Molecular methods for diagnostic and typing of yeasts

Regarding the rise and the epidemiological shifts in Candida infections, ac curate and rapid identification of yeasts to species level is exceedingly i mportant. Furthermore, non-albicans species (e.g. C. glabrata, C. dublinien sis, C. inconspicua, C. krusei and C. norvegensis) have recently emerged as azole-resistant pathogens. Standard methods fbr cultivation and differenti ation of Candida species are time-consuming, often insensitive and can fail to distinguish non-albicans species. To overcome low sensitivity, poor spe cificity and untolerable delay molecular tools to the diagnosis of Candida infection have been adopted, particularly the polymerase chain reaction (PC R). Several genus and species specific amplification-based diagnostic metho ds for detect ion of medically important yeasts have been published. As the incidence of nosocomial Candida infections has been risen significantly, t yping has become increasingly important in candidal epidemiology to define infectious processes as well as soul-ces and modes of transmission. For the development of rational infection-control measures, modern genotyping meth ods based on genomic DNA polymorphism (e.g. pulsed-field gel electrophoresi s, DNA amplification-based methods) have replaced conventional physiologica l techniques. However, reliability, sensitivity and efficiency of genotypin g methods have been controversially discussed and these DNA-based methods a re mostly insufficiently standardized. Criteria as typeability reproducibil ity and discriminatory power should be considered in evaluating typing syst ems.