title: Value of screening for oro-pharyngeal Chlamydia trachomatis infection.
abstract: OBJECTIVE
  To determine whether oro-pharyngeal colonisation by Chlamydia trachomatis occurs in patients at risk of genital chlamydia infection; to determine whether screening pharyngeal specimens by polymerase chain reaction (PCR) increases detection of C trachomatis compared with isolation and the immune dot blot test; and to correlate the detection of C trachomatis and Neisseria gonorrhoeae in the pharynx with a history of oro-genital contact.
  
  
  METHODS
  Thirteen homosexuals and 11 heterosexuals were included in the study. Urogenital and pharyngeal specimens were tested for C trachomatis and N gonorrhoeae using standard clinical diagnostic procedures. Two different PCR methodologies were also used to detect C trachomatis in the pharyngeal specimens. Results were correlated with the mode of sexual practice.
  
  
  RESULTS
  Oro-genital sexual contact was practised by 64.9% (72/111) of heterosexuals in addition to penetrative penovaginal intercourse. Additionally, 62.1% (77/124) of all patients did not use any form of barrier protection. Of those who admitted to oro-genital sexual contact, 17.6% of patients with a genital chlamydial infection and 36.4% of those with genital gonorrhoea also had asymptomatic pharyngeal colonisation. C trachomatis was detected in three of 124 (2.4%) pharyngeal specimens by PCR which were reported as negative by chlamydial culture; one was positive by the immune dot blot test.
  
  
  CONCLUSIONS
  The majority of patients practised unprotected oro-genital contact and significant pharyngeal colonisation by C trachomatis and N gonorrhoeae occurred if genital infection was present. Despite the use of PCR in a population at high risk of sexually transmitted disease, the prevalence of chlamydia in the pharynx was very low. This indicates that transmission of C trachomatis to the oro-pharynx does not pose a serious health risk and that screening of patients for oro-pharyngeal C trachomatis is not worthwhile.
authors.affiliation: Manchester Central Laboratory Services, Manchester Royal Infirmary.
authors.forename: S P
authors.initials: SP
authors.lastname: Jebakumar
authors.forename: C
authors.initials: C
authors.lastname: Storey
authors.forename: M
authors.initials: M
authors.lastname: Lusher
authors.forename: J
authors.initials: J
authors.lastname: Nelson
authors.forename: B
authors.initials: B
authors.lastname: Goorney
authors.forename: K R
authors.initials: KR
authors.lastname: Haye
mesh_terms: D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D002690:Chlamydia Infections / Q000517:prevention & control / Q000635:transmission*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D005260:Female; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D008403:Mass Screening; D008969:Molecular Sequence Data; D009960:Oropharynx / Q000382:microbiology*; D010608:Pharyngeal Diseases / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012725:Sexual Behavior; D014566:Urogenital System / Q000382:microbiology