Evaluation of a New Cellulose Sponge-Tipped Swab for Microbiological Sampling: a Laboratory and Clinical Investigation

Abstract

A new type of swab (Cellswab; Cellomeda, Turku, Finland), utilizing a highly absorbent cellulose viscose sponge material, was compared to some traditional swabs. The survival of 14 aerobic and 10 anaerobic and microaerophilic bacterial species in the Cellswab, two commercial swab transport systems (Copan, Brescia, Italy, and Orion Diagnostica, Espoo, Finland), and one Dacron swab (Technical Service Consultants Ltd.[TSC], Heywood, United Kingdom) was evaluated. Bacteria were suspended in broth, into which the swabs were dipped. The Cellswab absorbed 1.3 times more fluid and released 3.5 times more fluid upon plating than the other swabs. Aerobic bacteria were stored in dry tubes, the others in transport medium, at 4°C and room temperature (RT), for up to 14 days. Swab samples were transferred to plates at 0, 1, 2, 4, 7, and 14 days. For 10 strains the Cellswab yielded >10% of the original CFU for longer than all the other swabs. In the clinical study, the ability of the Cellswab to detect beta-hemolytic streptococci from throat samples (n ‫؍‬ 995) was compared to that of the TSC Dacron swab. The swabs performed equally, both when their samples were transferred to plates immediately and after storage for 1 day at 4°C or RT. The changes in normal microbiota after storage were also similar. The Cellswab was found to perform at least as well as ordinary swabs. It was better at storing fastidious strains, and at keeping bacteria viable for long storage times; it might well be a useful replacement or complement to ordinary swabs.

Comparison of 3 swab transport systems for direct release and recovery of aerobic and anaerobic bacteria

“…Swab transport devices should be able to maintain the viability of microorganisms present, and the swab should allow for release of a sufficient representative portion of the specimen material and preserve the integrity of nucleic acids for amplification testing. Limited studies describe organism or specimen release from swabs in transport systems (Drake et al, 2005;Österblad et al, 2003;Roelofsen et al, 1999).…”

“…Swab transport devices should be able to maintain the viability of microorganisms present, and the swab should allow for release of a sufficient representative portion of the specimen material and preserve the integrity of nucleic acids for amplification testing. Limited studies describe organism or specimen release from swabs in transport systems (Drake et al, 2005;Österblad et al, 2003;Roelofsen et al, 1999).Most swab collection devices currently on the market are prepared with rayon or Dacron fibers wound onto the tip of the swab shaft. The new ESwab (Copan Diagnostics, Murrieta, CA) is a nylon-tipped swab prepared by spray-on flocked fiber technology that potentially results in better specimen collection and a more efficient release of specimen material with less specimen entrapment than woven fibertipped swabs.…”

Surface Sampling of Spores in Dry-Deposition Aerosols

“…Lessons learned in restoring operations within large building complexes contaminated with Bacillus anthracis spores or ricin toxin have led to the development of more-efficient tools for the detection of biological pathogens and means of decontaminating affected facilities. A key step in determining the extent of contamination during the initial stages of a bioterrorist attack and in ascertaining if a building can be reoccupied in the final stages of cleanup is our ability to effectively sample an area and deliver a specimen for testing.Currently there are several commercially available sampling products (2,3,8,9,16,23), but test data demonstrate that they are limited in their ability to detect and recover biological samples, with estimated recovery efficiencies ranging from approximately 10% to 40% (8,11,19). Studies have also shown that a significant proportion of the biological agent that can be sampled from a solid surface remains adhered to the sampling materials despite efforts to wash it off for testing or is lost during the sample processing (1,7,19).…”

Direct detection and characterization of Clostridium difficile from a novel collection device to improve laboratory workflow

“…Critical points for a rapid and accurate detection of C. difficile are the collection of an appropriate fecal sample and its maintenance until analysis. The implementation of collection devices that incorporate a flocked swab has been reported to improve clinical material adsorption and release from the swab , facilitating a rapid and reliable identification of microorganisms.…”