Triazole resistance in clinical Aspergillus fumigatus isolates in India, a multicenter surveillance study.

Raees A Paul; Shivaprakash M Rudramurthy; Inderpaul S Sehgal; Umabala Pamidimukkala; Ranganathan N Iyer; Malini Capoor; Bansidhar Tarai; Anjali Shetty; Sanjay Bhattachharya; Jayanthi Savio; Shamsul Karim; Peralam Y Prakash; Immaculata Xess; Ujjwayini Ray; Anupma J Kindo; Rakesh Singh; Dipti Sharma; Kamini Walia; Harsimran Kaur; Anup Ghosh; Valliappan Muthu; Ritesh Agarwal; Rajeev Soman; Arunaloke Chakrabarti

doi:10.1016/j.diagmicrobio.2026.117541

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Triazole resistance in clinical Aspergillus fumigatus isolates in India, a multicenter surveillance study.

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Abstract

BACKGROUND: Triazole resistance in Aspergillus fumigatus is a global public health concern associated with treatment failure, notably in invasive aspergillosis. However, population-level data on triazole resistance from India remain limited, with most reports originating from single-center studies. METHODS: We conducted a multicenter surveillance study to assess the prevalence of triazole resistance among clinical A. fumigatus isolates across India. Antifungal susceptibility testing was performed using the CLSI broth microdilution method (M38-Ed3), and molecular characterization was conducted on resistant isolates. A total of 518 isolates were analyzed: 115 prospectively collected from 13 tertiary-care hospitals from 2015-2020, and 403 archived isolates obtained from the National Culture Collection of Pathogenic Fungi (1994-2020). RESULTS: The overall pooled prevalence of non-wildtype isolates was 4.1% for itraconazole (95% CI: 2.54-6.17%), 3.9% for posaconazole (95% CI: 2.39-5.94%), while 1.4% were resistant to voriconazole (95% CI: 0.55-2.77%). One multi-azole-resistant isolate from an immunocompromised, mold-active triazole-naïve patient carried the TR34/L98H mutation, suggesting environmental acquisition. Prevalence of resistance did not differ significantly across geographic regions or between public and private sector hospitals. Linear regression analysis revealed a significant temporal increase in median MICs of all three licensed triazoles between 1994 and 2020. Approximately 29% of isolates exhibited amphotericin B MICs exceeding the epidemiological cutoff value; however, the clinical significance of this finding remains uncertain. CONCLUSIONS: Azole resistance among clinical A. fumigatus isolates in India remains uncommon (<5%), supporting the continued use of triazoles as first-line therapy. However, the observed temporal increase in triazole MICs underscores the need for sustained national surveillance to detect emerging resistance trends.

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Aspergillus fumigatus Humans India Antifungal Agents Triazoles Microbial Sensitivity Tests Drug Resistance, Fungal Aspergillosis Prevalence Fungal Proteins Antifungal prophylaxis Azole resistance Invasive aspergillosis cyp51A mutation Journal Article Multicenter Study

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Raees A Paul, Shivaprakash M Rudramurthy, Inderpaul S Sehgal, Umabala Pamidimukkala, Ranganathan N Iyer, Malini Capoor, Bansidhar Tarai, Anjali Shetty, Sanjay Bhattachharya, Jayanthi Savio, Shamsul Karim, Peralam Y Prakash, Immaculata Xess, Ujjwayini Ray, Anupma J Kindo, Rakesh Singh, Dipti Sharma, Kamini Walia, Harsimran Kaur, Anup Ghosh, Valliappan Muthu, Ritesh Agarwal, Rajeev Soman, Arunaloke Chakrabarti. 2026-07-08. Triazole resistance in clinical Aspergillus fumigatus isolates in India, a multicenter surveillance study.. https://doi.org/10.1016/j.diagmicrobio.2026.117541

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