Vaginal self-sampling represents a promising alternative to increase women’s participation to screening for HPV and sexually transmitted diseases. Clinical specimens for nucleic acids amplification tests (NAATs) are traditionally transported in viral or bacterial culture media. Copan developed eNATTM, a molecular medium designed for storage and transport of clinical samples for the detection infectious agents by NAATs, able to inactivate pathogens viability and preserve nucleic acids at room temperature for extended periods of time. The objectives of this study were to validate the performance of eNATTM medium associated with FLOQSwabsTM (Copan, Brescia, Italy) for sample cellularity and nucleic acid stability in self- and clinician-collected vaginal samples.
Paired self-collected and physician administered vaginal samples using FLOQSwabsTM were randomly collected from 35 asymptomatic women attending the Cytology Unit, Synlab, Brescia, Italy. A further sample was also self-collected by all women at home. Samples were transported in eNATTM medium and stored at -20°C until testing at the Microbiology Laboratory of the University Milano-Bicocca. Sample cellularity was evaluated, following nucleic acid extraction (NucliSENS®easyMAG, bioMérieux), by means of CCR5 gene and beta-actin mRNA quantification by real-time PCR as previously described1, 2. A separate sample aliquot was stored at -80°C and re-extracted and re-tested after 1 year to assess nucleic acid stability in eNATTM. Samples were also tested for the presence of HPV using AnyplexII HPV28 (Seegene).
CCR5 and beta-actin copy numbers/2 ml eNATTM median values were found to be 12275 and 169 x 106; 12805 and 164 x 106 respectively for home and point of care self-collected samples, for clinician-collected samples values were 13333 and 165 x 106 respectively. Cellularity values after 1 year were found to be 14464 and 43 x 106; 12530 and 52 x 106 for home and point of care self-collected samples and 12971 and 64 x 106 for clinician-collected samples respectively. No statistical difference was found between sample cellularity in the different groups. HPV was detected in 26.5% (9/34) of women; 45% were positive in both samples, 33% only in self-collected and 22% only in clinician-collected samples.
Cellularity of both self- and clinician-collected vaginal samples using FLOQSwabsTM showed comparable results. Sample storage in eNATTM medium for 1 year at -80°C showed good nucleic acid stability for both DNA and RNA. Data obtained demonstrated a good performance of both FLOQSwabsTM and eNATTM medium in vaginal sample collection, transport and storage for NAATs.
1. F. Broccolo et al. J Clin Microbiol 2002; 4652-4658.
2. C. Jobin et al. J Immunol 1997; 158:226-234.