title: Spontaneous pharyngeal Chlamydia trachomatis RNA clearance. A cross-sectional study followed by a cohort study of untreated STI clinic patients in Amsterdam, The Netherlands.
abstract: OBJECTIVE
  Pharyngeal Chlamydia trachomatis (chlamydia) might contribute to ongoing chlamydia transmission, yet data on spontaneous clearance duration are rare. We examined the prevalence, spontaneous clearance, chlamydial DNA concentration and genotypes of pharyngeal chlamydia among clinic patients with sexually transmitted infection (STI).
  
  
  METHODS
  Female patients at high risk for an STI who reported active oral sex and male patients who have sex with men (MSM) were screened for pharyngeal chlamydia RNA using a nucleic acid amplification test. A repeat swab was obtained to evaluate spontaneous clearance in untreated patients with pharyngeal chlamydia. Quantitative chlamydia DNA load was determined by calculating the chlamydia/human cell ratio.
  
  
  RESULTS
  Pharyngeal chlamydia was detected in 148/13 111 (1.1%) MSM and in 160/6915 (2.3%) women. 53% of MSM and 32% of women with pharyngeal chlamydia did not have a concurrent anogenital chlamydia infection. In 16/43 (37%) MSM and in 20/55 (36%) women, the repeat pharyngeal swab was negative (median follow-up 10 days, range 4-58 days). Patients with an initial chlamydial DNA concentration above the median were less likely to clear. Of 23 MSM with pharyngeal chlamydia who had sex with a lymphogranuloma venereum (LGV)-positive partner recently or in the past, two were LGV biovar positive (8.7%).
  
  
  CONCLUSIONS
  The pharynx is a reservoir for chlamydia and LGV, and may play a role in ongoing transmission. Although delay in ribosomal RNA decline after resolution of the infection might have led to an underestimation of spontaneous clearance, in high-risk STI clinic patients, testing the pharynx for chlamydia should be considered.
authors.affiliation: STI Outpatient Clinic, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands Department of Research, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands Public Health Laboratory, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands.
authors.forename: Martijn S
authors.initials: MS
authors.lastname: van Rooijen
authors.affiliation: Department of Research, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands Center for Infection and Immunology Amsterdam (CINIMA), Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Maarten F Schim
authors.initials: MF
authors.lastname: van der Loeff
authors.affiliation: Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, The Netherlands Faculty of Health, Medicine & Life Sciences, Department of Genetics and Cell Biology, Institute for Public Health Genomics, Research Institute GROW, University of Maastricht, Maastricht, The Netherlands.
authors.forename: Servaas A
authors.initials: SA
authors.lastname: Morré
authors.affiliation: Public Health Laboratory, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands Department of Medical Microbiology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
authors.forename: Alje P
authors.initials: AP
authors.lastname: van Dam
authors.affiliation: Public Health Laboratory, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands Department for Research and Education, Naturalis NBC, Leiden, The Netherlands.
authors.forename: Arjen G C L
authors.initials: AG
authors.lastname: Speksnijder
authors.affiliation: STI Outpatient Clinic, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands Center for Infection and Immunology Amsterdam (CINIMA), Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands Department of Dermatology, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Henry J C
authors.initials: HJ
authors.lastname: de Vries
mesh_terms: D000328:Adult; D058491:Bacterial Load; D002690:Chlamydia Infections / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009426:Netherlands; D021141:Nucleic Acid Amplification Techniques; D010614:Pharynx / Q000382:microbiology*; D012329:RNA, Bacterial / Q000032:analysis* / Q000235:genetics; D012335:RNA, Ribosomal / Q000032:analysis* / Q000235:genetics
chemical_list: D012329:RNA, Bacterial; D012335:RNA, Ribosomal
keywords: CHLAMYDIA TRACHOMATIS; ORAL CAVITY; ORAL SEX; SCREENING; TESTING