Azole resistance in Aspergillus species in Southern Taiwan: An epidemiological surveillance study.

Abstract

Poor clinical outcomes for invasive aspergillosis are associated with antifungal resistance. Performing antifungal susceptibility tests on clinically relevant Aspergillus isolates from patients and environmental regions with known azole resistance is recommended. The aim of the study was to assess the presence of azole resistance in clinical Aspergillus spp. isolates and those from hospital environments and farmlands within a 40km radius of the hospital. Clinical Aspergillus spp. isolates were cultured, as well as environmental Aspergillus spp. isolates obtained from air samples. Samples were subcultured in azole-containing agar plates. Isolates with a positive screening test were subjected to YeastOne methods to determine their minimum inhibitory concentrations of antifungals. Resistance mechanisms were investigated in the azole-resistant Aspergillus spp. isolates. No azole-resistant clinical or environmental Aflavus, Aoryaze, Aniger or Aterreus isolates were found in the present study. All Afumigatus clinical isolates were azole-susceptible. Seven Afumigatus environmental isolates were associated with cyp51A mutations, including two that harboured TR34 /L98H mutations with S297T/F495I substitutions, two with TR34 /L98H mutations and three with TR46 /Y121F/T289A mutations. One of these isolates was collected from farmland, one was from A ward and five were from B ward. The proportion of azole-resistant Afumigatus was 10.2% (6/59) and 3.2% (1/31) in the hospital environments and the farmlands near the hospital, respectively. The results showedthat azole-resistant Afumigatus existed within hospital environments. This emphasises the importance of periodic surveillance in hospital environments and monitoring for the emergence of azole-resistant Afumigatus clinical isolates.