The human gut microbiota is increasingly recognized as a player in colorectal cancer (CRC). While particular imbalances in the gut microbiota have been linked to colorectal adenomas and cancer, no specific bacterium has been identified as a risk factor. Recent studies have reported a high abundance of Fusobacterium in CRC subjects compared to normal subjects, but this observation has not been reported for adenomas, CRC precursors. We assessed the abundance of Fusobacterium species in the normal rectal mucosa of subjects with (n = 48) and without adenomas (n = 67). We also confirmed previous reports on Fusobacterium and CRC in 10 CRC tumor tissues and 9 matching normal tissues by pyrosequencing. We extracted DNA from rectal mucosal biopsies and measured bacterial levels by quantitative PCR of the 16S ribosomal RNA gene. Local cytokine gene expression was also determined in mucosal biopsies from adenoma cases and controls by quantitative PCR. The mean log abundance of Fusobacterium or cytokine gene expression between cases and controls was compared by t-test. Logistic regression was used to compare tertiles of Fusobacterium abundance. Adenoma subjects had a significantly higher abundance of Fusobacterium species compared to controls (p = 0.01). Compared to the lowest tertile, subjects with high abundance of Fusobacterium were significantly more likely to have adenomas (OR 3.66, 95% CI 1.37–9.74, p-trend 0.005). Cases but not controls had a significant positive correlation between local cytokine gene expression and Fusobacterium abundance. Among cases, the correlation for local TNF-α and Fusobacterium was r = 0.33, p = 0.06 while it was 0.44, p = 0.01 for Fusobacterium and IL-10. These results support a link between the abundance of Fusobacterium in colonic mucosa and adenomas and suggest a possible role for mucosal inflammation in this process.

Vaginal dysbiosis has been shown to increase the risk of some adverse birth outcomes. HIV infection may be associated with shifts in the vaginal microbiome. We characterized microbial communities in vaginal swabs collected between 16–20 gestational weeks in the Zambian Preterm Birth Prevention Study to investigate whether HIV and its treatment alter the microbiome in pregnancy. We quantified relative abundance and diversity of bacterial taxa by whole-genome shotgun sequencing and identified community state types (CST) by hierarchical clustering. Associations between exposures—HIV serostatus (HIV+ vs HIV-) and preconceptional ART (ART+ vs ART-)—and microbiome characteristics were tested with rank-sum, and by linear and logistic regression, accounting for sampling by inverse-probability weighting. Of 261 vaginal swabs, 256 (98%) had evaluable sequences; 98 (38%) were from HIV+ participants, 55 (56%) of whom had preconceptional ART exposure. Major CSTs were dominated by: L. crispatus (CST 1; 17%), L.] iners (CST 3; 32%), Gardnerella vaginalis (CST 4-I; 37%), G. vaginalis & Atopobium vaginae (CST 4-II; 5%), and other mixed anaerobes (CST 4-III; 9%). G. vaginalis was present in 95%; mean relative abundance was higher in HIV+ (0.46±0.29) compared to HIV- participants (0.35±0.33; rank-sum p = .01). Shannon diversity was higher in HIV+/ART+ (coeff 0.17; 95%CI (0.01,0.33), p = .04) and HIV+/ART- (coeff 0.37; 95%CI (0.19,0.55), p < .001) participants compared to HIV-. Anaerobe-dominant CSTs were more prevalent in HIV+/ART+ (63%, AOR 3.11; 95%CI: 1.48,6.55, p = .003) and HIV+/ART- (85%, AOR 7.59; 95%CI (2.80,20.6), p < .001) compared to HIV- (45%). Restricting the comparison to 111 women in either CST 3 (L. iners dominance) or CST 1 (L. crispatus dominance), CST 3 frequency was similar in HIV- (63%) and HIV+/ART- participants (67%, AOR 1.31; 95%CI: (0.25,6.90), p = .7), but higher in HIV+/ART+ (89%, AOR 6.44; 95%CI: (1.12,37.0), p = .04). Pregnant women in Zambia, particularly those with HIV, had diverse anaerobe-dominant vaginal microbiota.

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Microbiome studies are revealing complex microbiota in biofilm-mediated human diseases commonly linked with specific bacterial pathogens. Streptococcus mutans has been implicated as the primary pathogen in childhood dental caries (tooth decay). While the role of polymicrobial communities is appreciated, it remains unclear whether other microorganisms are active contributors, inactive cohabitants, or interact with known pathogens such as S. mutans. Here, we integrate multi-omics of human dental plaque (biofilm) from two community-based samples of preschool-age children in a discovery-validation pipeline involving bioinformatics, laboratory, and in vivo experimental approaches to identify disease-relevant inter-species interactions. In metagenomics and metatranscriptomics analyses among 416 preschool-age children, we identify 16 taxa strongly associated with childhood caries. Using multiscale imaging, virulence assays, microcalorimetry, and computational analyses, we investigate biofilm formation dynamics, microscale spatial arrangement, and metabolic activity by Selenomonas sputigena, Prevotella salivae and Leptotrichia wadei either individually or with S. mutans. Notably, we discover that the flagellated S. sputigena, a subgingival anaerobe with previously unknown role in supragingival biofilm virulence, becomes trapped in foreign streptococcal exoglucans, loses its motility but actively proliferates to build a honeycomb-like multicellular superstructure encapsulating S. mutans and enhances acidogenesis. Rodent model experiments reveal a previously unrecognized ability of S. sputigena to colonize supragingival tooth surfaces. While incapable of causing caries on its own, S. sputigena exacerbates the disease severity in vivo when co-infected with S. mutans, causing extensive lesions on tooth enamel. Our data reveal a pathobiont from a disparate habitat in a prevalent disease that cooperates with a known pathogen to build a unique 3D spatial structure and heighten biofilm virulence—which may be relevant to other polymicrobial diseases.

Green tea and probiotic bacteria have been reported to have beneficial health effects individually. The purpose of this study was to determine if green tea (GT) or epigallocatechin‐3‐gallate (EGCG), the main flavonoid component of GT, would stimulate the growth rate and increase the cell density in planktonic cultures of the probiotic bacterial strains Lactobacillus acidophilus NCFM (L. acid.) and Lactobacillus gasseri ATCC 33323 (L. gas.). Aqueous GT and EGCG extracts were prepared and matched for total phenol content. Growth rate was determined using a 96‐well microtiter plate assay. Cell density was assessed via optical density at 600nm. GT (1, 2, 10, 20, 30 and 40%) and EGCG (1, 2 and 10%) enhanced the maximum specific growth rate (MSGR) of L. acid. vs. the control. GT (4, 10, 20, 30, and 40%) and EGCG (1, 2, 4, 10, and 20%) also enhanced the MSGR of L. gas. relative to the control. GT (10 and 30%) and EGCG (1% only) increased the cell density of both L. acid. and L. gas. relative to the control. In summary, in preliminary results, GT and EGCG increased the growth rate and final cell densities of both L. acid. and L. gas., suggesting that combinations of probiotic cultures with tea components may promote survival, growth or activity in the gastrointestinal tract. This project was supported by North Carolina State University, the NC Dairy Foundation, and the Southeast Dairy Foods Research Center.