of medical concern. In modern times, the primary factor contributing to the lack

considered. Antifungal resistance is a major health issue, especially for immuno-

Fungal pathogen represents a signicant clinical and industrial relevance, as well as a source of opportunistic infectious agents in individuals with compromised immune systems (Day 2017; Latgé 1999). The Aspergillus genus encompasses around 350 species, with the number of newly discovered species increasing every year. There exists an array of approximately 40 distinct species of Aspergilli, all of which have the potential to induce infections and elicit allergic responses in humans. Certain species of Aspergillus have gained medicinal importance (Kocsubé and Varga 2017; Samson and Varga 2009). Aspergillus species may infect humans with compro- mised immune systems and, less often, healthy people. The most common species is A. fumigatus (67–73%). A. avus follows with 10–16%, while A. terreus accounts for 3–4% and A. niger has the lowest laboratory rate of invasive disease (2.4%) but clinical studies show 4–8.7% of invasive aspergillosis (IA) (Pagano etal. 2001; Posch et al. 2018; Steinbach et al. 2012). As reported earlier, ~ 20% isolates of Aspergillus are resistant to the available antifungals drugs (WHO Fungal Priority Pathogens List to Guide Research 2022). There has been a notable rise in the occur­rence of cancer, viral infections such as HIV, malignancies, organ transplantation, and autoimmune diseases, which subsequently result in secondary fungal diseases (Denning etal. 2013; Zheng and Zhang 2014). The COVID-19 pandemic has added increased cases to ICUs with an estimated overall mortality of 35.5% (Armstrong and Kane 2021). Risk factors for ventilator-associated pneumonia and CAPA include dysregulation in immune system and diffuse alveolar damage in severe SARS-CoV-2 infection or therapy with corticosteroids or anti-interleukin-6 (Paramythiotou etal. 2021; Somers etal. 2021). Despite the increased number of CAPA cases, the number of CAPA cases varied greatly between hospitals and nations, with ICU reported rates ranging from 3% to 33% (Arastehfar etal. 2020).

us understand their biology and processes. High-throughput methods such as micro­array, RNA-seq, and mass spectrometry can help identify pathogenesis, virulence, and drug-resistance factor (Cerqueira et al. 2014). This book chapter examined drug-resistance mechanisms and molecular factors such as transcriptional factors genes/proteins and signaling cascades. In particular, the current study may help us understand Aspergillus drug-resistance mechanisms at the molecular and cellu­lar level.