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Previous issue date: 2015-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / V?rios estudos t?m sido desenvolvidos com rela??o aos riscos ? sa?de humana associados ao
uso recreativo de praias contaminadas com esgotos dom?sticos. Esses res?duos cont?m v?rios
micro-organismos, incluindo Candida tropicalis, agente etiol?gico tanto de infec??es
superficiais quanto sist?micas, al?m de indicador de contamina??o fecal do meio ambiente.
Nesse contexto, o presente trabalho teve como objetivo caracterizar isolados de C. tropicalis
oriundos da areia da Praia de Ponta Negra, Natal, Rio Grande do Norte, Brasil, quanto a
express?o de fatores de virul?ncia in vitro, a adapta??o ao estresse osm?tico e a
susceptibilidade ?s f?rmacos antif?ngicos. Foram analisados 62 isolados ambientais de C.
tropicalis, observando-se grande varia??o entre os mesmos para os diversos fatores de
virul?ncia avaliados. Em geral, os isolados ambientais foram mais aderentes a c?lulas
epiteliais bucais humanas (CEBH) do que a cepa de refer?ncia de C. tropicalis ATCC13803,
al?m de serem altamente produtoras de biofilme. Em rela??o ? morfog?nese, a maioria dos
isolados exibiu fen?tipo rugoso em meio Spider (34 isolados, 54,8%). Na avalia??o da
atividade enzim?tica, a maioria dos isolados teve maior produ??o de proteinase do que a cepa
de refer?ncia de C. tropicalis ATCC13803. Adicionalmente, 35 isolados (56,4%) tiveram alta
atividade hem?litica (?ndice de hem?lise > 55). Com rela??o ? resist?ncia de C. tropicalis ao
estresse osm?tico, 85,4% dos isolados foram resistentes em meio contendo 15% de cloreto de
s?dio, o que corrobora com a alta capacidade de sobreviv?ncia descrita para essa levedura no
ambiente mar?timo. Finalmente, no que diz respeito ? sensibilidade aos antif?ngicos foi
observada elevada resist?ncia aos az?licos testados (fluconazol, voriconazol e itraconazol),
com ocorr?ncia do fen?meno ?Low-high? e de efeito semelhante ao crescimento paradoxal
que ocorre para as equinocandinas. As cepas resistentes aos tr?s az?licos testados foram 15
(24,2%). Para a anfotericina B tamb?m ocorreu resist?ncia (14 isolados, 22,6%), ao passo
que para as equinocandinas todas as cepas foram sens?veis. Portanto, nossos resultados
demonstram que isolados de C. tropicalis oriundos da areia de praia do nordeste brasileiro
podem expressar plenamente atributos de virul?ncia e apresentam alta capacidade de
persist?ncia no ambiente costeiro, al?m de serem significativamente resistentes aos
antif?ngicos mais empregados na pr?tica cl?nica atual. Isso constitui potencial risco ? sa?de
dos frequentadores desse ambiente, especialmente indiv?duos imunocomprometidos e em
extremos et?rios. / Several studies have been developed regarding health risks associated with the recreational
use of beaches contaminated with domestic sewage. These wastes contain various microorganisms,
including Candida tropicalis, etiologic agent of both superficial infections such as
systemic, as well as indicator of fecal contamination for the environment. In this context, the
objective of this study was to characterize C. tropicalis isolates from the sandy beach of
Ponta Negra, Natal, Rio Grande do Norte, Brazil, regarding the expression of in vitro
virulence factors, adaptation to osmotic stress and susceptibility to antifungal drugs. We
analyzed 62 environmental isolates of C. tropicalis and observed a great variation between
them for the various virulence factors evaluated. In general, environmental isolates were
more adherent to CEBH than C. tropicalis ATCC13803 reference strain, besides the fact they
were also highly biofilm producers. In relation to morphogenesis, most isolates presented
wrinkled phenotype in Spider medium (34 isolates, 54.8 %). When assessing enzyme
activity, most isolates had higher proteinase production than C. tropicalis ATCC13803
reference strain. In addition, 35 isolates (56.4 %) had high hemolytic activity (hemolysis
index > 55). With regard to C. tropicalis resistance to osmotic stress, 85.4% of the isolates
were able to grow in a liquid medium containing 15% sodium chloride, corroborating to high
survival capacity described for this yeast at marine environment. Finally, with regard to
sensitivity to antifungal drugs, it was observed high resistance to the azoles tested, with the
occurrence of the "Low-high" phenomenon and similar effect to the paradoxical growth
which occurs to the echinocandins. For the three azoles tested we verified that 15 strains were
resistant (24.2 %). Some strains were also resistant to amphotericin B (14 isolates, 22.6 %),
while all of them were sensitive for the echinocandins tested. Therefore, our results
demonstrate that C. tropicalis isolated from the sand of northeast of Brazil can fully express
virulence attributes and showed a high persistence capacity on the coastal environment, in
addition of being significantly resistant to most applied antifungals in current clinical
practice. This constitutes a potential health risk to visitors of this environment, especially
immunocompromised individuals and those with extreme age range.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/20304 |
| Date | 26 March 2015 |
| Creators | Alves, Diana Luzia Zuza |
| Contributors | 25849518860, http://lattes.cnpq.br/1463249528959656, Pedrosa, Matheus de Freitas Fernandes, 96728647449, Melo, Analy Salles de Azevedo, 01170549845, Chaves, Guilherme Maranh?o |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIAS FARMACEUTICAS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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