Severe Ulcerative Colitis Linked to Oral Bacteria

Researchers studying genomes of Campylobacter concisus, a bacterium found in the mouth, have discovered a new strain with a novel plasmid that appears to be associated with patients with ulcerative colitis (UC) who have required surgery for their disease, according to a study published in the journal Microbial Genomics.

The molecule, called pSma1, could be a marker of the progression of UC or perhaps a target for therapy, the researchers noted.

Several strains of C. concisus may colonize the oral cavity of healthy people, but most are killed by stomach acids. However, some can survive and colonize in the intestines. The presence of C. concisus  has also been linked to other diseases in the gastrointestinal tract, such as diarrheic diseases and Barrett esophagus.

The researchers also found that pSma1 was present in two strains of Streptococcus agalactiae and one strain of Xanthomonas citri pv. citri in the public databases.

“Of the six C. concisus plasmids identified in this study, only pSma1 was found to be associated with patients with UC who have had IPAA due to severe UC,” the researchers wrote. “This interesting finding suggests that future studies should be conducted to evaluate the potential use of pSma1 as a marker for predicting disease prognosis in patients with UC by examining a larger group of patients and controls.”

They concluded, “This study provides fundamental genomic data for understanding C. concisus plasmids, evolution, genomospecies features, secretion systems and pathogenicity.”


--Rebecca Mashaw



Liu F, Chen S, Luu LDW, et al. Analysis of complete Campylobacter concisus genomes identifies genomospecies features, secretion systems and novel plasmids and their association with severe ulcerative colitis. Microbial Genomics. 2020; 6(11). First published online October 28, 2020.