Comparison of three real-time PCR assays for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in young pregnant women

Chlamydia trachomatis prevalence in females in São Paulo, Brazil: 11 years' surveillance of the infection

BACKGROUND

Chlamydia trachomatis (CT) infection is the most prevalent sexually transmitted bacterial disease worldwide whose greatest impact is on the female reproductive system. The objective was to assess the prevalence of Chlamydia infection in a large population of female patients from a private health service in São Paulo (Brazil), identifying the main age groups affected by the agent and the evolution of the prevalence.

METHODS

A cross-sectional study was conducted based on the results of all molecular biology tests. The tests were carried out between January 2005 and December 2015. The positivity of test results was determined by year and age group.

RESULTS

A total of 85,292 patients who performed 103,576 tests for Chlamydia were considered eligible for the statistical data. The overall prevalence of C. trachomatis infection in the study population was 2.2% (95% CI: 2.07-2.25). A higher prevalence of infection was observed in the ≤ 25 years and ≤ 30 years age groups, with rates of 6.0% (95% CI: 5.59-6.35) and 4.4% (95% CI: 4.08-4.50), respectively. There was a significant increase in the positivity of the exams over time, especially in the ≤ 35 years age group. The prevalence at 26-30 years was 3.1% (95% CI: 2.82-3.30); 31-35 years 1.7% (95% CI: 1.50-1.82); 36-40 years 1.0% (95% CI: 0.86-1.16); 41-60 years 0.6% (95% CI: 0.50-0.70) and the prevalence at ≥ 61 years was 0.4% (95% CI: 0.11-0.75).

CONCLUSION

The screening of asymptomatic young women would have the potential to reduce infection, transmission, and sequelae of infection by this agent.

Doxycycline versus azithromycin for the treatment of anorectal Chlamydia trachomatis infection in women concurrent with vaginal infection (CHLAZIDOXY study): a multicentre, open-label, randomised, controlled, superiority trial

BACKGROUND

Anorectal infections with Chlamydia trachomatis are commonly found in women. Although the efficacy of doxycycline and azithromycin is comparable in the treatment of urogenital infection, their efficacies toward anorectal infection remain unclear. We therefore aimed to compare a single dose of azithromycin with a 7-day course of doxycycline for the treatment of anorectal C trachomatis infection in women with concurrent vaginal infection.

METHODS

We did a multicentre, open-label, randomised, controlled, superiority trial involving four sexually transmitted infection screening centres and three pregnancy termination centres in France. We included sexually active adult women (≥18 years) with a positive C trachomatis vaginal swab who agreed to provide self-collected anorectal swabs for C trachomatis detection. Participants were randomly assigned (1:1), using block sizes of six and eight and stratification by each investigating centre, to orally receive either azithromycin (a single 1-g dose, with or without food) or doxycycline (100 mg in the morning and evening at mealtimes for 7 days [ie, 100 mg of doxycycline twice per day for 7 days]). All laboratory staff who did the bacteriological analyses, but not the participants and the investigators, were masked to the treatment groups. The primary outcome was the microbiological anorectal cure rate defined as a C trachomatis-negative nucleic acid amplification test (NAAT) result in anorectal specimens 6 weeks after treatment initiation among women who had a baseline C trachomatis-positive anorectal NAAT result. The primary analysis was done in the modified intention-to-treat population, with multiple imputation, which included all women who underwent randomisation and had a C trachomatis-positive vaginal and anorectal NAAT result at baseline. Adverse events were reported in all women who underwent randomisation. This study is registered with ClinicalTrials.gov, number NCT03532464.

FINDINGS

Between Oct 19, 2018, and April 17, 2020, we randomly assigned a total of 460 participants to either the doxycycline group (n=230) or the azithromycin group (n=230). Four (1%) of 460 participants were excluded because they refused to take doxycycline or were found to be ineligible after randomisation. Among the 456 participants, 357 (78%) had a concurrent C trachomatis-positive anorectal NAAT result at baseline; 184 (52%) of 357 were in the doxycycline group and 173 (48%) were in the azithromycin group (ie, the modified intention-to-treat population). Microbiological anorectal cure occurred in 147 (94%) of 156 participants in the doxycycline group (28 missing values) versus 120 (85%) of 142 in the azithromycin group (31 missing values; adjusted odds ratio with imputation of missing values 0·43 [95% CI 0·21-0·91]; p=0·0274). Reported adverse events possibly related to treatment were notified in 53 (12%) of 456 women: 24 (11%) of 228 in the doxycycline group and 29 (13%) of 228 in the azithromycin group. Gastrointestinal disorders were the most frequently occurring, in 43 (9%) of 456 women: 17 (8%) of 228 in the doxycycline group and 26 (11%) of 228 in the azithromycin group.

INTERPRETATION

The microbiological anorectal cure rate was significantly lower among women who received a single dose of azithromycin than among those who received a 1-week course of doxycycline. This finding suggests that doxycycline should be the first-line therapy for C trachomatis infection in women.

FUNDING

French Ministry of Health.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Evaluation of the Diagnostic Efficacy of Xpert CT/NG for Chlamydia trachomatis and Neisseria gonorrhoeae

BACKGROUND

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are widely spread across the world. Asymptomatic or inconspicuous CT/NG infections are difficult to diagnose and treat. Traditional methods have the disadvantages of low detection rate, inaccurate results, and long detection time. However, Xpert CT/NG makes up for the aforementioned shortcomings and has research value and popularization significance.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were systematically searched, and studies were screened using Xpert CT/NG for diagnosing CT/NG. QUADAS-2 was used to evaluate the quality of the eligible studies. Then, two groups of researchers independently extracted data from these studies. Meta-analyses of sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the curve (AUC) of the summary receiver operating characteristic (SROC) curve were conducted using Meta-DiSc 1.4. Finally, Deek's funnel plots were made using Stata 12.0 to evaluate publication bias.

RESULTS

14 studies were identified, and 46 fourfold tables were extracted in this meta-analysis. The pooled SEN, SPE, PLR, NLR, DOR, and AUC in diagnosing CT were 0.94 (95% confidence interval (CI): 0.93-0.95), 0.99 (95% CI: 0.99-1.00), 97.17 (95% CI: 56.76-166.32), 0.07 (95% CI: 0.04-0.12), 1857.25 (95% CI: 943.78-3654.86), and 0.9960, respectively. The pooled SEN, SPE, PLR, NLR, DOR, and AUC in diagnosing NG were 0.95 (95% CI: 0.93-0.96), 1.00 (95% CI: 1.00-1.00), 278.15 (95% CI: 152.41-507.63), 0.08 (95% CI: 0.06-0.12), 4290.70 (95% CI: 2161.78-8516.16), and 0.9980, respectively.

CONCLUSIONS

Xpert CT/NG had high diagnostic sensitivity and specificity for CT and NG. However, more evidence is required to confirm that Xpert CT/NG might serve as the primary method for detecting CT and NG and even the gold standard for diagnosis in the future.

Randomized, open-label, multicenter study of azithromycin compared with doxycycline for treating anorectal Chlamydia trachomatis infection concomitant to a vaginal infection (CHLAZIDOXY study)

BACKGROUND

Chlamydia trachomatis can lead to a persistent infection in the lower gastrointestinal tract, suggesting a potential role of autoinoculation of cervical chlamydial infection from the rectal site, contributing to repeat infections. Moreover, around 75% of women with urogenital C. trachomatis have concurrent anorectal infection. Current treatment guidelines for urogenital C. trachomatis infection recommend either a single 1 g dose of azithromycin or doxycycline 100 mg twice daily for 7 days. Doxycycline appears to be more effective in treating anorectal infections as suggested in a population of men who have sex with men, but no randomized controlled trial (RCT) had directly compared azithromycin with doxycycline for the treatment of rectal infections. We propose an open-label RCT to compare the microbial cure obtained with a single 1 g dose of azithromycin versus 100 mg of doxycycline twice daily for 7 days, for the treatment of anorectal C. trachomatis infection concurrent to urogenital infection in women.

METHODS AND STUDY DESIGN

A total of 460 women with C. trachomatis urogenital infection will be enrolled in the study. Women will be asked to provide self-collected anorectal swabs and will be randomized to receive either a 1 g single dose of azithromycin or doxycycline 100 mg twice daily for 7 days. Clinical and biological data will be collected and patients will complete questionnaires about their sexual behavior. The primary outcome is the microbial cure rate, defined as a C. trachomatis negative nucleic acid amplification test (NAAT) result in the anorectal specimens 6 weeks after treatment initiation among women with a C. trachomatis positive urogenital and anorectal NAAT result at the baseline. The secondary outcome is autoinoculation from the rectum to the vagina, which will be evaluated based on the number of women with the same C. trachomatis genotype profile that will be identified in an anorectal-positive specimen obtained 6 weeks after treatment initiation and in a vaginal-positive specimen obtained four months after treatment.

DISCUSSION

The results of this trial will establish which treatment is more efficacious against anorectal infection and could affect recommendations for the treatment of urogenital C. trachomatis infection, taking into account concurrent anorectal infection.

TRIAL REGISTRATION NUMBERS

EudraCT number: 2017-002595-15. CLINICALTRIALS.

GOV IDENTIFIER

NCT03532464. Date of registration: May 31, 2018.

WORLD HEALTH ORGANISATION INTERNATIONAL CLINICAL TRIALS REGISTRY

NTC03532464. Secondary ID: CHUBX 2016/26. Date of registration: May 09, 2018.

Evaluation of a Hydrogel-Based Diagnostic Approach for the Point-of-Care Based Detection of Neisseria gonorrhoeae

Eleven primer pairs were developed for the identification of Neisseria gonorrhoeae. The sensitivity and specificity of these primers were evaluated by Real Time (RT)-PCR melt curve analyses with DNA from 145 N. gonorrhoeae isolates and 40 other Neisseria or non-Neisseria species. Three primer pairs were further evaluated in a hydrogel-based RT-PCR detection platform, using DNA extracted from 50 N. gonorrhoeae cultures. We observed 100% sensitivity and specificity in the hydrogel assay, confirming its potential as a point-of-care test (POCT) for N. gonorrhoeae diagnosis.

Evaluation of the cobas Cdiff Test for Detection of Toxigenic Clostridium difficile in Stool Samples

Nucleic acid amplification tests (NAATs) are reliable tools for the detection of toxigenic Clostridium difficile from unformed (liquid or soft) stool samples. The objective of this study was to evaluate performance of the cobas Cdiff test on the cobas 4800 system using prospectively collected stool specimens from patients suspected of having C. difficile infection (CDI). The performance of the cobas Cdiff test was compared to the results of combined direct and broth-enriched toxigenic culture methods in a large, multicenter clinical trial. Additional discrepancy analysis was performed by using the Xpert C. difficile Epi test. Sample storage was evaluated by using contrived and fresh samples before and after storage at -20°C. Testing was performed on samples from 683 subjects (306 males and 377 females); 113 (16.5%) of 683 subjects were positive for toxigenic C. difficile by direct toxigenic culture, and 141 of 682 subjects were positive by using the combined direct and enriched toxigenic culture method (reference method), for a prevalence rate of 20.7%. The sensitivity and specificity of the cobas Cdiff test compared to the combined direct and enriched culture method were 92.9% (131/141; 95% confidence interval [CI], 87.4% to 96.1%) and 98.7% (534/541; 95% CI, 97.4% to 99.4%), respectively. Discrepancy analysis using results for retested samples from a second NAAT (Xpert C. difficile/Epi test; Cepheid, Sunnyvale, CA) found no false-negative and 4 false-positive cobas Cdiff test results. There was no difference in positive and negative results in comparisons of fresh and stored samples. These results support the use of the cobas Cdiff test as a robust aid in the diagnosis of CDI.

Detection of Neisseria gonorrhoeae and Chlamydia trachomatis from pooled rectal, pharyngeal and urine specimens in men who have sex with men

OBJECTIVES

Screening of men who have sex with men (MSM) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) requires sampling from anorectal and pharyngeal sites in addition to urogenital sampling. Due to the cost of testing multiple anatomical sites individually testing of pooled specimens has potential merit. The Cepheid GeneXpert CT/NG assay (GeneXpert), which also has potential for point-of-care nucleic acid testing in the sexual health clinic, has not been assessed for pooled specimen testing.

METHODS

We prospectively compared GeneXpert testing of pooled pharyngeal and rectal swabs with urine samples to standard of care testing of individual specimens from 107 participants using the Roche cobas 4800 CT/NG assay (cobas) for CT and NG in high-risk MSM attending an inner city sexual health clinic.

RESULTS

We found testing of pooled pharyngeal, rectal and urine samples by the GeneXpert to have 100% agreement for NG and 94% overall agreement for CT when compared with individual specimen testing by cobas. For CT testing, 14 cases were detected for both tests, 4for cobas only, 2 for GeneXpert only and 89 participants were negative for both tests.

CONCLUSIONS

Pooled specimen CT and NG testing by the GeneXpert was accurate when compared with single specimen testing and has potential for screening MSM for CT and NG. The role of pooled specimen testing with the GeneXpert as a point-of-care nucleic acid test in MSM requires further investigation.

Use of Nucleic Acid Amplification Testing for Diagnosis of Extragenital Sexually Transmitted Infections

Nucleic acid amplification testing (NAAT) is the preferred method to detect Chlamydia trachomatis and Neisseria gonorrhoeae, but no commercial tests are cleared by the U.S. Food and Drug Administration for use with extragenital swab samples. This study evaluated the performance of the Gen-Probe Aptima Combo2 assay (Aptima) and the Cepheid Xpert CT/NG assay (Xpert) to detect C. trachomatis and N. gonorrhoeae in rectal and pharyngeal samples from 224 men and 175 women reporting a history of anal receptive sexual intercourse. Discordant results between the NAATs were repeated using the assays APTIMA CT or APTIMA GC, which target alternate primers, as the confirmatory tests. C. trachomatis was detected from 59 rectal swabs and 8 pharyngeal samples, with 97.7% and 99.5% agreement between the two test systems, respectively. For C. trachomatis, Xpert was 95% sensitive (95% CI, 86 to 99%) and Aptima was 92% sensitive (95% CI, 81 to 97%) from rectal swabs, while both systems were 100% sensitive from pharyngeal samples. N. gonorrhoeae was detected from 30 rectal and 40 pharyngeal samples, with 99.5% and 97.5% agreement between the two test systems. The sensitivity of Xpert for N. gonorrhoeae from rectal swabs was 100% (95% CI, 88 to 100%) versus 93% (95% CI, 78 to 99%) for Aptima. From pharyngeal swab samples, Xpert was 98% sensitive (95% CI, 87 to 99.9%) versus 93% (95% CI, 80 to 98%) for Aptima. For C. trachomatis, neither system was >95% sensitive from the rectum, though both were >99.5% specific. For N. gonorrhoeae, Xpert had higher sensitivity than Aptima, but with more false positives from pharyngeal samples.