MATERIALS AND METHODS

1. PREVALENCE OF CHLAMYDIA TRACHOMATIS, NEISSERIA GONORRHOEAE AND TRICHOMONAS VAGINALIS IN YOUNG WOMEN IN KENYA USING THE GEN-PROBE APTIMA ASSAYS J Moncada1, A Rogér1, J Schachter1, EA Bukusi2, W Harrison1 and CR Cohen1 1University of California, San Francisco, USA and 2 Kenya Medical Research Institute, Kenya BACKGROUND Data on STD rates in Kenya for sex workers and high risk populations are generally available. However, there are few prevalence studies using nucleic acid amplified tests (NAATs) in young, low risk adults. Using PCR, Hawken et al found 1.9% and 0.7% for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) in women, respectively (JAIDS, 2002, 31: 529-535). As part of a randomized placebo controlled trial of the safety and tolerability of VivaGel, we screened for the presence of CT, NG and Trichomonas vaginalis(TV) among young women in Kisumu, Kenya using Gen-Probe’s APTIMA COMBO 2 Assay (AC2) (San Diego, CA) and their TV (ASR, analyte specific reagent) assay. Of the commercially available NAATs for CT and NG, the Gen-Probe assays are the most sensitive and are highly specific. MATERIALS AND METHODS Patient Population: Non-pregnant, asymptomatic, sexually active females (18-24 years old) were recruited through community mobilization activities in and around Kisumu, Kenya. The Institutional Review Boards at UCSF and KEMRI approved this study and written consent was obtained from all patients. Women who were infected with a treatable STI were contacted by the study staff and offered/given treatment for free at the research clinic. Specimens: Clinicians obtained a cervico-vaginal swab using the AC2 collection kit. Swabs were kept refrigerated at 4ºC, sent to the UCSF laboratory and tested within 30 days of collection. NAAT: We used Gen-Probe’s APTIMA COMBO 2 Assay, (AC2) (San Diego, CA) for CT and NG, and their TV (ASR, analyte specific reagent) assay on urogenital specimens collected. The target for CT is the 23s RNA, whereas the TV and NG targets are the 16s rRNA. We followed the package insert for the AC2 assay. For TV testing, the oligonucleotides are added to the amplification reagents and the acridinium ester-labeled probes are added to the hybridization reagent, otherwise, the SOP is similar to the other APTIMA assays. Cutoff for a positive TV result was > 50,000 rlu. RESULTS We screened 216 asymptomatic subjects. Overall, 16.2% (35 females) were infected with an STD. Prevalences were 6.5% for CT, 0.9% for NG and 10.6% for TV. Four dual infections (CT and TV) were detected. Figure – Prevalence of Sexually Transmitted Infections CONCLUSIONS Using a more sensitive NAAT, we found a higher prevalence of CT (6.5%) and a similar prevalence of NG (0.9%) in our population than was reported by the Hawken et al study conducted in Mombasa. Rates for TV were also high (10.6%) in our population. The majority of females had single infections, but dual infections were seen with CT and TV. Routine STI screening programs should be developed for young women as most STI infections are asymptomatic in women, CT and TV are strongly associated with increased risk for HIV infection, and CT is a major cause of tubal factor infertility and pelvic inflammatory disease. ACKNOWLEDGMENTS This study was supported by the STI Clinical Trials Group (NIAID-DMID HHSN266200400074C). In addition, this study was supported by NIH/NCRR UCSF-CTSI Grant Number UL1 RR024131. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the NIH. We would also like to acknowledge the VivaGel research team in Kisumu, and Director, KEMRI for their support of this research. Information on NCRR is available at http://www.ncrr.nih.gov/. Information on Re-engineering the Clinical Research Enterprise can be obtained from http://nihroadmap.nih.gov/clinicalresearch/overview-translational.asp.