title: Comparison of an rRNA-based and DNA-based nucleic acid amplification test for the detection of Chlamydia trachomatis in trachoma.
abstract: OBJECTIVE
  The World Health Organisation (WHO) hopes to achieve global elimination of trachoma, still the leading cause of preventable blindness worldwide, in part through mass antibiotic treatment. DNA-based nucleic acid amplification tests (NAATs) are currently used to evaluate the success of treatment programmes by measuring the prevalence of C trachomatis infection. Some believe that newer ribosomal RNA (rRNA)-based tests may be much more sensitive since bacterial rRNA is present in amounts up to 10 000 times that of genomic DNA. Others believe that rRNA-based tests are instead less sensitive but more specific, due to the presence of dead or subviable organisms that the test may not detect. This study compares an rRNA-based test to a DNA-based test for the detection of ocular C trachomatis infection in children living in trachoma-endemic villages.
  
  
  METHODS
  An rRNA-based amplification test and DNA-based polymerase chain reaction (PCR) were performed on swab specimens taken from the right upper tarsal conjunctiva of 56 children aged 0-10 years living in two villages in Amhara, Ethiopia.
  
  
  RESULTS
  The rRNA-based test detected ocular C trachomatis infection in 35 (63%) subjects compared with 22 (39%) detected by PCR (McNemar's test, p = 0.0002). The rRNA-based test gave positive results for all subjects that were positive by PCR, and also detected infection in 13 (23%) additional subjects.
  
  
  CONCLUSIONS
  The rRNA-based test appears to have significantly greater sensitivity than PCR for the detection of ocular chlamydial infection in children in trachoma-endemic villages. Using the rRNA-based test, we may be able to detect infection that was previously missed with PCR. Past studies using DNA-based tests to assess prevalence of infectious trachoma following antibiotic treatment may have underestimated the true prevalence of infection.
authors.affiliation: F.I. Proctor Foundation, University of California San Francisco, San Francisco, CA 94143-0412, USA.
authors.forename: Jon L
authors.initials: JL
authors.lastname: Yang
authors.forename: Julius
authors.initials: J
authors.lastname: Schachter
authors.forename: Jeanne
authors.initials: J
authors.lastname: Moncada
authors.forename: Dereje
authors.initials: D
authors.lastname: Habte
authors.forename: Mulat
authors.initials: M
authors.lastname: Zerihun
authors.forename: Jenafir I
authors.initials: JI
authors.lastname: House
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Zhou
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Hong
authors.forename: Kathryn
authors.initials: K
authors.lastname: Maxey
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Gaynor
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Lietman
mesh_terms: D002648:Child; D002675:Child, Preschool; D002692:Chlamydia trachomatis / Q000235:genetics / Q000302:isolation & purification*; D003228:Conjunctiva / Q000382:microbiology; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D012329:RNA, Bacterial / Q000032:analysis*; D012335:RNA, Ribosomal / Q000032:analysis*; D015203:Reproducibility of Results; D014141:Trachoma / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012335:RNA, Ribosomal