| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1139-1 | ||||
Resumo:Abstract:
Over the last years, the interest in the processes that occurs during the intermicrobial interactions between fungi and bacteria in different diseases has increased. In this context, the bacteria Pseudomonas aeruginosa and fungal species from the Scedosporium/Lomentospora genera are widespread opportunistic pathogens that are usually co-isolated in cystic fibrosis patients. The available literature reports that P. aeruginosa can inhibit the in vitro growth of Scedosporium/Lomentospora species; however, the complex mechanisms behind this phenomenon are mostly unknown. In the present work, we have explored the inhibitory effect of bioactive molecules secreted by P. aeruginosa (3 mucoid and 3 non-mucoid strains) on S. apiospermum (n = 6 strains), S. minutisporum (n = 3), S. aurantiacum (n = 6) and L. prolificans (n = 6) under cultivation in a cystic fibrosis mimic environment. It is relevant to highlight that all bacterial and fungal strains used in the present study were recovered from cystic fibrosis patients. The growth of Scedosporium/Lomentospora species was negatively affected by the direct interaction with all P. aeruginosa strains. Moreover, the fungal growth, but not the fungal mature biofilms, were inhibited by the conditioned supernatants obtained from bacteria-fungi co-cultivations and by the conditioned supernatants from the bacterial pure cultures. The direct and indirect interaction with fungal cells induced the production of the bacteria siderophores pyoverdine and pyochelin in 4/6 clinical strains of P. aeruginosa; and the induction in siderophores production was dependent on fungal active metabolism. The inhibitory effects of these four bacterial strains and their secreted molecules on fungal cells were partially reduced with the addition of 5-flucytosine, a classical repressor of pyoverdine and pyochelin production. In sum, our results demonstrated that distinct clinical strains of P. aeruginosa can behave differently towards Scedosporium/Lomentospora species, even when isolated from the same cystic fibrosis patient. Additionally, the production of siderophores by P. aeruginosa was induced when co-cultivated with Scedosporium/Lomentospora species, indicating competition for iron and deprivation of this essential nutrient, leading to fungal growth inhibition.
Development Agency: Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), and Conselho Nacional de Desenvolvimento Cienlfico e Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES; financial code—001). Mello,T.P. was supported by FAPERJ #E-26/201.993/2020 and #E-26/201.994/2020. Palavras-chave: Scedosporium/Lomentospora, Pseudomonas aeruginosa, cystic fibrosis, pyoverdine, pyochelin Agência de fomento:FAPERJ; CNPq; CAPES | |||||