[Identifications of atypical mycobacteria by DNA-DNA hybridization and their biotypings with chromogenic substrates].
We developed a new biotyping system for mycobacterial strains. Various chromogenic substrates were incubated with mycobacterial cell suspensions for four hours at 37 degrees C, and strains were typed by their patterns of hydrolysis of these substrates. Commercially available microtiter plate DNA-DNA hybridization system and our biotyping system with chromogenic substrates were applied for the identification of clinically isolated atypical mycobacterial strains, and the results were compared with those obtained by the usual biological methods. Both new methods were proved to be satisfactorily quick and reproducible. The DNA probe method could distinguish M. avium from M. intracellulare and M. nonchromogenicum. Differentiation of these species has been very difficult by other methods. Our new biotyping system also could not differentiate these three species, but could classify some mycobacterial species into several subtypes. The DNA probe method is quick and accurate but expensive. On the contrary, our new biotyping system was found to have the same level of accuracy as the usual methods, but much quicker than the usual methods and less expensive than DNA probe method. We recommend our new biotyping system to the clinical laboratories which hesitate to accept DNA probe method because of its high expenses despite of its high accuracy.
Shutoh
E
E
Department of Microbiology, Meiji College of Pharmacy, Tokyo, Japan.
Arai
T
T
Toyoda
T
T
Aoyagi
T
T
D002863:Chromogenic Compounds; D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis*; D009170:Nontuberculous Mycobacteria / Q000145:classification / Q000235:genetics*; D009693:Nucleic Acid Hybridization
D002863:Chromogenic Compounds; D003470:Culture Media; D004269:DNA, Bacterial