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BACKGROUND: Approximately 60% of individuals with cystic fibrosis (CF) are affected by Aspergillus fumigatus infection. This condition is correlated with a decline in lung function and is identified as an independent risk factor contributing to hospital admissions among CF patients. This study investigates the dynamic interplay of A. fumigatus within the context of CF patients, tracing its evolution over time, with a specific emphasis on colonization dynamics. METHODS: An analysis was conducted on 83 sequential A. fumigatus isolates derived from sputum samples of six patients receiving care at a renowned CF hospital in Brazil. Employing microsatellite genotyping techniques, alongside an investigation into cyp51A gene mutations, this research sheds light on the genetic variations, colonization, and resistance of A. fumigatus within the CF respiratory environment. RESULTS: Our research findings indicate that CF patients can harbor A. fumigatus strains from the same clonal complexes for prolonged periods. Additionally, we identified that clinical isolates have the potential to spread among patients in the same healthcare facility, evidencing hospital contamination. Two patients who underwent long-term Itraconazole treatment did not show phenotypic resistance. However, one of these patients exhibited mutations in the cyp51A gene, indicating the need to monitor resistance to azoles in these patients colonized for long periods by A. fumigatus. We also observed co-colonization or co-infection involving multiple genotypes in all patients over time. CONCLUSION: This comprehensive examination offers valuable insights into the pathogenesis of A. fumigatus infections in CF patients, potentially shaping future therapeutic strategies and management approaches. This enhanced understanding contributes to our knowledge of A. fumigatus impact on disease progression in individuals with cystic fibrosis. Additionally, the study provides evidence of cross-contamination among patients undergoing treatment at the same hospital.
RESUMEN
Aspergillus stands as the predominant fungal genus in the airways of cystic fibrosis (CF) patients, significantly contributing to their morbidity and mortality. Aspergillus fumigatus represents the primary causative species for infections, though the emergence of rare species within the Aspergillus section Fumigati has become noteworthy. Among these, Aspergillus lentulus is particularly significant due to its frequent misidentification and intrinsic resistance to azole antifungal agents. In the management of invasive aspergillosis and resistant infections, combination antifungal therapy has proven to be an effective approach. This report documents a case involving the death of a CF patient due to a pulmonary exacerbation linked to the colonization of multiple Aspergillus species, including A. lentulus, A. fumigatus, and A. terreus, and treated with Itraconazole (ITC) monotherapy. We delineated the procedures used to characterize the Aspergillus isolates in clinical settings and simulated in vitro the impact of the combination antifungal therapy on the isolates obtained from the patient. We evaluated three different combinations: Amphotericin B (AMB)+Voriconazole (VRC), AMB+Anidulafungin (AND), and VRC+AND. Notably, all strains isolated from the patient exhibited a significant decrease in their minimum inhibitory concentration (MIC) or minimum effective concentration (MEC) values when treated with all antifungal combinations. The VRC+AMB combination demonstrated the most synergistic effects. This case report emphasizes the critical importance of susceptibility testing and precise identification of Aspergillus species to enhance patient prognosis. It also underscores the potential benefits of combined antifungal treatment, which, in this case, could have led to a more favourable patient outcome.
RESUMEN
BACKGROUND: Aspergillus fumigatus is an important concern for immunocompromised individuals, often resulting in severe infections. With the emergence of resistance to azoles, which has been the therapeutic choice for Aspergillus infections, monitoring the resistance of these microorganisms becomes important, including the search for mutations in the cyp51A gene, which is the gene responsible for the mechanism of action of azoles. We conducted a retrospective analysis covering 478 A. fumigatus isolates. METHODS: This comprehensive dataset comprised 415 clinical isolates and 63 isolates from hospital environmental sources. For clinical isolates, they were evaluated in two different periods, from 1998 to 2004 and 2014 to 2021; for environmental strains, one strain was isolated in 1998, and 62 isolates were evaluated in 2015. Our primary objectives were to assess the epidemiological antifungal susceptibility profile; trace the evolution of resistance to azoles, Amphotericin B (AMB), and echinocandins; and monitor cyp51A mutations in resistant strains. We utilized the broth microdilution assay for susceptibility testing, coupled with cyp51A gene sequencing and microsatellite genotyping to evaluate genetic variability among resistant strains. RESULTS: Our findings reveal a progressive increase in Minimum Inhibitory Concentrations (MICs) for azoles and AMB over time. Notably, a discernible trend in cyp51A gene mutations emerged in clinical isolates starting in 2014. Moreover, our study marks a significant discovery as we detected, for the first time, an A. fumigatus isolate carrying the recently identified TR46/F495I mutation within a sample obtained from a hospital environment. The observed cyp51A mutations underscore the ongoing necessity for surveillance, particularly as MICs for various antifungal classes continue to rise. CONCLUSIONS: By conducting resistance surveillance within our institution's culture collection, we successfully identified a novel TR46/F495I mutation in an isolate retrieved from the hospital environment which had been preserved since 1998. Moreover, clinical isolates were found to exhibit TR34/L98H/S297T/F495I mutations. In addition, we observed an increase in MIC patterns for Amphotericin B and azoles, signaling a change in the resistance pattern, emphasizing the urgent need for the development of new antifungal drugs. Our study highlights the importance of continued monitoring and research in understanding the evolving challenges in managing A. fumigatus infections.
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The performance of a visual slide-based DNA microarray for the identification of non-albicans Candida spp. was evaluated. Among 167 isolates that had previously been identified by Vitek 2, the agreement between DNA microarray and sequencing results was 97.6%. This DNA microarray platform showed excellent performance.