V Harindra

Incidence and reinfection rates of genital chlamydial infection among women aged 16–24 years attending general practice, family planning and genitourinary medicine clinics in England: a prospective cohort study by the Chlamydia Recall Study Advisory Group

Background: In England, screening for genital chlamydial infection has begun; however, screening frequency for women is not yet determined. Aim: To measure chlamydia incidence and reinfection rates among young women to suggest screening intervals. Methods: An 18-month prospective cohort study of women aged 16–24 years recruited from general practices, family planning clinics and genitourinary medicine (GUM) clinics: baseline-negative women followed for incidence and baseline-positive women for reinfection; urine tested every 6 months via nucleic acid amplification; and behavioural data collected. Extra test and questionnaire completed 3 months after initial positive test. Factors associated with infection and reinfection investigated using Cox regression stratified by healthcare setting of recruitment. Results: Chlamydia incidence was mean (95% CI) 4.9 (2.7 to 8.8) per 100 person-years (py) among women recruited from general practices, 6.4 (4.2 to 9.8) from family planning clinics and 10.6 (7.4 to 15.2) from GUM clinics. Incidence was associated with young age, history of chlamydial infection and acquisition of new sexual partners. If recently acquiring new partners, condom use at last sexual intercourse was independently associated with lower incidence. Chlamydia reinfection was mean (95% CI) 29.9 (19.7 to 45.4) per 100/person-year from general practices, 22.3 (15.6 to 31.8) from family planning clinics and 21.1 (14.3 to 30.9) from GUM clinics. Factors independently associated with higher reinfection rates were acquisition of new partners and failure to treat all partners. Conclusions: Sexual behaviours determined incidence and reinfection, regardless of healthcare setting. Our results suggest annual screening of women aged 16–24 years who are chlamydia negative, or sooner if partner change occurs. Rescreening chlamydia-positive women within 6 months of baseline infection may be sensible, especially if partner change occurs or all partners are not treated.

Chlamydia trachomatis Incidence and Re-Infection among Young Women – Behavioural and Microbiological Characteristics

Background This study aimed to estimate rates of chlamydia incidence and re-infection and to investigate the dynamics of chlamydia organism load in prevalent, incident and re-infections among young Australian women. Methods 1,116 women aged 16 to 25 years were recruited from primary care clinics in Australia. Vaginal swabs were collected at 3 to 6 month intervals for chlamydia testing. Chlamydia organism load was measured by quantitative PCR. Results There were 47 incident cases of chlamydia diagnosed and 1,056.34 person years of follow up with a rate of 4.4 per 100 person years (95% CI: 3.3, 5.9). Incident infection was associated with being aged 16 to 20 years [RR = 3.7 (95%CI: 1.9, 7.1)], being employed [RR = 2.4 (95%CI: 1.1, 4.9)] and having two or more new sex partners [RR = 5.5 (95%CI: 2.6, 11.7)]. Recent antibiotic use was associated with a reduced incidence [RR:0.1 (95%CI: 0.0, 0.5)]. There were 14 re-infections with a rate of 22.3 per 100 person years (95%CI: 13.2, 37.6). The median time to re-infection was 4.6 months. Organism load was higher for prevalent than incident infections (p<0.01) and for prevalent than re-infections (p<0.01). Conclusions Chlamydia is common among young women and a high proportion of women are re-infected within a short period of time, highlighting the need for effective partner treatment and repeat testing. The difference in organism load between prevalent and incident infections suggests prevalent infection may be more important for ongoing transmission of chlamydia.

Opportunistic screening for genital chlamydial infection. II: prevalence among healthcare attenders, outcome, and evaluation of positive cases.

Objectives: To determine the prevalence and treatment outcomes among young women screened opportunistically for genital Chlamydia trachomatis and to evaluate the impact of screening in those participating. Design: An opportunistic screening programme (1 September 1999 to 31 August 2000) using urine samples, tested by ligase chain reaction (LCR). In-depth interviews were used for programme evaluation. Setting: Screening was offered in two health authorities at general practice, family planning, genitourinary medicine (GUM), adolescent sexual health, termination of pregnancy clinics and women’s services in hospitals (antenatal, colposcopy, gynaecology and infertility clinics). Main participants: Sexually active women (16–24 years) attending for any reason. Main outcome measures: Screening data: prevalence of infection by age and healthcare setting; proportion of positive patients attending for treatment. Evaluation data: participants’ attitudes and views towards screening and follow up. Results: In total, 16 930 women (16–24 years) were screened. Prevalence was higher in younger women (16–20) than those aged 21–24 years and was highly variable at different healthcare settings (range 3.4%–17.6%). Prevalence was approximately 9% in general practice. The role of the project health advisers in managing results and coordinating treatment of positive individuals was essential; the vast majority of all positives were known to be treated. Women felt that screening was beneficial. Improving awareness and education about sexually transmitted infections is required to alleviate negative reactions associated with testing positive for infection. Conclusions: Prevalence of infection outside GUM clinics is substantial and opportunistic screening using urine samples is an acceptable method of reaching individuals with infection who do not normally present at specialist clinics.

Mycoplasma genitalium Incidence, Organism Load, and Treatment Failure in a Cohort of Young Australian Women

BACKGROUND Mycoplasma genitalium (MG) is an emerging sexually transmitted infection (STI) that is potentially associated with reproductive tract sequelae in women. This study aimed to estimate MG incidence and treatment failure and provide estimates of organism load in infection. METHODS 1110 women aged 16-25 years were recruited from primary care clinics in Australia. Women were tested for MG at baseline, 6 months, and 12 months, and MG organism load was measured by quantitative polymerase chain reaction (PCR). MG-positive cases were screened for MG 23S ribosomal RNA (rRNA) gene point mutations shown to confer azithromycin resistance using high-resolution melt following PCR. RESULTS MG incidence rate was 1.3 per 100 person-years (n=14; 95% confidence interval [CI], .8-2.3); women reporting 3 or more sex partners in the last 12 months had an increased rate of incident infection (rate ratio [RR], 5.1; 95% CI, 1.3-19.6]). There were 3 cases of MG reinfection (0.8 per 100 person-years [95% CI, .1-.9]. Organism load was higher for prevalent than incident infection (P=.04). There were 3 cases of treatment failure (9.4% [95% CI, 2.0-25.0]); organism load was higher in cases with treatment failure than in successfully treated cases (P<.01). An MG 23S rRNA mutation was detected in 5 cases (3 cases of treatment failure and 2 successfully treated). CONCLUSIONS Although MG incidence was relatively low, testing should be recommended for women considered to be at increased risk based on sexual history. Our results also suggest that organism load might be important in azithromycin treatment failure.

Using chlamydia positivity to estimate prevalence: evidence from the Chlamydia Screening Pilot in England

Studies have suggested that positivity can be used to estimate the prevalence of Chlamydia trachomatis in large-scale chlamydia screening programmes. A recent pilot of opportunistic screening in England estimated that the prevalence among 16–24-year-old women in Portsmouth and Wirral was 9.8% and 11.2%, respectively. This study assessed the continued validity of positivity as an approximate for prevalence. We re-analysed data from the Chlamydia Screening Pilot to estimate positivity, calculated as total positive tests divided by total tests, and compared these estimates with the previously reported prevalence, measured as the number of women testing positive divided by the total number of women screened. Overall positivity was 9.4% in Portsmouth and 11.0% in the Wirral; these estimates were not statistically different from prevalence, regardless of health-care setting, age group or symptoms. We conclude that positivity can be used as a proxy for prevalence.

Maximising retention in a longitudinal study of genital Chlamydia trachomatis among young women in Australia

BackgroundCohort studies are an important study design however they are difficult to implement, often suffer from poor retention, low participation and bias. The aims of this paper are to describe the methods used to recruit and retain young women in a longitudinal study and to explore factors associated with loss to follow up.MethodsThe Chlamydia Incidence and Re-infection Rates Study (CIRIS) was a longitudinal study of Australian women aged 16 to 25 years recruited from primary health care clinics. They were followed up via the post at three-monthly intervals and required to return questionnaires and self collected vaginal swabs for chlamydia testing. The protocol was designed to maximise retention in the study and included using recruiting staff independent of the clinic staff, recruiting in private, regular communication with study staff, making the follow up as straightforward as possible and providing incentives and small gifts to engender good will.ResultsThe study recruited 66% of eligible women. Despite the nature of the study (sexual health) and the mobility of the women (35% moved address at least once), 79% of the women completed the final stage of the study after 12 months. Loss to follow up bias was associated with lower education level [adjusted hazard ratio (AHR): 0.7 (95% Confidence Interval (CI): 0.5, 1.0)], recruitment from a sexual health centre as opposed to a general practice clinic [AHR: 1.6 (95% CI: 1.0, 2.7)] and previously testing positive for chlamydia [AHR: 0.8 (95% CI: 0.5, 1.0)]. No other factors such as age, numbers of sexual partners were associated with loss to follow up.ConclusionsThe methods used were considered effective for recruiting and retaining women in the study. Further research is needed to improve participation from less well-educated women.

Screening for genital chlamydia infection: DNA amplification techniques should be the test of choice

Our objective was to compare the sensitivities for the detection of Chlamydia trachomatis, of the ligase chain reaction (LCR) on first voided urine (FVU) specimens and enzyme immunoassay (EIA) on pooled endocervical/endourethral swabs from women and endourethral swabs from men. Men and women taking part in the UK chlamydia screening pilot were tested for chlamydia using LCR on a FVU. Patients attending genitourinary medicine clinics also had cervical and/or urethral swabs taken for chlamydia testing by EIA. In women, EIA on pooled swabs detected 575 of the 785 chlamydia positives and in men, EIA detected 209 of 351 positives. The sensitivity of EIA was 73% and 60% in women and men respectively. By using the EIA test, therefore, 27-40% of patients infected with chlamydia will be given a false negative result. We propose that it is unethical to use non-molecular testing in the future.

Opportunistic chlamydia screening; should positive patients be screened for co-infections?

This study examines the requirement for testing patients for other sexually transmitted infections (STIs) and bacterial vaginosis (BV) when diagnosed with genital chlamydia during opportunistic screening. Data were collected on all patients participating in the Department of Health chlamydia screening pilot study in Portsmouth. One thousand two hundred and forty-five women and 490 men with genital chlamydia were seen in Portsmouth genitourinary medicine (GUM) department. Of the women screened in GUM, 28% had coexisting STIs and 21% had BV. The corresponding figures for those initially screened in the community were 4% and 17%. An increased number of female sexual partners of male patients (76%) and male partners of female patients (55%) of the GUM group had co-infections; 58% of male partners from the community group had another STI. The increased morbidity associated with these infections warrants screening of all patients with chlamydia for other STIs and BV.

Who has chlamydia? The prevalence of genital tract Chlamydia trachomatis within Portsmouth and South East Hampshire, UK

Objective To determine the prevalence of genital tract Chlamydia trachomatis infection in women and men attending different health care settings in Portsmouth and South East Hampshire. Design Prospective, opportunistic screening. Setting Multiple health care sites. Participants Consenting sexually active women and men. Intervention A urine sample was tested for Chlamydia trachomatis and positive patients were offered treatment and partner notification. Main outcome measures The presence or absence of chlamydia infection according to age, gender, health care setting and reason for attendance. Results A total of 14 756 samples were tested giving an overall prevalence of 9.6%. The prevalence was significantly higher in women attending for a termination of pregnancy, antenatal care, women and men attending genitourinary medicine and in those with genital tract symptoms. The prevalence was different for men and women at different ages. Conclusion The prevalence of genital Chlamydia trachomatis infection was high but differed at various health care settings and by reason for attendance.

Which treatment for genital tract Chlamydia trachomatis infection

A national opportunistic chlamydia screening programme, mainly targeting young sexually active women, is gradually being introduced across the UK and in future will predominantly occur in primary care sites. The relative efficacy of recommended antibiotic treatments for chlamydia has been poorly studied and especially that of single dose azithromycin. In Portsmouth, 1536 patients treated for chlamydia, with four different antibiotic regimens, during the Department of Health pilot study, were asked to return for test of cure. No difference in treatment outcome was found using doxycycline, oxytetracycline, erythromycin or azithromycin. Directly observed therapy with azithromycin may be especially helpful in treating young chlamydia-positive patients.