'The difference in determinants of Chlamydia trachomatis and Mycoplasma genitalium in a sample of young Australian women.'

BACKGROUND Differences in the determinants of Chlamydia trachomatis ('chlamydia') and Mycoplasma genitalium (MG) genital infection in women are not well understood. METHODS A cohort study of 16 to 25 year old Australian women recruited from primary health care clinics, aimed to determine chlamydia and MG prevalence and incidence. Vaginal swabs collected at recruitment were used to measure chlamydia and MG prevalence, organism-load and chlamydia-serovar a cross-sectional analysis undertaken on the baseline results is presented here. RESULTS Of 1116 participants, chlamydia prevalence was 4.9% (95% CI: 2.9, 7.0) (n = 55) and MG prevalence was 2.4% (95% CI: 1.5, 3.3) (n = 27). Differences in the determinants were found - chlamydia not MG, was associated with younger age [AOR:0.9 (95% CI: 0.8, 1.0)] and recent antibiotic use [AOR:0.4 (95% CI: 0.2, 1.0)], and MG not chlamydia was associated with symptoms [AOR:2.1 (95% CI: 1.1, 4.0)]. Having two or more partners in last 12 months was more strongly associated with chlamydia [AOR:6.4 (95% CI: 3.6, 11.3)] than MG [AOR:2.2 (95% CI: 1.0, 4.6)] but unprotected sex with three or more partners was less strongly associated with chlamydia [AOR:3.1 (95%CI: 1.0, 9.5)] than MG [AOR:16.6 (95%CI: 2.0, 138.0)]. Median organism load for MG was 100 times lower (5.7 × 104/swab) than chlamydia (5.6 × 10⁶/swab) (p < 0.01) and not associated with age or symptoms for chlamydia or MG. CONCLUSIONS These results demonstrate significant chlamydia and MG prevalence in Australian women, and suggest that the differences in strengths of association between numbers of sexual partners and unprotected sex and chlamydia and MG might be due to differences in the transmission dynamics between these infections.This project was funded by the Commonwealth of Australia, as part of a National Chlamydia Pilot program that is currently running to test the effectiveness of a number of models for chlamydia testing in Australia. This project will assist in developing possible recommendations for a National Chlamydia Program. The analysis of MG was funded by the National Health and Research Council (research grant number 509144)

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

<p>Abstract</p> <p>Background</p> <p>Cohort 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.</p> <p>Methods</p> <p>The 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.</p> <p>Results</p> <p>The 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.</p> <p>Conclusions</p> <p>The 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.</p

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

<p>Abstract</p> <p>Background</p> <p>Cohort 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.</p> <p>Methods</p> <p>The 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.</p> <p>Results</p> <p>The 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.</p> <p>Conclusions</p> <p>The 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.</p

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

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.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.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).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

System dynamics modeling of chlamydia infection for screening intervention planning and cost-benefit estimation

Genital Chlamydia trachomatis infection is the most common sexually transmitted infection in the UK. It constitutes a major public health problem given that the majority of infections are asymptomatic which can lead to serious long-term medical consequences if not treated. This paper describes a System Dynamics model for capturing Chlamydia infection dynamics within a population, incorporating the behaviour of different risk groups, and provides a cost-benefit study for screening using data collected from the Department of Health opportunistic Chlamydia screening programme in Portsmouth. Furthermore, we demonstrate that high-risk groups are key in determining the overall infection dynamics of the system, and quantify screening rates required to manage infection prevalence within the wider population

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. We aimed to measure chlamydia incidence and re-infection 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 (GPs), family planning (FP) and genitourinary medicine (GUM): baseline-negative women followed for incidence and baseline-positive women for re-infection; urine tested every six months via nucleic acid amplification; and behavioural data collected. Extra test and questionnaire completed three months after initial positive test. Factors associated with infection and re- infection investigated using Cox regression stratified by healthcare setting of recruitment. Results: Chlamydia incidence was 4.9 (2.7-8.8) per 100 person-years (py) among women recruited from GPs, 6.4 (4.2-9.8) from FP, 10.6 (7.4-15.2) from GUM. Incidence was associated with young age, history of chlamydial infection, and new sex partner acquisition. If recently acquiring new partners, condom use at last sex was independently associated with lower incidence. Chlamydia re-infection was 29.9 (19.7-45.4) per 100/py from GPs, 22.3 (15.6-31.8) from FP, and 21.1 (14.3-30.9) from GUM. Factors independently associated with higher re-infection rates were acquiring new partners and failure to treat all partners. Conclusions: Sexual behaviours determined incidence and re-infection, 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. Re-screening chlamydia- positive women within six months of baseline infection may be sensible, especially if partner change occurs or all partners are not treated

'The difference in determinants of Chlamydia trachomatis and Mycoplasma genitalium in a sample of young Australian women'

BACKGROUND: Differences in the determinants of Chlamydia trachomatis ('chlamydia') and Mycoplasma genitalium (MG) genital infection in women are not well understood. METHODS: A cohort study of 16 to 25 year old Australian women recruited from primary health care clinics, aimed to determine chlamydia and MG prevalence and incidence. Vaginal swabs collected at recruitment were used to measure chlamydia and MG prevalence, organism-load and chlamydia-serovar a cross-sectional analysis undertaken on the baseline results is presented here. RESULTS: Of 1116 participants, chlamydia prevalence was 4.9% (95% CI: 2.9, 7.0) (n = 55) and MG prevalence was 2.4% (95% CI: 1.5, 3.3) (n = 27). Differences in the determinants were found - chlamydia not MG, was associated with younger age [AOR:0.9 (95% CI: 0.8, 1.0)] and recent antibiotic use [AOR:0.4 (95% CI: 0.2, 1.0)], and MG not chlamydia was associated with symptoms [AOR:2.1 (95% CI: 1.1, 4.0)]. Having two or more partners in last 12 months was more strongly associated with chlamydia [AOR:6.4 (95% CI: 3.6, 11.3)] than MG [AOR:2.2 (95% CI: 1.0, 4.6)] but unprotected sex with three or more partners was less strongly associated with chlamydia [AOR:3.1 (95%CI: 1.0, 9.5)] than MG [AOR:16.6 (95%CI: 2.0, 138.0)]. Median organism load for MG was 100 times lower (5.7 × 10(4)/swab) than chlamydia (5.6 × 10(6)/swab) (p < 0.01) and not associated with age or symptoms for chlamydia or MG. CONCLUSIONS: These results demonstrate significant chlamydia and MG prevalence in Australian women, and suggest that the differences in strengths of association between numbers of sexual partners and unprotected sex and chlamydia and MG might be due to differences in the transmission dynamics between these infections

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

Kaplan Meier curve showing proportion remaining free from chlamydia re-infection over time among a cohort of sexually active 16 to 25 year old women.

<p>Kaplan Meier curve showing proportion remaining free from chlamydia re-infection over time among a cohort of sexually active 16 to 25 year old women.</p