First Detection of TR ₄₆ /Y121F/T289A and TR ₃₄ /L98H Alterations in Aspergillus fumigatus Isolates from Azole-Naive Patients in Denmark despite Negative Findings in the Environment

Abstract

e Azole-resistant Aspergillus fumigatus harboring the TR 34 /L98H or TR 46 /Y121F/T289A alterations is increasingly found in Europe and Asia. Here, we present the first clinical cases of TR 46 /Y121/T289A and three cases of TR 34 /L98H outside the cystic fibrosis (CF) population in Denmark and the results of environmental surveys. Four patients (2012 to 2014) with 11 A. fumigatus and 4 Rhizomucor pusillus isolates and 239 soil samples (spring 2010 and autumn 2013, respectively) with a total of 113 A. fumigatus isolates were examined. Aspergillus isolates were screened for azole resistance using azole-containing agar. Confirmatory susceptibility testing was done using the EUCAST microbroth dilution EDEF 9.1 reference method. For relevant A. fumigatus isolates, CYP51A sequencing and microsatellite genotyping were performed. Three patients harbored TR 34 /L98H isolates. Two were azole naive at the time of acquisition and two were coinfected with wild-type A. fumigatus or R. pusillus isolates, complicating and delaying diagnosis. The TR 46 /Y121F/T289A strain was isolated in 2014 from a lung transplant patient. Genotyping indicated that susceptible and resistant Aspergillus isolates were unrelated and that no transmission between patients occurred. Azole resistance was not detected in any of the 113 soil isolates. TR 34 /L98H and TR 46 /Y121F/T289A alterations appear to be emerging in the clinical setting in Denmark and now involve azole-naive patients. Two recent soil-sampling surveys in Denmark were unable to indicate any increased prevalence of azole-resistant A. fumigatus in the environment. These findings further support the demand for real-time susceptibility testing of all clinically relevant isolates and for studies investigating the seasonal variation and ecological niches for azole-resistant environmental A. fumigatus.

First Detection of TR34 L98H and TR46 Y121F T289A Cyp51 Mutations in Aspergillus fumigatus Isolates in the United States

“…Each was also at risk for invasive aspergillosis, and two had confirmed disease, including one with disseminated infection. It is not known if these isolates may have also been recovered from environmental sources, which has been reported in several studies, mainly in Europe, of A. fumigatus isolates with these mechanisms of azole resistance (9,14); however, this has not been a consistent finding (30). Of the 26 azole-resistant isolates included in this study, 6 did not contain mutations within the CYP51A gene.…”

In Vitro Activity of ASP2397 against Aspergillus Isolates with or without Acquired Azole Resistance Mechanisms

“…Acknowledging the caveat that in vitro efficacy should always be confirmed in vivo, this is obviously a finding with promising implications at a time when azole-resistant A. fumigatus strains are emerging and the only fungicidal alternative is amphotericin B, with infusion-related side effects and renal toxicity (9)(10)(11)(12)(13)(14)(15). In this context, it is noteworthy that trailing growth was not a common phenomenon at the higher concentrations such as is found for the Aspergillus fungistatic echinocandins.…”

“…The cornerstone in management of the disease is azole treatment due to the superiority of voriconazole in a randomized clinical trial and in postmarketing studies for treatment of invasive aspergillosis and the oral availability of azole drugs for outpatient treatment of chronic aspergillosis (1)(2)(3)(4)(5)(6)(7)(8). However, increasing numbers of reports document emerging azole resistance in Europe, Africa, and the Asia-Pacific region, which highlights the importance of safe and efficacious alternatives (9)(10)(11)(12)(13)(14)(15). Amphotericin B is active but is associated with significant toxicity even in its lipid formulations, and echinocandins have only static activity against Aspergillus.…”

Multiple cyp51A -Based Mechanisms Identified in Azole-Resistant Isolates of Aspergillus fumigatus from China

“…Our explanation for this genotypic diversity is that either this patient was infected by both azole-susceptible and azole-resistant A. fumigatus or Shhs18 was introduced from the hospital environment later due to the patient's extremely feeble condition (having undergone a tracheotomy procedure). However, such genotypic diversity of A. fumigatus in the same patient has been noted by others (26), lending somewhat greater weight to the former hypothesis.…”

“…The latter has been widely reported as the TR34/L98H and TR46/ Y121F/T289A mutations (26)(27)(28). In a global epidemiological survey (ARTEMIS) (29), eight strains of itraconazole-resistant A. fumigatus with a TR34/L98H mutation were isolated from Hangzhou (China).…”