Preservation of viral DNA after storage: comparison of two transport systems

Many commercial swab/transport systems have been developed to preserve and stabilise clinical material prior to downstream microbiological investigation. Some have been designed to enhance viral or bacterial stability using growth supplements or suppressants, some of which may have an impact or limit their potential use. Traditionally, swabs taken for viral investigations were required to be placed in a specialised viral transport medium containing antibiotics to prevent or reduce bacterial contamination that may have a deleterious effect on downstream detection methods.

Two such microbiological swab transport systems are the Copan Eswab with a nylon flocked swab and the Sigma Transwab (Medical Wire & Equipment [MWE]) incorporating a foam-tipped swab. Both are liquid culture systems based on modified liquid Amies transport medium and each has proven applications in bacteriology.

This investigation looks at the potential use of these bacterial transport systems for the detection of viral pathogens in clinical samples, and the effect that storage conditions and the presence of bacterial contamination may have on the detection of viral DNA.