‘Swabs’ then and now: cotton to flocked nylon

Abstract

Microbiological sample collections using cotton-tipped swabs (with or without serum), Dacron™, rayon and calcium alginate, with shafts of wood, plastic and various thicknesses and types of metal have all been used over the years. The swabs have been contained in glass or plastic tubes with and without various types of transport media. Swabs are an easy and popular method of sample collection, although microbiology laboratories traditionally prefer tissue, body fluids or aspirates ahead of swabs. As microbiology laboratories increasingly adopt near patient testing and molecular detection methods to reduce test turnaround times, new sample collection methods are required to maximise the sensitivity of these expensive tests and reduce the possibility of failed tests due to sample inhibitors or poor collection techniques. Flocked nylon swabs have been developed by Copan in the last decade and are produced using a technique of spraying nylon fibres onto a rigid core. This has the effect of increasing the surface area for sample collection and also provides easy elution of the collected material. These swabs are polymerase chain reaction (PCR) inhibitor-free, RNase-negative and DNase-free and there is in addition a range of flocked swabs, specifically intended for forensic DNA investigations that are certified human DNA-free. The advantages, disadvantages and appropriate use of swab collections for microbial detection in the 21st century will be presented.