Real-time polymerase chain reaction quantification of specific butyrate-producing bacteria, Desulfovibrio and Enterococcus faecalis in the feces of patients with colorectal cancer.
OBJECTIVE
Bacterial metabolites produced in the bowel are potentially related to the genesis of colorectal cancer. Butyrate is protective against cancer, whereas hydrogen sulfide and oxygen free radicals can be toxic to the epithelium. The present study was designed to quantitate Eubacterium rectale, Faecalibacterium prausnitzii (both butyrate-producing bacteria), Desulfovibrio (sulfate-reducing bacteria), and Enterococcus faecalis (that produces extracellular superoxide) in the feces of patients with colorectal cancer.


METHODS
DNA was extracted from feces of 20 patients with colorectal cancer, nine patients with upper gastrointestinal cancer and 17 healthy volunteers. Real-time polymerase chain reaction using primers aimed at 16S rDNA was used to quantitate the above bacterial species or genus, and this was expressed relative to amplification of universal sequences conserved among all bacteria.


RESULTS
Levels of E. rectale and F. prausnitzii were decreased approximately fourfold (P = 0.0088 and 0.0028, respectively) in colorectal cancer patients compared to healthy control volunteers. Levels of Desulfovibrio were not significantly different between the three groups. E. faecalis populations were significantly higher in colorectal cancer patients compared to healthy volunteers (P = 0.0294).


CONCLUSIONS
Butyrate producers were decreased and E. faecalis increased in the feces of colon cancer patients. These shifts in the colonic bacterial population could potentially lead to epithelial cell damage and increased turnover and may be a factor leading to colon cancer.
Balamurugan
Ramadass
R
The Wellcome Trust Research Laboratory, Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India.
Rajendiran
Ethendhar
E
George
Sarah
S
Samuel
G Vijay
GV
Ramakrishna
Balakrishnan S
BS
D000293:Adolescent; D000328:Adult; D000368:Aged; D002087:Butyrates / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000302:isolation & purification; D003901:Desulfovibrio / Q000302:isolation & purification* / Q000378:metabolism; D013293:Enterococcus faecalis / Q000302:isolation & purification* / Q000378:metabolism; D005051:Eubacterium / Q000302:isolation & purification / Q000378:metabolism; D005243:Feces / Q000382:microbiology*; D005260:Female; D006094:Gram-Positive Bacteria / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
D002087:Butyrates; D004269:DNA, Bacterial