Survey of sexually transmitted disease laboratory methods in US Army laboratories

Longitudinal association of gonorrhea and bacterial vaginosis with repeat chlamydia diagnoses among U.S. Army women: a retrospective cohort analysis

BACKGROUND

Historically, sexually transmitted infections have affected the health of the U.S. military. To determine whether gonorrhea, bacterial vaginosis, genital herpes, and trichomoniasis are predictors of repeat chlamydia diagnoses among U.S. Army women, medical data reported into the Defense Medical Surveillance System during the 2006-2012 period were analyzed.

METHODS

For all inpatient and outpatient medical records, the first and second International Classification of Diseases, version 9 (ICD-9) diagnostic positions were reviewed for each chlamydia case to determine the occurrence of repeat diagnoses. The Andersen-Gill regression model, an extension of the Cox model for multiple failure-time data, was used to study associations between predictors and repeat chlamydia diagnoses.

RESULTS

Among 28,201 women with a first chlamydia diagnosis, 5145 (18.2%), 1163 (4.1%), 267 (0.9%), and 88 (0.3%) had one, two, three, and four or more repeat diagnoses, respectively. Overall, the incidence of repeat chlamydia was 8.31 cases per 100 person-years, with a median follow-up time of 3.39 years. Gonorrhea (hazard ratio (HR) = 1.58, 95% CI: 1.44-1.73) and bacterial vaginosis (HR = 1.40, 95% CI: 1.09-1.79) were significant predictors for repeat chlamydia. These estimated hazard ratios were attenuated, but remained significant, after controlling for age, race/ethnicity, marital status, and military rank. No significant association was found for genital herpes (HR = 1.13, 95% CI: 0.55-2.29) and trichomoniasis (HR = 1.43, 95% CI: 0.43-4.68).

CONCLUSIONS

This large cohort study suggests that gonorrhea and bacterial vaginosis were associated with repeat chlamydia diagnoses among U.S. Army women. These findings can be used in formulating new interventions to prevent repeat chlamydia diagnoses.

Accurate detection of Neisseria gonorrhoeae ciprofloxacin susceptibility directly from genital and extragenital clinical samples: towards genotype-guided antimicrobial therapy

INTRODUCTION

Increasing use of nucleic acid amplification tests (NAATs) as the primary means of diagnosing gonococcal infection has resulted in diminished availability of Neisseria gonorrhoeae antimicrobial susceptibility data. We conducted a prospective diagnostic assessment of a real-time PCR assay (NGSNP) enabling direct detection of gonococcal ciprofloxacin susceptibility from a range of clinical sample types.

METHODS

NGSNP, designed to discriminate an SNP associated with ciprofloxacin resistance within the N. gonorrhoeae genome, was validated using a characterized panel of geographically diverse isolates (n = 90) and evaluated to predict ciprofloxacin susceptibility directly on N. gonorrhoeae-positive NAAT lysates derived from genital (n = 174) and non-genital (n = 116) samples (n = 290), from 222 culture-confirmed clinical episodes of gonococcal infection.

RESULTS

NGSNP correctly genotyped all phenotypically susceptible (n = 49) and resistant (n = 41) panel isolates. Ciprofloxacin-resistant N. gonorrhoeae was responsible for infection in 29.7% (n = 66) of clinical episodes evaluated. Compared with phenotypic susceptibility testing, NGSNP demonstrated sensitivity and specificity of 95.8% (95% CI 91.5%-98.3%) and 100% (95% CI 94.7%-100%), respectively, for detecting ciprofloxacin-susceptible N. gonorrhoeae, with a positive predictive value of 100% (95% CI 97.7%-100%). Applied to urogenital (n = 164), rectal (n = 40) and pharyngeal samples alone (n = 30), positive predictive values were 100% (95% CI 96.8%-100%), 100% (95% CI 87.2%-100%) and 100% (95% CI 82.4%-100%), respectively.

CONCLUSIONS

Genotypic prediction of N. gonorrhoeae ciprofloxacin susceptibility directly from clinical samples was highly accurate and, in the absence of culture, will facilitate use of tailored therapy for gonococcal infection, sparing use of current empirical treatment regimens and enhancing acquisition of susceptibility data for surveillance.

Chlamydia trachomatis infection rates among a cohort of mobile soldiers stationed at Fort Bragg, North Carolina, 2005-2010

Background

Fort Bragg, a large Army installation with reported high Chlamydia trachomatis (Ct) infection rates, is characterized by a highly mobile population and a surrounding Ct-endemic community. We assessed the rates of Ct incidence and recurrence among the installation’s active component Army personnel and determined the association of soldier transience, sociodemographic factors, and history of sexually transmitted infection (STI) with these rates.

Methods

A cohort of soldiers stationed at Fort Bragg during 2005 to mid-2010 was followed for incident and recurrent Ct infection using laboratory-confirmed reportable disease data. Linkage to demographic and administrative data permitted multivariate analysis to determine association of covariates with initial or recurrent infection.

Results

Among 67,425 soldiers, 2,198 (3.3%) contracted an incident Ct infection (crude incidence, 21.7 per 1,000 person-years). Among soldiers followed for incident infection, 223 (10.6%, crude incidence 110.8 per 1,000 person-years) contracted a recurrent Ct infection. Being female, of lower rank, under 26 years of age, of non-white race, single, or with a high school diploma or less was significantly associated with incident Ct infection. Having breaks in duty or having deployments during follow-up was associated with a lower infection rate. Among women, having prior deployments was associated with a lower rate of both incident and recurrent infection. Specifically associated with recurrent infection in women was age under 21 years or no education beyond high school.

Conclusions

This analysis reaffirms risk factors for Ct infection determined in other studies. In addition, infection risk was lower for more mobile soldiers and tied to the specific location of their regular duty assignment. The findings support the STI prevention efforts at Fort Bragg and the surrounding community, regardless of how often or for how long soldiers have deployed for military operations.

Results of a 25-year longitudinal analysis of the serologic incidence of syphilis in a cohort of HIV-infected patients with unrestricted access to care

BACKGROUND

The well-described biologic and epidemiologic associations of syphilis and HIV are particularly relevant to the military, as service members are young and at risk for sexually transmitted infections. We therefore used the results of serial serologic testing to determine the prevalence, incidence, and risk factors for incident syphilis in a cohort of HIV-infected Department of Defense beneficiaries.

METHODS

Participants with a positive nontreponemal test at HIV diagnosis that was confirmed on treponemal testing were categorized as prevalent cases, and participants with an initial negative nontreponemal test who subsequently developed a confirmed positive nontreponemal test were categorized as incident cases.

RESULTS

At HIV diagnosis, the prevalence of syphilis was 5.8% (n = 202). A total of 4239 participants contributed 27,192 person-years (PY) to the incidence analysis and 347 (8%) developed syphilis (rate, 1.3/100 PY; [1.1, 1.4]). Syphilis incidence was highest during the calendar years 2006 to 2009 (2.5/100 PY; [2.0, 2.9]). In multivariate analyses, younger age (per 10 year increase hazard ratio [HR], 0.8; [0.8-0.9]), male gender (HR, 5.6; [2.3-13.7]), non-European-American ethnicity (African-American HR, 3.2; [2.5-4.2]; Hispanic HR, 1.9; [1.2-3.0]), and history of hepatitis B (HR, 1.5; [1.2-1.9]) or gonorrhea (HR, 1.4; [1.1-1.8]) were associated with syphilis.

CONCLUSIONS

The significant burden of disease both at and after HIV diagnosis, observed in this cohort, suggests that the cost-effectiveness of extending syphilis screening to at-risk military members should be assessed. In addition, HIV-infected persons continue to acquire syphilis, emphasizing the continued importance of prevention for positive programs.