ABSTRACT
OBJECTIVES: To audit the time taken to obtain laboratory confirmation of infection with Mycobacterium tuberculosis using in-house methods of polymerase chain reaction (PCR) and culture and referral to a reference laboratory. METHODS: Retrospective collection of data from laboratory records covering a period of 1 year. RESULTS: Median time to microbiological diagnosis of a new infection using the in-house services in addition to the reference laboratory was 22.0 days. Using reference laboratory results alone, median time to diagnosis would have been 61.5 days. CONCLUSIONS: Development of on-site laboratory facilities to identify Mycobacterium tuberculosis can reduce the time to its identification by almost two-thirds.
Subject(s)
Tuberculosis/diagnosis , Clinical Laboratory Techniques , Humans , Mycobacterium tuberculosis/isolation & purification , Polymerase Chain Reaction , Time FactorsABSTRACT
We have previously demonstrated homology between a 181-bp fragment of IS6110 and DNA from mycobacteria other than tuberculosis-causing mycobacteria (MOTT). Genomic DNA from 14 strains of MOTT was digested with PvuII and was hybridized with a probe derived from the 181-bp fragment and the INS1/INS2 international standard probe at high stringency. Multiple banding patterns were obtained from isolates of M. avium-M. intracellulare, M. fortuitum, M. kansasii, and M. malmoense. Differences in the banding patterns between and within species were obtained. This suggests that mycobacteria possess a family of IS3-like elements. The species of isolates suspected of being M. tuberculosis must be carefully determined before IS6110 restriction fragment length polymorphism analysis, and caution must be used in designing and evaluating diagnostic PCR tests based on this element.
