Clostridium innocuum is a significant vancomycin-resistant pathogen for extraintestinal clostridial infection

Abstract

Vancomycin-resistant C. innocuum is a previously unrecognized, yet prominent, cause for EICI. Genome analysis showed that the species could carry a lipopolysaccharide-like structure that is associated with cytotoxicity to cells in vitro.

Clostridium innocuum is a vancomycin-resistant pathogen that may cause antibiotic-associated diarrhoea

“…[18]. The virulence factor of C. innocuum is likely to be bound to the bacterial surface envelope, like the cell-wall proteins and highmolecular-weight surface layer proteins previously reported in C. difficile [18,23,24]. Isolates showing higher cytotoxicity were associated with more severe disease in our patients.…”

“…Clostridium innocuum isolates exerted cytotoxic effects on both Vero and HT-29 cells. In our previous study, only bacterial pellets of C. innocuum, rather than culture supernatant, were cytotoxic [18]. By genome sequence comparison, we did not identify any genes encoding toxins reported in other Clostridium species (C. botulinum, C. difficile, C. perfringens, C. septicum and C. tetani) in the genome of C. innocuum In Vero cells, isolates from severe colitis group were significantly more cytotoxic than those from diarrhoea group 24 hours after inoculation (16.0% ± 2.8% vs. 13.7% ± 1.8%; p 0.042) as well as 48 hours after inoculation (21.7% ± 3.7% vs. 18.1% ± 3.0%; p 0.033).…”

“…Ileal segments (A) and histologic examination with H&E staining of ileal tissues (B) from mice infected with Clostridium innocuum S8898 and S9195 and control. [18]. The virulence factor of C. innocuum is likely to be bound to the bacterial surface envelope, like the cell-wall proteins and highmolecular-weight surface layer proteins previously reported in C. difficile [18,23,24].…”

“…When a patient has AAD and stool culture grows C. difficileelike colonies but is negative for C. difficile toxin A or B, further identification for C. innocuum should be performed. Our previous report demonstrated that Clostridium species identification by 16S rRNA gene sequencing is better than matrix-assisted desorption ionizationetime of flight mass spectrometry [18]. Furthermore, the study highlights that C. innocuum may be selected by prior vancomycin treatment because it is intrinsically resistant to vancomycin.…”

“…Severe C. innocuum infections have been described [17]. In a previous study, we found that C. innocuum was the second most common aetiologic agent for extraintestinal clostridial infection [18]. In addition to bacteraemia, C. innocuum could cause empyema, pylephlebitis, intra-abdominal infection and pelvic abscesses [19,20].…”