Useofa Pilin GeneProbeToStudyMolecular Epidemiology of Pseudomonas aeruginosa

Twenty-one different restriction fragment length polymorphism (RFLP)typeswere foundamong 249isolates. RFLPtype7was recovered onlyfrompatients withthermal burns(9of14isolates) inbothVancouver, British Columbia, andEdmonton, Alberta, Canada. NoneoftheotherRFLP typesshoweda clearpredilection for disease state orenvironmental niche. Multiple morphologically different isolates fromindividual patients with CFwerestudied; eachisolate in33of40sputumsamples hadan identical RFLPtype,despite considerable LPS serotypeheterogeneity. Sequential isolates from23patients were studied; in10isolates there was a clear change inboththeRFLPtypeandtheLPSserotype. We conclude thatpatients withCF usually harbora single P. aeruginosa RFLPtypeintheir sputa, butthat one strain can replace another as thepredominant colonizing type.