A one-year survey of Microsporum audouinii infections in Belgium: epidemiological and genotypic characterization.

During recent years the proportion of tinea capitis infections due to Microsporum audouinii has increased in both Belgium and other European countries. To better understand the emergence of this species, the Belgian National Reference Centre for dermatophytes launched an epidemiological survey on the main anthropophilic dermatophytes causing tinea capitis in Belgium and included the genomic characterization of M. audouinii isolates. In total, 116 strains of M. audouinii were confirmed and characterized by the DiversiLab(®) system (bioMérieux). Six genotypic variants were identified, among which one major group included 90 isolates and the reference strain. Another variant group (11 strains) was exclusively confined to a geographical region in south Belgium. Analysis of epidemiological characteristics of the infected population showed that the main age category was 5- to 9-year-old children with a sex ratio (male/female) of 1.97. Data concerning the geographic origin of the family revealed a majority of Belgian nationality (44.7%), suggesting that the infection originated in Belgium. Other nationalities were primarily African. At this time, no clear correlation has been established between one particular strain and a specific country of origin.