4C 4 Chlamydia Trachomatis (Ct) Treatment Failure after 1 Gram Azithromycin Among Men- a Multi-Centered Study

Wednesday, June 11, 2014: 3:30 PM
Larissa Wilcox, BS1, Lisa Manhart, PhD2, Jane Schwebke, MD3, Stephanie N. Taylor, MD4, Scott A. White, MPH1, Leandro A. Mena, MD, MPH5, Christine Khosropour, MPH2, Lalitha Venkatasubramanian, BS6, Norine Schmidt, MPH1, David H. Martin, MD7 and Patricia Kissinger, PhD1, 1Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, 2Department of Epidemiology, University of Washington, Seattle, WA, 3Department of Medicine/Infectious Disease, University of Alabama at Birmingham, Birmingham, AL, 4Section of Infectious Diseases, Louisiana State University Health Sciences Center, New Orleans, LA, 5Division of Infectious Diseases, University of Mississippi Medical Center and Mississippi State Department of Health, Jackson, MS, 6FHI 360, Durham, NC, 7Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA

Background:  Treatment failure rates after the recommended 1 g azithromycin among Chlamydia trachomatis (Ct)-infected men have ranged from (5%-23%) in 3 recent studies. Reasons for the disparate results are unclear. Methodological issues or geographic differences may account for this inconsistency. The purpose of this study was to conduct a secondary analysis of combined data from three studies, removing the confounding effects of premature test-of-cure (TOC) and sexual re-exposure comparing the rates by geographic location.

Methods:  Data from cohorts of men in 4 U.S. cities who received 1 g azithromycin under directly observed therapy (DOT) for the treatment of uncomplicated Ct infections were pooled. Baseline/TOC was performed using Gen-Probe APTIMA Combo 2 (GPAC-2) NAAT urine test. Sexual re-exposure was elicited via ACASI survey for all but Birmingham which was provider-elicited.  Men who were GPAC-2+ prior to 3 weeks were excluded from analysis.  Rates of re-test positive were compared for men who denied sex or used a condom for all sex acts to those who reported sexual re-exposure/new exposure.

Results:  Among 323 included, pooled crude and weighted Ct re-test positive rates were 9.0% and 14.9%.  Rates varied by city:  New Orleans 13/225 (5.8%), Jackson  2/33 (6.1%), Seattle 8/45 (17.8%), and Birmingham 6/27 (22.2%). Rates of sexual re-exposure were: New Orleans (51.1%), Jackson (45.5%), Seattle (33.3%) and Birmingham (8.3%). In pooled analyses, re-test positive rates among those who reported no sexual exposure were 8.5% (95% C.I. 5.4%-12.8%) and among those who reported sexual exposure 9.5% (95% C.I. 5.5%-12.7%). 

Conclusions:  Overall treatment failure was 9.0% and varied by geographic location (range 5.8%-22.2%) and re-infection did not appear to account for this.  Given that test-of-cure is not recommended for Ct infections, this rate is of concern.  Susceptibility testing should be performed to determine if sensitivity to azithromycin has declined and/or varies by region.