Current knowledge on the strain typing of the pathogenic fungus Histoplasma capsulatum var. capsulatum: a review of the findings

The classification of microbial strains is currently based on different typing methods, which must meet certain criteria in order to be widely used. Phenotypic and genotypic methods are being employed in the epidemiology of several fungal diseases. However, some problems associated to the phenotypic methods have fostered genotyping procedures, from DNA polymorphic diversity to gene sequencing studies, all aiming to differentiate and to relate fungal isolates or strains. Through these studies, it is possible to identify outbreaks, to detect nosocomial infection transmission, and to determine the source of infection, as well as to recognize virulent isolates. This paper is aimed at analyzing the methods recently used to type Histoplasma capsulatum, causative agent of the systemic mycosis known as histoplasmosis, in order to recommend those that yield reproducible and accurate results.