Tampon-collected genital cells in the detection of Chlamydia trachomatis by polymerase chain reaction

Long-term trends of Chlamydia trachomatis in a clinic population at the Royal Women's Hospital, Melbourne

BACKGROUND

Chlamydia trachomatis (C. trachomatis) prevalence has been reported to be increasing. Whether this is a true increase over time or confounded by increases in testing and/or use of more sensitive assays is to be determined.

MATERIALS AND METHODS

One laboratory service has been detecting C. trachomatis for the past 30 years within the Royal Women's Hospital Melbourne. We conducted a retrospective audit of records over the period 1986-2016 from a clinic population routinely offered chlamydia screening. These were women presenting for family planning advice (termination of pregnancy, intrauterine device insertion or considered at high risk), who underwent chlamydia testing in the context of various diagnostic assays used over this time period. Assays utilised included culture, enzyme immunoassay (EIA), DNA probe, and nucleic acid amplification testing (NAAT). Non-parametric test for trend was used to determine significant differences between prevalence estimates across ordered groups. Least squares regression was conducted to describe a linear trend matching known data points.

RESULTS

Overall, there was no significant change for chlamydia prevalence which was 2.2%, in the 30-year study period (P = 0.7). Over time diagnostic assays changed from culture, to EIA, DNA probe, to the more sensitive NAAT. The bulk of the positives were in women under 25 years of age (57%).

CONCLUSION

Chlamydia prevalence has been stable over 30 years, remaining a problem in young women. Screening for those at risk needs underscoring in a national sexual health program.

Advances in sampling and screening for chlamydia

Chlamydia is the most commonly diagnosed bacterial sexually transmitted infection in the developed world, with diagnosis rates continuing to increase each year. As chlamydia is largely asymptomatic, screening and treatment is the main way to detect cases and reduce transmission. Recent advances in self-collected specimens and laboratory tests has made chlamydia screening easier to implement as well as possible in nonclinical settings. This review will discuss new approaches to specimen collection and how these have expanded opportunities for reaching target populations for chlamydia screening. Furthermore, it will discuss how advanced molecular microbiological methods can be used with self-collected specimens to further our knowledge of the epidemiology of chlamydia and the dynamics of transmission.

Diagnosis of sexually transmitted infections (STI) using self-collected non-invasive specimens

Paramount in control of transmission of sexually transmitted infections (STIs) is their prompt recognition and appropriate treatment. In countries where definitive diagnoses are difficult, a 'syndromic approach' to management of STIs is recommended and practiced, yet many STIs have common symptoms or are asymptomatic and therefore go undetected and untreated. This is of particular concern with the recognition that HIV transmission is increased with co-existent STIs: the attributable risk for each STI varying with the prevalence within a particular population. Hence, HIV public health prevention approaches must include STI preventative strategies to be effective. Even then, microbiological screening is incorporated into STI control strategies; lack of access to appropriate services (especially in rural and remote areas), reluctance of at-risk populations to attend for treatment, fear of invasive genital examinations, and lower sensitivities of conventional diagnostic assays reduces the effectiveness of such programmes. Therefore, accurate, cost-effective, reliable diagnostic assays (preferably those which can be used in the field) are needed to impact on the incidence of the various STIs, as well as HIV. With the advent of molecular technologies, including target and signal amplification methods, diagnoses of STIs have been revolutionised and allow the use of non or minimally invasive sampling techniques, some of which are self-collected by the patient, e.g. first-void urine, cervico-vaginal lavage, low vaginal swabs, and tampons. Most studies evaluating such self-sampling with molecular diagnostic techniques have demonstrated an equivalent or superior detection of STIs as compared to conventional sampling and detection methods. These sampling methods can also be used to determine prevalence of STIs in various populations, but particularly those with difficult access to medical care. In this article, the utility of self-sampling collection devices for detection of various STIs, particularly in women, is reviewed as one step towards formulating appropriate strategies in control of STIs, and which are especially suited for remote areas.

Tampons as a self-administered collection method for the detection and quantification of genital HIV-1

OBJECTIVE

To assess the detection and quantitation of HIV-1 from tampon eluents in comparison with cervicovaginal lavage (CVL) and plasma specimens from the same women.

METHODS

Ninety-seven tampon, 105 CVL, and 104 plasma specimens from 105 HIV-1 seropositive women were analyzed using Version 3 of the Chiron bDNA assay, with sensitivity of 50 HIV-1 RNA copies/ml. Data analyses used McNemar's test, Wilcoxon signed rank test, and Mantel--Haenszel chi-squared and odds ratios with 95% confidence intervals to assess differences in proportions.

RESULTS

In women for whom both plasma and genital specimens were available, HIV-1 was detected less frequently in genital specimens: [tampons (33/97, 34%) and CVL (48/104, 46%)] than plasma specimens (86/104, 83%) (P < 0.001 for both plasma versus tampon and for plasma versus CVL). However, the proportion of genital specimens with detectable virus did not differ significantly by collection method (P = 0.14). Among women with detectable virus using both collection methods (n = 23), viral load was similar for tampon eluents (median, 355 copies/ml; range, 52--120,898) and CVL specimens (median, 265 copies/ml; range, 61--35,637;P = 0.88).

CONCLUSION

Tampon eluent specimens are slightly less sensitive than CVL specimens in the detection of genital HIV-1, although quantification of viral load, when detectable by both methods, was similar.

Assessment of Chlamydia trachomatis prevalence by PCR and LCR in women presenting for termination of pregnancy

OBJECTIVES

To determine the prevalence of Chlamydia trachomatis in a patient population presenting for legal termination of pregnancy by polymerase chain reaction (PCR) and ligase chain reaction (LCR), from first catch urine and self administered tampons, and comparing with the traditionally collected endocervical swab tested by both PCR and culture.

METHODS

Consecutive women attending for legal termination of pregnancy were screened for chlamydia by patient collected first catch urine and tampon, and physician collected endocervical swab.

RESULTS

Of 1175 patients with complete samples, there were 33 (2.8%) in whom chlamydia was detected by two or more assays from one or more sample site. Chlamydia was detected equally well by both PCR and LCR in first catch urine (p = 0.25), tampon (p = 0.5), and endocervical swab (p = 0.5). However, both PCR and LCR were significantly better than culture of an endocervical swab (p = 0.0005) for detection of C trachomatis.

CONCLUSION

The prevalence of chlamydia in patients presenting for termination of pregnancy was 2.8%. A simple efficient way of performing screening for chlamydia for women presenting for termination of pregnancy is by first catch urine or tampon, which can be tested by the highly sensitive amplification assays, PCR or LCR.

Evaluation of patient-administered tampon specimens for Chlamydia trachomatis and Neisseria gonorrhoeae

BACKGROUND

The patient-administered tampon specimen has proven to be an easy and sensitive method for the diagnosis of genital Chlamydia trachomatis and Neisseria gonorrhoeae infections in women by polymerase chain reaction (PCR). This method avoids the need for endocervical sampling and stringent criteria for transport.

GOAL

To evaluate two commercial amplification systems for the detection of C trachomatis and N gonorrhoeae from tampon specimens.

STUDY DESIGN

A group of 400 positive and negative tampon specimens tested by an in-house PCR method were selected from a pool of more than 2,000 previously collected tampons. Overall, 93 C trachomatis-positive and 77 N gonorrhoeae-positive specimens were evaluated. Each specimen was tested by Roche Cobas Amplicor and Abbott LCx (LCR), and results were compared to the in-house PCR method.

RESULTS

Detection of C trachomatis by both assays was not significantly different from the in-house PCR assay. Fewer tampons were positive for N gonorrhoeae by LCR than either the in-house assay (P = 0.0001) or by Roche Amplicor (P = 0.01). However, tampon specimens tested by Roche Amplicor required DNA extraction to achieve comparative sensitivity.

CONCLUSION

Both commercial assays can be applied to tampon-collected specimens for automated detection of sexually transmitted diseases. The detection of C trachomatis was similar to the in-house PCR test for both assays (P = 0.73, 0.68). Detection of N gonorrhoeae resulted in fewer positive tampon specimens when tested by ligase chain reaction than both Roche Amplicor and in-house PCR.

Patient-administered tampon-collected genital cells in the assessment of Chlamydia trachomatis infection using polymerase chain reaction

BACKGROUND

Diagnosis of genital Chlamydia trachomatis infection in women traditionally requires a speculum examination to collect endocervical cells, followed by cell culture. This method is time consuming, requires stringent transport conditions, and is technically demanding.

GOALS

To compare tampons as a patient-administered collection method followed by detection with polymerase chain reaction (PCR) with the traditional endocervical swab culture followed by cell culture detection.

STUDY DESIGN

At the emergency department of a hospital for obstetrics and gynecology, 1,000 consecutive women with symptoms suggestive of infection with C. trachomatis were tested for C. trachomatis infection by PCR on both tampon (PCR-T) and swab (PCR-S) specimen and by culture of the swab specimen.

RESULTS

Seventeen PCR-T and 16 PCR-S specimens were positive; 16 endocervical specimens were positive by culture, and 14 of the endocervical samples were positive by the three methods. Sixty-one PCR-S samples were inadequate as shown by the lack of amplification of the beta-globin gene segment, indicating poor collection of specimens by endocervical swab for chlamydial testing.

CONCLUSIONS

Tampon specimens collected for PCR detection provided an easy and sensitive method of detection of C. trachomatis and overcame the obstacle of endocervical sampling and subsequent stringent transport requirements of culture.

Evaluation of vaginal tampons for collection of specimens for detection of Chlamydial infection

BACKGROUND AND OBJECTIVES

Previous studies have shown that self-inserted vaginal tampons can be used to obtain specimens for detection of Neisseria gonorrhoeae. There is a need to expand testing for infection with Chlamydia trachomatis to women who do not undergo regular gynecologic examinations.

GOAL

To compare self-inserted tampons with clinician-obtained endocervical swabs for collection of samples to be examined for chlamydial infection.

STUDY DESIGN

Women referred because of recently detected untreated chlamydial infection inserted a vaginal tampon. Two endocervical swabs were obtained after the tampon was removed. One swab was cultured for Chlamydia trachomatis. The other swab and the tampon were examined with the Testpack Chlamydia antigen detection test.

RESULTS

Sixty-nine women were studied. Chlamydial infection was detected by culture in 75.4%, by Testpack (swab) in 63.8%, and by Testpack (tampon) in 52.2%.

CONCLUSIONS

Tampon-obtained specimens evaluated in the Testpack Chlamydia test were relatively insensitive. More sensitive tests for the detection of Chlamydia trachomatis infection with self-obtained specimens should be evaluated.