Sexual Health Sexual Health Society
Publishing on sexual health from the widest perspective

Time to clearance of Chlamydia trachomatis ribosomal RNA in women treated for chlamydial infection

Cybèle A. Renault A B , Dennis M. Israelski A B , Vivian Levy A B E , Bruce K. Fujikawa B , Timothy A. Kellogg C and Jeffrey D. Klausner C D
+ Author Affiliations
- Author Affiliations

A Stanford University School of Medicine, Division of Infectious Diseases and Geographic Medicine, 300 Pasteur Drive, Grant Building, Stanford, CA 94305-5107, USA.

B San Mateo County Health System, 222 West 39th Avenue, San Mateo, CA 94403, USA.

C San Francisco Department of Public Health, STD Prevention and Control Services, 1360 Mission Street, Suite 401, San Francisco, CA 94103, USA.

D Department of Medicine, University of California, 505 Parnassus Avenue, San Francisco, CA 94122, USA.

E Corresponding author. Email:

Sexual Health 8(1) 69-73
Submitted: 9 March 2010  Accepted: 24 May 2010   Published: 24 January 2011


Background: The dynamics of chlamydia clearance after treatment administration for chlamydial urogenital infection are unknown. We estimated the time to clearance of Chlamydia trachomatis (CT) ribosomal RNA (rRNA) after administration of azithromycin for cervical chlamydial infection using APTIMA Combo 2 (Gen-Probe, Inc., San Diego, CA, USA). Methods: A total of 115 women diagnosed with urogenital chlamydial infection, defined as a positive APTIMA urine or endocervical specimen, were enrolled in the present study. Vaginal swabs on the day of treatment (Day 0) and on Days 3, 7, 10 and 14 after treatment with 1 g of azithromycin were self-obtained by participants. Specimens were tested in a single laboratory. Our analysis was limited to women who were CT-confirmed by vaginal swab at baseline, who returned all follow-up swabs, and who reported sexual abstinence during the follow-up period (n = 61). Results: Among 61 participants, 48 (79%) had a negative APTIMA at Day 14. Subjects with a negative APTIMA at each time-point were as follows: 0/61 (0%) on Day 0, 7/61 (12%) on Day 3, 28/61 (46%) on Day 7, 40/61 (66%) on Day 10, and 48/61 (79%) on Day 14. Multiple linear regression analysis predicted time to clearance at 17 days (95% confidence interval, 16–18 days) after administration of azithromycin. Seventeen of the 94 participants (18.1%) who screened positive for chlamydia had a negative vaginal swab on Day 0, indicating possible spontaneous clearance of CT. Conclusions: After treatment, CT rRNA declined with time. As rRNA was still detectable in 21% of the women 14 days after treatment, APTIMA should not be used as a test-of-cure in the 14-day period following azithromycin administration.

Additional keywords: APTIMA, test-of-cure, transcription-mediated amplification.


We acknowledge the patients and the clinical and administrative staff at Daly City Youth Health Center, Sequoia Teen Wellness Center, San Mateo Medical Center Sexually Transmitted Diseases Clinic and San Mateo Medical Center Adolescent Clinic. This study and authors (Drs. Renault and Israelski) were supported by the California HIV/AIDS Research Program (CH05-SMCHC-612).


[1] Centers for Disease Control and Prevention (CDC) STD Treatment Guidelines. MMWR Recomm Rep 2006; 55 1–100.

[2] Morre SA,  Sillekens PT,  Jacobs MV,  de Blok S,  Ossewaarde JM,  van Arle P, et al. Monitoring of Chlamydia trachomatis infections after antibiotic treatment using RNA detection by nucleic acid sequence based amplification. Mol Pathol 1998; 51 149–54.
CrossRef | CAS | PubMed |

[3] Roosendaal R,  Walboomers JM,  Veltman OR,  Melgers I,  Burger C,  Bleker OP, et al. Comparison of different primer sets for detection of Chlamydia trachomatis by the polymerase chain reaction. J Med Microbiol 1993; 38 426–33.
CrossRef | CAS | PubMed |

[4] Vogels WH,  van Voorst Vader PC,  Schroder FP. Chlamydia trachomatis infection in a high-risk population: comparison of polymerase chain reaction and cell culture for diagnosis and follow-up. J Clin Microbiol 1993; 31 1103–7.
CAS | PubMed |

[5] Gaydos CA,  Crtochfelt KA,  Howell MR,  Kralian S,  Hauptman P,  Quinn TC. Molecular amplification assays to detect chlamydial infections in urine specimens from high school female students and to monitor the persistence of chlamydia DNA after therapy. J Infect Dis 1998; 177 417–24.
CrossRef | CAS | PubMed |

[6] Chong S,  Jang D,  Song X,  Mahony J,  Petrich A,  Barriga P, et al. Specimen processing and concentration of Chlamydia trachomatis added can influence false-negative rates in the LCx assay but not in the APTIMA Combo 2 assay when testing for inhibitors. J Clin Microbiol 2003; 41 778–82.
CrossRef | CAS | PubMed |

[7] Workowski KA,  Lampe MF,  Wong KG,  Watts MB,  Stamm WE. Long-term eradication of Chlamydia trachomatis genital infection after antimicrobial therapy. Evidence against persistent infection. JAMA 1993; 270 2071–5.
CrossRef | CAS | PubMed |

Rent Article (via Deepdyve) Export Citation Cited By (26)