Noninvasive detection of Chlamydia trachomatis urethritis in men by a rapid enzyme immunoassay test.

BACKGROUND. The purpose of this investigation was to evaluate the ability of a rapid enzyme immunoassay test to noninvasively detect Chlamydia trachomatis urethritis in men from a urine specimen. METHODS. Urethral samples and urine from 207 patients were evaluated. Urethral and urine sediment Gram stains, leukocyte esterase dipstick tests, and enzyme immunoassay analyses of centrifuged and uncentrifuged urine were compared with urethral C trachomatis culture. RESULTS. The prevalence of infection in this population was 10.3%. Sensitivity and specificity of the enzyme immunoassay on the centrifuged urine specimen were 70% and 96%, respectively. The positive and negative predictive values were 67% and 97%, respectively. The uncentrifuged urine enzyme immunoassay sensitivity was 35.7% and specificity was 98.9%. Leukocyte esterase test sensitivity compared with that of the Neisseria gonorrhoeae and/or C trachomatis cultures was 83.3%, and specificity was 52%. CONCLUSIONS. The rapid enzyme immunoassay clinically complemented the screening urine sediment Gram stain and the leukocyte esterase test. The judicious use of a noninvasive C trachomatis rapid enzyme immunoassay test to identify organism-specific urethritis may improve patient management of sexually transmitted disease.     

Urinary leukocyte esterase screening for asymptomatic sexually transmitted disease in adolescent males

The objective of this study was to evaluate the effectiveness of urinary leukocyte esterase on random urine specimens as a screening test for chlamydial and gonococcal urethral infections in asymptomatic males. Random urine specimens were obtained on 106 consecutive asymptomatic adolescent males during intake physical examination at a residential vocational training program. Results of urinary leukocyte esterase were compared to those of urethral cultures for Chlamydia trachomatis and Neisseria gonorrhoeae. Five subjects had positive chlamydia cultures, three subjects had positive gonococcal cultures, and one patient had positive cultures for both organisms. Sixteen subjects had leukocyte esterase tests reported as "trace" or greater. When compare to positive culture results for either Chlamydia or gonorrhea, urinary leukocyte esterase activity had a sensitivity of 78%, specificity of 91%, and positive predictive value of 44%. A random urine specimen for urinary leukocyte esterase activity is a cost-effective screening method for chlamydial and gonococcal urethral infections in asymptomatic adolescent males.     

Asymptomatic Chlamydia trachomatis infections in teenage males

This study examined the prevalence of Chlamydia trachomatis infections of the urethra in asymptomatic teenage males in a juvenile detention setting. Gonorrhea cultures, chlamydia smears using the direct immunofluorescent antibody (DFA) technique, and 15–20 ml of a first-catch urine (FCU) sample were obtained. Of the 227 adolescent males screened, 205 had experienced sexual intercourse. Twenty-seven (13.2%) of the sexually active adolescents had positive DFA smears for C. trachomatis. Three (1.5%) had positive Neisseria gonorrhoeae cultures. A urine leukocyte count of greater than 10 per high-power field gave a 91% specificity but only a 26% sensitivity for a positive DFA. The high prevalence of chlamydia in this population and the relative low cost of the DFA screen for chlamydia make this a useful procedure for discovering unsuspected disease, particularly in a high-risk population. The FCU screen for leukocytec was of limited value in identifying asymptomatic infection.     

First catch urine sediment for Chlamydia trachomatis and Neisseria gonorrhoeae culture in adolescent males with pyuria

Traditionally, only symptomatic males or those with a history of exposure are tested for sexually transmitted diseases (STDs). Since urethral infections with Chlamydia trachomatis and Neisseria gonorrhoeae are frequently asymptomatic, a practical, sensitive, and acceptable screening method is desirable. Fifty sexually active males with pyuria (age 13 to 22 years old) diagnosed with 1+ or 2+ leukocyte esterase (LE) dipstick on first catch urine (FCU) were further evaluated by culture of urethral swabs and centrifuged FCU samples for N. gonorrhoeae and C. trachomatis. Eighty-six percent had one or more positive cultures: 17 (34%) N. gonorrhoeae, 18 (36%) C. trachomatis, and 8 (16%) both organisms. FCU culture for N. gonorrhoeae had a 100% sensitivity, specificity, and positive and negative predictive value when compared to urethral swab cultures. FCU culture for C. trachomatis had a 32% sensitivity, 95% specificity, 89% positive predictive value, and a 53% negative predictive value compared to urethral culture. On the basis of the results of this study, one urethral swab can be eliminated when evaluating male adolescents for urethritis by using spun FCU culture for N. gonorrhoeae. Continued efforts should be made to develop optimal tests to detect STDs which are reliable and encourage compliance in this high-risk group.     

A solid-phase enzyme immunoassay in detection of cervical gonorrhea in a low-prevalence population

An evaluation of a solid-phase enzyme immunoassay (Gonozyme) for detection of gonococcal antigen in cervical swab specimens was undertaken in 504 asymptomatic women undergoing routine gynecologic examination. The immunoassay was positive in all seven women with culture-proven gonorrhea. Negative immunoassay results were obtained in 482 of the 497 women with negative cultures (97.0 percent specificity). The enzyme immunoassay's performance equals or exceeds that of other rapid alternative methods of diagnosing cervical gonorrhea such as Gram stain or limulus lysate assay. Its usefulness, however, is limited by less than 100 percent specificity, particularly in low-prevalence populations. More studies are needed to ascertain the performance of both this immunoassay and modified Thayer-Martin culture techniques in diagnosing cervical gonorrhea in low-prevalence populations.     

Screening for sexually transmitted infections among economically disadvantaged youth in a national job training program.

PURPOSE: To evaluate results of screening for syphilis, gonorrhea, and chlamydia among youth in a federally funded job training program. METHODS: Data were evaluated from medical records of 12,881 randomly selected students in 54 U.S. job training centers during 1996. The intake medical evaluation includes serologic testing for syphilis. The policy was for females to receive a pelvic examination with gonorrhea and chlamydia testing and for males to be first screened with a urine leukocyte esterase (LE) assay, with follow-up gonorrhea and chlamydia testing for those with positive LE results. RESULTS: Adjusting for our sampling strategy, among females, an estimated 9.2% had a positive chlamydia test, 2.7% a positive gonorrhea test, and 0.4% had a positive syphilis test. Gonorrhea and chlamydia rates among females were highest in African-American followed by Native American students. Chlamydia infection was most common in younger women < or = 17 years of age. An estimated 0.1% of males had a positive syphilis test, and 4.8% of males a positive urine LE test. Of 103 LE-positive males tested for gonorrhea and chlamydia, only 27 (26%) had a positive test for one of these STDs. CONCLUSIONS: Our study supports routine screening of adolescents for gonorrhea and chlamydia, including those youth from socioeconomically disadvantaged backgrounds. Because individuals from such backgrounds may not regularly interact with traditional clinical health care systems, screening and treatment should be offered in alternative settings, such as the job training program described in this study.     

Pilot study to assess the presence of Chlamydia trachomatis in urine from 18-30-year-old males using EIA/IF and PCR

CONTEXT: To increase detection, urine samples from young males could be opportunistically tested for Chlamydia trachomatis. OBJECTIVE: To determine C. trachomatis prevalence in urine, optimum specimen and compare sensitivity/feasibility of routine use of different testing methods. DESIGN: Group A, 'sterile' pyuria samples June 1998-January 1999, tested by enzyme immunoassay (EIA) and, if reactive, by immunofluorescence (IF). Subsequently batch-tested by polymerase chain reaction (PCR). Group B, consecutive urine samples October 1998-January 1999; batch-tested by PCR. SETTING: Microbiology laboratory. SAMPLES: From males aged 18-30 years; group A = 71, group B = 83. MAIN OUTCOME MEASURES: Chlamydia trachomatis positive if EIA- and IF- or PCR-positive. RESULTS: Group A: 12 EIA/IF-positive; 9/12 and 15 EIA-negative samples PCR-positive. Group B: 11 PCR-positive; 8/11 showed 'sterile' pyuria. CONCLUSIONS: Opportunistic testing of urine from young men shows a significant number of C. trachomatis infections. 'Sterile' pyuria samples are optimal. EIA/IF are less sensitive than PCR but can be routinely performed and detect a significant proportion of cases.     

Estimating the prevalence of multiple diseases from two‐stage hierarchical pooling

Testing protocols in large‐scale sexually transmitted disease screening applications often involve pooling biospecimens (e.g., blood, urine, and swabs) to lower costs and to increase the number of individuals who can be tested. With the recent development of assays that detect multiple diseases, it is now common to test biospecimen pools for multiple infections simultaneously. Recent work has developed an expectation–maximization algorithm to estimate the prevalence of two infections using a two‐stage, Dorfman‐type testing algorithm motivated by current screening practices for chlamydia and gonorrhea in the USA. In this article, we have the same goal but instead take a more flexible Bayesian approach. Doing so allows us to incorporate information about assay uncertainty during the testing process, which involves testing both pools and individuals, and also to update information as individuals are tested. Overall, our approach provides reliable inference for disease probabilities and accurately estimates assay sensitivity and specificity even when little or no information is provided in the prior distributions. We illustrate the performance of our estimation methods using simulation and by applying them to chlamydia and gonorrhea data collected in Nebraska. Copyright © 2016 John Wiley & Sons, Ltd.     

Diagnosing gonorrhea: A comparison of standard and rapid techniques

A timely and accurate technique for diagnosing gonorrhea is necessary if prompt therapy is to be instituted. We screened 567 adolescents who presented for routine gynecologic care or for specific gynecologic or urologic problems. Each patient was tested by standard culture, Gonozyme (Abbott Labs), and Gram's stain. One hundred five patients (18.5%) had an ELISA immunoassay or culture evidence of infection. Overall sensitivity was 90% for Gonozyme and 56% for Gram's stain (females 41%, males 94%). Overall specificity was 97% for Gonozyme and 99% for Gram's stain. No increase in sensitivity of either test was found in women with signs of upper genital tract involvement. The predictive value of a negative Gonozyme was 98% and 85% for a positive result compared to Gram's stain values of 99% and 95%, respectively. Overall clinical efficacy was 96% for Gonozyme and 93% for Gram's stain. Gonozyme, although a sensitive and specific test, has a limited role in the diagnosis of gonorrhea. Gram's stain, although more limited in women, may serve as a useful adjunct in diagnosing gonorrhea.     

Impact of switching laboratory tests on reported trends in Chlamydia trachomatis infections

Improvements in the sensitivity and specificity of laboratory testing methods for Chlamydia trachomatis infections in recent years have created potential problems with interpreting data on chlamydia prevalence trends. A switch to a more sensitive test can result in an increase in chlamydia positivity even with no increase in the true disease prevalence. To examine the impact of switching laboratory testing methods on chlamydia positivity trends among women, the authors analyzed data from chlamydia screening programs in family planning clinics in two geographic areas of the United States. Data from 7,287 tests performed in Philadelphia, Pennsylvania, indicated a 46% increase in positivity (from 4.1% to 6.0%) when the clinics switched from a nucleic acid probe assay to a ligase chain reaction test. Data from 35,306 tests performed in Oregon and Washington State laboratories showed a 21% increase in positivity (from 3.3% to 4.0%) when clinics switched from a direct immunofluorescent antibody testing procedure to an enzyme immunoassay with negative gray zone confirmation. These increases were within ranges consistent with the variability of the testing methods and occurred primarily in asymptomatic women and in women over age 20 years. Any switch in laboratory testing methods must be considered when interpreting data on chlamydial infection trends.     

STI phase and the geography of sexual partnerships: prevalence of long-distance sexual contacts among chlamydia, gonorrhea, and coinfected STI cases in Manitoba, Canada

We utilized public health data and a geographic information system (ArcGIS) to study long-distance sexual partnerships (opposite and same sex partnerships) among chlamydia, gonorrhea, and coinfected STI (sexually transmitted infection) cases. The top 10% of relationships among chlamydia and gonorrhea cases and their contacts equaled or exceeded 198 km and 237 km respectively; the top 15% of partnerships among coinfected cases equaled or exceeded 207 km. This research also detected proportionately more long-distance partnerships among gonorrhea cases than among chlamydia cases. Wasserheit and Aral's four-phase model for understanding the impact of control programs on STI incidence over time offers one framework for interpreting these results: as chlamydia was in an early decline phase during the period under study, while gonorrhea had reached a phase of low endemicity, our results could suggest that in later phases of an STI control program, the overall proportion of long-distance relationships among cases and contacts may increase.     

Epidemiologic differences between chlamydia and gonorrhea.

To assess the prevalence, demographics, and transmission patterns of genital chlamydia infection, we screened 3,078 patients, and compared identified cases (N = 511) to gonorrhea cases (N = 291) diagnosed in the same setting. Chlamydia cases were younger and more likely to be White than their gonorrhea counterparts. Chlamydia cases were distributed diffusely; geographic overlap between the two diseases was only about 40 percent. Gonococcal coinfection was noted in less than 10 percent of patients with chlamydia. Nearly half of men with chlamydia and four-fifths of women were asymptomatic and most cases were identified through screening or contact tracing. Populations at high risk for chlamydia are seemingly different from those for gonorrhea. Differences may be due to control interventions (active for gonorrhea, passive for chlamydia). Chlamydia case reporting and control initiatives are recommended.     

Gonorrhea and chlamydia screening in sexually active young women: the processes of change.

A pilot study conducted with young women in an urban clinic examined a Transtheoretical Model processes of change measure to better understand strategies and behavioral mechanics that facilitate seeking gonorrhea and chlamydia screening. This information may be useful in developing interventions to improve sexually transmitted infection (STI) screening. Consistent with other studies, greater use of experiential and behavioral processes was associated with the action/maintenance stages for seeking gonorrhea and chlamydia screening.     

A community–based approach to the control of sexually transmitted diseases in the Northern Territory

Abstract: A program to control sexually transmitted diseases (STDs) was undertaken during a Men's Health Week in a remote Aboriginal community in Western Arnhem Land, Northern Territory. A total of 151 men aged 13 years and over who attended over a five–day period underwent a full physical examination, and first–void urine specimens were tested for the presence of leukocytes, chlamydia (by enzyme immunoassay antigen detection) and gonorrhoea (by culture and antigen detection). Blood was taken for syphilis serology from all patients and for human immunodeficiency virus (HIV) from patients with a proven STD or at the patient's request. Consent for testing was obtained from all participants. Patients with a positive urinary leukocyte test or symptoms were offered urethral swab investigations and treated empirically according to a set protocol. Patients with STDs detected by subsequent laboratory investigations were followed up and treated. The overall prevalence of one or more of syphilis, gonorrhoea or chlamydia was 17.4 per cent. No men presented with genitourinary symptoms and none was HIV–infected. In this population, STDs were an important cause of morbidity, and a community–based approach was adopted to identify infected persons. The use of urine for the detection of gonorrhoea and chlamydia was highly acceptable. Although not used in this study, polymerase chain reaction and ligase chain reaction technology will facilitate similar activities in the future. ( Aust N Z J Public Health 1997; 21: 519–23)     

Performance of urine leukocyte esterase in asymptomatic male youth: Another look with nucleic acid amplification testing as the gold standard for Chlamydia detection

PurposeTo re-evaluate the sensitivity and specificity of leukocyte esterase (LE) for screening adolescent and young adult males for Chlamydia trachomatis using a nucleic acid amplification test (NAAT) as the gold standard.MethodsThis study was conducted at two Massachusetts Department of Youth Services sites and one Job Corps site. Recently admitted asymptomatic sexually active male youth aged 14 to 25 years (mean 16.6 years) were recruited between January 2001 and July 2003 (N = 1008). Participants provided first part voided urine specimens for testing with LE and Chlamydia NAAT. The sensitivity, specificity, and positive and negative predictive value of urine LE for identification of Chlamydia infection were determined using NAAT as the gold standard.ResultsFifty-seven (5.7%) participants were infected with Chlamydia as defined by a positive NAAT. Defining trace + as the LE cut point resulted in sensitivity and specificity of 57.9% and 78.3%, respectively. Defining 1+ as the cut point resulted in sensitivity and specificity of 47.4% and 96.1%, respectively.ConclusionsUrine leukocyte esterase is a moderately sensitive method to screen for Chlamydia. Nevertheless, a substantial proportion of infections are not detected with LE screening. When feasible, urine NAAT provides a much more sensitive and equally noninvasive method of detecting Chlamydia. However, if LE is used as an initial screen followed by NAAT confirmation of LE positive samples, we recommend using trace LE as the cut point for positive results.     

Application of the case-crossover design to reduce unmeasured confounding in studies of condom effectiveness

This analysis examined how unmeasured confounding affects estimates of the effectiveness of condoms in preventing sexually transmitted infections. Data were analyzed from a prospective cohort study of 1,122 female sexually transmitted disease clinic patients in Alabama (1992-1995), wherein participants were evaluated for sexually transmitted infections at six 1-month intervals. Associations between condom use and incident gonorrhea and chlamydia infection were compared between case-crossover and cohort analyses. In a case-crossover analysis of 228 follow-up visits ending in gonorrhea/chlamydia ("case intervals") and 743 self-matched follow-up visits not ending in gonorrhea/chlamydia ("noncase intervals") (183 women), consistent condom use without breakage or slippage was associated with significantly reduced risk of infection relative to nonuse (adjusted risk odds ratio = 0.49, 95% confidence interval: 0.26, 0.92). Conversely, a cohort analysis of 245 case intervals and 3,896 noncase intervals (919 women) revealed no significant reduction in infection risk from consistent use of condoms (adjusted risk odds ratio = 0.79, 95% confidence interval: 0.53, 1.17). Dose-response relations between the number of unprotected sex acts and infection were stronger in the case-crossover analysis (p for trend = 0.009) than in the cohort analysis (p for trend = 0.18). These findings suggest that epidemiologic studies confounded by unmeasured differences between condom users and nonusers underestimate condom effectiveness against these infections. The case-crossover method provides an additional technique for reducing unmeasured confounding in studies of condom effectiveness.     

Condom effectiveness for reducing transmission of gonorrhea and chlamydia: the importance of assessing partner infection status

This analysis examined the importance of differential exposure to infected partners in epidemiologic studies of latex condom effectiveness for prevention of sexually transmitted infections. Cross-sectional, enrollment visit data were analyzed from Project RESPECT, a trial of counseling interventions conducted at five publicly funded US sexually transmitted disease clinics between 1993 and 1997. The association between consistent condom use in the previous 3 months and prevalent gonorrhea and chlamydia (Gc/Ct) was compared between participants known to have infected partners and participants whose partner infection status was unknown. Among 429 participants with known Gc/Ct exposure, consistent condom use was associated with a significant reduction in prevalent gonorrhea and chlamydia (30% vs. 43%; adjusted prevalence odds ratio = 0.42, 95% confidence interval: 0.18, 0.99). Among 4,314 participants with unknown Gc/Ct exposure, consistent condom use was associated with a lower reduction in prevalent gonorrhea and chlamydia (24% vs. 25%; adjusted prevalence odds ratio = 0.82, 95% confidence interval: 0.66, 1.01). The number of unprotected sex acts was significantly associated with infection when exposure was known (p for trend < 0.01) but not when exposure was unknown (p for trend = 0.73). Restricting analyses to participants with known exposure to infected partners provides a feasible and efficient mechanism for reducing confounding from differential exposure to infected partners in condom effectiveness studies.     

Prevalence and Predictors of Sexually Transmitted Infections in Hazardously-Drinking Incarcerated Women

Incarcerated women are at high risk for sexually transmitted infections. Left untreated, these infections can have severe adverse health effects. In this study the authors present prevalence rates of trichomonas, chlamydia, and gonorrhea, and factors related to having a sexually transmitted infection in a sample of 245 hazardously-drinking incarcerated women who reported heterosexual intercourse in the previous 3 months. Vaginal swabs were collected following the self-report baseline assessment. Participants averaged 34.0 (±8.8) years of age; 174 (71.3%) were non-Hispanic Caucasian, 47 (19.3%) were African-American, 17 (7.0%) were Hispanic, and 6 (2.5%) were of other racial or ethnic origins. Twenty-three percent of participants tested positive for chlamydia, trichomonas, or gonorrhea. Being African-American, more frequent sex with a casual partner, and reporting more than one male partner were significantly positively related to sexually transmitted infection, while more frequent sex with a main partner was inversely related. Due to the high rates of infection in this population, jail admission provides a public health opportunity to access a concentrated group of sexually transmitted infectious women. Sexually transmitted infection testing targeted at specific demographic factors, for instance younger age, will miss infected women. Risky sexual partnerships, as well as the benefit of maintaining stable main partnerships may be important topics during sexually transmitted infection prevention interventions.     

Prevalence and predictors of sexually transmitted infections in hazardously-drinking incarcerated women

Incarcerated women are at high risk for sexually transmitted infections. Left untreated, these infections can have severe adverse health effects. In this study the authors present prevalence rates of trichomonas, chlamydia, and gonorrhea, and factors related to having a sexually transmitted infection in a sample of 245 hazardously-drinking incarcerated women who reported heterosexual intercourse in the previous 3 months. Vaginal swabs were collected following the self-report baseline assessment. Participants averaged 34.0 (±8.8) years of age; 174 (71.3%) were non-Hispanic Caucasian, 47 (19.3%) were African-American, 17 (7.0%) were Hispanic, and 6 (2.5%) were of other racial or ethnic origins. Twenty-three percent of participants tested positive for chlamydia, trichomonas, or gonorrhea. Being African-American, more frequent sex with a casual partner, and reporting more than one male partner were significantly positively related to sexually transmitted infection, while more frequent sex with a main partner was inversely related. Due to the high rates of infection in this population, jail admission provides a public health opportunity to access a concentrated group of sexually transmitted infectious women. Sexually transmitted infection testing targeted at specific demographic factors, for instance younger age, will miss infected women. Risky sexual partnerships, as well as the benefit of maintaining stable main partnerships may be important topics during sexually transmitted infection prevention interventions.     

Racial/ethnic and sexual behavior disparities in rates of sexually transmitted infections, San Francisco, 1999-2008

Background  

Racial/ethnic minorities and men who have sex with men (MSM) represent populations with disparate sexually transmitted infection (STI) rates. While race-specific STI rates have been widely reported, STI rates among MSM is often challenging given the absence of MSM population estimates. We evaluated the race-specific rates of chlamydia and gonorrhea among MSM and non-MSM in San Francisco between 1999-2008.