Sexual behaviour in Britain: reported sexually transmitted infections and prevalent genital Chlamydia trachomatis infection

BACKGROUND

Studies of the epidemiology of sexually transmitted infections (STI) are largely based on surveillance data. As part of a national survey of sexual attitudes and lifestyles (Natsal 2000) in Britain, we estimated the frequency of self-reported STIs, and the prevalence of urinary Chlamydia trachomatis infection.

METHODS

We did a stratified probability sample survey of 11161 men and women aged 16-44 years in Britain. Computer assisted self-interviews contained items on the nature and timing of previously diagnosed STIs. Half of all sexually experienced respondents aged 18-44 years were invited to provide a urine sample for ligase chain reaction testing for C trachomatis infection.

FINDINGS

10.8% of men and 12.6% of women reported ever having an STI, 3.6% of men and 4.1% of women reported ever being diagnosed with genital warts, and 1.4% of men and 3.1% of women reported previous infection with C trachomatis. 76% of men and 57% of women ever diagnosed with an STI had been to a GUM clinic. C trachomatis was found in 2.2% (95% CI 1.5-3.2) of men and 1.5% (95% CI 1.11-2.14) of women with age-specific prevalence being highest among men aged 25-34 (3.1%) and women aged 16-24 years (3.0%). Non-married status, age, and reporting partner concurrency or two or more sexual partners in the past year were independently associated with infection with C trachomatis.

INTERPRETATION

We show substantial heterogeneity in distribution of reported STIs, and the demographic and behavioural determinants of prevalent genital chlamydial infection. The results have potentially wide application for proposed chlamydia screening programmes which, given the demonstrated prevalence, must now proactively seek to involve men.

Patient-delivered partner treatment with azithromycin to prevent repeated Chlamydia trachomatis infection among women: a randomized, controlled trial

BACKGROUND

Repeated infection with C trachomatis increases the risk for serious sequelae: pelvic inflammatory disease, ectopic pregnancy, infertility, and chronic pelvic pain. A substantial proportion of women treated for C trachomatis infection are reinfected by an untreated male sex partner in the first several months after treatment. Effective strategies to ensure partner treatment are needed.

GOAL

The goal of the study was to determine whether repeated infections with C trachomatis can be reduced by giving women doses of azithromycin to deliver to male sex partners.

STUDY DESIGN

A multicenter randomized controlled trial was conducted among 1,787 women aged 14 to 34 years with uncomplicated C trachomatis genital infection diagnosed at family planning, adolescent, sexually transmitted disease, and primary care clinics or emergency or other hospital departments in five US cities. Women treated for infection were randomized to one of two groups: patient-delivered partner treatment (in which they were given a dose of azithromycin to deliver to each sex partner) or self-referral (in which they were asked to refer their sex partners for treatment). The main outcome measure was C trachomatis DNA detected by urine ligase chain reaction (LCR) or polymerase chain reaction (PCR) by 4 months after treatment.

RESULTS

The characteristics of study participants enrolled in each arm were similar except for a small difference in the age distribution. Risk of reinfection was 20% lower among women in the patient-delivered partner treatment arm (87/728; 12%) than among those in the self-referral arm (106/726; 15%); however, this difference was not statistically significant (odds ratio, 0.80; 95% confidence interval, 0.62-1.05; = 0.102). Women in the patient-delivered partner treatment arm reported high compliance with the intervention (82%).

CONCLUSION

Patient-delivered partner treatment for prevention of repeated infection among women is comparable to self-referral and may be an appropriate option for some patients.

Systematic review: noninvasive testing for Chlamydia trachomatis and Neisseria gonorrhoeae

BACKGROUND

Testing of urine samples is noninvasive and could overcome several barriers to screening for chlamydial and gonococcal infections, but most test samples are obtained directly from the cervix or urethra.

PURPOSE

To systematically review studies that assessed the sensitivity and specificity of nucleic acid amplification tests for Chlamydia trachomatis and Neisseria gonorrhoeae in urine specimens and to compare test characteristics according to type of assay, site of sample collection, presence of symptoms, disease prevalence, and characteristics of the reference standard.

DATA SOURCES

Relevant studies in all languages were identified by searching the MEDLINE database (January 1991 to December 2004) and by hand-searching the references of identified articles and relevant journals.

STUDY SELECTION

Studies were selected that evaluated 1 of 3 commercially available nucleic acid amplification tests, included data from tests of both a urine sample and a traditional sample (obtained from the cervix or urethra), and used an appropriate reference standard.

DATA EXTRACTION

From 29 eligible studies, 2 investigators independently abstracted data on sample characteristics, reference standard, sensitivity, and specificity.

DATA SYNTHESIS

Articles were assessed qualitatively and quantitatively. Summary estimates for men and women were calculated separately for chlamydial and gonococcal infections and were stratified by assay and presence of symptoms. The pooled study specificities of each of the 3 assays exceeded 97% when urine samples were tested, for both chlamydial infection and gonorrhea and in both men and women. The pooled study sensitivities for the polymerase chain reaction, transcription-mediated amplification, and strand displacement amplification assays, respectively, were 83.3%, 92.5%, and 79.9% for chlamydial infections in women; 84.0%, 87.7%, and 93.1% for chlamydial infections in men; and 55.6%, 91.3%, and 84.9% for gonococcal infections in women. The pooled specificity of polymerase chain reaction to gonococcal infections in men was 90.4%. In subgroup analyses, the sensitivity did not vary according to the prevalence of infection or the presence of symptoms but did vary according to the reference standard used.

LIMITATIONS

Few published studies present data on the transcription-mediated amplification or strand displacement amplification assays, and few studies report data from asymptomatic patients or low-prevalence groups.

CONCLUSIONS

Results of nucleic acid amplification tests for C. trachomatis on urine samples are nearly identical to those obtained on samples collected directly from the cervix or urethra. Although all 3 assays can also be used to test for N. gonorrhoeae, the sensitivity of the polymerase chain reaction assay in women is too low to recommend its routine use to test for gonorrhea in urine specimens.

Untreated gonococcal and chlamydial infection in a probability sample of adults

CONTEXT

The prevalence and distribution of gonococcal and chlamydial infections in the general population are poorly understood. Development of nucleic acid amplification tests, such as the ligase chain reaction assay, provides new opportunities to estimate the prevalence of untreated infections in the population.

OBJECTIVE

To estimate the overall prevalence of untreated gonococcal and chlamydial infections and to describe patterns of infection within specific demographic subgroups of the young adult population in Baltimore, Md.

DESIGN AND SETTING

Cross-sectional behavioral survey based on a probability sample of Baltimore households with collection of urine specimens between January 1997 and September 1998.

PARTICIPANTS

A total of 728 adults aged 18 to 35 years completed the interview portion of the study, and 579 of these respondents also provided a urine specimen adequate for testing.

MAIN OUTCOME MEASURE

Prevalence of untreated infection, as measured by the percentage of specimens testing positive for gonococcal and chlamydial infection by ligase chain reaction, weighted to reflect variations in probabilities of sample selection from the population. Alternate estimates of the prevalence of recent treated infection were derived from clinically diagnosed cases reported to the Baltimore City Health Department and by diagnoses reported by participants in the survey.

RESULTS

An estimated 5.3% (SE, 1.4%) of the population aged 18 to 35 years has an untreated gonococcal infection, and 3.0% (SE, 0.8%) is estimated to have an untreated chlamydial infection. While 7.9% (SE, 1.6%) of the population is estimated to have either an untreated gonococcal or chlamydial infection, estimated prevalence is substantially higher among black women (15.0%; SE, 3.7%). Few participants with untreated infections reported dysuria or discharge during the 6 months preceding testing. The estimated number of untreated gonococcal infections in the population (9241; SE, 2441) substantially exceeds both the number of such infections diagnosed among Baltimore adults aged 18 to 35 years and reported to the Baltimore City Health Department during 1998 (4566), and the estimated number of diagnoses derived using participants' reports for the 12 months prior to the survey (4708 [SE, 1918] to 5231 [SE, 2092]). The estimated number of untreated chlamydial infections (5231; SE, 1395) is also greater than the number of cases reported to the health department in 1998 (3664) but is slightly less than the estimated number of diagnoses derived using participants' reports of chlamydial infections diagnosed during the 12 months prior to the survey (5580 [SE, 1918] to 6975 [SE, 2441]).

CONCLUSION

In 1997-1998, the estimated number of undiagnosed gonococcal and chlamydial infections prevalent in the population of Baltimore adults aged 18 to 35 years approached or exceeded the number of infections that were diagnosed and treated annually.

Urine specimens from pregnant and nonpregnant women inhibitory to amplification of Chlamydia trachomatis nucleic acid by PCR, ligase chain reaction, and transcription-mediated amplification: identification of urinary substances associated with inhibition and removal of inhibitory activity

The presence of endogenous amplification inhibitors in urine may produce false-negative results for the detection of Chlamydia trachomatis nucleic acids by tests such as PCR, ligase chain reaction (LCR), and transcription-mediated amplification (TMA). Consecutive urine specimens from 101 pregnant women and 287 nonpregnant women submitted for urinalysis were processed for C. trachomatis detection. Aliquots were spiked with the equivalent of one C. trachomatis elementary body and were tested by three commercial assays: AMPLICOR CT/NG, Chlamydia LCX, and Chlamydia TMA. The prevalence of inhibitors resulting in complete inhibition of amplification was 4.9% for PCR, 2.6% for LCR, and 7.5% for TMA. In addition, all three assays were partially inhibited by additional urine specimens. Only PCR was more often inhibited by urine from pregnant women than by urine from nonpregnant women (9.9 versus 3.1%; P = 0.011). A complete urinalysis including dipstick and a microscopic examination was performed. Logistic regression analysis revealed that the following substances were associated with amplification inhibition: beta-human chorionic gonadotropin (odds ratio [OR], 3.3) and crystals (OR, 3.3) for PCR, nitrites for LCR (OR, 14.4), and hemoglobin (OR, 3.3), nitrites (OR, 3.3), and crystals (OR, 3.3) for TMA. Aliquots of each inhibitory urine specimen were stored at 4 and -70 degreesC overnight or were extracted with phenol-chloroform and then retested at dilutions of 1:1, 1:4, and 1:10. Most inhibition was removed by storage overnight at 4 or -70 degreesC and a dilution of 1:10 (84% for PCR, 100% for LCR, and 92% for TMA). Five urine specimens (three for PCR and two for TMA) required phenol-chloroform extraction to remove inhibitors. The results indicate that the prevalence of nucleic acid amplification inhibitors in female urine is different for each technology, that this prevalence may be predicted by the presence of urinary factors, and that storage and dilution remove most of the inhibitors.

Multicenter evaluation of the AMPLICOR and automated COBAS AMPLICOR CT/NG tests for detection of Chlamydia trachomatis

The fully automated COBAS AMPLICOR CT/NG and semiautomated AMPLICOR CT/NG tests were evaluated in a multicenter trial for the ability to detect Chlamydia trachomatis infections. Test performance compared to that of culture was evaluated for 2,236 matched endocervical swab and urine specimens obtained from women and for 1,940 matched urethral swab and urine specimens obtained from men. Culture-negative, PCR-positive specimens that tested positive in a direct fluorescent-antibody test or in a confirmatory PCR test for an alternative target sequence were resolved as true positives. The overall prevalences of chlamydia were 2.4% in women and 7.2% in men. The COBAS AMPLICOR and AMPLICOR formats yielded concordant results for 98.1% of the specimens. With the infected patient as the reference standard, the resolved sensitivities of COBAS AMPLICOR were 89.7% for endocervical swab specimens, 89.2% for female urine specimens, 88.6% for male urethral swab specimens, and 90.3% for male urine specimens. When results were analyzed as if only a single test had been performed on a single specimen type, the resolved sensitivity was always higher. The resolved specificities of PCR were 99.4% for endocervical swab specimens, 99.0% for female urine specimens, 98.7% for male urethral swab specimens, and 98.4% for male urine specimens. The internal control revealed that 2.4% of the specimens were inhibitory when initially tested. Nevertheless, valid results were obtained for 98.6% of the specimens because 59.1% of the inhibitory specimens were not inhibitory when a second aliquot was tested. The COBAS AMPLICOR and AMPLICOR CT/NG tests for C. trachomatis exhibited equally high sensitivity and specificity with both urogenital swab and urine specimens and thus are well suited for screening for C. trachomatis infection.

Piezoelectric immunosensors for urine specimens of Chlamydia trachomatis employing quartz crystal microbalance microgravimetric analyses

The assembly of a biosensor for Chlamydia trachomatis based on the microgravimetric quartz crystal microbalance (QCM) analysis of the bacteria association to an antibody-functionalized electrode is described. The sensing interfaces consist of a primary cystamine monolayer assembled onto Au electrodes associated with the quartz crystal. The monolayer is further modified with sulfosuccinylimidyl 4-(p-maleimidophenyl)butyrate (sulfo-SMPB) and the goat IgG-anti-mouse IgG Fc-specific Ab or the fragmented F(ab')2 anti-mouse IgG Ab that act as sublayers for the association of the sensor-active anti-C. trachomatis LPS-Ab. Bacteria in the concentration range from 260 ng.mL-1 to 7.8 micrograms.mL-1 are sensed by the functionalized crystals. The association of C. trachomatis to the sensing interface can be confirmed and amplified via interaction of the crystal with various anti-C. trachomatis antibodies. Urine-pretreated functionalized quartz crystals are applied in the analysis of C. trachomatis in urine samples. The sensitivity limits of the electrodes for sensing the bacteria in urine samples corresponds to approximately 260 ng.mL-1. The functionalized crystals assembled via association of anti-C. trachomatis LPS-Ab to the fragmented F(ab')2 anti-mouse IgG Ab reveal long-term stability upon storage at 4 degrees C.

Effect of a clinical practice improvement intervention on Chlamydial screening among adolescent girls

CONTEXT

Chlamydia trachomatis infection is a serious public health concern that disproportionately affects adolescent girls. Although annual C trachomatis screening of sexually active adolescent girls is recommended by health professional organizations and is a Health Employer Data and Information Set (HEDIS) performance measure, this goal is not being met.

OBJECTIVE

To test the effectiveness of a system-level, clinical practice improvement intervention designed to increase C trachomatis screening by using urine-based tests for sexually active adolescent girls identified during their routine checkups at a pediatric clinic.

DESIGN, SETTING, AND PARTICIPANTS

A randomized cluster of 10 pediatric clinics in the Kaiser Permanente of Northern California health maintenance organization, where adolescent girls aged 14 to 18 years had a total of 7920 routine checkup visits from April 2000 through March 2002.

INTERVENTION

Five clinics were randomly assigned to provide usual care and 5 to provide the intervention, which required that leadership be engaged by showing the gap between best practice and current practice; a team be assembled to champion the project; barriers be identified and solutions developed through monthly meetings; and progress be monitored with site-specific screening proportions.

MAIN OUTCOME MEASURE

Chlamydia trachomatis screening rate for sexually active 14- to 18-year-old girls during routine checkups at each participating clinic.

RESULTS

The population of adolescents was ethnically diverse with an average age of 15.4 years. Twenty-four percent of girls in the experimental clinics and 23% in the control clinics were sexually active. Of the 1017 patients eligible for screening in the intervention clinic, 478 (47%) were screened; of 1194 eligible for screening in the control clinic, 203 (17%) were screened. At baseline, the proportion screened was 0.05 (95% confidence interval [CI], 0.00-0.17) in the intervention and 0.14 (95% CI, 0.01-0.26) in the control clinics. By months 16 to 18, screening rates were 0.65 (95% CI, 0.53-0.77) in the intervention and 0.21 (95% CI, 0.09-0.33) in the control clinics (time period by study group interaction, F(6,60) = 5.33; P<.001). The average infection rate for the experimental clinics was 5.8% (23 positive test results out of 393 total urine tests and a total of 3986 clinic visits) vs 7.6% in controls (12 positive test results out of 157 tests and 3934 clinic visits).

CONCLUSIONS

Implementation of this clinical practice intervention in a large health maintenance organization system is feasible, and it significantly increased the C trachomatis screening rates for sexually active adolescent girls during routine checkups.

Diagnosis of Chlamydia trachomatis urethritis in men by polymerase chain reaction assay of first-catch urine

To determine the accuracy of a recently developed polymerase chain reaction (PCR) urine assay to detect Chlamydia trachomatis urethral infection in men, we obtained urethral swabs and first-catch urine from 365 men attending a sexually transmitted diseases clinic. Thirty-three (9%) of the 365 men were infected with C. trachomatis as defined by urethral culture. Thirty-two of the 33 men with culture-positive urethral swabs also had PCR-positive urine assays. Of 332 patients with culture-negative urethral swabs, 325 had PCR-negative urine. Compared with chlamydia culture of urethral specimens, PCR assay of urine samples thus had a sensitivity of 97% and a specificity of 98%. The positive predictive value of the urine PCR assay was 82%, and the negative predictive value was 99%. Analysis of discrepant results indicated that six of seven PCR-positive, urethral culture-negative patients probably had chlamydial urethritis. All six patients had symptoms of urethritis and had either a positive urethral swab PCR or a positive urine PCR with a different amplification target. After resolution of discrepant results, (defining true positives as the 33 culture-positive patients and the 6 PCR-positive, culture-negative patients just described), the sensitivity and specificity of culture were 85% (33 of 39) and 100% (326 of 326), respectively. The revised sensitivity and specificity of PCR were 97% (38 of 39) and 99.7% (325 of 326), respectively. We conclude that this urine PCR assay provides a highly sensitive, noninvasive alternative method for the detection of C. trachomatis urethral infection in high-risk men attending a sexually transmitted diseases clinic. This assay could greatly facilitate the testing of larger numbers of male patients for chlamydial infection and should be studied in other settings.

Noninvasive tests for diagnosis of Chlamydia trachomatis infection: application of ligase chain reaction to first-catch urine specimens of women

Ligase chain reaction (LCR) to diagnose Chlamydia trachomatis infection was evaluated using first-catch urine (FCU) specimens from 4053 women. Results were compared with those of cell culture (TC) isolation from cervix (all) and urethra (2812 women). The reference standard was TC positivity or positive LCR for chlamydial plasmid DNA confirmed by direct fluorescent antibody test or LCR for another chlamydial gene. Compared with cervical culture, LCR was 88.2% sensitive and 100% specific. Adding urethral culture increased TC sensitivity from 67.1% to 74% and reduced LCR sensitivity to 85.9%. The prevalence of chlamydial infection was 5% (142/2812) by the dual culture system and 5.9% (165/2812) by LCR on FCU specimens. LCR on FCU specimens is highly sensitive and specific for diagnosing chlamydial infection. It is more sensitive than TC and may well present public health authorities with a useful noninvasive screening test for chlamydial infection in asymptomatic women.

A school-based Chlamydia control program using DNA amplification technology

OBJECTIVES

Chlamydia trachomatis is the most prevalent bacterial sexually transmitted disease (STD) in the United States, with the highest rates reported among adolescents. Chlamydia has severe consequences including pelvic inflammatory disease and infertility, and is believed to be a cofactor in human immunodeficiency virus transmission. Given that chlamydia is predominantly asymptomatic, most cases are identified through routine screening in health care settings. Over time, screening and treatment appear to be associated with a decrease in the prevalence of disease in areas with consistent chlamydia control programs. The new availability of sensitive and specific urine tests for chlamydia (polymerase chain reaction [PCR] and ligase chain reaction [LCR]) provides the opportunity to screen large numbers of at-risk youth in a noninvasive manner. We used PCR/LCR testing to investigate the feasibility of a school-based chlamydia control program and to determine the prevalence of chlamydia infection among junior and senior high school students.

DESIGN

At three junior/senior high schools, all students, regardless of symptoms or sexual history, were given the opportunity to be tested for chlamydia using urine-based PCR or LCR testing. Only students with parental consent were eligible. Parents could not obtain test results, except if their children told them. During the five 3-week testing periods, throughout the day, classes were escorted to the testing area and each student was individually counseled regarding the opportunity to participate in the testing.

SETTING

Three urban public schools in Louisiana.

PARTICIPANTS

A total of 1933 students in grades 7 through 12, including 861 girls and 1072 boys.

INTERVENTION

All students were informed about the test and taught about chlamydia during the homeroom period. Students were asked to provide a first-void urine specimen of not more than 30 mL. Specimens were refrigerated and delivered to the laboratory on the same day. Infected students were counseled and offered treatment with azithromycin, 1 g orally. They were also referred for or offered additional STD and human immunodeficiency virus testing. Infected students were asked to refer their sex partners to the city STD clinic for treatment.

MAIN OUTCOME MEASURE

Prevalence of C trachomatis infection by grade and gender.

RESULTS

Parental consent was obtained for 2849 (86.9%) of the 3278 matriculated students in grades 7 through 12. Fifty-one parents (1.6%) returned consent forms refusing permission for their child to participate in this screening and treatment program. The remaining 378 (11.5%) could not be reached by mail or telephone. Among all students with consent, 1933 (67.8% of those consented and 59.0% of those matriculated) were tested. Girls were less likely to be tested than boys (861/1363 [63. 2%] vs 1072/1465 [73.2%]). The overall prevalence of C trachomatis was 6.5%, with rates among girls more than twice that of boys (9.7% vs 4.0%). Generally, rates of infection increased with age. The prevalence rates among boys were for 7th grade, 2/208 (1%); 8th grade, 2/196 (2%); 9th grade, 10/236 (4.2%); 10th grade, 12/185 (6. 5%); 11th grade, 8/146 (5.5%); and 12th grade, 9/101 (8.9%). For boys 15 to 19 year old, the prevalence of chlamydia was 5.7%. Among girls, the prevalence rates were 7th grade, 0/105 (0%); 8th grade, 11/166 (6.6%); 9th grade, 23/218 (10.6%); 10th grade 23/146 (15.8%); 11th grade, 13/118 (11%); and 12th grade, 13/107 (12.1%). Among girls 15 to 19 years old, 12.7% were infected. Of 126 infected students, treatment was provided to 111 (88%). For this project, the laboratory cost of LCR testing was $17.76 per test. Without considering clinical staff time to collect the specimens, the average laboratory cost per infected student identified was $272. For students 15 to 19 years of age, of whom 104 (8.9%) of 1170 were infected, the laboratory cost was $200 per case identified.

CONCLUSION

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Diagnosis of Legionella pneumophila, Mycoplasma pneumoniae, or Chlamydia pneumoniae lower respiratory infection using the polymerase chain reaction on a single throat swab specimen

Diagnosis of Mycoplasma pneumoniae and Chlamydia pneumoniae lower respiratory infections using DNA amplification by polymerase chain reaction (PCR) on throat swab specimens has been reported. In this study we determined the sensitivity of the detection of Legionella pneumophila in simulated throat swab specimens by PCR. Next, we compared the sensitivity and specificity of a single throat swab PCR with the current tests for diagnosis of Legionella spp., M. pneumoniae, and C. pneumoniae in patients with lower respiratory tract infections. Patients' work-up included: (a) throat swab specimen for Legionella spp., M. pneumoniae, and C. pneumoniae PCR; (b) throat swab specimen for C. pneumoniae culture; (c) sputum specimen for L. pneumophila direct fluorescent antibody and culture; (d) urine specimen for L. pneumophila serogroup 1 antigen detection; and (e) serum specimen for L. pneumophila, M. pneumoniae, and C. pneumoniae acute and convalescent antibody titers. A total of 155 patients with lower respiratory infection were enrolled in this prospective study. Throat swab PCR was positive for Legionella spp. in five of the six patients with legionellosis, indicating the presence of this organism in the oropharynx of patients with Legionnaires disease. Mycoplasma pneumoniae PCR was positive in eight of the nine patients with mycoplasma infection. Chlamydia pneumoniae PCR was positive in the two patients with C. pneumoniae infection. None of the other 138 patients with negative PCR had other positive confirmatory tests for respiratory infection by these three organisms (100% specificity). PCR was able to detect 15 of the 17 infected (88.2%). Results of this investigation indicate that PCR on a single throat swab specimen is a rapid, sensitive, and specific test that may greatly simplify the diagnosis of lower respiratory infection caused by Legionella spp., Mycoplasma pneumoniae, or C. pneumoniae.

Chlamydia trachomatis load at matched anatomic sites: implications for screening strategies

Urethral and endocervical swabs and self-collected vaginal swabs (SCVSs) and urine specimens are all used as samples for diagnosis of urogenital infection with Chlamydia trachomatis. We have now determined chlamydial organism load in matched specimens from different anatomic sites and examined its relation to clinical signs and symptoms in men and women. Organism load was measured with assays based on the ligase chain reaction or real-time PCR analysis. The mean organism loads in 58 infected men were 1,200 and 821 elementary bodies (EBs) per 100 microl of sample for first-void urine (FVU) and urethral swabs, respectively (P>0.05). Organism load in FVU samples or urethral swabs was positively associated with symptoms (P<0.01) and clinical signs (P<0.01) in men. The mean organism loads in 73 infected women were 2,231, 773, 162, and 47 EBs/100 microl for endocervical swabs, SCVSs, urethral swabs, and FVU samples, respectively (P<0.001 for each comparison). Only the presence of multiple symptoms or clinical signs was associated with organism load in women. These results show that FVU is a suitable noninvasive sample type for men, given the fact that its chlamydial load did not differ significantly from that of urethral swabs. Given their higher organism load compared with FVU, SCVSs are the preferred noninvasive sample type for women.

Molecular amplification assays to detect chlamydial infections in urine specimens from high school female students and to monitor the persistence of chlamydial DNA after therapy

Polymerase chain reaction (PCR) and ligase chain reaction (LCR) were compared for the diagnosis of Chlamydia trachomatis infections by testing urine specimens from 408 high school female students. After therapy, sequential urine specimens were tested to determine persistence of chlamydial DNA in urine. Baseline PCR of cervical specimens was positive in 53 (13.0%) students, and PCR and LCR of urine specimens were positive in 63 (15.4%) and 60 (14.7%), respectively. After discrepant analysis, 64 (15.7%) patients could be confirmed as truly infected. Follow-up urine specimens from 33 infected patients demonstrated that at 1-3 days after therapy, PCR and LCR were positive for 40% and 73.3%, respectively. Only at 15 days after therapy did all specimens test negative. Urine tests for Chlamydia organisms should not be used as a test of cure within 3 weeks after treatment. Use of urine assays for screening sexually active adolescents has the potential to significantly improve control of chlamydial infections.

Prevalence and Correlates of Trichomonas vaginalis Infection Among Men and Women in the United States

Background

The epidemiology of Trichomonas vaginalis (TV) infection in the United States is poorly defined.

Methods

Males and females aged 18-59 years who participated in the 2013-2014 National Health and Nutrition Examination Survey and provided a urine specimen were tested for TV infection (n = 4057). Participants were also examined for Chlamydia trachomatis (CT) infection, genital human papillomavirus (HPV) infection, and herpes simplex virus type 2 serostatus. Weighted adjusted prevalence ratios (aPRs) were estimated by multivariable Poisson regression.

Results

TV infection prevalence was 0.5% and 1.8% among males and females, respectively. TV infection prevalence was 4.2% among black males, 8.9% among black females, and 0.03% and 0.8%, respectively, among males and females of other races/ethnicities. TV infection prevalence (aPR [95% confidence interval]) was positively associated with female sex (6.1 [3.3-11.3]), black race (vs other races/ethnicities; 7.9 [3.9-16.1]), older age (vs 18-24 years; 3.0 [1.2-7.1] for 25- to 39-year-olds and 3.5 [1.3-9.4] for 40- to 59-year-olds), having less than a high school education (vs completing high school or more; 2.0 [1.0-4.1]), being below the poverty level (vs at or above the poverty level; 4.0 [2.1-7.7]), and having ≥2 sexual partners in the past year (vs 0-1 sexual partners; 3.6 [2.0-6.6]). There were no TV and CT coinfections. Genital HPV detection was not independently associated with TV infection. Among persons aged 18-39 years, there was a significant racial disparity in all sexually transmitted infections examined, and this disparity was greatest for TV infection.

Conclusions

There is a high and disproportionate burden of urinary TV infection in the adult civilian, noninstitutionalized black population in the United States that warrants intervention.

Comparison of three commercially available amplification assays, AMP CT, LCx, and COBAS AMPLICOR, for detection of Chlamydia trachomatis in first-void urine

We compared the Gen-Probe transcription-mediated amplification assay (AMP CT), the Abbott LCx assay, and the Roche COBAS AMPLICOR assay for the detection of Chlamydia trachomatis in a mixed population in urine samples. First-void urine, urethral specimens, and cervical specimens in females were obtained from 1,000 patients (544 males and 456 females) visiting the outpatient sexually transmitted disease clinic of our hospital. The prevalence of C. trachomatis infection was 7.7% as determined by tissue culture of urethral and cervical specimens. The sensitivities of LCx, COBAS AMPLICOR, and AMP CT compared to cell culture were 79, 86, and 78%, respectively. Sensitivity and specificity were recalculated by using a new "gold standard", i.e., a sample was considered to be true positive if two or more techniques yielded positive results. Specimens positive only by cell culture or positive in only one commercial amplification technique were retested by a previously described in-house PCR. After discordance analysis the sensitivities of LCx, COBAS AMPLICOR, and AMP CT were 84, 93, and 85%, respectively. Specificity exceeded 99% for all three assays. With each method the sensitivity was lower for urine samples from females compared to urine samples from males. By application of this new gold standard, existing differences between methods are highlighted; future evaluations of new techniques should be validated against two or more amplification assays.

Opportunistic screening for genital chlamydial infection. I: acceptability of urine testing in primary and secondary healthcare settings

OBJECTIVES

To determine the acceptability of opportunistic screening for Chlamydia trachomatis in young people in a range of healthcare settings.

DESIGN

An opportunistic screening programme (1 September 1999 to 31 August 2000) using urine samples tested by ligase chain reaction (LCR). Data on uptake and testing were collected and in-depth interviews were used for programme evaluation.

SETTING

General practice, family planning, genitourinary medicine clinics, adolescent sexual health clinics, termination of pregnancy clinics, and women's services in hospitals (antenatal, colposcopy, gynaecology and infertility clinics) in two health authorities (Wirral and Portsmouth and South East Hampshire). Main participants: Sexually active women aged between 16 and 24 years attending healthcare settings for any reason.

MAIN OUTCOME MEASURES

Uptake data: proportion of women accepting a test by area, healthcare setting, and age; overall population coverage achieved in 1 year. Evaluation data: participants' attitudes and views towards opportunistic screening and urine testing.

RESULTS

Acceptance of testing by women (16-24 years) was 76% in Portsmouth and 84% in Wirral. Acceptance was lower in younger women (Portsmouth only) and varied by healthcare setting within each site. 50% of the target female population were screened in Portsmouth and 39% in Wirral. Both the opportunistic offer of screening and the method of screening were universally acceptable. Major factors influencing a decision to accept screening were the non-invasive nature of testing and treatment, desire to protect future fertility, and the experimental nature of the screening programme.

CONCLUSIONS

An opportunistic model of urine screening for chlamydial infection is a practical, universally acceptable method of screening.

Pooling urine samples for ligase chain reaction screening for genital Chlamydia trachomatis infection in asymptomatic women

The accuracy of pooling urine samples for the detection of genital Chlamydia trachomatis infection by ligase chain reaction (LCR) was examined. A model was also developed to determine the number of samples to be pooled for optimal cost savings at various population prevalences. Estimated costs included technician time, laboratory consumables, and assay costs of testing pooled samples and retesting individual specimens from presumptive positive pools. Estimation of population prevalence based on the pooled LCR results was also applied. After individual urine specimens were processed, 568 specimens were pooled by 4 into 142 pools and another 520 specimens were pooled by 10 into 52 pools. For comparison, all 1,088 urine specimens were tested individually. The sample-to-cut-off ratio was lowered from 1.0 to 0.2 for pooled samples, after a pilot study which tested 148 samples pooled by 4 was conducted. The pooling algorithm was 100% (48 of 48) sensitive when samples were pooled by 4 and 98.4% (61 of 62) sensitive when samples were pooled by 10. Although 2.0% (2 of 99) of the negative pools of 4 and 7.1% (1 of 14) of the negative pools of 10 tested presumptive positive, all samples in these presumptive-positive pools were negative when retested individually, making the pooling algorithm 100% specific. In a population with 8% genital C. trachomatis prevalence, pooling by four would reduce costs by 39%. The model demonstrated that with a lower prevalence of 2%, pooling eight samples would reduce costs by 59%. Pooling urine samples for detection of C. trachomatis by LCR is sensitive, specific, and cost saving compared to testing individual samples.

Urine-based screening of adolescents in detention to guide treatment for gonococcal and chlamydial infections. Translating research into intervention

OBJECTIVES

To determine the utility of urine-based ligase chain reaction assays for Neisseria gonorrhoeae and Chlamydia trachomatis in (1) the acceptability of such testing to adolescent detainees, (2) the potential use of these tests for identifying asymptomatic infections, and (3) the effectiveness of this approach for ensuring treatment of infected adolescents.

DESIGN

Cross-sectional screening and verification of treatment for infected cases.

SUBJECTS

Adolescents admitted to a short-term juvenile detention center.

MAIN OUTCOME MEASURES

Neisseria gonorrhoeae and C trachomatis infection rates, and timing and location of treatment for infected patients.

RESULTS

Refusal rate was 1.5%. Of 263 participants, 46 (17.5%) were female subjects. Chlamydia trachomatis infections were identified in 28.3% of the female and 8.8% of the male subjects. Neisseria gonorrhoeae infections were present in 13.1% of the female and 2.8% of the male subjects. Overall, 37 participants (14%) were positive for N gonorrhoeae, C trachomatis, or both, only one of whom had symptoms. Almost 70% (25/36) of asymptomatic infected subjects were treated within 28 days of screening. A treatment was documented in 36 of the 37 infected youth, including 20 who were followed up and treated after release from the detention center, by 6 months after testing.

CONCLUSION

Urine ligase chain reaction tests were effective for identifying and guiding treatment of unsuspected N gonorrhoeae and C trachomatis infections in teenagers admitted to a short-term detention center where traditional swab specimens may be difficult to obtain.

Evaluation of nucleic acid amplification tests as reference tests for Chlamydia trachomatis infections in asymptomatic men

Urine ligase chain reaction (LCR) and PCR tests and urethral swab culture were compared for their abilities to detect Chlamydia trachomatis infection in 3,639 asymptomatic men by using one-, two-, and three-test reference standards. Frozen urine at four of five participating centers was also tested by a transcription-mediated amplification assay which was used as a reference test. LCR increased the yield of positive results by 27% and PCR increased the yield of positive results by 26% over the yield of positive results by culture (n = 295). LCR and PCR sensitivities were similar, ranging from 80.4 to 93.5%, depending on the reference standard. Culture sensitivity was substantially less. A multiple-test standard yielded LCR, PCR, and culture specificities of 99.6%, with or without discrepant analysis. Test performance varied among centers partly due to different interpretations of the testing protocols. The study confirms that urine LCR and PCR for the detection of C. trachomatis have substantially improved sensitivities over that of urethral swab culture for testing of asymptomatic men, enabling screening of this important target group. These tests, perhaps in combination, are also candidate reference tests for the conduct of test evaluation studies.

The role of chlamydiae in genitourinary disease

The incidence of chlamydial organisms in early morning urine specimens obtained from 53 men and 50 women without evidence of urinary tract pathology was 2 per cent in both groups. Early morning urine specimens and/or prostatic fluid or semen was examined in 50 patients with chronic prostatitis and 39 (56 per cent) yielded this organism. Of 31 patients with epididymo-orchitis the early morning urine specimens yielded chlamydiae in 12 (39 per cent) and in those with the acute form of disease the incidence was 56 per cent. The chlamydia recovery rate was 27 per cent in 119 women with cystourethritis. Within these groups of patients approximately 50 per cent of sexual partners had urine cultures positive for chlamydia. The importance of reinfection and the need for careful treatment of patients and consort should be stressed. An appropriate transport medium is necessary for specimen collection and adequate culture facilities are required to achieve effective chlamydial recovery. Trimethoprim-sulfamethoxazole and tetracycline were used effectively in the study for primary and secondary drug therapy.

Cost-effectiveness of five strategies for gonorrhea and chlamydia control among female and male emergency department patients

BACKGROUND

Previous studies have shown screening for gonorrhea and chlamydia to be cost-effective for limiting the sequelae of infection and the associated costs of management.

GOAL

To evaluate the cost-effectiveness of enhanced screening for gonorrhea and chlamydia in an emergency department (ED) setting.

STUDY DESIGN

Five strategies were compared with use of decision analysis for theoretical cohorts of 10,000 female and 10,000 male ED patients aged 18 years to 31 years: standard ED practice, three enhanced screening strategies, and mass treatment. Main outcome measures were untreated gonorrhea or chlamydia cases and their sequelae, transmission to a partner, congenital outcomes, and cost to prevent a case. This analysis, from the perspective of the healthcare sector, included medical case costs expressed in US dollars (1999), discounted at an annual rate of 3%.

RESULTS

Mass treatment was the most cost-effective strategy among women and men. Of the screening strategies for women, universal screening combined with standard practice was the most cost-effective; it was used for treating 499 more cases of gonorrhea and chlamydia than was standard practice, saving $95.70 per case treated. Standard ED practice remained the most cost-effective strategy for men under a variety of circumstances.

CONCLUSION

The authors recommend urine ligase chain reaction screening for gonorrhea and chlamydia in women aged 18 years to 31 years in the ED, in conjunction with standard ED practice, to decrease the occurrence of the sequelae and costs associated with infection.

Correlating Chlamydia trachomatis infectious load with urogenital ecological success and disease pathogenesis

The association of infectious burden of Chlamydia trachomatis with patient characteristics and clinical disease may have implications for understanding disease pathogenesis. We examined chlamydial load from 171 urine samples where load was based on copy number of organisms per copy number of eukaryotic cells derived by real-time quantitative PCR. High- (E, F, G) and low-prevalence (Ia, H, J, Ja) genotypes in the population had similar loads, suggesting a similar propensity for replicating in vivo, despite their differential ecological success. Symptomatic and asymptomatic patients also had similar chlamydial loads, indicating that virulence differences are likely not associated with variations in replication. There was a significant difference in genotypes by age for F (<31 years; P = 0.031) and for H where the mean age was lower than for the most prevalent genotype, E (P=0.013). Also, men had a significantly lower load than women when the genotype was F (P=0.042), although there was no significant difference in load between partners. Patients with recurrent chlamydial infections had a significant reduction in load with each subsequent episode regardless of genotype (P=0.007), suggesting that immune defenses do not block chlamydial entry but may impact replication. Additionally, the probability of being infected with J was 7.7-fold higher in patients with prior chlamydial infections (P=0.016), and although the loads were lower when compared with patients without prior infection, the results did not reach statistical significance. These findings suggest that chlamydial burden could be an important marker for recurrence and host immune response, which would facilitate pathogenesis research.

Comparison of performances of two commercially available tests, a PCR assay and a ligase chain reaction test, in detection of urogenital Chlamydia trachomatis infection

The diagnostic performance of a PCR test (Roche Cobas Amplicor CT/NG Test) and that of a ligase chain reaction (LCR) test (Abbott LCx Chlamydia trachomatis assay) were compared by using endocervical and urethral swab specimen culture as a reference test. First-void urine (FVU) and endocervical and urethral swab specimens were collected from 1,015 unselected patients attending a sexually transmitted disease clinic and a clinic for adolescents in Helsinki, Finland. Chlamydia trachomatis was cultured from samples from the endocervix or urethra. PCR was performed with fresh and frozen urine and the culture transport medium. LCR was performed with fresh and frozen urine and LCx swab transport medium. Diagnostic consistency and diagnostic accuracy were statistically tested. The test results were identical for 984 patients (97%). Discrepant results were observed for 31 patients. Overall, LCR and PCR showed excellent kappa coefficients of consistency for both swab and FVU specimens (0.93 and 0.95, respectively). Sixty-one patients (6%) were culture positive. Testing of FVU by LCR or PCR increased the overall positivity rates to 7.0 and 7.7%, respectively. While PCR of FVU detected the greatest number of C. trachomatis infections (sensitivity, 96.1%), for some PCR-positive FVU specimens the results could not be confirmed (specificity, 99.6%). PCR and LCR were more sensitive than culture (sensitivities, 92 and 93% versus 79% for culture) in the diagnosis of genital C. trachomatis infection. In conclusion, both tests can be recommended for use in the clinical laboratory and for the screening of asymptomatic C. trachomatis infections.

Screening women in jails for chlamydial and gonococcal infection using urine tests: feasibility, acceptability, prevalence, and treatment rates

BACKGROUND

Women entering jails are at high risk for sexually transmitted diseases; however, screening for chlamydial and gonococcal infection is not routinely performed in most jails. New urine tests have made it easier to screen for these infections in nonclinical settings.

GOAL

The feasibility and acceptability of urine-based screening for women entering jails and the prevalence of and treatment rates for chlamydial and gonococcal infections were determined.

STUDY DESIGN

Women entering jails in Chicago, Illinois; Birmingham, Alabama; and Baltimore, Maryland, who signed consent forms were tested for chlamydial and gonococcal infection by means of the urine ligase chain reaction assay. Those testing positive were treated in jail; health department staff members attempted to contact those already released.

RESULTS

Most women who were approached agreed to be tested (range, 87-98%, depending on city), and most of these women provided a specimen (range, 92-100%). Among 5364 women aged 16 to 75 years who were tested, the prevalence of chlamydial and gonococcal infections was high, especially among those <25 years of age (range, 15.3-21.5% for chlamydial infection and 8.2-9.2% for gonorrhea, depending on city). The majority of women testing positive were treated in jail or outside of jail (61-85%).

CONCLUSIONS

Screening women in jails for chlamydial and gonococcal infection with urine tests is feasible, is acceptable to most women, and leads to detection and treatment of many infections. Routine screening should reduce medical complications in this population and should prevent transmission in the community, given that many women are soon released.