RAPID DIFFERENTIATION OF MYCOBACTERIUM-AVIUM AND MYCOBACTERIUM-PARATUBERCULOSIS BY PCR AND RESTRICTION ENZYME ANALYSIS

Mycobacterium avium subsp. avium (M. avium) and M. avium subsp. paratu berculosis (M. paratuberculosis), intracellular bacteria that can caus e chronic granulomatous enteritis in cattle, are difficult to distingu ish on the basis of growth and biochemical characteristics. We report the development of a PCR-based strategy for the rapid differentiation of isolates of M. paratuberculosis. Restriction fragment length polymo rphism was identified by PCR amplification and subsequent restriction enzyme digestion with PstI of a 960-bp fragment of the 65-kDa heat sho ck protein (hsp65) from 21 clinical isolates of M. paratuberculosis an d 14 isolates of M. avium. These results indicate that a restriction f ragment length polymorphism in the hsp65 gene can be used for the rapi d differentiation of clinical isolates of M. paratuberculosis and M. a vium.