Monitoramento de ar hospitalar; Fungos filamentosos; Aspergillus; Sequenciamento genético; Sensibilidade antifúngica.
Name: JHULLY PIMENTEL
Publication date: 06/12/2024
Examining board:
Name |
Role |
|---|---|
| KENIA VALERIA DOS SANTOS | Examinador Interno |
| PATRICIO GODOY MARTINEZ | Examinador Externo |
| SARAH GONCALVES TAVARES | Presidente |
Summary: Analyzing indoor air quality in hospitals is essential for understanding the fungal microbiota in the environment. This analysis helps assess health risks to patients and healthcare professionals, address antifungal resistance, and implement more effective control measures. This study aimed to evaluate the occurrence and diversity of filamentous fungi in the air of two hospital wards at Cassiano Antônio Moraes University Hospital (HUCAM) from November 2022 to September 2023. Eight air samplings were conducted, with two samples collected per season. The evaluation focused on two wards located on different floors, each with distinct ventilation systems. The ward Q2, located on the second floor, utilized natural ventilation from November 2022 to January 2023 and switched to split air conditioning from March to September 2023. In contrast, Ward Q4, situated on the fourth floor, used split air conditioning throughout the entire period. For air sampling, a six-stage air sampler equipped with Petri dishes containing Sabouraud dextrose agar (SDA) supplemented with 0.5% chloramphenicol was employed. Each sampling session lasted 30 minutes and was conducted in both the rooms and bathrooms (both dry and humid). Climatic parameters, specifically temperature and relative humidity, were monitored throughout the study. Petri dishes containing Sabouraud Dextrose Agar (SDA) with visible fungal growth were quantified, and the fungi were re-isolated and identified morphologically. Aspergillus isolates were characterized using both macromorphological and micromorphological techniques, as well as through DNA sequencing of the beta-tubulin gene region. Additionally, in vitro antifungal susceptibility testing was conducted on these isolates against various antifungal agents, including amphotericin B (AMB), itraconazole (ITR), posaconazole (POS), voriconazole (VOR), and anidulafungin (AND). The testing was performed using the broth microdilution method, following the Clinical and Laboratory Standards Institute (CLSI) document M38-A2 from 2008. During the study, noticeable clinical differences were observed among patients hospitalized across different wards. The fourth floor had a higher number of patients susceptible to fungal infections. On the second floor, during the first analysis period, which featured natural ventilation, the fungal concentration varied between 50 CFU/m³ and 458 CFU/m³. After the installation of air conditioning in the second period, the variation in fungal concentration decreased, ranging between 33 CFU/m³ and 172 CFU/m³. In contrast, the fourth floor did not have any changes to its ventilation system, and the fungal concentration variation was lower, ranging from 29 to 187 CFU/m³. Climatic parameter results indicated that the second-floor experienced higher temperatures and relative humidity compared to the fourth floor, even after changes to the ventilation system. During the study, a total of 583 filamentous fungi isolates were identified and categorized into 17 different fungal genera. Autumn exhibited the highest diversity of fungal genera, with 13 out of the 17 (76.5%), while winter showed the lowest diversity, having only eight genera (47.06%). The predominant genera identified included Penicillium (38.59%, n=225/583), Cladosporium (29.99%, n=169/583), and Aspergillus (6.35%, n=37/583). There were fewer occurrences of other genera such as Curvularia (n=4/583, 0.69%), Lomentospora (n=2/583, 0.34%), Alternaria (n=1/583, 0.17%), and Fusarium (n=1/583, 0.17%). Among the recovered Aspergillus isolates, 37 were identified, with the highest occurrences in summer (n=14/583, 2.4%) and spring (n=9/583, 1.5%). Phylogenetic analysis allowed for a detailed examination of 27 Aspergillus isolates, which were identified at the species level and categorized into eight sections and 14 distinct species. The in vitro susceptibility tests revealed significant findings regarding fungal isolates. Of the A. fumigatus isolates, three (75%) were identified as non-wild type for ITR (CIM 1 g/mL), alongside one A. flavus isolate. Emerging Aspergillus species demonstrated elevated CIMs for triazoles. Similarly, some emerging species from the section Circumdati showed higher CIMs for AMB. Notably, all isolates exhibited low CIMs for AND, ranging from 0.03 to 0.5 g/mL. These findings highlight the considerable diversity of filamentous fungi present in the air of hospital wards, particularly the prevalence of pathogenic genera. The implications of this study emphasize the urgent need for continuous monitoring of these pathogens in indoor hospital environments to prevent fungal infections. Additionally, it supports the development of air management control strategies and informs periodic mycological analyses, especially in areas with high-risk patients.
