Detection of Streptococcus Gallolithicus in People Undergoing Colonoscopy by Chain Reaction (PCR) and Culture

Streptococcus galloliticus is one of the bacteria associated with colorectal cancer in humans. No studies have been performed to identify this bacterium in the large intestine using PCR test and compare it with microbial culture in patients undergoing colonoscopy in northern Iran.

In a descriptive study to diagnose Streptococcus gallolyticus, biopsy specimens were obtained from 55 individuals undergoing colonoscopy referred to Babol and Chalous hospitals. To detect bacteria after DNA extraction, first designed primers (PCO3, PCO4) were used to qualitatively analyze the extracted DNA and then the specific gene of Streptococcus gallolyticus was amplified. In addition to culture, diagnostic tests such as gram staining, catalase test, hydrolase, hydrate hydrolysis and scolin hydrolysis were used.

In this descriptive study, out of 55 biopsy specimens of individuals undergoing colonoscopy, 3 specimens (5.5%) with 95% confidence interval were positive and 52 cases (5.94%) were negative for Streptococcus gallolyticus DNA. There was a significant relationship between the two diagnostic methods of culture and PCR (p.value 0.015).

The simultaneous application of the two methods is recommended in cases where the result is rapid.