Evaluation of Copan FLOQSwab for the molecular detection of Chlamydia trachomatis by Abbott RealTime CT PCR

Non-invasive detection of IgG antibodies from common pathogenic viruses using oral flocked swabs

Salivary antibodies are useful in surveillance and vaccination studies. However, low antibody levels and degradation by endonucleases are problematic. Oral flocked swabs are a potential non-invasive alternative for detecting viral antibodies. Seroprevalence for Cytomegalovirus (CMV), Varicella-Zoster virus (VZV), Epstein-Barr virus (EBV), Measles and Mumps IgG antibodies were determined from 50 matched serum, saliva and swabs samples from healthy volunteers using commercial ELISAs. CMV IgG, VZV IgG, and EBV EBNA-1 IgG, VCA IgG, and Measles IgG swab versus serum sensitivities were 95.8%, 96.0%, 92.1%, 95.5%, 84.5%, respectively, and swabs correlated well with saliva. Sensitivity of Mumps IgG in swabs and saliva was poor at 60.5%, and 68.2%, respectively. Specificities for IgG antibodies were 100% for CMV, EBV and Mumps, but could not be determined for VZV and Measles due to exclusively seropositive volunteers. Except for Mumps IgG, swabs correlate well with serum, are easy to self-collect and are stable at room temperature.

Comparing mail-in self-collected specimens sent via United States Postal Service versus clinic-collected specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in extra-genital sites

Objectives

To evaluate the concordance between clinic-collected extra-genital specimens and self-collected mailed-in extra-genital specimens among participants seeking sexually transmitted infection testing at a free clinic in Hollywood, CA.

Methods

A convenience sample of 210 men who have sex with men were enrolled between February 29, 2016 and December 21, 2016 and received mail-in testing kits for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). All testing was performed using the GeneXpert® CT/NG (Cepheid, Sunnyvale, CA).

Results

From the 210 mail-in kits distributed, 149 mail-in kits (71.0%) were returned to the laboratory, resulting in 145 pairs (clinic-collected and mail-in) of rectal test results and 148 pairs of pharyngeal test results for both CT and NG detection. The concordance was 95.0% for all CT rectal tests, 99.3% for all CT pharyngeal tests, 95.7% for all NG rectal tests, and 97.2% for all NG pharyngeal tests.

Conclusion

Roughly two-thirds of mail-in test kits were returned and concordance was generally high, however more than one-third of positive results were missed in mail-in samples. The prevalence of potential false-negative results among mail-in samples warrants caution when implementing mail-in STI testing strategies.

Influence of storage time on DNA of Chlamydia trachomatis, Ureaplasma urealyticum, and Neisseria gonorrhoeae for accurate detection by quantitative real-time polymerase chain reaction

The shipment and storage conditions of clinical samples pose a major challenge to the detection accuracy of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Ureaplasma urealyticum (UU) when using quantitative real-time polymerase chain reaction (qRT-PCR). The aim of the present study was to explore the influence of storage time at 4°C on the DNA of these pathogens and its effect on their detection by qRT-PCR. CT, NG, and UU positive genital swabs from 70 patients were collected, and DNA of all samples were extracted and divided into eight aliquots. One aliquot was immediately analyzed with qRT-PCR to assess the initial pathogen load, whereas the remaining samples were stored at 4°C and analyzed after 1, 2, 3, 7, 14, 21, and 28 days. No significant differences in CT, NG, and UU DNA loads were observed between baseline (day 0) and the subsequent time points (days 1, 2, 3, 7, 14, 21, and 28) in any of the 70 samples. Although a slight increase in DNA levels was observed at day 28 compared to day 0, paired sample t-test results revealed no significant differences between the mean DNA levels at different time points following storage at 4°C (all P>0.05). Overall, the CT, UU, and NG DNA loads from all genital swab samples were stable at 4°C over a 28-day period.

A comparison of flocked swabs and traditional swabs, using multiplex real-time PCR for detection of common gastroenteritis pathogens in Botswana

We compared the performance of flocked and matched traditional rectal swabs collected from 236 children admitted with gastroenteritis in Botswana. All samples were tested using real time multiplex-PCR assays for nine enteric pathogens. There was a 20% higher detection of Shigella from flocked swabs, but most other pathogens had similar detection rates.