Fecal microbes, short chain fatty acids, and colorectal cancer across racial/ethnic groups.
AIM
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.


CONCLUSION
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.
['Hester|Christina M|CM|', 'Jala|Venkatakrishna R|VR|', 'Langille|Morgan Gi|MG|', 'Umar|Shahid|S|', 'Greiner|K Allen|KA|', 'Haribabu|Bodduluri|B|']
D001741:African Americans D000368:Aged D001419:Bacteria D015179:Colorectal Neoplasms D004269:DNA, Bacterial D005227:Fatty Acids D005243:Feces D005260:Female D006630:Hispanic or Latino D006801:Humans D007198:Indians, North American D007615:Kansas D008297:Male D054892:Metagenome D056186:Metagenomics D008875:Middle Aged D010865:Pilot Projects D012336:RNA, Ribosomal, 16S D021521:Ribotyping D012307:Risk Factors D044465:Whites
Short chain fatty acids Colorectal cancer Butyrate Microbiota Racial/ethnic disparities