Until now, no simple and rapid technique existed for epidemiological study of strains belonging to the Nocardia genus. The application of the arbitrarily primed PCR procedure to generate randomly amplified polymorphic DNA (RAPD) fingerprints for such analysis of Nocardia isolates was investigated. Fifty-one unrelated clinical isolates of N. asteroides were tested. Two conditions of RAPD using two different primers generated RAPD fingerprints that allowed the differentiation of all strains. The patterns were reproducible and discriminating. The results highlight the diversity of N. asteroides species and confirm that RAPD analysis is a highly valuable tool for studying the epidemiology of the Nocardia genus. Several examples describe the advantage of RAPD analysis for establishing the relationship between isolates from a given patient (long-term infections, coinfections) and from different patients (i.e. during an outbreak). In the future, this technique will help us to investigate the source of infection in cases of nosocomial transmission, to understand the outcome of nocardiosis, and to follow the evolution and acquisition of resistance to Nocardia strains.
Etude epidemiologique des souches appartenant au genre Nocardia par RAPD : validation et applications.La technique de RAPD (random amplified polymorphic DNA) a ete evaluee comme outil moleculaire pour l'etude epidemiologique des souches appartenant au genre Nocardia. Cette technique a demontre, dans les conditions du protocole que nous avons developpees, une reproductibilite, une typabilite et un pouvoir discriminant excellents. Les resultats mettent en evidence la diversite des souches cliniques rencontrees. Comme nous l'avons montre a l'aide de quelques exemples, cette technique permet d'etudier les liens eventuels existant entre les souches isolees de differents patients (bouffee epidemique), de comprendre, de suivre et d'etudier les formes de nocardiose chronique ou les cas d'infections multiples. Elle devrait permettre a l'avenir d'etudier les voies de transmission ainsi que l'evolution et l'acquisition de resistance chez ces bacteries.