Molecular Phylogenetic Analysis of a Geographically and Temporally Matched Set ofCandida albicansIsolates from Humans and Nonmigratory Wildlife in Central Illinois

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Abstract
This study explored whether wildlife species serve as the reservoir for humanCandida albicansstrains in a given geographic area.C.albicansisolates were collected from nonmigratory wildlife admitted to the University of Illinois Wildlife Medical Clinic. A geographically and temporally matched set ofC.albicansoral isolates was collected from healthy human volunteers. Multilocus sequence typing was used to assign strains to genetic clades. Clade 1 isolates, particularly diploid sequence type 69 (DST 69), were most common in humans. Clade 1 strains were less frequently recovered from wildlife, while clade 8 strains, particularly DST 90, were overrepresented in the wildlife collection. All instances where a wildlife and human isolate shared the same DST occurred within clade 1. Clade distributions between human and wildlife isolates were significantly different, demonstrating population isolation between the groups. These differences may indicate limited strain transfer between groups or differential selection ofC.albicansisolates in humans and wildlife. Wildlife strains had an amphotericin B MIC significantly lower than that of human isolates; strains with increased susceptibility were from several clades.C.albicansisolates were collected from domestic animals to provide comparisons with human and wildlife data sets.C.albicansisolation from canine and feline oral and anal swabs was infrequent; companion animal isolates were closely related to clade 1 human isolates. Collectively, the data suggest a greater likelihood ofC.albicanstransfer from humans to animals than from animals to humans. The nontransient human population may maintain the connection between geography and theC.albicansgenetic groups recovered from humans.