MOLECULAR EPIDEMIOLOGY OF LEGIONELLA-PNEUMOPHILA SEROGROUP-1 BY RIBOTYPING WITH A NONRADIOACTIVE PROBE AND PCR FINGERPRINTING

Hybridization with acetylaminofluorene-labelled 16+23 S rRNA from Esch erichia coli was used to detect DNA polymorphism among Legionella pneu mophila serogroup 1 isolates. Isolates from unrelated patients showed at least four different rRNA restriction patterns, whereas those from related patients showed a single pattern. Amplification of genomic reg ions with an arbitrary primer by polymerase chain reaction was used to further analyze the isolates. Related isolates showed closely related patterns while unrelated isolates displayed six distinct patterns. We could differentiate the majority of unrelated isolates with the combi nation of the patterns obtained with the ribotyping and the PCR finger printing, while strains from the same outbreak remained highly related . The ribotyping and the PCR fingerprinting are proposed as useful and easy to perform epidemiological markers of L. pneumophila serogroup 1 infection.