recovered from swine manure storage pits. To date, 6 cases of R. peoriensis infection have been reported, including 2 cases of bacteremia, 1 of abdominal fuid collection, and 3 of wound infection. In the present study, we report a 76-yr-old man with R. peoriensis bacteremia who developed aspiration pneumonia. Gram staining of a purifed colony revealed Gram-positive, rod-shaped bacteria. Biochemical identifcation using API 20 A (bioMérieux, France) indicated presence of Clostridium spp. We performed both 500-bp and full-gene sequencing of 16S rRNA of the isolate. The sequence was analyzed with MicroSeq ID 16S rRNA Library v2.0 (Applied Biosystems, USA), GenBank Basic Local Alignment Search Tool (BLAST) (http://www.ncbi.nlm.nih.gov/ genbank), and EzTaxon database v2.1 (http://www.eztaxon.org). The 500-bp 16S rRNA sequence of the blood culture isolate showed 99.16-99.79% similarity with R. peoriensis and the full-gene 16S rRNA sequence showed 98.87-99.50% similarity with R. peoriensis. The organism was confrmed as R. peoriensis by using all of the mentioned databases except for MicroSeq, which did not include the RNA sequence of this bacterium. This case suggests that identifcation of R. peoriensis might be challenging in clinical laboratories with no access to molecular methods, as certain commercial identifcation systems may not identify, or may misidentify, this organism. To the best of our knowledge, this is the frst report of the isolation of R. peoriensis in Korea. © The Korean Society for Laboratory Medicine.