Detection of Viral, Bacterial and Human Genomic DNA from Preserved Stool Samples

INTRODUCTION Stool is an excellent sample source for diagnosing cases of viral and bacterial gastroenteritis and is also a noninvasive source of human genomic DNA from exfoliated cells of the colon, which is often used in diagnosis of colorectal cancer. The isolation of high quality DNA from stool is not without its problems however. The presence of phenolic compounds, metabolites and polysaccharides in stool make the isolation of quality nucleic acid samples that are free of PCR inhibitors very challenging. Furthermore, the presence of RNases and DNases in stool poses a logistical problem in the form of nucleic acid degradation that occurs during sample collection and transport. Current techniques which do not make use of preservative require that stool be collected into vials, transported on ice and then frozen at -20°C when received by the diagnostic testing facility. The addition of preservative to the collection vials eliminates the need to immediately process or freeze the stool samples and allows the samples to be shipped at ambient temperature.