Analysis with a combination of macrorestriction endonucleases reveals a high degree of polymorphism among Bordetella pertussis isolates in eastern France

From 1990 to 1996, routine screening fur whooping cough identified 399 pati ents with a calmodulin-dependent adenylate cyclase-positive test result and yielded 69 Bordetella pertussis isolates. None of the patients were fully vaccinated, and most were less than 6 months old, Analysis of total DNA by pulsed-field gel electrophoresis (PFGE) after XbaI, SpcI, or DraI macrorest riction yielded 19, 15, and 5 different patterns, respectively, whereas rib otyping failed to demonstrate any strain polymorphism. Discrimination among the isolates was improved by combining the PFGE profiles, Some patterns we re more frequent, but the corresponding patients were not clearly epidemiol ogically related. The patterns for two strains obtained during a 3-month pe riod from patients who were neighbors differed by the length of a single DN A fragment. These data strongly suggest that one type of isolate is widely spread throughout the world and is carried by individuals other than patien ts who develop a true illness.