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Published on: July 11, 2016
Ruminococcus gnavus bacteraemia showing morphological diversity on Gram staining: a case report and literature review
Tatsuya Hioki1, Kensuke Kataoka2, Yoshikazu Mutoh3
1Department of Clinical Laboratory, Tosei General Hospital, 160 Nishioiwake-cho, Seto, Aichi, 489-8642, Japan.
Abstract:
Ruminococcus gnavus , a Gram-positive anaerobic coccus, is a common constituent of the human gut microbiota but rarely causes any disease in humans. Herein, we report a case of R. gnavus bacteraemia in an immunocompromised 73-year-old man with sigmoid colon perforation. R. gnavus is usually reported as Gram-positive diplococci or short chains on Gram staining; however, in our patient, a blood isolate showed Gram-positive cocci in long chains, and organisms from an anaerobic subculture showed morphological diversity. This case provides insight into the morphological diversity of R. gnavus , which might help with the recognition of these bacteria in the preliminary identification stage on Gram staining.
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