Molecular epidemiology of Blastomyces dermatitidis.
The inhalation of conidia of Blastomyces dermatitidis, a fungus found in soil, causes disease in humans and animals. We studied the genetic diversity of this pathogen by extracting DNA yeasts and analyzing them with a polymerase chain reaction (PCR)-based typing system we developed, which used restriction fragment analysis of amplicons from the regions between the rDNA repeats and allowed us to class isolates into 3 major groups. Strains were further differentiated by use of PCR fingerprinting with 3 different primers. Fifty-nine isolates collected over 35 years from 15 regions (United States, India, Africa, Canada) were analyzed. Genotypic groups A, B, and C contained 17, 23, and 19 isolates, which were divided into 5, 15, and 12 types, respectively. All 16 isolates from North America in group A were from the upper midwestern United States or Canada, whereas 0 of 20 isolates from the southeastern United States were in group A. Studies of the largest collection from 1 locale (Eagle River, WI), revealed that the soil isolates studied were not responsible for the majority of cases in this outbreak, as previously proposed, and that >1 strain was present in the environment and in patients. Overall, these results provide a tool for the epidemiological study of blastomycosis and illuminate the genetic and geographic diversity of this important pathogen.
McCullough
M J
MJ
Department of Medicine, Division of Infectious Diseases, Santa Clara Valley Medical Center, San Jose, CA 95128-2699, USA.
DiSalvo
A F
AF
Clemons
K V
KV
Park
P
P
Stevens
D A
DA
D000349:Africa / Q000453:epidemiology; D001483:Base Sequence; D001758:Blastomyces / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D001759:Blastomycosis / Q000453:epidemiology* / Q000235:genetics*; D002170:Canada / Q000453:epidemiology; D015169:Colony Count, Microbial; D004271:DNA, Fungal / Q000032:analysis*; D005838:Genotype; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013045:Species Specificity; D014481:United States / Q000453:epidemiology
D004271:DNA, Fungal