Pharyngeal gonorrhea screening in adolescents: is it necessary?

A prospective study was performed to examine the prevalence of pharyngeal gonorrhea in two urban female adolescent populations and to compare pharyngeal infection with a history of orogenital activity and concurrent genital gonorrhea. Group I was drawn from a children's hospital adolescent clinic and group II was drawn from a public health clinic for sexually transmitted diseases. None of the 240 adolescents in group I had a pharyngeal culture positive for Neisseria gonorrhoeae compared with 3.4% in group II. Only 2.5% of group I had genital gonorrhea, but 33% of group II had positive genital cultures. In only two of the 20 patients with pharyngeal gonococcal infection was the pharynx the only infected site. The addition of routine pharyngeal culturing for gonorrhea yielded only 1% additional gonorrhea cases. There was a significant relationship between concurrent genital and pharyngeal gonorrhea. These findings indicate that routine screening for pharyngeal gonorrhea is not productive in some adolescent populations. A more economic approach would be to use gonorrhea treatment that is effective against both genital and pharyngeal gonorrhea or to obtain pharyngeal cultures in those adolescents returning for test-of-cure cultures after antibiotic treatment for genital gonorrhea.

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

PURPOSE: To evaluate current Chlamydia trachomatis screening guidelines, which recommend that all sexually active female adolescents undergoing a pelvic examination be tested for chlamydial infection, and determine if instead providers should target particular subpopulations of these adolescents. METHODS: Data were collected from 148,650 sexually active females, ages 15-19 years, tested by direct immunofluorescent antibody in 160 family planning clinics from 1988-92. Trends in chlamydia prevalence by demographic, behavioral, and clinical risk factors were analyzed. Logistic regression modeling was used to identify selective screening criteria. Predictive models were developed for all years combined, as well as for the years when prevalence was highest and lowest. RESULTS: The prevalence of C. trachomatis in this population was 10%, with a 42% decrease (13.2-7.6%) over the 5-year period. Logistic regression identified nine demographic, behavioral, and clinical predictors (p < 0.0001) associated with chlamydial infections. Predictor models from the highest and lowest prevalence years varied little from the combined model. Individual year predictor models showed poor sensitivity and were similar for these 2 years. The screening criteria could not identify a group of adolescents with a prevalence less than 6%. CONCLUSIONS: Several individual risk factors were strongly associated with C. trachomatis, but no single risk factor or combination of risk factors used for selective screening could identify more than 42% of infections in our population. These findings support earlier national recommendations and the need for universal screening of sexually active female adolescents.

Prevalence of metronidazole-resistant Trichomonas vaginalis in a gynecology clinic.

OBJECTIVE: To determine the prevalence of in vitro resistance to metronidazole among unselected isolates of Trichomonas vaginalis and correlate in vitro findings with response to metronidazole therapy. STUDY DESIGN: Vaginal fluid from women attending a gynecology clinic at an urban hospital was cultured, isolates were tested for in vitro resistance to metronidazole, and these results were correlated with therapeutic outcome. RESULTS: Among 911 women, T vaginalis was detected by culture in 82 (9.0%). Of the 82 isolates, 2 (2.4%; 95% CI, 0.3-8.5%) had low-level in vitro resistance (minimum lethal concentration, 50 micrograms/mL). Women with positive wet mount examinations were treated with metronidazole, 2 g, once and asked to return in one week. Of the 42 infected women agreeing to return for a repeat examination and culture, 26 (61.9%) did, and all (including one woman with a resistant isolate) were cured. CONCLUSION: Isolates of T vaginalis resistant to metronidazole occur widely throughout the United States. Although the in vitro susceptibility of T vaginalis to metronidazole has been very poorly studied, our study is consistent with a decade-old prevalence estimate of in vitro resistance (5%), and suggests that high-level resistance is uncommon. This study confirmed, in the absence of reinfection, the continuing clinical effectiveness of single-dose metronidazole for the large majority of trichomoniasis cases.

Chlamydia positivity versus prevalence. What's the difference?

BACKGROUND: Data on chlamydia screening collected as part of Regional Infertility Prevention Projects often do not include personal identifiers, therefore repeat tests for patients during a year cannot be identified. Consequently, positivity is calculated and used to monitor chlamydia prevalence. GOALS: To assess how well positivity can estimate prevalence in family planning and sexually transmitted disease (STD) clinic settings. STUDY DESIGN: Analyzed data from chlamydia screening programs in three geographic areas of the United States that used unique patient identifiers. RESULTS: The relationship between positivity and prevalence is related to both the percentage of tests that are repeat tests and the percentage of repeat tests that are positive. On average, the percentage of positive repeat tests was the same as or higher than prevalence in family planning clinics; thus, positivity was the same as or higher than prevalence. In STD clinics, the percentage of positive repeat tests was consistently lower than prevalence; thus, positivity underestimated prevalence. However, the absolute difference between positivity and prevalence was less than 0.5% in family planning and STD clinics. CONCLUSIONS: Positivity can be used to monitor chlamydia prevalence in women screened in family planning and STD clinic settings.

PIP: Data collected from US family planning (FP) and sexually transmitted disease (STD) programs that offer screening for chlamydia are used to monitor trends in chlamydia prevalence and identify high-risk groups. Because personal identifiers are often not collected and repeat tests for patients during the year cannot be identified, the proportion of total tests that are positive is used to estimate prevalence. To determine how well positivity estimates prevalence, data that used personal identifiers was analyzed from 16 states that are part of US Regional Infertility Prevention Projects in 3 geographic areas. In 1988-96, a total of 880,069 chlamydia tests were performed in FP clinics in the 3 regions; the percentage of women having a repeat test in a given year ranged from 2.7% to 11.9%. On average, the percentage of positive repeat tests was the same as or higher than the chlamydia prevalence in FP clinics. Over 26,000 tests for chlamydia infection were performed in STD clinics in 1 of these regions (VIII) in 1994-96; about 11% of women were tested more than once. In STD clinics, the percentage of positive repeat tests was much lower than chlamydia prevalence. Overall, however, the absolute difference between positivity and prevalence was less than 0.5% in both settings, confirming that positivity can be used to monitor chlamydia prevalence. As the positivity of initial and repeat tests diverges and the percentage of repeat tests increases, the difference between positivity and prevalence will widen.

Predictors of Chlamydia trachomatis infection among female adolescents: a longitudinal analysis.

Screening guidelines recommend testing all sexually active female adolescents for Chlamydia trachomatis during a pelvic examination at each clinic visit. Such criteria have been based on cross-sectional studies; new evaluations should take into account multiple clinic visits and assess whether criteria are appropriate when a prior test is negative and risk factors are absent. Because repeated observations on an individual may be correlated, the authors used the generalized estimating equation method. Little information exists on subsequent risk of infection; as control programs develop, approaches targeting high-risk populations for recurrent infections are needed. Using data on females aged 15-19 years who visited family planning clinics more than once from 1988 to 1992 (n = 26,921) in Region X (Alaska, Idaho, Oregon, and Washington), the authors constructed a retrospective cohort. Teens with chlamydia at their first visit were at high risk for subsequent infection (odds ratio = 1.6, 95% confidence interval 1.4-1.7). Among teens uninfected at the first visit and without risk factors at the second, prevalence at the second visit was 6%. When intervisit correlations using the generalized estimating equation method were taken into account, predictors of chlamydial infection were consistent with those in previous cross sectional studies cervicitis, friable cervix, and multiple, new, or symptomatic sex partner(s). These findings support screening sexually active female adolescents at each visit, even if prior tests results are available.

Prevalence of self-medication with antibiotics among patients attending a clinic for treatment of sexually transmitted diseases.

To ascertain the prevalence of self-medication with antimicrobial agents among patients attending a clinic for treatment of sexually transmitted diseases (STDs), we administered a questionnaire to and collected a urine specimen for antimicrobial testing from 551 patients before treatment. We defined self-medication as an antimicrobial agent taken on the patient's own initiative by self-report during the week before the visit to the clinic or a positive urine assay for antimicrobial agents at the time of the clinic visit. We tested urine for the presence of antimicrobial agents by a disk diffusion method using Sarcina lutea as the test organism. A total of 75 (14%) of the 551 participants were self-medicators: 19 reported antimicrobial use and had a positive urine test, 27 reported antimicrobial use but had a negative urine test, and 29 denied antimicrobial use but had a positive urine test. Thus, 29 (60%) of the 48 patients with antimicrobial agents detected in their urine at the time of the clinic visit denied self-medication. Self-medicators acquired their antibiotics either from their medicine cabinet (44%) or from a family member or friend (56%). Self-medication was associated with self-report of prior use of unprescribed antimicrobial agents (P < .0001). We concluded that use of unprescribed antimicrobial agents (usually beta-lactam agents or tetracyclines) among STD clinic attendees in our study was common and that self-reporting was not a reliable method of screening for self-medicators.

Trends in the prevalence of chlamydial infections. The impact of community-wide testing.

BACKGROUND: Evaluation of existing testing programs should guide the national effort to expand programs for the prevention of chlamydial infections. The Columbus (Ohio) Health Department instituted community-wide testing for Chlamydia trachomatis in 1988. GOALS: To assess trends in the prevalence of chlamydial infection, the coverage of screening, and concurrent trends in the prevalence of gonorrhea. STUDY DESIGN: This was a cross-sectional study of women 15 to 44 years of age tested for C. trachomatis at over 50 provider sites in Columbus, Ohio, from 1989 to 1992. RESULTS: The prevalence of chlamydial infection among all women tested decreased by 33% from 1989 to 1992. Prevalence decreased least (19%) among black women 15 to 19 years of age, the group with the highest initial prevalence (20.2%), even though 42% of this population in the city was tested. Prevalence did not decrease at all among prenatal patients 15 to 19 years of age. For women tested for both gonorrhea and chlamydia, gonorrhea decreased by 39% during the 4-year period. CONCLUSIONS: Screening appeared to have limited effect on the prevalence of chlamydial infection for groups with highest initial prevalence, despite the relatively high percentage of the population tested. Expanding screening programs to include men and instituting behavioral interventions may be necessary to reduce more rapidly the prevalence of chlamydia among these women.

Screening women for gonorrhea: demographic screening criteria for general clinical use.

OBJECTIVES: The purpose of this analysis was to derive potential gonorrhea screening criteria for women. METHODS: Data corresponding to 44,366 gonorrhea cultures from women 15 through 44 years of age in Columbus, Ohio, were analyzed. RESULTS: Characteristics that were associated with gonococcal infection and were suitable for screening decisions included patient's age and marital status and previous prevalence of gonorrhea at provider site. Probabilities of infection ranged from .001 for married women 25 through 44 years of age at low-prevalence provider sites to .078 for unmarried women 15 through 19 years of age at high-prevalence sites. CONCLUSIONS: Patient's age and marital status and prevalence of gonorrhea at provider site can be used as indicators to ensure testing of high-prevalence groups.

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.