title: Fecal microbes, short chain fatty acids, and colorectal cancer across racial/ethnic groups.
abstract: OBJECTIVE
  To investigate differences in microbes and short chain fatty acid (SCFA) levels in stool samples from Hispanic and non-Hispanic African American, American Indian, and White participants.
  
  
  METHODS
  Stool samples from twenty participants were subjected to analysis for relative levels of viable bacteria and for SCFA levels. Additionally, the samples were subjected to 16S rRNA gene pyrosequencing for identification of bacteria present in the stool. We used a metagenome functional prediction technique to analyze genome copy numbers and estimate the abundance of butyrate kinase in all samples.
  
  
  RESULTS
  We found that African Americans had significantly lower levels of acetate, butyrate, and total SCFAs than all other racial/ethnic groups. We also found that participant microbial profiles differed by racial/ethnic group. African Americans had significantly more Firmicutes than Whites, with enriched Ruminococcaceae. The Firmicutes/Bacteroidetes ratio was also significantly higher for African Americans than for Whites (P = 0.049). We found Clostridium levels to be significantly and inversely related to total SCFA levels (P = 0.019) and we found Bacteroides to be positively associated (P = 0.027) and Clostridium to be negatively associated (P = 0.012) with levels of butyrate. We also identified a correlation between copy number for a butyrate kinase predicted from 16S rRNA gene abundance and levels of butyrate in stool.
  
  
  CONCLUSIONS
  The identified differences in gut flora and SCFA levels may relate to colorectal cancer mortality differentials and may be useful as targets for future clinical and behavioral interventions.
authors.affiliation: Christina M Hester, K Allen Greiner, Department of Family Medicine Research Division, University of Kansas Medical Center, Kansas City, KS 66160, United States.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Hester
authors.affiliation: Christina M Hester, K Allen Greiner, Department of Family Medicine Research Division, University of Kansas Medical Center, Kansas City, KS 66160, United States.
authors.forename: Venkatakrishna R
authors.initials: VR
authors.lastname: Jala
authors.affiliation: Christina M Hester, K Allen Greiner, Department of Family Medicine Research Division, University of Kansas Medical Center, Kansas City, KS 66160, United States.
authors.forename: Morgan Gi
authors.initials: MG
authors.lastname: Langille
authors.affiliation: Christina M Hester, K Allen Greiner, Department of Family Medicine Research Division, University of Kansas Medical Center, Kansas City, KS 66160, United States.
authors.forename: Shahid
authors.initials: S
authors.lastname: Umar
authors.affiliation: Christina M Hester, K Allen Greiner, Department of Family Medicine Research Division, University of Kansas Medical Center, Kansas City, KS 66160, United States.
authors.forename: K Allen
authors.initials: KA
authors.lastname: Greiner
authors.affiliation: Christina M Hester, K Allen Greiner, Department of Family Medicine Research Division, University of Kansas Medical Center, Kansas City, KS 66160, United States.
authors.forename: Bodduluri
authors.initials: B
authors.lastname: Haribabu
mesh_terms: D001741:Black or African American; D000368:Aged; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D015179:Colorectal Neoplasms / Q000208:ethnology* / Q000378:metabolism / Q000382:microbiology / Q000401:mortality; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis*; D005243:Feces / Q000737:chemistry* / Q000382:microbiology*; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D007198:Indians, North American; D007615:Kansas / Q000453:epidemiology; D008297:Male; D054892:Metagenome; D056186:Metagenomics; D008875:Middle Aged; D010865:Pilot Projects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D021521:Ribotyping; D012307:Risk Factors; D044465:White People
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S
keywords: Butyrate; Colorectal cancer; Microbiota; Racial/ethnic disparities; Short chain fatty acids