@article{5a127cf8602045d5943299279ae21569,
title = "Clostridium innocuum: Microbiological and clinical characteristics of a potential emerging pathogen",
abstract = "Clostridium innocuum is an anaerobic, gram-positive, spore-forming bacterium identified by Smith and King in 1962 after being isolated from a patient with an appendiceal abscess. Its name, C. innocuum, reflected its clinically “innocuous” nature based on observed lack of virulence in animal models of infection. Since that time, C. innocuum has been identified as both part of the normal intestinal flora and the cause of a rare, intrinsically vancomycin-resistant opportunistic infection in immunocompromised patients. More recently, reports from Taiwan suggest that C. innocuum, in addition to being a known extraintestinal pathogen, may also be a diarrheal pathogen that causes a C. difficile infection-like antibiotic-associated diarrheal illness. However, unanswered questions about the clinical relevance of C. innocuum remain. Here we review the microbiological and clinical characteristics of this emerging pathogen.",
keywords = "C. innocuum, Clinical microbiology, Clinical review, Emerging pathogen, Minireview",
author = "Cherny, {Kathryn E.} and Muscat, {Emily B.} and Reyna, {Megan E.} and Kociolek, {Larry K.}",
note = "Funding Information: C. innocuum falls into the RIC group of Clostridium species (C. ramosum, C. innocuum, and C. clostridioforme) [8]. This group is routinely misidentified due to Gram-stain variability, rare formation of spores, atypical Clostridial colonial morphology, and variable antibiotic susceptibilities [8,9]. Proper identification of C. innocuum with current laboratory microbiology methods and kits is difficult, and like its fellow group members, it is frequently misidentified [10]. Misidentification of C. innocuum as Clostridioides difficile has also been reported, as C. innocuum grows on cycloserine-cefoxitin-fructose agar (CCFA), a selective agar used for isolation of C. difficile from patients with diarrhea. Although C. innocuum grows readily on CCFA, and our personal experience in our laboratory supports this, the ability of C. innocuum to grow on other C. difficile selective media, such as chromogenic agar, is currently unknown. Exacerbating this misidentification is the similarity of both species{\textquoteright} colony morphology [11]. Although the difference in odor of C. innocuum has not been reported, our personal experience in our laboratory suggests that like C. difficile, C. innocuum cultures typically demonstrate a horse barn odor, albeit not as strong as C. difficile.This work was supported by grants from the National Institute of Allergy and Infectious Diseases at the National Institutes of Health (grant R21 AI144549 to L.K.K. and T32 916225 to K.E.C.). The funders had no role in the study design, data collection and interpretation, or the decision to submit the work for publication. Research reported in this publication was supported, in part, by the National Institutes of Health's National Center for Advancing Translational Sciences, Grant Number UL1TR001422. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors declare no conflicts of interest relevant to this review. Funding Information: This work was supported by grants from the National Institute of Allergy and Infectious Diseases at the National Institutes of Health (grant R21 AI144549 to L.K.K. and T32 916225 to K.E.C.). The funders had no role in the study design, data collection and interpretation, or the decision to submit the work for publication. Research reported in this publication was supported, in part, by the National Institutes of Health's National Center for Advancing Translational Sciences , Grant Number UL1TR001422 . The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors declare no conflicts of interest relevant to this review. Publisher Copyright: {\textcopyright} 2021",
year = "2021",
month = oct,
doi = "10.1016/j.anaerobe.2021.102418",
language = "English (US)",
volume = "71",
journal = "Anaerobe",
issn = "1075-9964",
publisher = "Academic Press Inc.",
}
