title: Evaluation of Virulence FactorsIn vitro, Resistance to Osmotic Stress and Antifungal Susceptibility ofCandida tropicalisIsolated from the Coastal Environment of Northeast Brazil.
abstract: Several studies have been developed regarding human health risks associated with the recreational use of beaches contaminated with domestic sewage. These wastes contain various micro-organisms, includingCandida tropicalis. In this context, the objective of this study was to characterizeC. tropicalisisolates from the sandy beach of Ponta Negra, Natal, Rio Grande do Norte, Brazil, regarding the expression ofin vitrovirulence factors, adaptation to osmotic stress and susceptibility to antifungal drugs. We analyzed 62 environmental isolates and observed a great variation among them for the various virulence factors evaluated. In general, environmental isolates were more adherent to human buccal epithelial cells (HBEC) thanC. tropicalisATCC13803 reference strain, and they also showed increased biofilm production. Most of the isolates presented wrinkled phenotypes on Spider medium (34 isolates, 54.8%). The majority of the isolates also showed higher proteinase production than control strains, but low phospholipase activity. In addition, 35 isolates (56.4%) had high hemolytic activity (hemolysis index > 0.55). With regard toC. tropicalisresistance to osmotic stress, 85.4% of the isolates were able to grow in a liquid medium containing 15% sodium chloride. The strains were highly resistant to the azoles tested (fluconazole, voriconazole and itraconazole). Fifteen strains were resistant to the three azoles tested (24.2%). Some strains were also resistant to amphotericin B (14 isolates; 22.6%), while all of them were susceptible for the echinocandins tested, except for a single strain of intermediate susceptibility to micafungin. Our results demonstrate thatC. tropicalisisolated from the sand can fully express virulence attributes and showed a high persistence capacity on the coastal environment; in addition of showing high minimal inhibitory concentrations to several antifungal drugs used in current clinical practice, demonstrating that environmental isolates may have pathogenic potential.
authors.affiliation: Medical and Molecular Micology Laboratory, Department of Clinical and Toxicological Analyses, Federal University of Rio Grande do Norte Natal, Brazil.
authors.forename: Diana L
authors.initials: DL
authors.lastname: Zuza-Alves
authors.affiliation: Medical and Molecular Micology Laboratory, Department of Clinical and Toxicological Analyses, Federal University of Rio Grande do Norte Natal, Brazil.
authors.forename: Sayama S T Q
authors.initials: SS
authors.lastname: de Medeiros
authors.affiliation: Medical and Molecular Micology Laboratory, Department of Clinical and Toxicological Analyses, Federal University of Rio Grande do Norte Natal, Brazil.
authors.forename: Luanda B F C
authors.initials: LB
authors.lastname: de Souza
authors.affiliation: Medical and Molecular Micology Laboratory, Department of Clinical and Toxicological Analyses, Federal University of Rio Grande do Norte Natal, Brazil.
authors.forename: Walicyranison P
authors.initials: WP
authors.lastname: Silva-Rocha
authors.affiliation: Department of Mycology, Federal University of Pernambuco São Paulo, Brazil.
authors.forename: Elaine C
authors.initials: EC
authors.lastname: Francisco
authors.affiliation: Department of Oceanography and Limnology, Federal University of Rio Grande do Norte Natal, Brazil.
authors.forename: Maria C B
authors.initials: MC
authors.lastname: de Araújo
authors.affiliation: Department of Tropical Medicine, Federal University of Pernambuco Recife, Brazil.
authors.forename: Reginaldo G
authors.initials: RG
authors.lastname: Lima-Neto
authors.affiliation: Department of Mycology, Federal University of Pernambuco, Recife Pernambuco, Brazil.
authors.forename: Rejane P
authors.initials: RP
authors.lastname: Neves
authors.affiliation: Department of Mycology, Federal University of Pernambuco São Paulo, Brazil.
authors.forename: Analy S de Azevedo
authors.initials: AS
authors.lastname: Melo
authors.affiliation: Medical and Molecular Micology Laboratory, Department of Clinical and Toxicological Analyses, Federal University of Rio Grande do Norte Natal, Brazil.
authors.forename: Guilherme M
authors.initials: GM
authors.lastname: Chaves
keywords: Candida tropicalis; antifungal susceptibility; coastal environment; osmotic stress; virulence factors