Browsing by Subject "Bioaerosols"

Now showing 1 - 4 of 4
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    Antibiotic resistance genes detected in lichens: insights from Cladonia stellaris
    (Oxford University Press, 2025-09-22) Paul B. L. George; Samantha Leclerc; Marc Veillette; Caroline Duchaine; Juan Carlos Villarreal A.; Alonso García, Marta; Biología Vegetal; Institut de Biologie Intégrative et des Systèmes
    Background and Aims Antibiotics are natural compounds produced by microorganisms that have long existed in ecosystems. However, the widespread clinical and agricultural use of antibiotics has intensified selective pressures on bacteria, leading to the proliferation of antibiotic resistance genes (ARGs). The increasing prevalence of these genetic elements in clinical and environmental settings now poses a major global health threat. While ARGs are well documented in anthropogenically influenced environments, their distribution and origins in remote ecosystems, such as boreal forests, remain poorly understood. Here, we investigate the occurrence, diversity and potential origins of ARGs in the boreal lichen Cladonia stellaris. Methods We conducted the first targeted assessment of ARGs in lichens by analysing 42 C. stellaris samples from northern and southern lichen woodlands in eastern Canada. Using high-throughput quantitative PCR, we screened for 33 ARGs and three mobile genetic elements (MGEs), quantifying their relative abundance. Bacterial community composition was characterized via 16S rRNA gene sequencing. Statistical analyses evaluated geographical patterns, co-occurrence between ARGs and bacterial taxa, and the influence of latitude on ARG distribution. Key Results Ten ARGs conferring resistance to four antibiotic classes (aminoglycosides, beta-lactams, quinolones and sulfonamides), along with one MGE, were detected. The ARGs blaCTX-M-1, qnrB and qepA were highly prevalent, with qepA often surpassing 16S rRNA gene abundance. Only qnrB showed significantly higher abundance in southern samples. Latitude significantly influenced ARG profiles, whereas bacterial community composition did not. Conclusions Our findings demonstrate that C. stellaris harbours diverse ARGs in remote boreal ecosystems with limited anthropogenic influence. Proposed explanations for ARG presence include long-distance dispersal via bioaerosols and endogenous development within lichen microbiomes, yet these remain speculative. Future work incorporating bacterial isolation, whole-genome sequencing, metatranscriptomics, air sampling and metabolomic profiling is necessary to unravel the ecology and evolution of ARGs in natural habitats.
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    Distribution of airborne pollen, fungi and bacteria at four altitudes using high-throughput DNA sequencing
    (Elsevier, 2020-10-11) Sánchez-Parra, Beatriz; Núñez, Andrés; García, Ana M.; Campoy, Pascual; Moreno, Diego A.; Genética y Microbiología
    The diversity and composition of bioaerosols in the atmosphere have been studied in the recent years in multiple places and under very different meteorological conditions. Pollen grains, fungal propagules and bacteria are the most studied airborne biological particles, usually individually, and correlated to environmental factors such as temperature, wind speed, rain, air pollution, etc. to understand their influence. However, the effect of the height on the distribution and composition of these bioaerosols has not been properly described so far. In this research, we analyzed concurrently these three biological particles at four different heights (1.5 m, 130 m, 500 m and 1000 m) by high-throughput DNA sequencing. We observed that the atmosphere contains a homogeneous distribution and composition of biological particles regardless of the altitude tested. Only a minority of the taxa is differently distributed. Therefore, we here deduce that the altitude does not drastically influence the airborne bioparticles distribution and composition under similar meteorological conditions. We also studied the co-occurrence between different bioaerosols, finding new potential relationships.
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    Effect of the passive natural ventilation on the bioaerosol in a small room
    (Elsevier, 2021-10-13) Núñez, Andrés; García, Ana M.; Genética y Microbiología
    Natural passive ventilation (windows opening) is frequently used in many houses and old buildings to renovate the air, remove unpleasant odors and dust, and reduce the physicochemical pollutants indoor. However, little is known about the effect on biological particles such as pollen grains and fungal spores (both allergenic) or bacteria (potentially infectious and pathogenic). In the present research, the bioaerosols composition in a small room naturally ventilated was analyzed by high-throughput DNA sequencing. Pollen grains were the most abundant particles outdoors while microbial phyla Actinobacteria, Firmicutes, Proteobacteria and Ascomycota were predominant indoors. The main divergences in bioaerosols between indoor and outdoor environments were caused by the different abundance of the biological particles rather than the different taxa composition. Keeping the window open for 2 h did not change significantly the microbial community present indoors, although there was a tendency to mix the components of both environments. The abundance of human-related and potentially harmful microorganisms was higher indoors and was not remarkably affected by natural ventilation. In our study, natural ventilation through window opening had a poor effect on removing these microorganisms from the atmosphere indoor, suggesting that additional mechanisms such as air filtering systems would be required in order to improve the air quality of these environments from a microbiological point of view.
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    The aerobiome in a hospital environment: characterization, seasonal tendencies and the effect of window opening ventilation
    (Elsevier, 2023-01-16) Núñez, Andrés; García, Ana M.; Genética y Microbiología
    The urban atmosphere carries biological particles (bioaerosols) that may cause several diseases and allergies. These bioaerosols infiltrate and mix with those present inside the buildings, including hospitals. However, little is known about the behavior of these particles around health facilities. Here, we described the bioaerosols composition of an urban hospital indoor and outdoor at two different periods (winter and summer) using DNA sequencing. We observed that the seasonality and composition of the bioaerosols outdoor was also displayed indoor, and, in some cases, the taxa showed different trends depending on the season. Pathogenic species of bacteria and fungi were found indoors at low levels but also outdoors, being mostly environmental species, which would reject the idea that hospitals may be acting as a source of emission via aerosols. Skin-related bacteria were the most prevalent group related to human microbiome, being more abundant indoors. Air temperature was the principal factor affecting the bioaerosols composition in the samples but, in general, meteorological parameters outdoors were poor descriptors of the bioaerosols indoors. Similarly, the concentrations of the main indoor air pollutants did not correlate with microbial abundances. Globally, natural ventilation through a window opening did not significantly alter the composition of the bioaerosols indoor.