Genital Chlamydia infections in sexually active female adolescents: do we really need to screen everyone?

The relative contribution of causal factors in the transition from infection to clinical chlamydial disease

Chlamydia is a major bacterial pathogen in humans and animals globally. Yet 80% of infections never progress to clinical disease. Decades of research have generated an interconnected network linking pathogen, host, and environmental factors to disease expression, but the relative importance of these and whether they account for disease progression remains unknown. To address this, we used structural equation modeling to evaluate putative factors likely to contribute to urogenital and ocular chlamydial disease in the koala (Phascolarctos cinereus). These factors include Chlamydia detection, load, and ompA genotype; urogenital and ocular microbiomes; host sex, age, weight, body condition; breading season, time of year; location; retrovirus co-infection; and major histocompatibility complex class II (MHCII) alleles. We show different microbiological processes underpin disease progression at urogenital and ocular sites. From each category of factors, urogenital disease was most strongly predicted by chlamydial PCR detection and load, koala body condition and environmental location. In contrast, ocular disease was most strongly predicted by phylum-level Chlamydiae microbiome proportions, sampling during breeding season and co-infection with koala retrovirus subtype B. Host MHCII alleles also contributed predictive power to both disease models. Our results also show considerable uncertainty remains, suggesting major causal mechanisms are yet to be discovered.

It takes 2: partner attributes associated with sexually transmitted infections among adolescents

OBJECTIVES

The aims of this study were to identify partner attributes associated with sexually transmitted infections (STIs) among adolescents and to summarize implications for research and prevention.

DESIGN

The design of this study was systematic review.

METHODS

We identified peer-reviewed studies published in 1990 through 2010 that assessed 1 or more partner attributes in relation to a biologically confirmed STI among adolescents (15-24 years) by searching MEDLINE and included articles. Studies that included adolescents but more than 50% of the sample or with mean or median age of 25 years or greater were excluded.

RESULTS

Sixty-four studies met the eligibility criteria; 61% were conducted in high-income countries; 80% were cross sectional; and 91% enrolled females and 42% enrolled males. There was no standard "partner" definition. Partner attributes assessed most frequently included the following: age, race/ethnicity, multiple sex partners, and STI symptoms. Older partners were associated with prevalent STIs but largely unrelated to incidence. Black race was associated with STIs but not uniformly. Partners with multiple partners and STI symptoms seem to be associated with STIs predominantly among females. Although significant associations were reported, weaker evidence exists for the following: other partner sociodemographics, sexual and other behaviors (sexual concurrency, intimate partner violence, substance use, travel), and STI history. There were no apparent differences by STI.

CONCLUSIONS

Partner attributes are independently associated with STIs among male and female adolescents worldwide. These findings reinforce the importance of assessing partner attributes when determining STI risk. Prevention efforts should continue to promote and address barriers to condom use. Increased efforts are needed to screen and treat STIs and reduce risky behavior among men. A standard partner definition would facilitate the interpretation of findings in future studies.

Female genital Chlamydia trachomatis infection: where are we heading?

INTRODUCTION

Urogenital infection by Chlamydia trachomatis is the most common bacterial sexually transmitted disease in the world. C. trachomatis is the etiologic agent of several common genital tract syndromes such as urethritis, cervicitis, and pelvic inflammatory disease in women.

MATERIALS AND METHODS

In this review, the pathophysiology of a chlamydial infection as well as diagnosis, therapy and prevention strategies regarding female chlamydial infection are reviewed.

RESULTS

A chlamydial infection results in minimal or even no symptoms in approximately two-thirds of women, remaining therefore clinically apparent and undiagnosed. C. trachomatis infections are of great socioeconomic and public health concern due to the potential for severe long-term consequences in women, including an increased risk of ectopic pregnancy, tubal infertility and chronic pelvic pain. Moreover, if the bacterium is transmitted during labor to a newborn, it can cause ophthalmia neonatorum and atypical neonatal pneumonia. Due to the documented increased risk of morbidity, several national guidelines are available, including a routine screening for young women and screening during pregnancy that is recommended in several countries.

DISCUSSION

A routine screening for young women and screening during pregnancy is recommended in several countries. However, additional prospective studies of the effectiveness of chlamydia screening are warranted and might be feasible within established screening programs. Moreover, the transition from cervicitis to infertility should be also evaluated in future controlled studies to underline the existing evidence. Additionally, there is an urgent need to educate and inform health-care providers about implementation of screening programs to reduce the spread of chlamydial infection. Moreover, awareness and use of screening programs by the public is needed, which requires informational campaigns for the general public using different media. For improved screening strategies and public awareness, novel approaches have to be developed and evaluated. Finally, guidelines should be actively disseminated to all medical practitioners to increase their use in daily practice. Although the major socioeconomic and public health concerns of C. trachomatis infection are recognized, several considerations and additional measures for addressing this increasingly urgent health problem remain.

Improving STD testing behavior among high-risk young adults by offering STD testing at a vocational school

BACKGROUND

Chlamydia trachomatis infection (CT) is the most prevalent bacterial STD. Sexually active adolescents and young adults are the main risk group for CT. However, STD testing rates in this group are low since exposed individuals may not feel at risk, owing-at least in part-to the infection's largely asymptomatic nature. Designing new testing environments that are more appealing to young people who are most at risk of acquiring chlamydia can be an important strategy to improve overall testing rates. Here we evaluate the effect of a school-based sexual health program conducted among vocational school students, aiming to obtain better access for counseling and enhance students' STD testing behavior.

METHODS

Adolescents (median age 19 years) attending a large vocational school were provided with sexual health education. Students filled in a questionnaire measuring CT risk and were offered STD testing. Using univariate and multivariate analysis, we assessed differences between men and women in STD-related risk behavior, sexual problems, CT testing behavior and determinants of CT testing behavior.

RESULTS

Of 345 participants, 70% were female. Of the 287 sexually active students, 75% were at high risk for CT; one third of women reported sexual problems. Of sexually active participants, 61% provided a self-administered specimen for STD testing. Independent determinants for testing included STD related symptoms and no condom use. All CT diagnoses were in the high-CT-risk group. In the high-risk group, STD testing showed an increased uptake, from 27% (previous self-reported test) to 65% (current test). CT prevalence was 5.7%.

CONCLUSIONS

Vocational school students are a target population for versatile sexual health prevention. When provided with CT testing facilities and education, self selection mechanisms seemed to increase CT testing rate dramatically in this high-CT-risk population expressing sexual problems. Considering the relative ease of testing and treating large numbers of young adults, offering tests at a vocational school is feasible in reaching adolescents for STD screening. Although cost-effectiveness remains an issue counseling is effective in increasing test rates.

Chlamydia prevalence and correlates among female adolescents in Hungary

PURPOSE

To evaluate the prevalence and the behavioral and historical determinants of genital chlamydial infection among adolescent females in Hungary.

METHODS

A total of 214 consecutive, unselected, self-referred, sexually active, nonpregnant female individuals aged 16-20 years were evaluated by polymerase chain reaction through the use of questionnaires.

RESULTS

The prevalence of chlamydial infection within this population was 7.9%. We find that the most important correlates of chlamydial infection were at least three lifetime sexual partners (p < .005), two or more sexual partners in the preceding 3 months (p < .05), and symptoms of vaginitis (p = .002).

CONCLUSIONS

The high prevalence of chlamydia in this study population may justify universal testing in Hungary.

La contraception des adolescentes en France en 2007

The two main objectives of adolescence contraception are the eviction of involuntary pregnancies and the prevention of sexually transmitted infections. In France, in spite of our rich contraceptive arsenal and a widely spread information, the rate of voluntary termination of pregnancy keeps growing among the teenagers population--and this, probably because the gap between theoretical effectiveness and practice of contraception is particularly wide among the young people. Every contraceptive means can be used by teenagers; the best option being, it seems, the "double DUTCH", which consists of concomitant use of condoms and hormonal contraception. Most often, the consultation for contraception is the first gynaecological consultation. That is the reason why it is usually stressful for teenagers who dread undergoing a gynaecological examination. If this examination is not necessary for most of young patients, it is essential to create a trustful relationship and to make explicit the several contraceptive methods. During this consultation it is interesting to look for common teenage troubles like addiction to smoking and eating disorders. For any prescription of hormonal contraception, it is important to explain the benefits and the possible side effects, to stress the observance and to tell the teenager about the recommendations in case of forgetting. Concerning condom - the only efficient way of preventing sexually transmitted infections--, it is useful to talk about it in concrete and straightforward terms, to show its handling and to inform about risks of tearing. With this state of mind, an emergency contraception can be prescribed straightaway in order to make its use easier. Also, without any moralizing speech, the need for maturity must be emphasized as well as taking care of one's body with the aim of avoiding a premature pregnancy or any sexually transmitted infection. This consultation must be coupled with a close follow-up, availability and mutual confidence which are the main elements vouching for a good observance and consequently an efficient contraception.

Urinary symptoms in adolescent females: STI or UTI?

PURPOSE

To determine if urinary symptoms or urinary tract infections (UTI) were associated with sexually transmitted infections (STI) and which history, clinical, and laboratory findings could distinguish these infections in symptomatic women.

METHODS

A cross-sectional sample of 296 sexually active females aged 14-22 years attending a hospital-based teen health center or emergency department were recruited. Genitourinary symptoms, medical and sexual history, and urinalysis results were recorded. STI was defined as a vaginal swab positive for Trichomonas vaginalis or urine nucleic acid amplification test positive for Neisseria gonorrheae or Chlamydia trachomatis. A urine culture with >10,000 colonies of a single pathogen was considered a positive UTI.

RESULTS

In the full sample, prevalence of UTI and STI were 17% and 33%, respectively. Neither urinary symptoms nor UTI was significantly associated with STI. Further analyses are reported for the 154 (51%) with urinary symptoms: Positive urine leukocytes, more than one partner in the last three months and history of STI predicted STI. Urinalysis results identified four groups: (1) Normal urinalysis-67% had no infection; (2) Positive nitrites or protein-55% had UTI; (3) Positive leukocytes or blood-62% had STI; and (4) Both nitrites/protein and leukocytes/blood positive-28% had STI and 65% had UTI. Those without a documented UTI were more likely to have trichomoniasis than those with a UTI, and 65% of those with sterile pyuria had STI, mainly trichomoniasis or gonorrhea.

CONCLUSIONS

Adolescent females with urinary symptoms should be tested for both UTI and STIs. Urinalysis results may be helpful to direct initial therapy.

[Screening of sexually transmitted diseases in clinical and non-clinical settings in Salvador, Bahia, Brazil]

The objectives were to study: (1) acceptance of STD screening in non-clinical settings for asymptomatic individuals; (2) risk factors and STD prevalence among individuals in non-clinical and clinical settings; and (3) non-clinical screening of asymptomatic populations as a feasible method for STD control. We recruited 139 males and 486 females between 18 and 30 years of age from a family planning clinic, schools, and community centers in low-income neighborhoods. We asked about STD symptoms and STD/HIV risk behaviors and tested the individuals for gonorrhea, Chlamydia, syphilis, and HIV. Except for HIV, women recruited directly from the community had higher STD rates than those who came in for care at the clinic. Screening in non-clinical settings in Brazil is feasible and has a high yield among young adults in low-income communities. Infected participants would likely never have otherwise sought care or been tested or treated. STD control efforts could be implemented in any site that can reach populations at risk and become a routine procedure in health care settings where people report for problems unrelated to STDs.

Knowledge About Sexually Transmitted Diseases in Women Among Primary Care Physicians

OBJECTIVES

Little is known about sexually transmitted disease (STD) knowledge of primary care providers. The objectives of this study were to determine the knowledge about the management of STDs among primary care physicians and to identify physician characteristics associated with possession of STD knowledge.

STUDY

A self-administered questionnaire was mailed to a random sample of 1600 obstetrician/gynecologists, pediatricians, family physicians, and internists practicing in Pennsylvania. Information on physician and patient demographics was gathered, and we assessed knowledge and practice patterns concerning the management of STDs in young women.

RESULTS

Physician knowledge regarding the evaluation and management of women with or at risk for STDs was associated with female gender (odds ratio [OR]: 2.1; 95% confidence interval [CI]: 1.4-3.2), age < or =40 (OR: 2.3; 95% CI: 1.4-3.6), and metropolitan practice location (OR: 1.7; 95% CI: 1.1-2.6). Familiarity with the Center for Disease Control and Prevention's (CDC's) STD treatment guidelines was independently associated with STD knowledge (OR: 2.0; 95% CI: 1.2, 3.3). Physicians with good STD knowledge were more likely to report routinely screening at-risk women for Chlamydia trachomatis (OR: 3.9; 95% CI: 2.3-6.8).

CONCLUSIONS

Inadequacies in physician knowledge may serve as a barrier to the appropriate diagnosis and treatment of STDs. Interventions to improve STD management practices should include continuing medical education and distribution of CDC's STD treatment guidelines to primary care providers.

The epidemiology of sexually transmitted infections in adolescents

This article addresses the epidemiology of several common sexually transmitted infections (STIs) in adolescents. Chlamydia is a common occurrence in adolescents, more so than is gonorrhea, but both are of particular concern because they may cause pelvic inflammatory disease. Many experts recommend screening for chlamydia in sexually active adolescents, particularly females. Trichomonas vaginalis is significant as a marker for risk of contracting other STIs and because of its association with pregnancy complications and with increased risk of transmission of HIV. Genital herpes simplex virus (HSV) infection, which usually has been caused by HSV-2, is a common finding in adolescents, and it now is caused also by HSV-1 in some populations. Human papillomavirus (HPV), though widespread in adolescents, usually is a self-limited infection, and malignancy resulting from HPV is a rare occurrence in this age group. The least common of the diseases discussed below is syphilis, but a recent sharp increase in incidence has occurred in men who have sex with men.

Diagnostic Tests for Chlamydial and Gonorrheal Infections

Chlamydia trachomatis and Neisseria gonorrhoeae are the two most prevalent bacterial sexually transmitted infections reported in the United States. The purpose of this article is to review the various tests available for diagnosing C. trachomatis and N. gonorrhoeae. The nucleic acid amplification tests are preferred owing to their high sensitivity and specificity and use on specimens obtained noninvasively. Non-amplified non-culture tests, such as the DNA probe test, remain a choice for settings in which nucleic acid amplification tests are not available or affordable. Culture is recommended for use on conjunctival, oropharyngeal, and rectal specimens and in cases of suspected abuse. In addition, for gonorrhea, culture is recommended when screening in populations with a low prevalence of infection. Point-of-care tests are limited by low sensitivity and should be used for only populations unlikely to return for follow-up.

Applying a mixed-integer program to model re-screening women who test positive for C. trachomatis infection

We proposed a mixed-integer program to model the management of C. trachomatis infections in women visiting publicly funded family planning clinics. We intended to maximize the number of infected women cured of C. trachomatis infections. The model incorporated screening, re-screening, and treatment options for three age groups with respective age-specific C. trachomatis infection and re-infection rates, two possible test assays, and two possible treatments. Our results showed the total budget had a great impact on the optimal strategy incorporating screening coverage, test selection, and treatment. At any budget level, the strategy that used a relatively small per-patient budget increase to re-screen all women who tested positive 6 months earlier always resulted in curing more infected women and more cost-saving than the strategy that was optimal under the condition of not including a re-screening option.

Chlamydia and gonorrhea screening in asymptomatic young women

BACKGROUND

Adolescent and young adult minority women are at high risk for chlamydia (CT) and gonorrhea (NGC) cervical infections, which are significant causes of pelvic inflammatory disease, impaired fertility, ectopic pregnancy and chronic pain. The purpose of this article is to review among young women in the United States: (1) the epidemiology of CT and NGC cervical infection and their medical complications; (2) current public health recommendations to promote asymptomatic CT and NGC screening; (3) current screening practices and challenges of implementing public health recommendations; (4) testing and cost issues; and (5) future directions in promoting asymptomatic CT and NGC screening.

METHODS

We conducted a MEDLINE search for articles published over the last two decades relating to CT and NGC screening in young women and then systematically reviewed all relevant articles.

RESULTS

The data indicate that CT and NGC infection are geographically widespread in the U.S. and asymptomatic infection is highly prevalent among economically disadvantaged young females. Public health recommendations promoting CT and NGC screening in asymptomatic young women are directed to both health care providers and clients. However, strategies to promote screening efforts have been primarily directed toward health care providers; there are no published studies on client-initiated screening strategies. Challenges of implementing public health recommendations and future directions for CT and NGC screening are discussed.

CONCLUSIONS

Young sexually active women continue to be at high risk for CT and NGC infection. The data indicate that implementation of health provider-based and client-initiated screening in private and public health care settings is a challenge. However, there is a great need to develop strategies to understand and promote client-initiated screening.

Limitations of screening tests for the detection of Chlamydia trachomatis in asymptomatic adolescent and young adult women

OBJECTIVE

The purpose of this study was to examine the performance of different test types, specimen sources, and collection methods for screening of genital Chlamydia trachomatis infection in young women.

STUDY DESIGN

Asymptomatic women aged 16 to 25 years collected their own vaginal swabs and a first-voided urine specimen; a clinician collected urethral, vaginal, and endocervical swabs for culture and nucleic acid amplification tests, polymerase chain reaction and ligase chain reaction. A positive culture, 2 positive nucleic acid amplification tests, or 1 positive nucleic acid amplification test confirmed by a separate nested polymerase chain reaction comprised the criterion standard to define a C. trachomatis-infected woman.

RESULTS

The prevalence of C. trachomatis was 22% (30/139 women). All 9 test results were available for 126 participants (91%). Sensitivities were comparable for polymerase chain reaction and ligase chain reaction (52%-63%), except for urine polymerase chain reaction (44%), and were lower for culture (22%-37%); specificities were 99% to 100%, except for urine ligase chain reaction (91%). Positive predictive values were >93%, except for urine ligase chain reaction (65%); negative predictive values were 83% to 91%. Combining nucleic acid amplification test results from 2 different specimens improved sensitivities without compromising specificity.

CONCLUSION

When C. trachomatis infection was defined by multiple tests from different specimen sources, the sensitivity of any 1 test from a single specimen source was lower than generally reported. The limitations of the use of a single test to identify C. trachomatis infection should be considered when test type, specimen source, and collection method for screening young women is being determined.

Prevalence of genital chlamydial infection in symptomatic and asymptomatic Jordanian patients

OBJECTIVE

To detect Chlamydia trachomatis infection among 230 patients, 130 with signs or symptoms associated with urethritis, and 100 asymptomatic patients, attending the Jordan University Hospital urology clinic.

METHODS

Routine urine examination and the leukocyte esterase test were done for each patient. C. trachomatis infection was detected using first-void urine specimens and a cryptic plasmid-based PCR technique specific for C. trachomatis.

RESULTS

The prevalence of chlamydial infection was 4.6% among symptomatic patients with urethritis. The difference in prevalence was statistically insignificant (P > 0.05) between males and females, as well as in relation to their marital status. Two-thirds of the Chlamydia-positive patients also had urine positive for leukocyte esterase.

CONCLUSION

The low prevalence of chlamydial infection in association with urethritis among Jordanian patients might be due to the conservative behavior of the Jordanian society towards free sexuality.

Developments in the screening for Chlamydia trachomatis: a review

Many studies have evaluated selective screening criteria for women in various settings. Most have concluded and all guidelines recommend that all women aged < 25 be screened yearly for C. trachomatis infection. Behavioral criteria, such as the number of sex partners, new or more than one sex partners, and previous infection, also can serve as criteria for screening women aged > 25. Because re-infection rates are high and occur within a few months, complications may be reduced further if partners are treated and women rescreened 4 to 6 months after initial infection. Revised recommendations for C. trachomatis screening programs have stated that more frequent screening may be considered among women < 20 and those with recent infection. Screening in nontraditional settings and careful evaluation of local prevalence and risk factor information should be encouraged. Private providers and emergency room providers should discuss screening recommendations and adopt a C. trachomatis screening policy for the population they serve. The HEDIS measure should serve to encourage at least annual screening of 15- to 25-year-old sexually active females through providers linked to managed care organizations. In general, high yields (ie, percentage of tests that are positive) in nontraditional settings and enhanced feasibility and acceptability of urine-based tests may encourage further innovative approaches to reach and screen populations at risk. Several issues remain to be addressed to increase the effectiveness of screening efforts. If more sensitive amplification tests are used widely, more infected persons will be identified and treated, and transmission patterns may change, particularly if partner treatment also occurs. Current screening criteria should continue to be re-evaluated. An important issue that affects testing methods includes the possible need for confirmation testing when using NAATs if the prevalence of C. trachomatis is less than 2%. If the sensitivity of an NAAT is 85% and specificity is 99%, in a hypothetical population of 10,000 with a prevalence of 2%, the positive predictive value is 170/268 (63%). A second important issue affecting testing methods and feasibility of using NAATs for screening large numbers of individuals is the pooling of urine specimens, which has been evaluated in several studies and found to be very effective for reducing costs. A research issue for pooling is the determination of the most cost-effective prevalence levels for pooling. An additional research question is in which populations should a NAAT be used for detection of C. trachomatis and N. gonorrhoeae. There are no recommendations for the routine screening of men because of the paucity of data showing that this strategy can reduce sequelae. The CDC is conducting a multisite study to examine the feasibility, acceptability, and usefulness of screening of asymptomatic men. There are a few studies have determining cost-effective prevalence threshold levels, particularly with NAATs. A recently developed decision analysis model by CDC designed to maximize the effectiveness of screening strategies for C. trachomatis infections may be useful for decision makers. It is intended to serve as an easy and flexible tool to determine cost effectiveness at a local level and takes into account positivity rates and test performance characteristics (SOCRATES). It is unclear if recurrent infection is caused by true re-infection by the same or a different partner or recurrence of initial infection. Recurrence may be caused by persistence of C. trachomatis or antibiotic resistance. This distinction is of scientific interest because the appropriate intervention differs (eg, identification of risk factors for the former and microbiologic investigations for the latter). Effective partner management and retesting are critical to reducing sequelae of C. trachomatis infection. Screening for C. trachomatis infection remains an essential component of C. trachomatis control. It is cost effective, most infections are asymptomatic, and symptom-based health care seeking and testing identify few of those infected. The likelihood that opportunities for screening are missed is high particularly in non-STD clinic settings. Local studies using NAATs to determine C. trachomatis prevalence and risk factors are helpful to health care providers so they can make evidence-based decisions on who to screen. The use of nontraditional, non-clinic-based test settings should be explored further. We have focused on summarizing the medical evidence regarding recommendations for screening for C. trachomatis. High-risk populations for C. trachomatis infection may overlap with populations for other STDs, and comprehensive STD prevention programs that involve a range of STD service providers are needed to successfully reduce the STD-related health burden in the population.

Adolescence and other risk factors for Chlamydia trachomatis genitourinary infection in women in Melbourne, Australia

OBJECTIVE

To establish the prevalence of and risk factors for Chlamydia trachomatis infection to determine the role of universal versus targeted testing.

METHODS

A prospective study of 1107 women attending two sexual and reproductive health clinics in Melbourne, Australia, was carried out. A questionnaire was used to establish risk factors. Urine samples were tested for C. trachomatis by PCR. The main outcome measures were prevalence of and risk factors for C. trachomatis infection.

RESULTS

Of 1107 recruitable women, 851 (76.9%) consented and were successfully tested. C. trachomatis was detected in 18 (4.8% (95% CI 2.9 to 7.5)) of 373 women in the inner city and eight (1.7% (95% CI (0.7 to 3.3)) of 478 women in the suburban clinic. Of women under 25 years, 17 (6.2% (95% CI 3.7 to 9.8)) of 273 in the inner city in contrast with three (1.7% (95% CI 0.4 to 5.0)) of 174 in the suburban clinic were infected. In the inner city clinic, age under 25 years (OR 5.4 (95% CI 0.7 to 41.5)), vaginal discharge (OR 4.1 (95% CI 1.5 to 11.1)), and recent change of sexual partner (OR 4.6 (95% CI 1.6 to 12.9)) were associated with C. trachomatis. In contrast, in the suburban clinic, only vaginal discharge (OR 3.5 (95% CI 0.9 to 14.3)) and recent change of sexual partner (OR 3.4 (95% CI 0.8 to 15.7)) were identified as risk factors. Multivariate analysis showed that recent change of partner (OR 4.5 (95% CI 1.5 to 13.8)) was the most strongly associated independent risk factor for infection in the inner city clinic.

CONCLUSION

The high prevalence of C. trachomatis indicates that universal testing should be undertaken in the inner city clinic. Young age may not be a risk factor for C. trachomatis in more affluent populations with lower prevalence rates. No risk factors were identified with sufficient sensitivity and specificity to be useful for targeted testing. Prevalence and identifiable risk factors for C. trachomatis are not transferable between populations, even in the same city.

Cellular immunity and Chlamydia genital infection: induction, recruitment, and effector mechanisms

Chlamydia trachomatis is one of the major causes of bacterial sexually transmitted disease worldwide. The initial infection of endocervical epithelium in females is asymptomatic and commonly ascends to fallopian tubes when left untreated. Immunity to Chlamydia develops after infection and appears to provide short-term protection. Consequently, a significant rate of reinfection occurs among sexually active individuals, which can result in reproductive disability. T helper type 1 responses are implicated in providing protective immunity but may also contribute to tubal infertility. The purpose of this chapter is to review the factors that regulate the induction and recruitment of protective cellular immune responses within the local genital mucosa. An understanding of these events is important for the design of a protective vaccine and control of immunopathologic reactions.

Self-collected vaginal swabs for the detection of multiple sexually transmitted infections in adolescent girls

OBJECTIVE

To evaluate the use of self-collected vaginal swabs to test for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis, and to describe the acceptability of this technique to adolescents.

DESIGN

Comparison of a new protocol for sexually transmitted infection (STI) testing with the current standard of care, using the same subjects. Survey of attitudes regarding the self-collection technique.

SETTING

A juvenile correctional facility in western Pennsylvania.

PARTICIPANTS

Convenience sample of 133 detainees, 12-17 years of age.

INTERVENTION

Girls were invited to undergo STI screening using a self-collected vaginal swab. Polymerase chain reaction was used to test this specimen for each of the above three infections. Pelvic exams and endocervical testing were performed at the discretion of the physician performing the intake physical, independent of the study.

MAIN OUTCOME MEASURES

The number of infections diagnosed using the self-testing protocol, compared to the number diagnosed using standard practices; acceptability of the self-collection technique.

RESULTS

Twenty-four percent of sexually active subjects had one or more infections diagnosed by self-testing: 11.3% had C. trachomatis, 8.5% had N. gonorrhoeae, and 11.7% had T. vaginalis. Only 30% of subjects with infections had pelvic exams while detained; therefore 70% of girls with infections would have been missed in the absence of the self-testing option. The self-collection technique was acceptable to 95% of subjects.

CONCLUSIONS

STI testing using self-collected vaginal specimens is highly acceptable to adolescent girls, and can dramatically increase the detection rate for these three treatable infections when pelvic exams are not performed.

Optimal resource allocation for curing Chlamydia trachomatis infection among asymptomatic women at clinics operating on a fixed budget

GOAL

The goal was to determine the optimal strategy for screening coverage, test selection, and treatment for infection in asymptomatic women for a given family-planning-program budget.

STUDY DESIGN

We developed a resource allocation model to determine the optimal strategy using data from 5078 visits by women universally screened for infection in a publicly funded family planning clinic system in Philadelphia. We maximized the number of infected women cured from the clinic perspective and maximized the cost-savings from the healthcare system perspective. The model incorporated the following age distributions: <20 years (27%), 20 to 24 years (30%), and >24 years (43%), with prevalences of 10.6%, 6.9%, and 2.3%, respectively. We modeled two screening test assays (DNA probe and ligase chain reaction [LCR] for cervical specimens) and two treatments (doxycycline and azithromycin). The model allowed for different test and treatment choices by age group.

RESULTS

At the baseline annual budget of $6 per visit, the strategy that maximized both the number of infected women cured and cost savings would be to screen all women with DNA probe and to treat all women with positive tests with azithromycin. This strategy would result in 183 women cured at a cost-savings of $140,176. Sensitivity analysis showed that the total budget had a great impact on the optimal strategy, incorporating screening coverage, test selection, and treatment.

CONCLUSIONS

Using resource allocation models enables clinic managers operating with a fixed budget to identify a strategy that maximizes the number of asymptomatic women cured and cost savings when the clinic age distribution and age-specific prevalences are known.

Detection of Chlamydia trachomatis in an Australian high school student population

OBJECTIVE

To assess the prevalence of Chlamydia trachomatis infections among an Australian high school adolescent population.

METHODS

Over a 4 year period, 14 high schools were selected in which an infertility prevention programme targeting C. trachomatis was delivered to senior student populations. Coded first catch urine specimens were analysed by Amplicor PCR and infected students treated. Data retrospectively obtained from chlamydia screening programmes conducted among disadvantaged young people detached from formal education were also collated for comparison.

RESULTS

Of a total student test population of 1174, 15 (1.3%; 95% CI 0.7% to 2.1%) were diagnosed with C. trachomatis. Of 516 females and 658 males, 12 (2.3%; 95% CI 1.1% to 4.1%) and 3 (0.5%; 95% CI 0.1% to 1.4%) were tested positive respectively. Data collated for three populations of disadvantaged youth returned at total of 89 C. trachomatis infections out of 560 people (15.9% 95%CI 13.0-19.2%).

CONCLUSION

The overall prevalence of C. trachomatis infection among this population of senior high school adolescents is low, and significantly differs from the higher chlamydia rates detected in disadvantaged adolescents detached from formal schooling (p<0.0001).

Screening positive urine pregnancy tests for sexually transmitted diseases expedites the treatment of infected adolescent gravidas

OBJECTIVE

To test the utility of screening the urine samples used to diagnose pregnancies at urban teen clinics for Chlamydia trachomatis and Neisseria gonorrhoeae by polymerase chain reaction (PCR). We hypothesized that urine screening would increase the proportion of teenagers treated for these two sexually transmitted diseases (STDs) before they initiated pregnancy-related care.

DESIGN

A randomly selected subset of the urine samples used to diagnose 212 teen pregnancies were tested for C. trachomatis and N. gonorrhoeae by PCR. Endocervical testing was at the providers' discretion. Bivariate analyses were used to compare the teenagers randomized to the urine screening group (n = 102) and the non-screening group (n = 110).

RESULTS

Of the 102 urine PCR tests, 14 (13.7%) were positive. Endocervical swabs were obtained in 31 (14.6%) of the 212 teenagers and five (16.1%) were positive. Since pelvic examinations were performed so infrequently, the net endocervical swab detection rate was significantly lower than the urine-based detection rate (1.8% compared to 13.7%; p = 0.001). Only one infected teenager was untreated when she initiated pregnancy-related care. Thus, the treatment rate was more than six times higher when urine samples were screened (12.7% compared to 1.8%; p = 0.003).

CONCLUSIONS

Screening the urine samples used to diagnose teen pregnancies for two common STDs is a simple, non-invasive procedure that is acceptable to providers and patients, and significantly increases the number of teenagers who are treated for genital infection before they initiate pregnancy-related care.

Risk factors for genital chlamydial infection

OBJECTIVE

To discuss the occurrence of genital chlamydia in developed countries and review the literature assessing the potential risk factors for this sexually transmitted disease.

DATA SOURCES

A MEDLINE search was performed for all English citations from 1985 to 2000 that contain the keywords "Chlamydia trachomatis", "chlamydial infections", "risk factors" and "sex behaviour". All relevant references cited in articles that were obtained from the search were also included.

DATA EXTRACTION

ALL ARTICLES OBTAINED FROM THE ABOVE SOURCES WERE EXAMINED, AND WERE INCLUDED IN THE REVIEW IF THEY MET THE FOLLOWING CRITERIA: primary study examining sociodemographic or behavioural risk factors associated with genital chlamydial infection using multivariate analysis; study subjects 12 years of age and older; and study setting in a developed country.

DATA SYNTHESIS AND CONCLUSIONS

Genital chlamydial infection has become the most commonly reported bacterial infection in North America over the past decade. Thirty-eight cross-sectional studies and six cohort studies were included in the present review. Most studies demonstrated that young men and women are at higher risk of being infected with chlamydia than older subjects. Chlamydia seems to be found in a diverse group of people, and unlike gonorrhea, is not concentrated in low income, minority core groups with high rates of partner change. However, a number of studies have shown that communities with well-established control programs are beginning to demonstrate this pattern. There is no clear evidence that chlamydia is associated with type of partners, contraceptive use, or age at first intercourse. Future research should follow this sexually transmitted disease as it evolves through the epidemiological stages to ensure that preventive and treatment services are reaching those people who are most likely to be infected.

Chlamydia screening in primary care: is it useful, affordable and universal?

Genital chlamydial infection, with its possible long-term morbidity, is a serious public health problem. The number of new diagnoses is rising rapidly and, in the UK, recent evidence suggests that the infection rate in young women exceeds 10%. Screening programmes can reduce the population prevalence of infection, but uncertainty remains as to the ideal screening model. This may prove to be opportunistic screening of sexually active young women, less than 25 years of age, in primary care settings, and contact tracing of the partners of those with chlamydia. Recent literature on the practicalities of genital chlamydia screening is reviewed.

Prevalence, incidence, and correlates of chlamydia and gonorrhea among young adult injection drug users

PURPOSE

To measure prevalence, incidence, and correlates of chlamydia and gonorrhea among injection drug users (IDUs).

METHODS

Participants (n = 2129; 63% male, 52% white, ages 18-30 years) in five US cities were tested for chlamydia and gonorrhea by urine LCR assay and completed a standardized questionnaire about demographics and recent sexual behavior. Logistic regression identified correlates of prevalent infection; incidence rates were calculated from 6-month follow-up data.

RESULTS

Chlamydia prevalence was 5.2% and did not differ by gender. Gonorrhea prevalence was 0.2% among men and 2.0% among women, P < .001. Among men, younger age [OR (95% CI): 0.89 (0.83-0.96)], age at sexual debut [0.91 (0.83-0.99)], and African American race [2.92 (1.53-5.59)] were associated with chlamydia. Among women, age at sexual debut [1.16 (1.02-1.31)] and commercial sex [1.96 (1.03-3.74)] were associated with chlamydia, and with gonorrhea [1.27 (1.04-1.56)] and [5.17 (1.66-16.11)], respectively. At 6 months, the cumulative incidence of chlamydia was 1.7% among men and 4.4% among women, P = .03; no men and 1.3% of women tested positive for gonorrhea, P = .01.

IMPLICATIONS

Prevalence and correlates of chlamydia and gonorrhea were similar to other samples, suggesting that screening criteria need not be modified for IDU populations. The number of behavioral correlates identified was limited; perhaps unmeasured sexual-network-level factors play a role in determining sexually transmitted disease (STD) prevalence.

Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae infection in pediatric private practice

BACKGROUND

Universal screening of sexually active adolescents for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) has been recommended in settings in which prevalence is 2% or greater. Although believed to be above 2%, the prevalence of CT and GC infection in private practice settings has not been clearly established and may affect screening practices.

OBJECTIVES

To determine CT and GC infection prevalence in 2 pediatric private practices.

DESIGN

Cross-sectional study.

SETTING

Two pediatric private practices in suburban North Carolina.

PATIENTS

Convenience sample of patients aged 15 to 24 years who were seen from August 1998 through June 1999.

MAIN OUTCOME MEASURES

Prevalence of CT and GC infection.

RESULTS

Of 1114 eligible patients, 803 (72%) completed questionnaires and provided urine specimens tested for CT and GC infection using ligase chain reaction assays. Mean age was 17.1 years (standard deviation: 1.8). Most participants were female (63%), white (87%), and from highly educated families (64% of their mothers graduated from college). Sexual activity was reported by 41%. Prevalence of CT infection in all participants was 0.9% (confidence interval [CI]: 0.4%-1.8%); in sexually active participants, 2.1% (CI: 0.9%-4.3%); in sexually active females, 2.7% (CI: 1.0%-5.7%); and in sexually active males, 0.9% (CI: 0.0%-5.1%). One case of GC infection was found.

CONCLUSIONS

The prevalence of CT and GC infection in this private practice population was much lower than reported in other settings. Screening recommendations may need to be reassessed if other low prevalence populations are found.

Predictors of Chlamydia trachomatis infection among women attending rural Midwest family planning clinics

Objective: To determine predictors of Chlamydia trachomatis infection among women 14–24 years of age attending family planning clinics throughout a rural Midwestern state.

Methods: The study population included 16 756 women between the ages of 14 and 24 years attending family planning clinics for annual examinations throughout the state of Iowa in 1997. All women under 25 years of age having annual exams were tested for C. trachomatis during the visit. At the time of exam, both behavioral and demographic data were collected on all women participating in the study.

Results: The majority of women in the study (96%) reported no symptoms of chlamydia. Only 2.5% of all women had a positive test result. In the multivariate model, the odds ratios were significantly increased among the youngest age (14–17 years; OR = 2.2), those with mucopurulent cervicitis (OR = 3.4), cervical friability (OR = 2.2), symptomatic for infection (OR = 1.8), risk history (OR = 1.6), and black race (OR = 1.2) and predictive of a C. trachomatis infection.

Conclusions: Risk factors predictive of C. trachomatis infection among younger aged women attending family planning clinics in a Midwest rural population are consistent with predictors of infection among women attending family planning clinics across theUnited States. The overall findings suggest the importance of developing screening guidelines as a means of lowering chlamydia rates. This may be a particularly difficult task in light of the low rate of symptoms that would lead a woman to seek medical care, even in younger age women who are at higher risk. In addition, screening guidelines would be more difficult to implement in a rural setting.

Sexually transmitted infections among HIV infected and HIV uninfected high-risk youth in the REACH study. Reaching for Excellence in Adolescent Care and Health

This review presents the findings of published research in the Reaching for Excellence in Adolescent Care and Health (REACH) Project on sexually transmitted infections (STIs) within the context of the project's scientific agenda. Methods employed in the study for specimen collection, management, and laboratory analysis are presented. This review presents published analyses of cross-sectional data; longitudinal analyses are underway. In addition, baseline prevalence data on selected STIs and sexual risk profiles of the subjects in REACH are presented. High STI rates were evident in both human immunodeficiency virus (HIV) infected and uninfected youth of both genders regardless of sexual orientation. High infection rates at baseline suggest that prevention-oriented programs for risk reduction among adolescents should focus on both HIV infected and at-risk, uninfected youth.

Adolescent chlamydia testing practices and diagnosed infections in a large managed care organization

GOAL

To determine chlamydia screening practices and the resulting positive test results for adolescents enrolled in a large nonprofit managed care organization.

STUDY DESIGN

The electronic medical records of all 12- to 19-year-olds enrolled in a large nonprofit managed care organization serving a demographically diverse patient population from January 1998 through December 1999 were reviewed retrospectively.

RESULTS

Among the 43,205 female and 44,133 male managed care organization members, ages 12 to 19 years in 1998-1999, 7575 adolescents (8.7%) (6914 females [16%] and 661 males [1.5%]) were tested for chlamydia. Among the members tested, chlamydia was diagnosed in 1109 adolescents (14.6%) (983 females [14.2] and 126 males [19.1%]); 761 (68.6%) adolescents were retested for chlamydia; and 182 (16.4%) had repeat positive test results. The median time to diagnosis of a repeat infection was 6 months.

CONCLUSIONS

Chlamydia imposes a large disease burden in the private, organized healthcare sector. Managed care organizations can use operational data to enhance chlamydia prevention services by defining testing practices and local disease prevalence.

Screening for chlamydial infection

OBJECTIVES

To examine data on the effectiveness of screening for chlamydial infection by a physician or other health care professional. Specifically, we examine the evidence that early treatment of chlamydial infection improves health outcomes, as well as evidence of the effectiveness of screening strategies in nonpregnant women, pregnant women, and men, and the accuracy of tests used for screening. This review updates the literature since the last recommendation of the U.S. Preventive Services Task Force published in 1996.

SEARCH STRATEGY

We searched the topic of chlamydia in the MEDLINE, HealthSTAR, and Cochrane Library databases from January 1994 to July 2000, supplemented by reference lists of relevant articles and from experts in the field. Articles published prior to 1994 and research abstracts were cited if particularly important to the key questions or to the interpretation of included articles.

SELECTION CRITERIA

A single reader reviewed all English abstracts. Articles were selected for full review if they were about Chlamydia trachomatis genitourinary infections in nonpregnant women, pregnant women, or men and were relevant to key questions in the analytic framework. Investigators read the full-text version of the retrieved articles and applied additional eligibility criteria. For all topics, we excluded articles if they did not provide sufficient information to determine the methods for selecting subjects and for analyzing data.

DATA COLLECTION AND ANALYSIS

We systematically reviewed three types of studies about screening in nonpregnant women that relate to three key questions: (1) studies about the effectiveness of screening programs in reducing prevalence rates of infection, (2) studies about risk factors for chlamydial infection in women, and (3) studies about chlamydial screening tests in women. Our search found too few studies on pregnant women to systematically review, although pertinent studies are described. We systematically reviewed two types of studies about screening in men: (1) studies about prevalence rates and risk factors for chlamydial infection in men and (2) studies about chlamydial screening tests in men.

MAIN RESULTS

Nonpregnant women. The results of a randomized controlled trial conducted in a large health maintenance organization indicate that screening women selected by a set of risk factors reduces the incidence of pelvic inflammatory disease (PID) over a 1-year period. Changes in population prevalence rates have not been well documented because few studies have employed a representative population sample. Age continues to be the best predictor of chlamydial infection in women, with most studies evaluating cut-offs at age younger than 25 years. Other risk factors may be useful predictors, but these are likely to be population specific. To determine the accuracy of screening tests for women, we retrieved and critically reviewed 34 articles on test performance. Results indicate that endocervical swab specimens and first-void urine specimens have similar performance when using DNA amplification tests and have better sensitivity than endocervical culture. Recurrent chlamydial infections in women have been associated with increased risks for PID and ectopic pregnancies. Pregnant women. The Second Task Force recommendations for screening pregnant women were based on two major studies demonstrating improved pregnancy outcomes following treatment of chlamydial infection. We identified no recent studies on this topic in our literature search. Very few studies describe risk factors for chlamydial infection in pregnant women. Nonculture testing techniques appear to perform well in pregnant women, although studies are limited. Men. No studies described the effectiveness of screening or early treatment for men in reducing transmission to women or in preventing acute infections or complications in men. Studies of prevalence rates and risk factors for chlamydial infection in men are limited. Age lower than 25 years is the strongest known risk factor cited so far. Results of urethral swab specimens compared to first-void urine specimens were similar for DNA amplification tests. DNA amplification techniques are more sensitive than culture.

CONCLUSIONS

Screening women for Chlamydia trachomatis reduces the incidence of PID, and it is associated with reductions in prevalence of infection in uncontrolled studies. No studies were found to determine whether screening asymptomatic men would reduce transmission or prevent acute infections or complications. Age is the strongest risk factor for men and women. A variety of tests can detect chlamydial infection with acceptable sensitivity and specificity, including new DNA amplification tests that use either endocervical swabs in women, urethral swabs in men, or first-void urine specimens from men and women.

Multicenter evaluation of the BDProbeTec ET System for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in urine specimens, female endocervical swabs, and male urethral swabs

The performance of the Becton Dickinson BDProbe Tec ET System Chlamydia trachomatis and Neisseria gonorrhoeae Amplified DNA Assays (BD Biosciences, Sparks, Md.) was evaluated in a multicenter study. Specimens were collected from 2,109 men and women, with or without symptoms, attending sexually transmitted disease, family planning, and obstetrics and gynecology clinics. Both swab and urine samples were collected, and the results obtained from 4,131 specimens were compared to those from culture and the LCx nucleic acid amplification test (Abbott Industries, Abbott Park, Ill.). PCR and cytospin of the culture transport medium with chlamydia direct fluorescent antibody staining were used to adjudicate chlamydia culture-negative results. Sensitivity and specificity were calculated both with and without use of the amplification control (AC), with little apparent difference in the results. Without the AC result, sensitivity for C. trachomatis and N. gonorrhoeae were 92.8 and 96.6%, respectively, for cervical swabs and 80.5 and 84.9% for urine from women. C. trachomatis and N. gonorrhoeae sensitivities were 92.5 and 98.5%, respectively, for male urethral swabs and 93.1 and 97.9% for urine from men. This amplified DNA system for simultaneous detection of chlamydial and gonococcal infections demonstrated superior sensitivity compared to chlamydia culture and has performance characteristics comparable to those of other commercially available nucleic acid-based assays for these organisms.

Is there a seasonal variation in gonorrhea and chlamydia in adolescents?

STUDY OBJECTIVE

To determine if a seasonal variation exists in gonorrhea and chlamydia in female adolescents. DESIGN, SETTING, PARTICIPASNTS: We conducted a retrospective chart review of 604 sexually active adolescent females 21 years of age and younger in a teen pregnancy prevention clinic in a small Midwestern city. Positive gonorrhea and chlamydia tests were evaluated for seasonal variation. Chi-square, odds ratios, and 95% confidence intervals were calculated.

RESULTS

A greater percentage of tests were positive in the fall than in other seasons (P = 0.028), and there was a trend towards more cases in the summer than winter and spring.

CONCLUSIONS

Increased emphasis should be placed on prevention and screening during summer and fall.

Incidence and prevalence of chlamydia, herpes, and viral hepatitis in a homeless adolescent population

BACKGROUND

High rates of unprotected intercourse and illegal drug use have been reported among homeless adolescents. As a transient population with the potential to act as disease vectors from one location to another, incidence and prevalence of sexually transmitted infections in this population are of particular concern.

GOAL

To assess a homeless adolescent population for incidence and prevalence of Chlamydia trachomatis, herpes simplex virus type 2, hepatitis B virus, hepatitis C virus, HIV, and psychosocial correlates of the acquisition of sexually transmitted infections.

STUDY DESIGN

Longitudinal with assessments at baseline, 3 months, and 6 months (n = 536; 319 males and 217 females).

RESULTS

Baseline prevalence of C trachomatis was 4.17% for males and 6.30% for females. Prevalence of herpes simplex virus type 2 was 5.73% for males and 12.50% for females. Hepatitis B virus and hepatitis C virus prevalences were 3.60% and 5.0%, respectively. HIV seroprevalence was 0.3%. The incidence of sexually transmitted infections was significantly higher among females than among males (16.7% versus 9.8%) and was associated with inconsistent condom use and, for females, number of partners and sex with older partners. Incident hepatitis B virus and hepatitis C virus infection rates were 3.44% and 6.61%, respectively; both were associated with injection drug use.

CONCLUSIONS

Among females, the incidence of herpes simplex virus type 2 (> 25%) and C trachomatis (12%) was relatively high. Inconsistent condom use was the primary factor associated with a significantly greater risk of incident sexually transmitted infections. This was especially true for females with multiple partners. Homeless adolescents also are at high risk for hepatitis B virus and hepatitis C virus infection, primarily associated with self-reported injection drug use.

Implementation of a screening program for chlamydial infection in incarcerated adolescents

BACKGROUND

In collaboration with the Houston Department of Health and Human Services, the authors implemented and evaluated a urine-based chlamydia screening program in incarcerated youth in Harris County, Texas, and assessed predictor variables for infection.

GOAL

To implement and evaluate chlamydia screening in incarcerated youth.

STUDY DESIGN

The authors determined prevalence of chlamydial infection, treatment rates, and predictor variables in 589 youth and repeated the measures 6 months later in 975 additional youth.

RESULTS

Initially, the prevalence of infection was 9.6% in males and 28.1% in females; 88% of infected youth were treated while incarcerated. White males had a significantly lower prevalence of chlamydial infection; however, consistent condom use was not associated with a lower prevalence of chlamydia. In the 6-month assessment of chlamydia prevalence in 975 youth, prevalence and treatment rates remained high and predictor variables were similar.

CONCLUSION

The authors instituted a screening program for chlamydial infection in incarcerated youth that was performing well at reassessment 6 months later.

Knowledge of genital Chlamydia trachomatis infection in family planning clinic attenders

The purpose of this study was to determine the level of awareness of genital Chlamydia infection and level of knowledge related to this infection in family planning (FP) clinic attenders. Clients attending FP clinics during a 3 month study period were invited to complete an anonymous self-administered questionnaire. Five hundred and sixteen questionnaires from female attenders were analysed. Results showed that 54% of respondents had heard of Chlamydia. Subjective knowledge assessment for Chlamydia was low compared to that for other infections. Mean knowledge scores relating to genital chlamydial infection were low. There was no significant age-related trend in knowledge scores. The implications of these findings are discussed in relation to increased Chlamydia screening activity in FP clinics.

Home sampling versus conventional swab sampling for screening of Chlamydia trachomatis in women: a cluster-randomized 1-year follow-up study

We compared the efficacy of a screening program for urogenital Chlamydia trachomatis infections based on home sampling with that of a screening program based on conventional swab sampling performed at a physician's office. Female subjects, comprising students at 17 high schools in the county of Aarhus, Denmark, were divided into a study group (tested by home sampling) and a control group (tested in a physician's office). We assessed the number of new infections and the number of subjects who reported being treated for pelvic inflammatory disease (PID) at 1 year of follow-up; 443 (51.1%) of 867 women in the intervention group and 487 (58.5%) of 833 women in the control group were available for follow-up. Thirteen (2.9%) and 32 (6.6%) new infections were identified in the intervention group and the control group, respectively (Wilcoxon exact value, P=.026). Nine (2.1%) women in the intervention group and 20 (4.2%) in the control group reported being treated for PID (P=.045), indicating that a screening strategy involving home sampling is associated with a lower prevalence of C. trachomatis and a lower proportion of reported cases of PID.

Participation in a school-based sexually transmitted disease screening program

BACKGROUND

A school-based chlamydia screening program was offered repeatedly in three Louisiana public high schools in an effort to expand sexually transmitted disease screening services for adolescents.

GOAL

To describe participation of a fixed cohort of students to elucidate the impact of screening on chlamydia prevalence.

STUDY DESIGN

Five opportunities for chlamydia testing were offered in 3 schools during 3 school years (1995-1996, 1996-1997, 1997-1998). Only students with parental consent could be tested. Students consistently enrolled during the 3 years (n = 1475) were included in this analysis.

RESULTS

During the 3 school years, parental consent was cumulatively obtained for 1443 students (97.8%), and 1305 students (88.5%) were tested at least once. Of those tested, 81.1% tested more than once. The prevalence of Chlamydia trachomatis infection at first test among students who tested more than once was 1.8% for males and 7.7% for females. Among students tested only once, 6.2% of males and 12.7% of females had chlamydial infection. Among students tested more than once, no significant difference in C. trachomatis prevalence was associated with repeat screenings. Incidence rates per 1000 person-months were 4.3 (2.2, males; 7.1, females; P < 0.0001). Reinfections explained only 5.6% of all incident cases.

CONCLUSION

The documented high response from both parents and students to this school-based chlamydia screening program offers great promise for sexually transmitted disease control among adolescents. Overall, C. trachomatis prevalence was two times higher among students testing only once than among those testing more than once. Routine and continued availability of school-based chlamydia screening programs can potentially reduce the burden of disease among adolescents.

Testing for Chlamydia and sexual history taking in adolescent females: results from a statewide survey of Colorado primary care providers

OBJECTIVES

Little is known about the practice patterns of primary care providers as they relate to assessing risk of and screening for chlamydial infections, an important cause of preventable reproductive morbidity in young women in the United States. The present cross-sectional study was undertaken to assess levels of chlamydia testing, sexual history taking, and prevention practices by Colorado primary care physicians, nurse practitioners, and physician assistants who provide gynecologic care to adolescent females (13-19 years old).

METHODS

Between July 1998 and October 1998, an anonymous, self-administered questionnaire was mailed to a 25% random sample (n = 1265) of Colorado physicians (family practitioners, internal medicine specialists, obstetrician-gynecologists, and pediatricians), nurse practitioners, and physician assistants. Practitioners were identified through professional organization membership, state-licensing bodies, and listings in the yellow pages.

RESULTS

After estimating the eligibility rate among non-respondents, the adjusted response rate was 71.5%. Only 53.8% of providers reported regularly testing sexually active female adolescents for chlamydia; 71.8% of providers regularly took a sexual history. Female providers reported significantly higher levels of regularly taking a sexual history (87. 2% vs 60.6% of males), feeling comfortable discussing sex (94.4% vs 77.8%), discussing sexually transmitted disease (STD) prevention (81. 5% vs 71.3%), and testing for chlamydia (64.4% vs 38.6%). Among provider types, obstetrician-gynecologists, nurse practitioners, and pediatricians were most likely to report regularly taking a sexual history (90.1%, 88.6%, and 76.0%, respectively). Internal medicine specialists were the least likely to report taking a sexual history (43.9%). Pediatricians and nurse practitioners were the most likely to report testing sexually active adolescent females for chlamydia (74.1% and 70.1%, respectively), whereas physician assistants and internal medicine specialists were the least likely (46.0% and 38.5%, respectively). In multivariate analysis, variables independently associated with regularly taking a sexual history included female provider gender (odds ratio [OR]: 5.5; 95% confidence interval [CI]: 2.9-10.9), obstetrics/gynecology specialty (OR: 4.0; 95% CI: 1.7-10. 3; referent group: family practitioners), and provider comfort level in discussing sex (OR: 4.9; 95% CI: 2.3-11.1). Variables independently associated with regularly testing adolescent females for chlamydia included female provider gender (OR: 2.8; 95% CI: 1. 6-4.8), regularly discussing STD prevention (OR: 2.1; 95% CI: 1.1-4. 1), and regularly discussing limiting the number of patients' sex partners (OR: 2.4; 95% CI: 1.4-4.1).

CONCLUSIONS

Only a little over one half of providers (54%) reported regularly performing chlamydia tests on adolescent females who are sexually active by history. Because this falls well short of the recommendations of the Centers for Disease Control and Prevention to test all sexually active female adolescents, efforts are needed to improve STD clinical practices of Colorado physician and nonphysician providers of primary care for adolescent females. Particular efforts are needed to close the provider gender gap.

Geomapping of chlamydia and gonorrhoea in Birmingham

OBJECTIVE

To investigate if the core population hypothesis is applicable to patients with genital chlamydia infections.

DESIGN

Retrospective cross sectional study.

SETTING

Two genitourinary medicine (GUM) clinics in the city of Birmingham and eight adjacent clinics.

SUBJECTS

All patients with chlamydia (n = 665) or gonorrhoea (n = 584) attending between 1 October 1995 and 30 September 1996 with a postcode within the Birmingham health district. Controls were 727 patients seen in the same period with no infection.

METHODS

Postcodes were used to calculate population prevalence rates per 100,000 aged 15-65 in the 39 wards of the city and to estimate the socioeconomic status using the Super Profile (SP). Ethnic specific rates were also calculated. Data were obtained on gonorrhoea and chlamydia isolation from all the major laboratories of the city over the same time period.

RESULTS

GUM clinic attenders accounted for 67.6% and 82.5% of all chlamydia and gonorrhoea isolates reported by the laboratories and that were available for our epidemiological analysis. Both infections were more common in men and in black ethnic groups. However, patients with gonorrhoea only infection were more likely to be of black ethnicity than those with chlamydia only infection (p = 0.0001) and to have different SP distribution (p = 0.0001). On logistic regression age < 20 years, male sex, black ethnicity, and living in neighbourhoods with SP J ("have nots") were predictive of both infections compared with controls. Overall chlamydia and gonorrhoea prevalence rates were 129 and 98.4 per 10(5) respectively. Corresponding rates for whites was 64.7 and 37.2 and for black ethnic groups 1105 and 1183 per 10(5) of each ethnic group. Eight adjacent wards accounted for 41% of the chlamydia and 66.5% of the gonorrhoea.

CONCLUSION

In a large urban setting patients attending GUM clinics with chlamydia belong to core population groups with similar, but not identical, sociodemographic characteristics to patients with gonorrhoea infection.

Pooling of urine specimens for detection of asymptomatic Chlamydia trachomatis infections by PCR in a low-prevalence population: cost-saving strategy for epidemiological studies and screening programs

Pooling, in groups of five, of urine specimens from asymptomatically infected men in a population with 4% prevalence, as determined by case finding, is 100% sensitive and specific and results in a 60.5% reduction in the number of tests needed. Pooling of urine specimens in groups of 10 for the estimation of population-based prevalence is 96.1% sensitive and 100% specific and saves 90% of the test costs.

Selective screening for chlamydial infection: which criteria to use?

BACKGROUND

Screening sexually active women for Chlamydia trachomatis is necessary to detect asymptomatic infections. Selective screening is a common strategy because universal screening is too costly in many settings. In order to guide local programs in the choice of selective screening criteria, we examined the performance of previously proposed screening criteria for C. trachomatis.

METHODS

A clinic-based, cross-sectional study was conducted in public family planning and sexually transmitted disease (STD) clinics in ten counties in North Carolina. Women (n = 4471 in family planning and n = 2201 in STD clinics) undergoing pelvic examination were enrolled consecutively. Nine sets of screening criteria, including age alone, were compared using sensitivity, specificity, number of tests required and receiver-operator characteristic (ROC) analysis. All women underwent testing with ligase chain reaction assay of cervical specimens to identify C trachomatis infection.

RESULTS

The prevalence of C. trachomatis was 7.8% and 11.0% in family planning and STD clinics, respectively. The sensitivities of published criteria ranged from 0.50 to 0.97. Specificities ranged from 0.05 to 0.66. In family planning clinics, the best performing criteria would detect 84% of infections while screening 51% of women. In STD clinics, the same criteria would detect 83% of infections but require testing 67% of women. Testing women aged < or =22 would detect 77% of infections in family planning and 74% of infections in STD clinics, while testing 51% and 48% of the women, respectively.

CONCLUSIONS

When site-specific criteria cannot be developed, age alone is an acceptable strategy for selective screening for chlamydial infection.

Repeated school-based screening for sexually transmitted diseases: a feasible strategy for reaching adolescents

OBJECTIVES

To determine whether repeated school-based screening and treatment for chlamydia and gonorrhea will decrease the prevalence of infection among students.

DESIGN

At three high schools serving over 2000 students, all 9th through 12th grade students were given the opportunity to be tested during three consecutive school years for chlamydia and gonorrhea, using urine ligase chain reaction tests. Five comparable schools with 5063 students enrolled served as wait-listed controls.

SETTING

Eight urban public high schools in Louisiana.

PARTICIPANTS

Annually, 52% to 65% of all enrolled students participated; among those enrolled in schools for > or = 2 years, 83.4% of students were tested at least once.

INTERVENTION

Education of all students; counseling and treatment of infected students with oral single-dose antibiotic therapy.

MAIN OUTCOME MEASURE

Prevalence of Chlamydia trachomatis and gonorrhea infection.

RESULTS

At first test, 286 (11.5%) of 2497 girls and 143 (6.2%) of 2308 boys were infected with chlamydia, and 48 (2.5%) of 1883 girls and 19 (1.2%) of 1628 boys had gonorrhea. Over 90% of infections were asymptomatic. With repeated testing, chlamydia prevalence among boys dropped to half the rate of comparison schools (3.2% vs 6.4%). Among girls chlamydia prevalence declined only slightly (10.3% vs 11. 9% in comparison schools).

CONCLUSION

There are high rates of asymptomatic sexually transmitted diseases (STDs) in the general urban school population. Repeated screening and treatment are associated with declines in chlamydia prevalence among boys. Expansion of STD screening and treatment programs to school settings is likely to be a critical component of a national strategy to control bacterial STDs.

High prevalence of genital Chlamydia trachomatis infection in women presenting in different clinical settings in Jamaica: implications for control strategies

OBJECTIVE

To determine the prevalence of genital Chlamydia trachomatis infection and risk factors in women attending family planning, gynaecology, and sexually transmitted disease (STD) clinics in Jamaica.

METHODS

Endocervical specimens from 645 women including 238 family planning, 170 gynaecology, and 237 STD clinic attendees were examined for C trachomatis using a direct fluorescence assay (DFA) and culture. Investigations were carried out for the presence of other STD pathogens and demographic, behavioural, historical, and clinical data recorded for each participant.

RESULTS

The prevalence of C trachomatis infection was 35%, 47%, and 55% in family planning, gynaecology, and STD clinic clients, respectively. The performance of the DFA was comparable to that of culture in screening for C trachomatis. Logistic regression analysis revealed that the independent risk factors for C trachomatis infection were non-barrier contraceptive methods in family planning clients (OR = 2.1; 95% confidence interval (CI) = 1.2-3.9; p = 0.0110), cervical ectopy in gynaecology clients (OR = 3.9; 95% CI = 1.4-10.6; p = 0.0076) and concomitant Trichomonas vaginalis infection in STD clients (OR = 3.5; 95% CI = 1.8-6.8; p = 0.003). Age, number of sex partners, and reason for visit were not identified as risk factors for C trachomatis infection.

CONCLUSIONS

Consistently high prevalence of C trachomatis infection occurs in Jamaican women. Universal screening or presumptive treatment should be evaluated as prevention and control measures for C trachomatis infection in this population where all women appear to be at risk.

Determination of Chlamydia trachomatis prevalence in an asymptomatic screening population: performances of the LCx and COBAS Amplicor tests with urine specimens

This study determined the performances of the LCx (Abbott) and COBAS Amplicor (Roche) tests with urine specimens for the detection of Chlamydia trachomatis in an asymptomatic screening population. Randomly selected women and men (age range, 15 to 40 years) registered in 20 general practices in Amsterdam, The Netherlands, were invited to participate in this study. Urine specimens (n = 2, 906; 1,138 specimens from men and 1,717 specimens from women) were tested for C. trachomatis by the COBAS Amplicor (Roche) and LCx (Abbott) tests. Samples which were positive by only one assay were subjected to discrepant analyses by a third assay (in-house plasmid PCR). By the LCx assay C. trachomatis DNA was detected in urine specimens from 46 of 1,717 women and 29 of 1,138 men, while the COBAS Amplicor detected C. trachomatis DNA in 52 and 35 specimens, respectively. When comparing the LCx and COBAS Amplicor tests, 32 test results (20 for women and 12 for men) were discrepant. After discrepant analyses the following sensitivities, specificities, and positive predictive values were found for the LCx and COBAS Amplicor tests: 78.6 versus 98.8%, 99.7 versus 99.9%, and 88.0 versus 95.4%, respectively. No prominent differences were found between men and women with regard to the test performances. After discrepant analyses the overall prevalences of C. trachomatis in women and men were 3.0 and 2.8%, respectively. For both women and men the prevalence in the younger age groups was higher than that in the older age groups. In conclusion, the COBAS Amplicor tests shows better diagnostic characteristics than the LCx assay for the detection of C. trachomatis in urine specimens from an asymptomatic screening population. In this asymptomatic population the overall prevalence of C. trachomatis was 2.9%.

Mailed, home-obtained urine specimens: a reliable screening approach for detecting asymptomatic Chlamydia trachomatis infections

The use of mailed, home-obtained urine specimens could facilitate screening programs for the detection of asymptomatic Chlamydia trachomatis infections. Since transport time could have an adverse effect on the sensitivity of C. trachomatis detection by PCR, the influence of DNA degradation on amplification was monitored over the course of 1 week. Therefore, urine specimens were aliquoted on the day of collection or arrival. Two groups of urine specimens were investigated. Group I contains first-void C. trachomatis-positive and -negative urine samples. DNA degradation was monitored in group I samples for 7 days at room temperature (RT) and at 4 degrees C by amplifying different lengths of the human beta-globin gene and the C. trachomatis plasmid target. DNA degradation was observed only for the larger human beta-globin fragments at days 5 to 7 at RT. In contrast, at 4 degrees C all targets could be amplified. Urine specimens were also frozen and thawed before aliquoting to mimic freezing during transport. This resulted in a lower sensitivity for the detection of C. trachomatis after thawing and 3 to 4 days at RT. In addition, mailed, home-obtained C. trachomatis-positive urine specimens (group II) were analyzed for 7 days after arrival by two commercially available C. trachomatis detection systems (PCR and ligase chain reaction [LCR]). The C. trachomatis plasmid target in mailed, home-obtained urine specimens could be amplified by both PCR and LCR after 1 week of storage and/or transport at RT. In conclusion, our findings indicate that mailed, home-obtained urine specimens are suitable for the sensitive detection of asymptomatic C. trachomatis infections by amplification methods, even if the transport time is up to 1 week at RT. These findings support the feasibility and validity of screening programs based on mailed, home-obtained urine specimens. Larger studies should be initiated to confirm our results.