Julius Schachter

Multicenter Evaluation of the BDProbeTec ET System for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Urine Specimens, Female Endocervical Swabs, and Male Urethral Swabs

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

Polymorphisms in Chlamydia trachomatis tryptophan synthase genes differentiate between genital and ocular isolates

We previously reported that laboratory reference strains of Chlamydia trachomatis differing in infection organotropism correlated with inactivating mutations in the pathogens tryptophan synthase (trpBA) genes. Here, we have applied functional genomics to extend this work and find that the paradigm established for reference serovars also applies to clinical isolates - specifically, all ocular trachoma isolates tested have inactivating mutations in the synthase, whereas all genital isolates encode a functional enzyme. Moreover, functional enzyme activity was directly correlated to IFN-gamma resistance through an indole rescue mechanism. Hence, a strong selective pressure exists for genital strains to maintain a functional synthase capable of using indole for tryptophan biosynthesis. The fact that ocular serovars (serovar B) isolated from the genital tract were found to possess a functional synthase provided further persuasive evidence of this association. These results argue that there is an important host-parasite relationship between chlamydial genital strains and the human host that determines organotropism of infection and the pathophysiology of disease. We speculate that this relationship involves the production of indole by components of the vaginal microbial flora, allowing chlamydiae to escape IFN-gamma-mediated eradication and thus establish persistent infection.

Azithromycin in control of trachoma

The new Global Initiative by the World Health Organization has an ambitious goal of eliminating blinding trachoma by 2020, twenty years into the next millennium. GET 2020 consists of a four-pronged strategy to reduce active trachoma through community-based antibiotic distribution and health education on face washing and environmental sanitation, and to reduce vision loss from trichiasis through provision of appropriate surgical services. The SAFE strategy – Surgery, Antibiotics, Face-washing, Environmental change – is currently being implemented or planned for five pilot countries where the antibiotic component will be based on the drug azithromycin under a donation programme by Pfizer, Inc. Azithromycin represents a breakthrough for the community-based, antibiotic treatment of ocular Chlamydia trachomatis infection. Trachoma is a community disease, which clusters in neighbourhoods and within families, children having the highest rates of disease.1 Treatment of a few cases in such a setting guarantees re-infection from familial or neighbourhood sources, unless the treatment is more widespread. Moreover, re-infection from extra-ocular sites can occur if only topical treatment is used,2 and re-infection from other people can occur if treatment of members of the community is not carried out at the same time. Previously, topical agents, such as tetracycline, have been the agents of choice. This was done due to the absence of systemic side effects in children (seen with oral tetracycline) and the high cost and lack of availability of oral erythromycin in many of these remote communities. However, topical tetracycline must be used every day for four to six weeks to be effective. It also stings, is messy to use, and results in blurred vision because of its oily base. Compliance (regular use of the prescribed medicine) with topical agents is typically quite poor.

Nucleic acid amplification tests in the diagnosis of chlamydial and gonococcal infections of the oropharynx and rectum in men who have sex with men.

Background: Several nucleic acid amplification tests (NAATs) are US Food and Drug Administration-cleared for detecting urogenital Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) infection, but they have not been adequately evaluated for the relatively common oropharyngeal or rectal CT and GC infections in men who have sex with men (MSM). Methods: Multiple swabs were collected from the oropharynx and rectum of MSM attending a city sexually transmitted disease clinic. The specimens were tested by standard culture and the following NAATs: Roches Amplicor (PCR), Becton Dickinsons ProbeTec (SDA), and Gen-Probes APTIMA Combo 2 (AC2) for the detection of CT and GC. Confirmatory testing of specimens with discrepant results was done by NAATs using alternate primers. Results: A total of 1110 MSM were enrolled. Based on initial findings on 205 MSM, PCR had a 78.9% GC specificity with oropharyngeal swabs. Thus, we discontinued PCR testing for the rest of the study. For oropharyngeal GC (89 infections detected), sensitivities were 41% for culture, 72% for SDA, and 84% for AC2. For rectal GC (88 infections detected), sensitivities were 43% for culture, 78% for SDA and 93% for AC2. For oropharyngeal CT (9 infections detected), sensitivities were 44% for culture, 67% for SDA, and 100% for AC2. For rectal CT (68 infections detected), sensitivities were 27% for culture, 63% for SDA, and 93% for AC2. Specificities of SDA and AC2 were ≥99.4% for both organisms and anatomical sites. Conclusions: AC2 and SDA were far superior to culture for the detection of CT or GC from the oropharynx and rectum with AC2 detecting twice as many infections as culture. Further analyses with larger pharyngeal samples are needed, but clearly NAATs can improve our ability to diagnose rectal and oropharyngeal infection with CT or GC in MSM.

Plasma cell endometritis in women with symptomatic bacterial vaginosis

Objective To evaluate the endometrial microbiology and histopathology in women with symptomatic bacterial vaginosis but no signs or symptoms of upper genital tract disease or other vaginal or cervical infections. Methods Endometrial biopsies were performed on 41 women complaining of vaginal discharge or pelvic pain at a sexually transmitted disease clinic. These women had neither culture nor serologic evidence of Neisseria gonorrhoeae or Chlamydia trachomatis infection. Twenty-two women with bacterial vaginosis diagnosed by Gram stain examination of vaginal fluid, but with neither signs nor symptoms of upper genital tract infection, were compared with 19 women who had no evidence of bacterial vaginosis on vaginal fluid Gram stain. Endometrial biopsies were evaluated for histopathologic evidence of plasma cell endometritis and were cultured for N gonorrhoeae, C trachomatis, aerobic and anaerobic bacteria, Mycoplasma species, and Ureaplasma urealyticum. Results Ten of 22 women with bacterial vaginosis had plasma cell endometritis, compared with one of 19 controls (odds ratio [OR] 15, 95% confidence interval [CI] 2–686; P < .01). Bacterial vaginosis-associated organisms were cultured from the endometria of nine of 11 women with and eight of 30 women without plasma cell endometritis (OR 12.4, 95% CI 2–132; P = .002). Conclusion Plasma cell endometritis was frequently present in women with bacterial vaginosis and without other vaginal or cervical infections. This suggests the possibility of an association between bacterial vaginosis and nonchlamydial, nongonococcal, upper genital tract infection.

Incentivising Safe Sex : A Randomised Trial of Conditional Cash Transfers for HIV and Sexually Transmitted Infection Prevention in Rural Tanzania

Objective The authors evaluated the use of conditional cash transfers as an HIV and sexually transmitted infection prevention strategy to incentivise safe sex. Design An unblinded, individually randomised and controlled trial. Setting 10 villages within the Kilombero/Ulanga districts of the Ifakara Health and Demographic Surveillance System in rural south-west Tanzania. Participants The authors enrolled 2399 participants, aged 18–30 years, including adult spouses. Interventions Participants were randomly assigned to either a control arm (n=1124) or one of two intervention arms: low-value conditional cash transfer (eligible for

Vaginal swabs are the specimens of choice when screening for chlamydia trachomatis and Neisseria gonorrhoeae : Results from a multicenter evaluation of the APTIMA assays for both infections

10 per testing round, n=660) and high-value conditional cash transfer (eligible for

Performance of the APTIMA Combo 2 Assay for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Female Urine and Endocervical Swab Specimens

20 per testing round, n=615). The authors tested participants every 4 months over a 12-month period for the presence of common sexually transmitted infections. In the intervention arms, conditional cash transfer payments were tied to negative sexually transmitted infection test results. Anyone testing positive for a sexually transmitted infection was offered free treatment, and all received counselling. Main outcome measures The primary study end point was combined prevalence of the four sexually transmitted infections, which were tested and reported to subjects every 4 months: Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Mycoplasma genitalium. The authors also tested for HIV, herpes simplex virus 2 and syphilis at baseline and month 12. Results At the end of the 12-month period, for the combined prevalence of any of the four sexually transmitted infections, which were tested and reported every 4 months (C trachomatis, N gonorrhoeae, T vaginalis and M genitalium), unadjusted RR for the high-value conditional cash transfer arm compared to controls was 0.80 (95% CI 0.54 to 1.06) and the adjusted RR was 0.73 (95% CI 0.47 to 0.99). Unadjusted RR for the high-value conditional cash transfer arm compared to the low-value conditional cash transfer arm was 0.76 (95% CI 0.49 to 1.03) and the adjusted RR was 0.69 (95% CI 0.45 to 0.92). No harm was reported. Conclusions Conditional cash transfers used to incentivise safer sexual practices are a potentially promising new tool in HIV and sexually transmitted infections prevention. Additional larger study would be useful to clarify the effect size, to calibrate the size of the incentive and to determine whether the intervention can be delivered cost effectively. Trial registration number NCT00922038 ClinicalTrials.gov.

Vaginal Swabs Are Appropriate Specimens for Diagnosis of Genital Tract Infection with Chlamydia trachomatis

Background: Vaginal swabs were recently U.S. Food and Drug Administration-cleared for detecting Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) using Gen-Probe Incorporated’s APTIMA COMBO2 Assay (AC2). We assessed the APTIMA CT Assay (ACT) for CT, APTIMA GC Assay (AGC) for GC, and AC2 for both organisms using patient- and clinician-collected vaginal swabs. Method: Women attending family planning, obstetrics and gynecology, or sexually transmitted disease (STD) clinics had first-catch urines (FCUs), patient-collected vaginal swabs, clinician-collected vaginal swabs, and endocervical swabs tested by ACT, AGC, and AC2. A second endocervical swab and FCU were tested using BD ProbeTec (Becton Dickinson) for CT and GC. We calculated sensitivity and specificity using vaginal swabs to detect CT and GC. Results: Of 1464 subjects enrolled, 180 had CT and 78 GC. ACT sensitivities and specificities for patient-collected vaginal swabs were 98.3% and 96.5%, respectively; for clinician-collected vaginal swabs, 97.2% and 95.2%, respectively. AGC sensitivities and specificities for patient-collected vaginal swabs were 96.1% and 99.3%, respectively; for clinician-collected vaginal swabs, 96.2% and 99.3%, respectively. AC2 results were similar. If an FCU tested positive for CT or GC, >94% of matching vaginal swabs were positive. Positive endocervical swabs showed slightly less concordance (>90% and >88%, respectively). More infected patients were identified using vaginal swabs than FCUs. With AC2, 171 CT-infected patients were identified using FCUs and 196 using patient-collected vaginal swabs. This difference was more pronounced for CT than for GC. Conclusions: Vaginal swab specimens allowed sensitive and specific detection of CT and GC in the APTIMA assays. Vaginal swabs identified as many infected patients as endocervical swabs and more than FCUs, and may well be the specimen of choice for screening.

Women find it easy and prefer to collect their own vaginal swabs to diagnose Chlamydia trachomatis or Neisseria gonorrhoeae infections.

ABSTRACT The greater sensitivity of nucleic acid amplification tests (NAATs) for Chlamydia trachomatis and Neisseria gonorrhoeae permits the use of urine and other noninvasive specimens, which can increase the reach and decrease the costs of public health screening programs aimed at controlling these infections. This study evaluated the performance of the APTIMA Combo 2 assay, a multiplex assay based on the transcription-mediated amplification reaction, for the simultaneous detection of both pathogens in endocervical swab and urine specimens from females. Combo 2 assay results were compared with patient infected status, which were available by using other commercial NAATs. Sensitivity and specificity for C. trachomatis were 94.2 and 97.6%, respectively, in swabs and 94.7 and 98.9%, respectively, in first-catch urine (FCU). Sensitivity and specificity for N. gonorrhoeae were 99.2 and 98.7%, respectively, in swabs and 91.3 and 99.3%, respectively, in FCU. The assay reliably detected both infections in coinfected patients. The Combo 2 assay can be recommended for use with endocervical swab and urine specimens from females, especially for screening tests for asymptomatic women in sexually transmitted disease surveillance programs. This Food and Drug Administration-cleared assay can be a useful tool in efforts to reduce the prevalence and incidence of C. trachomatis and N. gonorrhoeae infections in sexually active women and to prevent their costly and serious sequelae.