Performance Evaluation of Universal Transport Media Device using Clinically Relevant Bacteria

Swabs are routinely placed into non-propagating universal transport media (UTM) to preserve the viability and integrity of samples for clinical analysis. However, the variability in storage conditions as well as the transport medium itself creates inconsistent and unreliable results rendering this low cost alternative inefficient. The performance of a Puritan Medical Products Company LLC (PMP) Universal Transport Medium (UTM) for Viruses, Chlamydia, Mycoplasma, and Ureaplasma was compared to a Universal Viral Transport System of Becton, Dickinson and Company (BD) manufactured by Copan Diagnostics of Italia using five bacterial strains (two Mycoplasma species, two Chlamydiae species and one Ureaplasma species.). These were tested at two dilutions, two temperatures (4°C and 22°C) and over the course of four time points (0, 24, 48, 72h) between inoculated UTM devices. To quantify the Mycoplasma and Ureaplasma viable bacterial load in the UTM post test conditions, 100 μL of the sample was inoculated onto appropriate agar plates. The plates were incubated at optimal conditions for an appropriate amount of time, after which colonies were enumerated and recorded using a standard light microscope for quantitative analysis. To quantify the Chlamydiae species, 100 μL of the sample was inoculated onto shell vials and incubated for 24 to 48h after which the cover slips were collected, mounted and stained with fluorescent antibodies. Using fluorescent microscopy, individual foci were enumerated and recorded for quantitative analysis. For both devices, bacteria were viable through 72h of storage at both temperatures. As determined by viability, no differences were noted between the two devices that could not be ascribed to normal microbiological variance. The PMP UTM device performed in an equivalent fashion to the BD UTM thus making it a valid system for the collection, storage, and transport of clinical specimens. Detection of clinical pathogens requires specific equipment and training that are not always readily available. Swabs represent an alternative tool that require little training and equipment; however, recovery and detection of pathogens after collection has proven to be inconsistent. This derives the need for a transport medium that will preserve viability, inhibit propagation, and ensure quantitative detection via culture, PCR, immunostaining, etc. For accurate identification of various bacteriological agents that cause a myriad of different pathophysiological conditions, several transport media, namely Stuart medium, Amies medium, Cary and Blair medium, and others, are commercially available (Stuart et al., 1954; Cary and Blair, 1964; Amies, 1967). In addition, numerous viral transport media of differing composition are described in the literature. These include Universal Transport Medium (UTM-RT; Copan and BD), Bartels Viratrans medium, M4-RT, M5 media, modified liquid Stuart’s medium, Universal Collection Medium, and Multitrans medium (Starplex Scientific). Overall, however, limited media are available for the transport of viruses, Chlamydiae spp., Mycoplasma spp., and Ureaplasma spp. (Cornall and Urquhart, 1978; Johnson, 1990; Ogburn et al., 1994; Racioppi and Brinker, 1997; Taha et al., 2006; WHO, 2006; Adelson and Mordelchai, 2007). The objective of this study was to compare the performance of a PMP UTM to a BD UTM device. Comparison testing was accomplished through recovery, storage stability, and cytotoxicity studies. ____________________________