Elizabeth A. Hesse

Blind Evaluation of the Microwave-Accelerated Metal-Enhanced Fluorescence Ultrarapid and Sensitive Chlamydia trachomatis Test by Use of Clinical Samples

ABSTRACT Accurate point-of-care (POC) diagnostic tests for Chlamydia trachomatis infection are urgently needed for the rapid treatment of patients. In a blind comparative study, we evaluated microwave-accelerated metal-enhanced fluorescence (MAMEF) assays for ultrafast and sensitive detection of C. trachomatis DNA from vaginal swabs. The results of two distinct MAMEF assays were compared to those of nucleic acid amplification tests (NAATs). The first assay targeted the C. trachomatis 16S rRNA gene, and the second assay targeted the C. trachomatis cryptic plasmid. Using pure C. trachomatis, the MAMEF assays detected as few as 10 inclusion-forming units/ml of C. trachomatis in less than 9 min, including DNA extraction and detection. A total of 257 dry vaginal swabs from 245 female adolescents aged 14 to 22 years were analyzed. Swabs were eluted with water, the solutions were lysed to release and to fragment genomic DNA, and MAMEF-based DNA detection was performed. The prevalence of C. trachomatis by NAATs was 17.5%. Of the 45 samples that were C. trachomatis positive and the 212 samples that were C. trachomatis negative by NAATs, 33/45 and 197/212 were correctly identified by the MAMEF assays if both assays were required to be positive (sensitivity, 73.3%; specificity, 92.9%). Using the plasmid-based assay alone, 37/45 C. trachomatis-positive and 197/212 C. trachomatis-negative samples were detected (sensitivity, 82.2%; specificity, 92.9%). Using the 16S rRNA assay alone, 34/45 C. trachomatis-positive and 197/212 C. trachomatis-negative samples were detected (sensitivity, 75.5%; specificity, 92.9%). The overall rates of agreement with NAAT results for the individual 16S rRNA and cryptic plasmid assays were 89.5% and 91.0%, respectively. Given the sensitivity, specificity, and rapid detection of the plasmid-based assay, the plasmid-based MAMEF assay appears to be suited for clinical POC testing.

Acceptability of self-testing for trichomoniasis increases with experience

Objectives Self-testing and point-of-care (POC) tests could improve the detection of sexually transmitted infections (STIs) in adolescents. This study aimed to (1) validate a scale measuring acceptability of self-testing for trichomoniasis, (2) compare acceptability of self versus clinician testing using a POC test for trichomoniasis, (3) examine changes in acceptability after experience and review of results, and (4) examine predictors of acceptability. Methods Women (14–22 years old) performed the POC test and completed surveys assessing acceptability of self and clinician testing at baseline, after testing, and after discussion of results. Factor analysis examined scale structure; changes in mean scale scores were assessed with mixed models. Generalised linear models examined predictors of acceptability. Results Of 247 participants, 54 (22%) had a positive POC test for trichomoniasis. Factor analysis confirmed four acceptability subscales: trust of results, confidence, comfort, and effects of testing. At baseline, trust and confidence were higher, and comfort was lower, for clinician versus self testing. For self-testing, all subscale scores increased from baseline to after testing, and trust increased from after testing to after discussion. Trust of self and clinician results was not significantly different after discussion. A positive attitude towards home testing predicted higher self-test acceptability on all subscales. Tampon use was associated with increased self-test comfort at baseline. Concordance between self and clinician results predicted increased trust of self testing after discussion. Conclusions Many young women lack confidence in their ability to self-test for trichomoniasis. Allowing women to try a POC test and review the results with a clinician increases acceptability of self-testing.

Point-of-care testing improves accuracy of STI care in an emergency department

Objectives We aimed to examine the impact of a point-of-care (POC) test on overtreatment and undertreatment of sexually transmitted infections (STIs) by comparing treatment patterns for gonorrhoea (detected with nucleic acid amplification testing (NAAT)) with trichomoniasis (detected by POC test) for young women seen in an emergency department (ED). Methods We reviewed the database of a quality improvement (QI) project that aims to improve follow-up care for STIs in the ED. Data included the test result and antibiotic given (if any) during visits by women age 14–21 for whom an STI test was ordered. We generated Shewhart control charts and compared overtreatment and undertreatment rates for gonorrhoea and trichomoniasis using χ2 testing. Results Of 1877 visits over 18 months, 8.8% of women had gonorrhoea and 16.5% had trichomoniasis. Overtreatment was higher for women with gonorrhoea than trichomoniasis (54% vs 23%, p<0.001). Overtreatment for gonorrhoea decreased from 58% to 47% (p<0.01) and overtreatment for trichomoniasis decreased from 24% to 18% (p<0.01), which corresponded to improvements in patient follow-up for the QI project. Undertreatment was higher for women with gonorrhoea than trichomoniasis (29% vs 21%, p=0.03), and did not change over time. Conclusions A POC test improves the accuracy of STI care in an ED compared with NAAT testing. An unanticipated benefit of QI efforts to improve patient follow-up is the observed decrease in antibiotic use in the ED. Given the ability of gonorrhoea to develop antibiotic resistance, future efforts should focus on development of an accurate POC test for gonorrhoea.

Accuracy and Trust of Self-Testing for Bacterial Vaginosis

PURPOSE Two point-of-care tests are available to detect bacterial vaginosis (BV), a common vaginal condition. This study aimed to (1) compare the accuracy of two self-performed BV tests with clinician-performed BV tests and with clinical diagnosis of BV; and (2) compare trust of results for self-performed BV testing with clinician-performed BV testing. METHODS Participants (14-22 years old) in a study assessing self-testing for Trichomonas vaginalis were also asked to perform a self-test for BV (using a pH or sialidase test). Results were compared with clinician-performed tests and with clinical diagnosis of BV (defined by modified Amsel criteria). A two-item subscale from a larger acceptability scale was used to assess trust at baseline, after testing, and after discussion of results. RESULTS All 131 women performed self-BV testing correctly. Agreement between self- and clinician-performed tests was good (κ: .5-.7) Compared with clinical diagnosis of BV, self-pH was 73% sensitive and 67% specific, and self-sialidase was 40% sensitive and 90% specific. Trust in self-performed BV testing was lower than trust in clinician-performed BV testing at baseline, but increased after testing and discussion of results. CONCLUSIONS Young women can perform self-tests for BV with reasonable accuracy, which could increase testing when pelvic examinations are not feasible. Trust in self-testing increased after experience and after discussion of test results. Although the pH test is available over the counter, young women may continue to rely on clinicians for testing.

Using a Rapid Communication Approach to Improve a POC Chlamydia Test

Chlamydia trachomatis is a common sexually transmitted infection in young women. Available point-of-care (POC) diagnostic tests perform poorly, but development of new devices can be costly and time consuming. We explored the feasibility (user friendliness) and test characteristics (sensitivity and specificity) of a new prototype device to detect Chlamydia in adolescent women by using small numbers of subjects and rapid communication with the manufacturer. We compared cervical POC test results to the gold standard (cervical nucleic acid amplification testing). We also assessed the accuracy of the POC test on self-collected vaginal swabs by comparing results to cervical nucleic acid amplification test and to the cervical POC test. We frequently reviewed user experience and test results with the manufacturer. The results showed the feasibility and accuracy of the device. Feasibility - initial device malfunctions were identified and corrected. This device would be easy to use in a nonclinical setting, as it is self-contained and the color change for some specimens was dramatic and immediate. Accuracy-initial prototypes demonstrated low sensitivities (38%) for vaginal and cervical swabs. After feedback, the company developed new prototypes with improved sensitivity (80%). However, the increased sensitivity was accompanied by a high percentage of indeterminate results and false positives that lowered specificity.

Rapid Antigen Testing for Trichomoniasis in an Emergency Department

BACKGROUND AND OBJECTIVES: Trichomoniasis is a prevalent cause of vaginitis among adolescents that increases the risk of acquiring other sexually transmitted diseases and of negative pregnancy outcomes. Treatment of trichomoniasis is therefore essential for improving sexual and reproductive health outcomes. A timely, sensitive diagnostic test for T vaginalis may increase the accuracy of clinician’s treatment decisions, resulting in more infected women receiving treatment and fewer uninfected women receiving treatment. METHODS: This study was a retrospective observational assessment of electronic medical records before and after point-of-care (POC) implementation of the rapid antigen test. Records were collected from women aged 14 to 20 years who received a T vaginalis test in the emergency department during either study period. The main outcome measures were rates of accurate treatment, inaccurate treatment, and missed treatment of trichomoniasis in each study period. RESULTS: Overall rates of accurate treatment increased from 78.7% pre-POC to 87.7% post-POC (P = .02). Specifically, rates of not treating uninfected women increased from 61.4% pre-POC to 70.4% post-POC (P = .06), and rates of treating infected women were the same pre-POC (17.3%) and post-POC (17.3%; P = .99). Rates of inaccurate treatment decreased from 23.1% pre-POC to 13.1% post-POC (P = .02). Changes in missed treatment rates (14.0% pre-POC; 8.8% post-POC; P = .73) were not statistically significant. CONCLUSIONS: POC testing can improve clinical care by decreasing the use of antibiotics in uninfected women. The results of this study support the use of a T vaginalis rapid antigen POC test for adolescents presenting to the emergency department.

Feasibility and acceptability of point-of-care testing for sexually transmissible infections among men and women in mobile van settings

To demonstrate the feasibility and acceptability of mobile point-of-care and near-patient testing for sexually transmissible infections, we offered services during an annual community event and surveyed event-goers. Forty-two participants were tested. When provided with options, the majority of participants chose point-of-care or near-patient testing. Trichomoniasis, chlamydia and gonorrhea were detected. All but one infected participant were notified and prescribed treatment. Participants responding to a written questionnaire reported sample self-collection and testing in a van as acceptable, although men reported self-collection in a van as less acceptable than a doctors office. Providing mobile point-of-care and near-patient sexually transmitted infection testing to the general population is feasible and acceptable.

Syphilis among adolescents and young adults in Cincinnati, Ohio: testing, infection and characteristics of youth with syphilis infection

Little is known about the epidemiology of syphilis among adolescents and young adults. This study examined, among more than 17000 young people aged 13-22 years old, trends in rates of syphilis testing and infection; characteristics of infected adolescents; and agreement about syphilis staging and treatment between provider and chart reviewer. Rates of syphilis testing increased but rates of syphilis infection did not increase significantly over a 5-year period. A majority of infected men reported only opposite-sex sexual contact. High agreement between providers and chart reviewers was found. These findings demonstrate the need for complete assessment of risk factors and use of local epidemiology in screening practices.

P5.061 Microwave-Accelerated Metal-Enhanced Fluorescence (MAMEF) Point-Of-Care Test For the Detection of Chlamydia Trachomatis

Background Chlamydia trachomatis (CT) is the most prevalent bacterial sexually transmitted infection (STI) reported worldwide. Accurate point-of-care diagnostic tests are urgently needed for the rapid treatment of patients. To address this need, we have previously developed a 16S rRNA-based Microwave-Accelerated Metal-Enhanced Fluorescence (MAMEF) assay for the detection of CT. Here we report the development of an additional CT cryptic plasmid-based MAMEF assay, the use of the assays on clinical samples and the implication of MAMEF as a point-of-care test. Methods The cryptic plasmid-based assay was investigated with cultured, titered CT and vaginal specimens. Following the optimization of the assay, we tested a blinded cohort of dry-shipped vaginal swabs using both the 16S rRNA- and cryptic plasmid-based MAMEF assays, and compared the results to nucleic acid amplification tests (NAATs). Results The MAMEF assays detected as few as 10 IFU/mL of CT in less than 10 minutes including DNA extraction and detection. A total of 257 vaginal swabs from 245 adolescent women (ages 14–22) were analysed by MAMEF. The overall prevalence of CT by NAAT was 17.5%. Of the 45 NAAT CT-positive samples and 212 CT-negative samples, 33/45 and 197/212 were correctly identified by both MAMEF assays (sens 73.3%, spec 92.9%). Using the plasmid-based assay alone, 37/45 CT+ and 197/212 CT- were detected (sens 82.2%; spec 92.9%). Using the 16S rRNA assay alone, 34/45 CT+ and 197/212 CT- (sens 75.5%; spec 92.9). For the overall % agreement with NAAT, the individual 16S rRNA and cryptic plasmid were 89.8% and 91%, respectively. Conclusions Both CT MAMEF assays demonstrated moderate sensitivity and high specificity when using dry-shipped vaginal swabs. The cryptic plasmid assay was more sensitive than the 16S rRNA assay. MAMEF is an ultra-rapid platform with results in less than 10 minutes making it ideal as a point-of-care test.