Chlamydia trachomatis test-of-cure cannot be based on a single highly sensitive laboratory test taken at least 3 weeks after treatment

Summary of the Fourth Annual American Sexually Transmitted Diseases Association Workshop on Improving Sexually Transmitted Infection Control Efforts Through Cross-Sector Collaboration

ABSTRACT

The American Sexually Transmitted Diseases Association has, for several years, been conducting a cross-sector workshop to bring together a variety of stakeholders to develop ideas for collaboratively improving the sexually transmitted infection control efforts in the United States. In this summary, we share the content of discussions and ideas of the fourth annual workshop for future research and potential changes to practice with a focus on diagnostic capacity.

Randomized controlled trial of the relative efficacy of high-dose intravenous ceftriaxone and oral cefixime combined with doxycycline for the treatment of Chlamydia trachomatis and Neisseria gonorrhoeae co-infection

OBJECTIVES

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are the commonest bacterial causes of sexually transmitted infections in humans with high incidence of co-infection. Treatment with high doses of ceftriaxone (CRO) and cefixime (CFM) is strongly recommended due to the reduced drug susceptibility of NG. However, their safety and efficacy have not been confirmed. We compared the safety and efficacy of a single 1 g intravenous (IV) dose of ceftriaxone (CRO) plus doxycycline (DOX) versus a single 800 mg oral dose of cefixime (CFM) plus DOX for the treatment of NG-CT co-infection.

METHODS

An open-label randomized controlled trial was conducted on 125 individuals aged > 18 years with untreated gonorrhea and chlamydia to compare a single 1 g intravenous dose of CRO + DOX and a single 800 mg oral dose of CFM + DOX. The primary outcome was the clearance of NG from all the initially infected sites. Secondary outcomes included symptom resolution, changes in the serum clearance levels, glomerular filtration rate, and antibiotic minimum inhibitory concentrations.

RESULTS

Both regimens were highly effective in treating gonorrhea with success rates of 96.7% (95% confidence interval [CI] 88.8-99.1%) for CRO and 95.3% (95% CI 87.1-98.4%) for CFM. However, CRO + DOX was superior to CFM + DOX for the treatment of NG-CT co-infection (odds ratio 4.41, 95% CI 1.11-25.7). The safety profiles of the two regimens were similar.

CONCLUSIONS

CRO + DOX was superior to CFM + DOX for the treatment of NG-CT co-infection. CFM + DOX may be indicated in patients with CRO allergy and in settings where CRO is unavailable. Trial registration ClinicalTrials.gov (NCT05216744) on 31/01/22.

Brazilian Protocol for Sexually Transmitted Infections, 2020: infections that cause cervicitis

Infections that cause cervicitis are a topic presented in the "Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections", published by the Brazilian Ministry of Health in 2020. The document was developed based on scientific evidence and validated in discussions with experts. This article presents epidemiological and clinical aspects of infections that cause cervicitis and recommendations on screening, diagnosis, and treatment of affected people and their sexual partnerships. Also, it discusses strategies for surveillance, prevention, and control of these infections for health professionals and health service managers involved in the programmatic and operational management of sexually transmitted infections. Expanding access to diagnostic tests and early treatment are crucial for controlling the spread of pathogens that cause cervicitis. Associated factors to cervicitis: sexually active women younger than 25 years old, new or multiple sexual partners, partners with STI, previous history or presence of other STI, and irregular use of condoms.

[Brazilian Protocol for Sexually Transmitted Infections 2020: infections that cause cervicitis]

Infections that cause cervicitis are a topic presented in the "Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections", published by the Brazilian Ministry of Health in 2020. The document was developed based on scientific evidence and validated in discussions with experts. This article presents epidemiological and clinical aspects of infections that cause cervicitis, as well as recommendations on screening, diagnosis and treatment of affected people and their sexual partnerships. In addition, it discusses strategies for surveillance, prevention and control of these infections for health professionals and health service managers involved in the programmatic and operational management of sexually transmitted infections. Expanding access to diagnostic tests and early treatment are crucial for controlling the spread of pathogens that cause cevicitis.

Oropharyngeal Chlamydia trachomatis in women; spontaneous clearance and cure after treatment (FemCure)

OBJECTIVES

Women attending STI clinics are not routinely tested for oropharyngeal Chlamydia trachomatis (CT) infections. We aimed to assess spontaneous clearance of oropharyngeal CT and cure after antibiotic treatment in women.

METHODS

Women with vaginal or rectal CT (n=560) were recruited at STI clinics in 2016-2017, as part of the FemCure study (prospective cohort study). We included participants' data from week -1, that is, the diagnosis at initial visit, when clinics applied selective oropharyngeal testing. At week -1, a total of 241 women were oropharyngeally tested (30 positive) and 319 were untested. All FemCure participants provided nurse-collected oropharyngeal samples at study enrolment, that is, week 0, just prior to treatment (n=560), and after treatment at weeks 4 (n=449), 8 (n=433) and 12 (n=427). Samples were tested by nucleic acid amplification test, and at week 0 also by viability testing by viability PCR. Proportions of oropharyngeal CT test results were presented to represent spontaneous clearance and cure.

RESULTS

Of 30 women diagnosed with oropharyngeal CT at week -1, fifteen (50%) were negative at week 0 after a median of 9 days, that is, 'spontaneous clearance'. At week 0, a total of 560 participants were tested, and 46 (8.8%) were oropharyngeal CT positive; 12 of them (26.1%) had viable CT. Of the 46 positive, 36 women had an oropharyngeal test after treatment; 97.2% (35/36) were negative at week 4, that is, 'cure'. Of all women with follow-up visits, the proportion of oropharyngeal CT positive was between 0.5% and 1.6% between weeks 4 and 12. Of those not tested at week -1 (n=319), 8.5% (n=27) were oropharyngeal positive at week 0.

CONCLUSIONS

The clinical importance of oropharyngeal CT in women is debated. We demonstrated that spontaneous clearance of oropharyngeal CT among women is common; of those who did not clear for CT, three-quarters had non-viable CT. After regular treatment with azithromycin or doxycycline, cure rate (97%) of oropharyngeal CT is excellent.

TRIAL REGISTRATION NUMBER

NCT02694497.

Test of cure study: a feasibility study to estimate the time to test of cure (TOC) for Neisseria gonorrhoeae and Chlamydia trachomatis infections

OBJECTIVES

Test of cure (TOC) for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infection is an important tool in the public health management of STIs. However, there are limited data about the optimal time to perform TOC using nucleic acid amplification tests (NAATs) for NG and CT infections. A study was performed to assess the feasibility of a larger study to determine the optimal time to TOC using NAATS.

METHODS

The Sexually Transmitted Bacteria Reference Unit at Public Health England undertook testing of gonococcal and chlamydial nucleic acids within neat urine stored in different conditions over 25 days to provide evidence of the stability of the nucleic acid prior to recruitment. Individuals diagnosed with uncomplicated NG or CT infection were recruited from three sexual health clinics. Individuals were asked to return nine self-taken samples from the site of infection over a course of 35 days. Survival analyses of time to first negative NAAT result for NG and CT infection and univariate regression analysis of factors that affect time to clearance were undertaken.

RESULTS

At room temperature, chlamydial DNA in urine is stable for up to 3 weeks and gonococcal DNA for up to 11 days. We analysed data for 147 infections (81 NG and 66 CT). The median time to clearance of infection was 4 days (IQR 2-10 days) for NG infection and 10 days (IQR 7-14 days) for CT infection. Vaginal CT infections took longer to clear (p=0.031). NG infection in men who have sex with men took longer to clear (p=0.052).

CONCLUSION

Chlamydial and gonococcal nucleic acids are stable in urine before addition of preservatives, longer than recommended by the manufacturer. The TOC results suggest that it may be possible to undertake TOC for NG and CT infections earlier than current guidelines suggest and that anatomical site of infection may affect time to clearance of infection.

Recurrent/Intermittent Vaginal and Rectal Chlamydial Infection Following Treatment: A Prospective Cohort Study Among Female Sexually Transmitted Disease Clinic Patients

BACKGROUND

Rectal Chlamydia trachomatis (CT) is common among clinic-attending women, but little is known about clearance and health implications of rectal CT.

METHODS

At the municipal sexually transmitted disease clinic in Seattle, Washington, in 2017-2018, we enrolled women at high risk for urogenital CT into an 8-week prospective study. Women received standard CT treatment at enrollment. Women self-collected daily rectal and vaginal specimens for nucleic acid amplification tests (NAATs) and completed weekly sexual exposure diaries. We performed CT culture on the enrollment rectal specimen.

RESULTS

We enrolled 50 women; 13 (26%) tested positive for vaginal (n = 11) and/or rectal (n = 11) CT. Sixty percent of women with rectal CT per NAAT were also culture positive. Median time to CT clearance after azithromycin treatment was 8.0 days for vaginal CT and 7.0 days for rectal CT. Eight women with rectal CT at enrollment had at least 1 rectal CT-positive NAAT after clearance of the initial infection; none reported anal sex.

CONCLUSIONS

Most NAAT-positive rectal infections were culture positive, suggesting active infection. Time to NAAT clearance of rectal and genital tract CT was similar, and intermittent rectal CT positivity was common in the absence of anal sexual exposure. The cause of recurrent/intermittent rectal CT and the clinical implications of these infections require further study.

Spontaneous clearance of Chlamydia trachomatis accounting for bacterial viability in vaginally or rectally infected women (FemCure)

OBJECTIVES

Spontaneous clearance of Chlamydia trachomatis (CT) infections can occur between diagnosis and treatment. We followed CT patients to assess clearance using a conventional definition (no total CT-DNA, assessed by routine quantitative PCR methods) and a definition accounting for viability, assessed by viability PCR testing.

METHODS

Three outpatient STI clinics included CT-diagnosed women (The Netherlands, 2016-2017, FemCure study); participants had vaginal CT (vCT) and rectal CT (rCT) (group A: n=155), vCT and were rectally untested (group B: n=351), single vCT (group C: n=25) or single rCT (group D: n=29). Follow-up (median interval 9 days) vaginal and rectal samples underwent quantitative PCR testing (detecting total CT-DNA). When PCR positive, samples underwent V-PCR testing to detect 'viable CT' (CT-DNA from intact CT organisms; V-PCR positive). 'Clearance' was the proportion PCR-negative patients and 'clearance of viable CT' was the proportion of patients testing PCR negative or PCR positive but V-PCR negative. We used multivariable logistic regression analyses to assess diagnosis group (A-D), age, days since initial CT test (diagnosis) and study site (STI clinic) in relation to clearance and clearance of viable CT.

RESULTS

Clearance and clearance of viable CT at both anatomic sites were for (A) 0.6% and 3.9%; (B) 5.4% and 9.4%; (C) 32.0% and 52.0% and (D) 27.6% and 41.4%, respectively. In multivariate analyses, women with single infections (groups C and D) had higher likelihood of clearance than women concurrently infected with vCT and rCT (p<0.001).Of rectally untested women (group B), 76.9% had total CT-DNA and 46.7% had viable CT (V-PCR positive) at the rectal site.

CONCLUSIONS

Of untreated female vCT patients who had CT also at the rectal site, or who were rectally untested, only a small proportion cleared CT (in fact many had viable CT) at their follow-up visit (median 9 days). Among single site infected women clearance was much higher.

TRIAL REGISTRATION NUMBER

NCT02694497.

Molecular point-of-care testing for chlamydia and gonorrhoea in Indigenous Australians attending remote primary health services (TTANGO): a cluster-randomised, controlled, crossover trial

BACKGROUND

Timely diagnosis and treatment of sexually transmissible infections will prevent morbidity and onward transmission. We aimed to assess the efficacy of a point-of-care molecular test for Chlamydia trachomatis and Neisseria gonorrhoeae infections at the cluster level to improve infection management among Indigenous Australian communities with high prevalence of sexually transmissible infections.

METHODS

In this cluster-randomised crossover study, we recruited primary health services in Western Australia, Far North Queensland, and South Australia that provide care to Indigenous people in regional or remote locations. The services were eligible if they did 150 or more tests for C trachomatis or N gonorrhoeae infection per year among individuals aged 16-29 years, and if C trachomatis or N gonorrhoeae positivity was 10% or higher. Services were randomly assigned (1:1) by use of a random-number generator, stratified by geographical region, to either standard care conditions with routine laboratory-based sexually transmissible infection testing for 12 months followed by 12 months of intervention with molecular point-of-care testing, or the reverse sequence. The primary outcome was the proportion of people (aged 16-29 years) found to have C trachomatis or N gonorrhoeae who had a positive result at retesting 3 weeks to 3 months after treatment, and a secondary outcome was treatment within 7 days, both in those aged 16-29 years and at the cluster level. We did these analyses using data from all participants who had a positive result at testing, by point-of-care of laboratory testing (ie, the intention-to-treat population). The trial is registered with Australian and New Zealand Clinical Trials Registry (ACTRN12613000808741).

FINDINGS

Between June 1, 2013, and Feb 29, 2016, 12 health services were enrolled and randomly assigned to standard care followed by intervention (six) and the reverse sequence (six). After randomisation, one health service that was initially assigned to standard care was excluded because it no longer met the inclusion criteria. 455 individuals tested positive for C trachomatis or N gonorrhoeae infection in the intervention group, and 405 tested positive in the standard care group. In the intervention group, 12 (19%) of 63 individuals retested had a positive test result, compared with nine (13%) of 67 with positive retests in the standard care group (relative ratio [RR] 1·42, 95% CI 0·64-3·13; p=0·405), and 347 (76%) were treated within 7 days in the intervention group, compared with 191 (47%) in the standard care group (RR 1·66, 1·41-1·93; p<0·0001).

INTERPRETATION

Retesting rates were too low to draw conclusions on the effect of the intervention on repeat infections. Further research will be needed to determine whether point-of-care tests have an effect on reinfection rates, and the sustainability of using this technology. However, our findings show that time to treatment of C trachomatis or N gonorrhoeae infections in primary care clinics in remote areas in Australia with a high prevalence of sexually transmissible infections could be substantially reduced by the use of molecular point-of-care tests.

FUNDING

The National Health and Medical Research Council, Australia.

Observed Treatment Responses to Short-Course Doxycycline Therapy for Rectal Lymphogranuloma Venereum in Men Who Have Sex With Men

BACKGROUND

Lymphogranuloma venereum (LGV) has reestablished itself as an endemic sexually transmitted infection in the United Kingdom and elsewhere in Europe and North America over the last decade. Current guidelines suggest treatment with 21 days of doxycycline; however, the evidence base for LGV treatment including its duration is very limited.

METHODS

We conducted a retrospective review in 2 central London genitourinary medicine clinics of men who have sex with men (MSM) with LGV in whom less than 21 days of doxycycline was used initially.

RESULTS

Sixty MSM were treated initially with less than 21 days of doxycycline, of whom 50 (83%) were prescribed a 7-day course. Fifty percent of patients were asymptomatic, with the rest having rectal or other symptoms. Fifty-nine (97%) of 60 had a negative test of cure for LGV at a median of 31 days (7-200 days). Reinfection as opposed to treatment failure was considered likely in the patient testing positive. A second test of cure at a median of 139 days later (37-638 days) was completed in 30 patients, of whom 28 (93%) were negative for LGV.

CONCLUSIONS

Seven to 14 days of doxycycline is effective in most cases of LGV with negative TOCs in 59 of 60 patients. These data suggest that 7 days of doxycycline is effective in achieving cure of rectal LGV in most MSM. There is a case for a randomized controlled trial of LGV treatment including a 7-day regimen of doxycycline.

Spontaneous clearance of urogenital, anorectal and oropharyngeal Chlamydia trachomatis and Neisseria gonorrhoeae in women, MSM and heterosexual men visiting the STI clinic: a prospective cohort study

OBJECTIVE

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections can clear without treatment. Despite high prevalence of anorectal infections in men who have sex with men (MSM) and women, studies on anorectal clearance are scarce. Moreover it is unknown whether bacterial load affects urogenital/anorectal CT clearance. In this prospective cohort study, CT and NG clearance is assessed at three anatomical sites of men and women.

METHODS

CT-positive and NG-positive MSM, heterosexual men and women ≥18 years of age visiting our STI clinic between 2011 and 2013 underwent a repeat test when returning for treatment (n=482). The primary outcome was clearance, defined as a positive nucleic acid amplification test (NAAT) at screening-consultation, followed by a negative NAAT at treatment-consultation. Sociodemographics, sexual risk behaviour and CT bacterial load (inhouse quantitative PCR) were tested as determinants for clearance using multivariable logistic regression for CT and Fisher's exact test for NG.

RESULTS

CT clearance was 9.1% (10/110) for urine, 6.8% (20/292) for vaginal swabs, 12.7% (8/63) for anorectal swabs (ie, 4.0% [1/25] in MSM and 18.4% [7/38] in women) and 57.1% (4/7) for oropharyngeal swabs. For NG this was 33.3% (2/6), 28.6% (2/7), 20.0% (2/10) and 27.3% (6/22), respectively. The number of days between tests (median 10, IQR 7-14) was not associated with clearance. Lower bacterial load at screening was the only predictor for CT clearance (urine mean 1.2 vs 2.6 log CT/mL, p=0.001; vaginal swabs mean 2.1 vs 5.2 log CT/mL p<0.0001; anorectal swabs mean 2.0 vs 3.7 log CT/mL, p=0.002). None of the tested determinants were associated with NG clearance.

CONCLUSIONS

This study reports the largest number of anorectal infections tested for CT and NG clearance to date. Clearance in all sample types was substantial: between 7% and 57% for CT, and between 20% and 33% for NG (notwithstanding low absolute numbers). CT clearance was associated with a lower load at screening. However, not all individuals with low bacterial CT load cleared the infection, hampering STI guideline change.

Rising Chlamydia and Gonorrhoea Incidence and Associated Risk Factors Among Female Sex Workers in Australia: A Retrospective Cohort Study

BACKGROUND

Female sex workers in Australia have achieved some of the lowest documented prevalences of human immunodeficiency virus (HIV) and other sexually transmissible infections globally but rates overall are increasing in Australia and warrant closer investigation.

METHODS

We constructed a retrospective cohort using repeat testing data extracted from a network of 42 sexual health clinics. Poisson and Cox regression were used to determined trends in incidence and risk factors for HIV, chlamydia, gonorrhoea, and infectious syphilis among female sex workers.

RESULTS

From 2009 to 2015, 18,475 women reporting sex work attended a participating service. The overall incidence of urogenital chlamydia was 7.7/100 person years (PY), declining by 38% from 2009 to 2013 before increasing by 43% to 2015 (P < 0.001); anorectal chlamydia incidence was 0.6/100 PY, and pharyngeal was 1.9/100 PY, which increased significantly during the study period (P < 0.001, both). For gonorrhoea, the urogenital incidence was 1.4/100 PY, anorectal incidence was 0.3/100 PY, P < 0.001), and 3.6/100 PY for pharyngeal; urogenital incidence doubled during the study period, anorectal increased fivefold, and pharyngeal more than tripled (P < 0.001, all). Incidence of infectious syphilis was 0.4/100 PY, which remained stable from 2009 to 2015 (P = 0.09). There were seven incident infections of HIV among female sex workers (0.1/100 PY). Inconsistent condom use with private partners, higher number of private partner numbers, recent injecting drug use, younger age, and country of birth variously predicted sexually transmissible infections among female sex workers.

CONCLUSIONS

Although infectious syphilis and HIV remain uncommon in female sex workers attending Australian sexual health clinics, the increasing incidence of gonorrhoea across anatomical sites and increasing chlamydia after a period of decline demands enhanced health promotion initiatives.

What Is the Optimal Time to Retest Patients With a Urogenital Chlamydia Infection? A Randomized Controlled Trial

Urogenital chlamydia patients returned for a retest either at 8, 16, or 26 weeks posttreatment. The retest uptake was highest in the 8-week group; positivity rates were similar between groups.

Background

Chlamydia trachomatis is a common, often recurring sexually transmitted infection, with serious adverse outcomes in women. Current guidelines recommend retesting after a chlamydia infection, but the optimum timing is unknown. We assessed the optimal retest interval after urogenital chlamydia treatment.

Methods

A randomized controlled trial among urogenital chlamydia nucleic acid amplification test positive heterosexual clients of the Amsterdam sexually transmitted infection clinic. After treatment, patients were randomly assigned for retesting 8, 16, or 26 weeks later. Patients could choose to do this at home (and send a self-collected sample by mail) or at the clinic. Retest uptake and chlamydia positivity at follow-up were calculated.

Results

Between May 2012 and March 2013, 2253 patients were included (45% men; median age, 23 years; interquartile range, 21–26). The overall uptake proportion within 35 weeks after the initial visit was significantly higher in the 8-week group (77%) compared with the 16- and 26-week groups (67% and 64%, respectively, P < 0.001), and the positivity proportions among those retested were comparable (P = 0.169). The proportion of people with a diagnosed recurrent chlamydia infection among all randomized was similar between the groups (n = 69 [8.6%], n = 52 [7.4%], and n = 69 [9.3%]; P = 0.4).

Conclusions

Patients with a recent urogenital chlamydia are at high risk of recurrence of chlamydia and retesting them is an effective way of detecting chlamydia cases. We recommend inviting patients for a re-test 8 weeks after the initial diagnosis and treatment.

High chlamydia and gonorrhoea repeat positivity in remote Aboriginal communities 2009-2011: longitudinal analysis of testing for re-infection at 3 months suggests the need for more frequent screening

Background Extremely high rates of diagnosis of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) have been recorded in remote communities across northern and central Australia. Re-testing at 3 months, after treatment administered, of CT or NG is recommended to detect repeat infections and prevent morbidity and ongoing transmission.

METHODS

Baseline CT and NG laboratory data (2009-2010) from 65 remote health services participating in a cluster randomised trial was used to calculate the proportion of individuals re-tested after an initial CT or NG diagnosis at <2 months (not recommended), 2-4 months (recommended) and 5-12 months and the proportion with repeat positivity on re-test. To assess if there were difference in re-testing and repeat positivity by age group and sex, t-tests were used.

RESULTS

There was a total of 2054 people diagnosed with CT and/or NG in the study period; 14.9% were re-tested at 2-4 months, 26.9% at 5-12 months, a total of 41.8% overall. Re-testing was higher in females than in males in both the 2-4-month (16.9% v. 11.5%, P<0.01) and 5-12-month (28.9% v. 23.5%, P=0.01) periods. Women aged 25-29 years had a significantly higher level of re-testing 5-12 months post-diagnosis than females aged 16-19 years (39.8% v. 25.4%, P<0.01). There was a total of 858 people re-tested at 2-12 months and repeat positivity was 26.7%. There was higher repeat NG positivity than repeat CT positivity (28.8% v. 18.1%, P<0.01).

CONCLUSIONS

Just under half the individuals diagnosed with CT or NG were re-tested at 2-12 months post-diagnosis; however, only 15% were re-tested in the recommended time period of 2-4 months. The higher NG repeat positivity compared with CT is important, as repeat NG infections have been associated with higher risk of pelvic inflammatory disease-related hospitalisation. Findings have implications for clinical practice in remote community settings and will inform ongoing sexual health quality improvement programs in remote community clinics.

Not again! Effect of previous test results, age group and reason for testing on (re-)infection with Chlamydia trachomatis in Germany

Background

Infection with Chlamydia trachomatis (Ct) is the most commonly reported sexually transmitted infection in Europe. In Germany, Ct screening is offered free of charge to pregnant women since 1995 and to women < 25 years of age since 2008. For symptomatic individuals, testing is covered by statutory health insurance. Study results have shown that repeat Ct infection occurs in 10–20% of previously infected women and men. Our aim was to describe persons tested for Ct and to investigate the determinants of (repeat) Ct infection in women and men in Germany.

Methods

We analysed Ct test results from men and women tested between 2008 and 2014 in laboratories participating in the German Chlamydia trachomatis Laboratory Sentinel surveillance. Reinfection was defined as at least 2 positive laboratory tests within more than 30 days. We performed logistic regression stratified by sex and, for women, reason for testing to determine the effect of previous test results and age group on subsequent test results.

Results

In total, 2,574,635 Ct tests could be attributed to 1,815,494 women and 123,033 men. 5% of women and 14% of men tested positive at least once. 15–19- and 20–24-year-old women tested positive at least once respectively in 6.8 and 6.0%, while men respectively in 16.6 and 21.2%. Altogether, 23.1% of tested women and 11.9% of tested men were tested repeatedly between 2008 and 2014. Among those who previously tested positive, reinfection occurred in 2.0% of women and 6.6% of men. Likelihood to be tested Ct positive was higher in women and men with a positive Ct test in the past compared to previously tested Ct negative, odds ratios 4.7 and 2.6 (p < 0.01) respectively. Odds ratios ranged by age group and test reason.

Conclusion

A history of Ct infection increased the likelihood of infection with Ct in women and men taking into account the result of the previous test. Health education, safer sex and treatment of partners are necessary for women and men who have tested positive to prevent reinfection and complications and to interrupt the chain of transmission. To identify potential reinfection repeat testing after treatment should be performed.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3323-2) contains supplementary material, which is available to authorized users.

Review of Chlamydia trachomatis viability methods: assessing the clinical diagnostic impact of NAAT positive results

INTRODUCTION

Chlamydia trachomatis (chlamydia) is the most commonly diagnosed bacterial sexually transmitted infection (STI) worldwide. The advancement of molecular techniques has made chlamydia diagnostics infinitely easier. However, molecular techniques lack the information on chlamydia viability. Where in routine diagnostics the detection of chlamydia DNA or RNA might suffice, in other patient scenarios, information on the viability of chlamydia might be essential. Areas covered: In this review, the authors discuss the specific strengths and limitations of currently available methods to evaluate chlamydia viability: conventional cell culture, messenger RNA (mRNA) detection and viability-PCR (V-PCR). PubMed and Google Scholar were searched with the following terms: Chlamydia trachomatis, Treatment failure, Anal chlamydia, Microbial viability, Culture, Viability-PCR, Messenger RNA, and Molecular diagnostics Expert commentary: Several techniques are currently available to determine chlamydia viability and thus the clinical relevance of a positive test result in clinical samples. Depending on the underlying research question, all three discussed techniques have their merits when testing for viability. However, mRNA methods show the most promise in determining the presence of a true infection, in case the chlamydia reticulate body can be specifically detected. Further research is needed to understand how to best apply viability testing in current chlamydia diagnostics.

Biological and Behavioral Factors Associated With Positive Chlamydia Retests

BACKGROUND

Repeat chlamydia detection after treatment is common, and there is concern that treatment failure may be a cause.

METHODS

Within a randomized trial, we established a prospective cohort of 600 participants with anogenital chlamydia diagnoses (200 each of women, heterosexual men, and men who have sex with men [MSM]). Participants were invited for repeat testing at 3 months and to complete a behavioral survey at 4 months. Positive samples were analyzed for organism DNA load and genovar. We estimated repeat chlamydia positivity, reinfection and treatment failure rates, and investigated the biological and behavioral factors associated with a repeat positive test.

RESULTS

A total of 290 participants (100 women, 89 heterosexual men, 101 MSM) were retested at 1 to 4 months, with 43 repeat positives, including 26 classed as reinfection and 9 as treatment failures. Comparing MSM with heterosexual men and women combined, repeat positivity was higher (20.8% vs 11.6%, P = 0.04), and treatment failure was higher (6.9% vs 1.1%, P = 0.01), but there was no difference in reinfection rates (11.9% vs 7.4%, P = 0.21). Among MSM, the odds of repeat positivity increased by 90% with each additional log organism load in the original specimen (baseline) (adjusted odds ratio, 1.9; 95% confidence interval, 1.1-3.2). Among heterosexuals, the odds of repeat positivity decreased by 10% with each additional week delay in being retested for chlamydia (adjusted odds ratio, 0.9; 95% confidence interval, 0.8-0.9).

CONCLUSIONS

Positive retests were more common among MSM than heterosexuals. Treatment failure was more common in MSM with rectal chlamydia, reinforcing concerns about azithromycin treatment failure.

Test of cure, retesting and extragenital testing practices for Chlamydia trachomatis and Neisseria gonorrhoeae among general practitioners in different socioeconomic status areas: A retrospective cohort study, 2011-2016

Background

For Chlamydia trachomatis (CT), a test of cure (TOC) within 3–5 weeks is not recommended. International guidelines differ in advising a Neisseria gonorrhoeae (NG) TOC. Retesting CT and NG positives within 3–12 months is recommended in international guidelines. We assessed TOC and retesting practices including extragenital testing in general practitioner (GP) practices located in different socioeconomic status (SES) areas to inform and optimize local test practices.

Methods

Laboratory data of 48 Dutch GP practices between January 2011 and July 2016 were used. Based on a patient’s first positive CT or NG test, the proportion of TOC (<3 months) and retests (3–12 months) were calculated. Patient- and GP-related factors were assessed using multivariate logistic regression analyses.

Results

For CT (n = 622), 20% had a TOC and 24% had a retest at the GP practice. GP practices in low SES areas were more likely to perform a CT TOC (OR:1.8;95%CI:1.1–3.1). Younger patients (<25 years) were more likely to have a CT TOC (OR:1.6;95%CI:1.0–2.4). For CT (n = 622), 2.4% had a TOC and 6.1% had a retest at another STI care provider. For NG (n = 73), 25% had a TOC and 15% had a retest at the GP practice. For NG (n = 73), 2.7% had a TOC and 12.3% had a retest at another STI care provider. In only 0.3% of the consultations patients were tested on extragenital sites.

Conclusion

Almost 20% of the patients returned for a CT TOC, especially at GP practices in low SES areas. For NG, 1 out of 4 patients returned for a TOC. Retesting rates were low for both CT (24%) and NG (15%), (re)infections including extragenital infections may be missed. Efforts are required to focus TOC and increase retesting practices of GPs in order to improve CT/NG control.

Monitoring therapy success of urogenital Chlamydia trachomatis infections in women: A prospective observational cohort study

INTRODUCTION

The use of a nucleic acid amplification test (NAAT) as a test of cure after treatment is subject to discussion, as the presence of C. trachomatis nucleic acids after treatment may be prolonged and intermittent without presence of infectious bacteria. We used cell culture to assess if a positive RNA- or DNA-based NAAT after treatment indicates the presence of viable C. trachomatis.

METHODS

We included women with asymptomatic urogenital C. trachomatis infection visiting the Amsterdam STI clinic from September 2015 through June 2016. Endocervical swabs were collected prior to treatment with azithromycin, and during three follow-up visits 7, 21 and 49 days after treatment. Collected swabs were subjected to C. trachomatis culture and a RNA- and DNA-based NAAT. High-resolution multilocus sequence typing (hr-MLST) was used to further differentiate potential re-infections.

RESULTS

We included 90 women with a positive RNA-test prior to receiving treatment of whom 81 (90%) were also DNA-positive, and 69 (76.7%) culture-positive. Prolonged and intermittent positive RNA and DNA results over time were observed. Three women had culture positive results at the second visit, but all were negative at the third visit. Five women had NAAT-positive results at the fourth visit of whom three women were also culture-positive indicating a viable infection. All five women reported unprotected sexual contact since the first visit. From 2, hr-MLST sequence types were obtained. One had a different sequence type indicating a new infection the other was identical to the previously found indicating a potentially persisting infection.

CONCLUSION

Most RNA- or DNA-positive results after treatment of urogenital C. trachomatis may be caused by non-viable molecular remnants since they cannot be confirmed by culture. In a minority viable C. trachomatis was found in culture at the second visit, indicating that patients may remain infectious at least 7 days after treatment.

Time to clearance of Chlamydia trachomatis RNA and DNA after treatment in patients coinfected with Neisseria gonorrhoeae - a prospective cohort study

Background

Performing a test of cure (TOC) could demonstrate success or failure of antimicrobial treatment of Chlamydia trachomatis infection, but recommendations for the timing of a TOC using nucleic acid amplification tests (NAATs) are inconsistent. We assessed time to clearance of C. trachomatis after treatment, using modern RNA- and DNA-based NAATs.

Methods

We analysed data from patients with a C. trachomatis and Neisseria gonorrhoeae coinfection who visited the STI Clinic Amsterdam, The Netherlands, from March through October 2014. After treatment with ceftriaxone plus either azithromycin or doxycycline, patients self-collected anal, vaginal or urine samples during 28 consecutive days. Samples were analysed using an RNA-based NAAT (Aptima Combo 2) and a DNA-based NAAT (Cobas 4800 CT/NG). We defined clearance as three consecutive negative results, and defined “blips” as isolated positive results following clearance.

Results

We included 23 patients with C. trachomatis and N. gonorrhoeae coinfection. All patients cleared C. trachomatis during follow-up, and we observed no reinfections. The median time to clearance (range) was 7 days (1–13) for RNA, and 6 days (1–15) for DNA. Ninety-five per cent of patients cleared RNA at day 13, and DNA at day 14. The risk of a blip after clearance was 4.4 % (RNA) and 1.7 % (DNA).

Conclusions

If a TOC for anogenital chlamydia is indicated, we recommend performing it at least 14 days after initiation of treatment, when using modern RNA- and DNA-based assays. A positive result shortly after 14 days probably indicates a blip, rather than a treatment failure or a reinfection.

Diagnosis and Management of Uncomplicated Chlamydia trachomatis Infections in Adolescents and Adults: Summary of Evidence Reviewed for the 2015 Centers for Disease Control and Prevention Sexually Transmitted Diseases Treatment Guidelines

In preparation for the 2015 Centers for Disease Control and Prevention (CDC) Sexually Transmitted Diseases (STD) Treatment Guidelines, the CDC convened an advisory group in 2013 to examine recent abstracts and published literature addressing the epidemiology, diagnosis, and management of STDs. This article summarizes the key questions, evidence, and recommendations for the diagnosis and management of uncomplicated Chlamydia trachomatis (CT) infection in adolescents and adults that were considered in development of the 2015 CDC STD Treatment Guidelines. The evidence reviewed primarily focused on CT infection risk factors in women, clinical significance of oropharyngeal CT detection, acceptability and performance of CT testing on self-collected specimens in men, performance of CT point-of-care tests, efficacy of recommended and investigational CT infection treatments, and timing of test of cure following CT infection treatment in pregnant women.

Opportunities and pitfalls of molecular testing for detecting sexually transmitted pathogens

In the last 20 years, nucleic acid amplification tests (NAATs) have gradually replaced traditional methods for the detection of sexually transmitted infections. NAAT technology comes with some considerable benefits for diagnosis, including increased sensitivity, rapid result turnaround and suitability for high throughput screening of asymptomatic individuals using more-readily available specimens. However, the transition to NAAT has not come without its problems. False-negative and false-positive results have been reported owing to various technical issues. Furthermore, increased reliance on NAATs for diagnosis have created the need to develop NAAT-based methods to inform treatment, being an area that presents its own set of challenges. In this review article, we explore NAAT-based detection of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis. In doing so, we consider the benefits and limitations of NAAT-based technology and highlight areas where further research and development is in need.

Background review for the '2015 European guideline on the management of Chlamydia trachomatis infections'

SummaryChlamydia trachomatis infections are major public health concerns globally. Of particular grave concern is that the majority of persons with anogenital Chlamydia trachomatis infections are asymptomatic and accordingly not aware of their infection, and this silent infection can subsequently result in severe reproductive tract complications and sequelae. The current review paper provides all background, evidence base and discussions for the 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS 2015). Comprehensive information and recommendations are included regarding the diagnosis, treatment and prevention of anogenital, pharyngeal and conjunctival Chlamydia trachomatis infections in European countries. However, Chlamydia trachomatis also causes the eye infection trachoma, which is not a sexually transmitted infection. The 2015 European Chlamydia trachomatis guideline provides up-to-date guidance regarding broader indications for testing and treatment of Chlamydia trachomatis infections; clearer recommendation of using validated nucleic acid amplification tests only for diagnosis; advice on (repeated) Chlamydia trachomatis testing; recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection and recommendations to identify, verify and report Chlamydia trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of Chlamydia trachomatis patients are crucial to control its spread.

2015 European guideline on the management of Chlamydia trachomatis infections

Chlamydia trachomatis infections, which most frequently are asymptomatic, are major public health concerns globally. The 2015 European C. trachomatis guideline provides: up-to-date guidance regarding broader indications for testing and treatment of C. trachomatis infections; a clearer recommendation of using exclusively-validated nucleic acid amplification tests for diagnosis; advice on (repeated) C. trachomatis testing; the recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection; and recommendations to identify, verify and report C. trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of C. trachomatis patients are crucial to control its spread. For detailed background, evidence base and discussions, see the background review for the present 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS. 2015).

What is needed to guide testing for anorectal and pharyngeal Chlamydia trachomatis and Neisseria gonorrhoeae in women and men? Evidence and opinion

Background

Anorectal and pharyngeal infections with Chlamydia trachomatis (CT) and Neisseria gonorrheae (NG) are commonly observed in men who have sex with men (MSM). There is increasing evidence that such infections at extra-genital sites are also common in women. In both sexes, these infections are largely overlooked as they are not routinely tested for in regular care. Testing based on sexual behavior or symptoms would only detect half of these extra-genital infections. This paper elucidates the differences and similarities between women and MSM, regarding the epidemiology of extra-genital CT and NG. It discusses the clinical and public health impact of untested extra-genital infections, how this may impact management strategies, and thereby identifies key research areas.

Discussion

Extra-genital CT is as common in women as it is in MSM; NG in women is as common at their extra-genital sites as it is at their genital sites. The substantial numbers of extra-genital CT and NG being missed in women and MSM indicate a need to test and treat more patients and perhaps different choices in treatment and partner management strategies. Doing so will likely contribute to reduced morbidity and transmission in both sexes. However, in our opinion, it is clear that there are several knowledge gaps in understanding the clinical and public health impact of extra-genital CT and NG. Key research areas that need to be addressed concern associated morbidity (anorectal and reproductive morbidity due to extra-genital infections), ‘the best’ management strategies, including testing and treatment for extra-genital CT, extra-genital treatment resistance, transmission probabilities between partners and between anatomic sites in a woman, and impact on transmission of other infections. Data are also lacking on cost-effectiveness of pharyngeal testing, and of NG testing and anorectal CT testing in women. Gaps in the management of extra-genital CT and NG may also apply for other STIs, such Mycoplasma genitalium.

Summary

Current management strategies, including testing, to address extra-genital CT and NG in both sexes are suboptimal. Comparative data on several identified key themes in women and MSM are lacking and urgently needed to guide better management of extra-genital infections.

2015 UK national guideline for the management of infection with Chlamydia trachomatis

This guideline offers recommendations on the diagnostic tests, treatment regimens and health promotion principles needed for the effective management of Chlamydia trachomatis genital infection. It covers the management of the initial presentation, as well the prevention of transmission and future infection. The guideline is aimed at individuals aged 16 years and older presenting to healthcare professionals working in departments offering Level 3 care in sexually transmitted infections management within the UK. However, the principles of the recommendations should be adopted across all levels, using local care pathways where appropriate.

Retesting young STI clinic visitors with urogenital Chlamydia trachomatis infection in the Netherlands; response to a text message reminder and reinfection rates: a prospective study with historical controls

OBJECTIVES

The objective of this study is to assess the effect of reminder text messages 6 months after the initial treatment on retest and chlamydia reinfection rates in young heterosexuals compared with a historical control group and to assess factors associated with both outcomes.

METHODS

Heterosexual people (aged 16-23 years), testing positive for urogenital chlamydia, were offered a retest after 6 months. Participants received a text message reminder at 6 months after the initial chlamydia diagnosis. Rates of retest uptake and the result of the retest were analysed using Cox regression. Prevalence ratios (PRs) were calculated to identify factors associated with these outcomes. Furthermore, the retest rate was compared with the retest rate of a historical control group.

RESULTS

30.6% (253/838) of the study group returned within 5-8 months compared with 9.2% (140/1530) in the historical control group. Women and persons who were not notified for a sexually transmitted infection (STI) at inclusion were more likely to return for a retest. 20.4% (56/275) of participants had a chlamydia reinfection upon retesting. Reinfection was higher in participants reporting STI-related symptoms (PR 3.2, 95% CI 1.8 to 5.6) and in participants who were notified for an STI at retest (PR 5.3, 95% CI 2.4 to 11.5).

CONCLUSIONS

A text message reminder appeared to have a clear, positive impact on the resulting retest rate. These results also indicate that retesting is necessary to identify chlamydia reinfections.

Time to eradication of Mycoplasma genitalium after antibiotic treatment in men and women

OBJECTIVES

The objectives of this study were to evaluate the time to a Mycoplasma genitalium-negative test after start of treatment and to monitor if and when antibiotic resistance developed.

METHODS

Sexually transmitted disease (STD) clinic attendees with suspected or verified M. genitalium infection were treated with azithromycin (5 days, 1.5 g; n = 85) or moxifloxacin (n = 5). Subjects with symptomatic urethritis or cervicitis of unknown aetiology were randomized to either doxycycline (n = 49) or 1 g of azithromycin as a single dose (n = 51). Women collected vaginal specimens and men collected first-catch urine 12 times during 4 weeks. Specimens were tested for M. genitalium with a quantitative MgPa PCR and for macrolide resistance-mediating mutations with a PCR targeting 23S rRNA.

CLINICAL TRIALS REGISTRATION

NCT01661985.

RESULTS

Ninety M. genitalium cases were enrolled. Of 56 patients with macrolide-susceptible strains before treatment with azithromycin (1.5 g, n = 46; 1 g single oral dose, n = 10), 54 (96%) had a negative PCR test within 8 days. In four patients, M. genitalium converted from macrolide susceptible to resistant after a 10 day lag time with negative tests (azithromycin 1.5 g, n = 3; 1 g single oral dose, n = 1). Moxifloxacin-treated subjects (n = 4) were PCR negative within 1 week. Six of eight (75%) remained positive despite doxycycline treatment.

CONCLUSIONS

PCR for M. genitalium rapidly became negative after azithromycin treatment. Macrolide-resistant strains were detected after initially negative tests. Test of cure should be recommended no earlier than 3-4 weeks.

Dual Intervention to Increase Chlamydia Retesting: A Randomized Controlled Trial in Three Populations

INTRODUCTION

Chlamydia retesting 3 months after treatment is recommended to detect reinfections, but retesting rates are typically low. The purpose of this study is to determine if the addition of a postal home collection kit to a short message service (SMS) reminder at 3 months increases the percentage of patients retested for chlamydia at 1-4 months, compared to SMS alone.

DESIGN

In this unblinded randomized controlled trial, participants were randomized 1:1 to intervention (home arm) or control (clinic arm) status.

SETTING/PARTICIPANTS

Participants included 200 each of women, heterosexual men, and men who have sex with men diagnosed and treated for chlamydia at sexual health services.

INTERVENTION

Three months after chlamydia diagnosis, home arm participants received an SMS reminder and postal home collection kit (women, vaginal swab; heterosexual men, Copan UriSwab; men who have sex with men, UriSwab and rectal swab).

MAIN OUTCOME MEASURES

The main outcome measures were the percentage of participants retested at 1-4 months after chlamydia diagnosis and the percentage in each arm with repeat positive tests, by risk group and overall, analyzed by intention to treat. Data were collected from 2011 to 2013 and analyzed in 2014.

RESULTS

The percentage retested within 1-4 months of chlamydia diagnosis was significantly higher in home versus clinic arm participants among women (64% [66/103] vs 39% [38/97], p<0.001); heterosexual men (56% [57/101] vs 34% [34/99], p=0.002); men who have sex with men (62% [61/98] vs 44% [45/102], p=0.010); and overall (61% [184/302] vs 39% [117/298], p<0.001). The percentage in the home versus clinic arm with repeat positive tests was significantly higher among men who have sex with men (16% [16/98] vs 5% [5/102], p=0.021) and overall (10% [31/302] vs 4% [12/298], p=0.006).

CONCLUSIONS

The addition of a postal home collection kit to routine SMS reminders resulted in substantial improvements in chlamydia retesting rates in all three risk groups and detection of more repeat positive tests, compared with SMS alone. Extending the intervention to other primary care settings with low retesting rates should be considered.

Chlamydia (uncomplicated, genital)

INTRODUCTION

Genital chlamydia is the most commonly reported bacterial sexually transmitted infection in developed countries. The majority of infections affect young adults under the age of 25 years.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of antibiotic treatment for men and non-pregnant women with uncomplicated genital chlamydial infection? What are the effects of antibiotic treatment for pregnant women with uncomplicated genital chlamydial infection? We searched: Medline, Embase, The Cochrane Library, and other important databases up to February 2014 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 26 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions - for men and non-pregnant women: antibiotics (single-dose) and antibiotics (multiple-dose regimens); for pregnant women: antibiotics (single-dose), erythromycin or amoxicillin (multiple-dose regimens), and clindamycin (multiple-dose regimens).

Enrofloxacin and macrolides alone or in combination with rifampicin as antimicrobial treatment in a bovine model of acute Chlamydia psittaci infection

Chlamydia psittaci is a zoonotic bacterium with a wide host range that can cause respiratory disease in humans and cattle. In the present study, effects of treatment with macrolides and quinolones applied alone or in combination with rifampicin were tested in a previously established bovine model of respiratory C. psittaci infection. Fifty animals were inoculated intrabronchially at the age of 6-8 weeks. Seven served as untreated controls, the others were assigned to seven treatment groups: (i) rifampicin, (ii) enrofloxacin, (iii) enrofloxacin + rifampicin, (iv) azithromycin, (v) azithromycin + rifampicin, (vi) erythromycin, and (vii) erythromycin + rifampicin. Treatment started 30 hours after inoculation and continued until 14 days after inoculation (dpi), when all animals were necropsied. The infection was successful in all animals and sufficient antibiotic levels were detected in blood plasma and tissue of the treated animals. Reisolation of the pathogen was achieved more often from untreated animals than from other groups. Nevertheless, pathogen detection by PCR was possible to the same extent in all animals and there were no significant differences between treated and untreated animals in terms of local (i.e., cell count and differentiation of BALF-cells) and systemic inflammation (i.e. white blood cells and concentration of acute phase protein LBP), clinical signs, and pathological findings at necropsy. Regardless of the reduced reisolation rate in treated animals, the treatment of experimentally induced respiratory C. psittaci infection with enrofloxacin, azithromycin or erythromycin alone or in combination with rifampicin was without obvious benefit for the host, since no significant differences in clinical and pathological findings or inflammatory parameters were detected and all animals recovered clinically within two weeks.

Improving chlamydia knowledge should lead to increased chlamydia testing among Australian general practitioners: a cross-sectional study of chlamydia testing uptake in general practice

Background

Female general practitioners (GPs) have higher chlamydia testing rates than male GPs, yet it is unclear whether this is due to lack of knowledge among male GPs or because female GPs consult and test more female patients.

Methods

GPs completed a survey about their demographic details and knowledge about genital chlamydia. Chlamydia testing and consultation data for patients aged 16-29 years were extracted from the medical records software for each GP and linked to their survey responses. Chi-square tests were used to determine differences in a GP’s knowledge and demographics. Two multivariable models that adjusted for the gender of the patient were used to investigate associations between a GP and their chlamydia testing rates ― Model 1 included GPs’ characteristics such as age and gender, Model 2 excluded these characteristics to specifically examine any associations with knowledge.

Results

Female GPs were more likely than male GPs to know when to re-test a patient after a negative chlamydia test (18.8% versus 9.7%, p = 0.01), the correct symptoms suggestive of PID (80.5% versus 67.8%, p = 0.01) and the correct tests for diagnosing PID (57.1% versus 42.6%, p = 0.01). Female GPs tested 6.5% of patients, while male GPs tested 2.2% (p < 0.01). Model 1 found factors associated with chlamydia testing were being a female GP (OR = 2.5, 95% CI: 1.9, 3.3) and working in a metropolitan clinic (OR = 3.2; 95% CI: 2.4, 4.3). Model 2 showed that chlamydia testing increased as knowledge of testing guidelines improved (3-5 correct answers – AOR = 2.0, 95% CI: 1.0, 4.2; 6+ correct answers – AOR = 2.9, 95% CI: 1.4, 6.2).

Conclusions

Higher rates of chlamydia testing are strongly associated with GPs who are female, based in a metropolitan clinic and among those with more knowledge of the recommended guidelines. Improving chlamydia knowledge among male GPs may increase chlamydia testing.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0584-2) contains supplementary material, which is available to authorized users.

Spontaneous pharyngeal Chlamydia trachomatis RNA clearance. A cross-sectional study followed by a cohort study of untreated STI clinic patients in Amsterdam, The Netherlands

OBJECTIVES

Pharyngeal Chlamydia trachomatis (chlamydia) might contribute to ongoing chlamydia transmission, yet data on spontaneous clearance duration are rare. We examined the prevalence, spontaneous clearance, chlamydial DNA concentration and genotypes of pharyngeal chlamydia among clinic patients with sexually transmitted infection (STI).

METHODS

Female patients at high risk for an STI who reported active oral sex and male patients who have sex with men (MSM) were screened for pharyngeal chlamydia RNA using a nucleic acid amplification test. A repeat swab was obtained to evaluate spontaneous clearance in untreated patients with pharyngeal chlamydia. Quantitative chlamydia DNA load was determined by calculating the chlamydia/human cell ratio.

RESULTS

Pharyngeal chlamydia was detected in 148/13 111 (1.1%) MSM and in 160/6915 (2.3%) women. 53% of MSM and 32% of women with pharyngeal chlamydia did not have a concurrent anogenital chlamydia infection. In 16/43 (37%) MSM and in 20/55 (36%) women, the repeat pharyngeal swab was negative (median follow-up 10 days, range 4-58 days). Patients with an initial chlamydial DNA concentration above the median were less likely to clear. Of 23 MSM with pharyngeal chlamydia who had sex with a lymphogranuloma venereum (LGV)-positive partner recently or in the past, two were LGV biovar positive (8.7%).

CONCLUSIONS

The pharynx is a reservoir for chlamydia and LGV, and may play a role in ongoing transmission. Although delay in ribosomal RNA decline after resolution of the infection might have led to an underestimation of spontaneous clearance, in high-risk STI clinic patients, testing the pharynx for chlamydia should be considered.

Detection of anorectal and cervicovaginal Chlamydia trachomatis infections following azithromycin treatment: prospective cohort study with multiple time-sequential measures of rRNA, DNA, quantitative load and symptoms

Background

Determination of Chlamydia trachomatis (Ct) treatment success is hampered by current assessment methods, which involve a single post-treatment measurement only. Therefore, we evaluated Ct detection by applying multiple laboratory measures on time-sequential post-treatment samples.

Methods

A prospective cohort study was established with azithromycin-treated (1000 mg) Ct patients (44 cervicovaginal and 15 anorectal cases). Each patient provided 18 self-taken samples pre-treatment and for 8 weeks post-treatment (response: 96%; 1,016 samples). Samples were tested for 16S rRNA (TMA), bacterial load (quantitative PCR; Chlamydia plasmid DNA) and type (serovar and multilocus sequence typing). Covariates (including behavior, pre-treatment load, anatomic site, symptoms, age, and menstruation) were tested for their potential association with positivity and load at 3–8 weeks using regression analyses controlling for repeated measures.

Findings

By day 9, Ct positivity decreased to 20% and the median load to 0.3 inclusion-forming units (IFU) per ml (pre-treatment: 170 IFU/ml). Of the 35 cases who reported no sex, sex with a treated partner or safe sex with a new partner, 40% had detection, i.e. one or more positive samples from 3–8 weeks (same Ct type over time), indicating possible antimicrobial treatment failure. Cases showed intermittent positive detection and the number of positive samples was higher in anorectal cases than in cervicovaginal cases. The highest observed bacterial load between 3–8 weeks post-treatment was 313 IFU/ml, yet the majority (65%) of positive samples showed a load of ≤2 IFU/ml. Pre-treatment load was found to be associated with later load in anorectal cases.

Conclusions

A single test at 3–8 weeks post-treatment frequently misses Ct. Detection reveals intermittent low loads, with an unknown risk of later complications or transmission. These findings warrant critical re-evaluation of the clinical management of single dose azithromycin-treated Ct patients and fuel the debate on defining treatment failure. Clinicaltrials.gov Identifier: NCT01448876.

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.

A multiplexed microfluidic PCR assay for sensitive and specific point-of-care detection of Chlamydia trachomatis

BACKGROUND

Chlamydia trachomatis (Ct) is the most common cause of bacterial sexually transmitted diseases (STD) worldwide. While commercial nucleic acid amplification tests (NAAT) are available for Ct, none are rapid or inexpensive enough to be used at the point-of-care (POC). Towards the first Ct POC NAAT, we developed a microfluidic assay that simultaneously interrogates nine Ct loci in 20 minutes.

METHODOLOGY AND PRINCIPAL FINDINGS

Endocervical samples were selected from 263 women at high risk for Ct STDs (∼35% prevalence). A head-to-head comparison was performed with the Roche-Amplicor NAAT. 129 (49.0%) and 88 (33.5%) samples were positive by multiplex and Amplicor assays, respectively. Sequencing resolved 71 discrepant samples, confirming 53 of 53 positive multiplex samples and 12 of 18 positive Amplicor samples. The sensitivity and specificity were 91.5% and 100%, and 62.4% and 95.9%, respectively, for multiplex and Amplicor assays. Positive and negative predictive values were 100% and 91%, and 94.1% and 68.6%, respectively.

CONCLUSIONS

This is the first rapid multiplex approach to Ct detection, and the assay was also found to be superior to a commercial NAAT. In effect, nine simultaneous reactions significantly increased sensitivity and specificity. Our assay can potentially increase Ct detection in globally diverse clinical settings at the POC.