Adenomatous polyps (APs) with inflammation are risk factors for colorectal cancer. However, the role of inflammation-related gut microbiota in promoting the progression of APs is unknown.
Sequencing of the 16S rRNA gene was conducted to identify characteristic bacteria in AP tissues and normal mucosa. Then, the roles of inflammation-related bacteria were clarified by Spearman correlation analysis. Furthermore, colorectal HT-29 cells, normal colon NCM460 cells, and azoxymethane-treated mice were used to investigate the effects of the characteristic bacteria on progression of APs.
The expression levels of inflammation-related markers (diamine oxidase, D-lactate, C-reactive protein, tumor necrosis factor-α, interleukin-6 and interleukin-1β) were increased, whereas the expression levels of anti-inflammatory factors (interleukin-4 and interleukin-10) were significantly decreased in AP patients as compared to healthy controls. Solobacterium moorei (S. moorei) was enriched in AP tissues and fecal samples, and significantly positively correlated with serum inflammation-related markers. In vitro, S. moorei preferentially attached to HT-29 cells and stimulated cell proliferation and production of pro-inflammatory factors. In vivo, the incidence of intestinal dysplasia was significantly increased in the S. moorei group. Gavage of mice with S. moorei upregulated production of pro-inflammatory factors, suppressed proliferation of CD4+ and CD8+cells, and disrupted the integrity of the intestinal barrier, thereby accelerating progression of APs.
S. moorei accelerated the progression of AP in mice via activation of the NF-κB signaling pathway, chronic low-grade inflammation, and intestinal barrier disruption. Targeted reduction of S. moorei presents a potential strategy to prevent the progression of APs.

Solobacterium moorei JCM 10645T is an obligately anaerobic Gram-positive bacterium that was isolated from a human stool sample, generally known as a bacterium associated with sepsis, bacteremia, halitosis, and periodontal disease. In this study, we report the complete genome sequence of this strain, which is 2.615 Mbp with a 37.2% GC content.

Solobacterium moorei is an asporogenous, strictly anaerobic, short-to-long bacillus belonging to the family Erysipelotrichidae and phylum Firmicutes. This bacterium rarely causes bloodstream infections. Here, we report a case of the postoperative recurrence and metastasis of gastric antral adenocarcinoma combined with S. moorei bloodstream infection.

Solobacterium moorei is an anaerobic Gram-positive bacillus present within the oral and the intestinal microbiota that has rarely been described in human infections. Besides its role in halitosis and oral infections, S. moorei is considered to be an opportunistic pathogen causing mainly bloodstream and surgical wound infections. We performed a retrospective study of 27 cases of infections involving S. moorei in two French university hospitals between 2006 and 2021 with the aim of increasing our knowledge of this unrecognized opportunistic pathogen. We also reviewed all the data available in the literature and in genetic and metagenomic sequence databases. In addition to previously reported infections, S. moorei had been isolated from various sites and involved in intra-abdominal, osteoarticular, and cerebral infections more rarely or not previously reported. Although mostly involved in polymicrobial infections, in seven cases, it was the only pathogen recovered. Not included in all mass spectrometry databases, its identification can require 16S rRNA gene sequencing. High susceptibility to antibiotics (apart from rifampicin, moxifloxacin, and clindamycin; 91.3%, 11.8%, and 4.3% of resistant strains, respectively) has been noted. Our global search strategy revealed S. moorei to be human-associated, widely distributed in the human microbiota, including the vaginal and skin microbiota, which may be other sources for infection in addition to the oral and gut microbiota.

Solobacterium moorei (S. moorei) has been described as Gram-positive, non spore forming, obligate anaerobic bacillus from human feces. The traditional culture and identification of these strains is very difficult (as the strains are often not cultivable or they grow only relatively slowly, in addition to producing only a very few positive biochemical reactions in commercially available identification kits); thus, reliable identification may only be carried out using methods, such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and DNA sequencing. Regarding its pathogenic role, the relevance of S. moorei in halitosis (oral malodor) has a good standing, as it has been suggested by multiple studies, while the isolation of these bacteria from invasive infections is very rare; there are only a few reports available in the literature, regarding infections outside the oral cavity. Based on these reports, affected patients are predominantly characterized compromised immunity and are frequently associated with a dental focus of infection. The aim of our present review is to summarize the currently available knowledge on the pathogenic role of S. moorei in halitosis and other infections and to emphasize the relevance of this neglected anaerobic pathogen.

Solobacterium moorei is a strict anaerobic gram-positive rod. It is found in the human microbiota in different parts of the body, but it also appears to be an opportunistic pathogen in some infectious processes. We describe six cases of severe infections identified in 2016 in which S. moorei was isolated alone or in mixed culture involving other anaerobes or both aerobic and anaerobic bacteria. Three cases were associated with the oral cavity, including a middle ear infection, a wound infection after total laryngectomy, and a mandibular abscess as a result of bisphosphonate therapy. In the other three patients, the sites of infection had no connections with the oral cavity and included chronic osteomyelitis of the tibia, a superinfection of cutaneous tuberculosis associated with hidradenitis suppurativa, and the isolation of S. moorei from the blood culture of a cachectic man with several comorbidities. Based on our findings, S. moorei does not appear to be that virulent of a bacterium; except for the case with bacteraemia, S. moorei was recovered as a co-pathogen in patients with several immunosuppressive predisposing factors. We highlight the finding that the routine use of MALDI-TOF MS in microbiology laboratories can in a timely and detailed manner identify members of mixed infections involving different anaerobic bacteria that may be rare and difficult-to-culture and identify species, such as S. moorei.

BACKGROUND: Solobacterium moorei, the only species in the genus Solobacterium, is a Gram-positive, non-spore-forming, strict anaerobic, short to long bacillus. It has rarely been documented to cause blood stream infections. Here we report the first case of bacteremia caused by S.moorei in China.
METHODS: A 61-year-old male presented to Peking Union Medical College Hospital (Beijing) with thrombotic thrombocytopenic purpura (TTP) and several other underlying diseases. He also had persistent coma accompanied by intermittent convulsions, halitosis, and intermittent fever. Blood cultures taken when the patient had a high fever were positive, with the anaerobic bottle yielding an organism identified as S.moorei by 16S rRNA gene sequencing, whilst the aerobic bottle grew Streptococcus mitis. After replacement of venous pipeline, and empirical use of vancomycin and meropenem, the patient\'s body temperature and white blood cell count returned to normal. Unfortunately, the patient died of severe TTP.
CONCLUSIONS: This is the first case report of S. moorei isolation from blood stream in China. 16S rRNA gene sequencing is the only method that can identify S. moorei. Blood cultures must be taken before administration of antibiotics, and anaerobic culture should be considered for such rare pathogens in patients with oral diseases and immune deficiency.

Campylobacter rectus and Solobacterium moorei are anaerobic Gram-negative and Gram-positive rods, respectively, that are occasionally members of the human oral flora. Bacteraemia has rarely been reported. We present the first case of mixed C. rectus-S. moorei bacteraemia in an individual with diabetes and human immunodeficiency virus infection. Both bacteria were successfully identified by MALDI-TOF MS.

OBJECTIVE: Halitosis, also known as bad breath or oral malodour, is a condition affecting a large proportion of the population. Solobacterium moorei is a Gram-positive anaerobic bacterium that has been specifically associated with halitosis. In this study, we investigated the effects of essential oils, more particularly cinnamon bark oil, on growth, biofilm formation, eradication and killing, as well as hydrogen sulfide (H2S) production by S. moorei.
METHODS: A broth microdilution assay was used to determine the antibacterial activity of essential oils. Biofilm formation was assessed by a crystal violet staining assay and scanning electron microscopy. The biofilm of S. moorei was characterized by enzymatic treatments. Biofilm killing was determined by a luminescence assay monitoring ATP production. H2S production was quantified with a colorimetric assay. The biocompatibility of cinnamon oil was investigated using a gingival keratinocyte cell line.
RESULTS: Among the ten essential oils tested, cinnamon oil was found to be the most powerful against S. moorei with MIC and MBC values of 0.039% and 0.156%, respectively. The biofilm formed by S. moorei was then characterized. The fact that DNase I and to a lesser extent proteinase K significantly reduced biofilm formation by S. moorei and induced its eradication suggests that the extracellular matrix of S. moorei biofilm may be mainly containing a DNA backbone associated with proteins. At concentrations below the MIC, cinnamon oil reduced S. moorei biofilm formation that resulted from an attenuation of bacterial growth. It was also found that treatment of a pre-formed biofilm of S. moorei with cinnamon oil significantly decreased its viability although it did not cause its eradication. Cinnamon oil had an inhibitory effect on the production of H2S by S. moorei. Lastly, it was found that at concentrations effective against S. moorei, no significant loss of viability in gingival keratinocytes occurred after a 1-h exposure.
CONCLUSIONS: Our study brought evidence that cinnamon oil may be a promising substance to incorporate into oral hygiene products for controlling bad breath by inhibiting growth, killing biofilm, and reducing H2S production by S. moorei. Moreover, at the effective concentrations, cinnamon oil was found to have no toxic effects on oral keratinocytes.