Triazole Resistance in Aspergillus spp.: A Worldwide Problem?

Since the first description of an azole-resistant strain in 1997, there has been an increasing number of papers describing the emergence of azole resistance. Firstly reported in the USA and soon after in Europe, it has now been described worldwide, challenging the management of human aspergillosis. The main mechanism of resistance is the modification of the azole target enzyme: 14-α sterol demethylase, encoded by the 51A gene; although recently, other resistance mechanisms have also been implicated. In addition, a shift in the epidemiology has been noted with other species (mostly azole resistant) increasingly being reported as causative agents of human disease. This paper reviews the current situation of azole resistance and its implications in the clinical setting.