title: Molecular strain typing of Mycobacterium tuberculosis to confirm cross-contamination in the mycobacteriology laboratory and modification of procedures to minimize occurrence of false-positive cultures.
abstract: Molecular strain typing by restriction fragment length polymorphism analysis was used to demonstrate that two clusters of Mycobacterium tuberculosis cultures involving six patients resulted from cross-contamination in the mycobacteriology laboratory. Contaminated cultures were processed by the decontamination procedure and were read on the BACTEC instrument following acid-fast bacillus smear-positive specimens from patients with active tuberculosis. Investigation of these episodes suggested opportunities for modification of laboratory procedures to minimize cross-contamination and confirmed the adverse medical and public health consequences of false-positive cultures. Strain-typing results were used in decisions regarding patient care, including the curtailment of unnecessary treatment in one patient. Molecular strain typing appears to be a valuable means of identifying false-positive cultures of M. tuberculosis in selected settings.
authors.affiliation: Department of Medicine, Stanford University, California 94305.
authors.forename: P M
authors.initials: PM
authors.lastname: Small
authors.forename: N B
authors.initials: NB
authors.lastname: McClenny
authors.forename: S P
authors.initials: SP
authors.lastname: Singh
authors.forename: G K
authors.initials: GK
authors.lastname: Schoolnik
authors.forename: L S
authors.initials: LS
authors.lastname: Tompkins
authors.forename: P A
authors.initials: PA
authors.lastname: Mickelsen
mesh_terms: D015373:Bacterial Typing Techniques; D001431:Bacteriological Techniques; D004269:DNA, Bacterial / Q000235:genetics; D005069:Evaluation Studies as Topic; D005189:False Positive Reactions; D006801:Humans; D007755:Laboratories, Hospital; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial