Characterisation of human mycobacterial isolates using random amplified polymorphic DNA (RAPD) fingerprinting

Abstract number: P1814

Haghighi M., Moatazedian M., Aleyasin F., Mohabati Mobarez A., Ghazi Saeed K.

Objective: Tuberculosis is a global problem responsible for the deaths 2–3 million people each year. In this study, we developed a simple random amplified polymorphic DNA (RAPD) assay for rapid identification of different species of mycobacteria and compared with the traditional cultural and biochemical tests.

Methods: We studied 56 clinically isolates and 22 reference mycobacteria strains. The isolates categorised based on growth rate and photoreactive characteristics as nonchromogenic, photochromogen, scotochromogen and rapid grower groups.

Twenty seven commercial primers screened between seven, four, five and six DNA of reference strains of nonchromogenic, photochromogens, scotochromogens and rapid grower mycobacteria by RAPD respectively. The mean of similarity index (Jaccards similarity) of different primers for each clinical isolate compare to reference strain are evaluated. By using sub value 0.65 as a cut off point, maximum genomic similarity of each clinically isolate with related reference strain used for identification of each clinically isolates.

Result: By using short oligomer primers (10-mers) with arbitrarily chosen sequences in the polymerase chain reaction, distinctive and reproducible sets of RAPD profiles were observed for clinically and reference isolates of mycobacteria. The primers 308,304,301 in nonchromogenic mycobacteria, 348,313,AB1–15 in scotochromogens, 348,324,AB1–15,AB1–02 in photochromogens and 348.327,313,301 in rapid grower mycobacteria were identified to be the most suitable primer when tested with related clinical and reference strains. The mean of similarity index of different primers for clinical isolates compare to reference strain of nonchromogenic Mycobacteria group were equal to M. tuberculosis in 46 Isolates, Photochromogen mycobacteria group were equal to M. kansasii in 2 isolates, Scotochromogen mycobacteria group were equal to M.gordonae in 2 isolates and 1 isolate of each of M. flavescens and M. xenopi, Rapid grower's mycobacteria group were equal to M. fortuitum in 4 isolates and M. smegmatis in 1 isolate.

Conclusion: RAPD analysis should be useful in providing genotypic characters for taxonomic descriptions, for typing of Mycobacteria species. The complete procedure required only 48 h from receipt of a mycobacterial culture to final identification and it is a universal system of identifying Mycobacteria to the species level that does not require specialised knowledge and that even allows no specialised microbiologists to make proper identifications.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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