title: Amplification of residual DNA sequences in sterile bronchoscopes leading to false-positive PCR results.
abstract: PCR has been used successfully for the direct detection of Mycobacterium tuberculosis in uncultured patient samples. Its potential is hindered by the risk of false-positive results as a result of either amplicon carryover of cross-contamination between patient samples. In the present study, we investigated whether residual amplifiable human or M. tuberculosis DNA could remain in sterile bronchoscopes and potentially be a cause of false-positive PCR results in subsequent patient samples. Sterilized bronchoscopes were flushed with sterile saline, and the collected eluate was submitted for PCR amplification of IS6110 sequences and exon 8 of the human p53 gene. Of a total of 55 washes of sterile bronchoscopes from two institutions, 2 (3.6%) contained amplifiable M. tuberculosis DNA and 11 (20%) contained residual human DNA. These findings indicate that residual DNA can remain in sterilized bronchoscopes and can be a source of false-positive PCR results.
authors.affiliation: Department of Pathology, Evanston Hospital, Illinois 60201, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kaul
authors.forename: S
authors.initials: S
authors.lastname: Luke
authors.forename: C
authors.initials: C
authors.lastname: McGurn
authors.forename: N
authors.initials: N
authors.lastname: Snowden
authors.forename: C
authors.initials: C
authors.lastname: Monti
authors.forename: W A
authors.initials: WA
authors.lastname: Fry
mesh_terms: D020680:Bronchoscopes; D004269:DNA, Bacterial / Q000302:isolation & purification*; D004866:Equipment Contamination; D005189:False Positive Reactions; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D013242:Sterilization; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
chemical_list: D004269:DNA, Bacterial