Browsing by Author "Stevens, David A."
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- Activity of Diphenyl diselenide against Aspergillus isolatesPublication . Melo, Aryse Martins; Poester, Vanice Rodrigues; Munhoz, Lívia; Trápaga, Mariana; Roca, Beatriz; Klafke, Gabriel Baracy; Sabino, Raquel; Stevens, David A.; Xavier, Melissa OrzechowskiOrganoselenium compounds have been showing promising antimicrobial activity against bacteria and some fungal species. Among these compounds, diphenyl diselenide (PhSe)2 is a simple and chemically stable molecule with proven low toxicity to animal hosts. Although the mechanisms of action of this molecule are not totally clear, it has been reported that it has a prooxidative activity for microorganisms, due to glutathione depletion. Given the emergence of azole resistance Aspergillus sp. isolates is a global and rising concern, research towards new molecules with antifungal potential are necessary. Thus, the aim of this study was to evaluate the in vitro susceptibility of Aspergillus spp. clinical isolates to (PhSe)2.
- Anti-Aspergillus fumigatus IgG in patients with bronchiectasis and its relationship with clinical outcomePublication . Rodrigues Trápaga, Mariana; Rodrigues Poester, Vanice; Sanchotene, Karine Ortiz; Martins Melo, Aryse; Benelli, Jéssica Louise; Basso, Rossana Patricia; Klafke, Gabriel Baracy; Fernandes Ramos, Daniela; Veríssimo, Cristina; Sabino, Raquel; Stevens, David A.; Xavier, Melissa OrzechowskiAspergillosis is a mycosis, most commonly afecting the airways. This mycosis can worsen the clinical condition of patients with concurrent lung diseases. We assayed for the presence of serum anti-A. fumigatus IgG in bronchiectasis patients from a tertiary hospital in south Brazil and evaluated the relationship with clinical outcome. Thirty-one patients with bronchiec tasis, without cystic fbrosis, were included. Clinical and epidemiological data were collected from all participants. Positive serological tests were detected in 13% (4/31) of the patients. The mortality rate for the year following the assay was, in the seropositive group, 75% (3/4), whereas in the seronegative group, 15% (4/27). An illustrative case is also shown and discussed. Our study highlights the diagnostic challenge and the possible impact of Aspergillus infection on these patients, indicating the necessity of more and larger investigations in the feld
- Antifungal susceptibility of 175 Aspergillus isolates from various clinical and environmental sourcesPublication . Sabino, Raquel; Carolino, Elisabete; Veríssimo, Cristina; Martinez, Marife; Clemons, Karl V.; Stevens, David A.Some environmental Aspergillus spp. isolates have been described as resistant to antifungals, potentially causing an emerging medical problem. In the present work, the antifungal susceptibility profile of 41 clinical and 134 environmental isolates of Aspergillus was determined using the CLSI microdilution method. The aim of this study was to compare environmental and clinical isolates with respect to their susceptibility, and assess the potential implications for therapy of isolates encountered in different environments. To our knowledge, this is the first report comparing antifungal susceptibility profiles of Aspergillus collected from different environmental sources (poultries, swineries, beach sand, and hospital environment). Significant differences were found in the distribution of the different species sections for the different sources. Significant differences were also found in the susceptibility profile of the different Aspergillus sections recovered from the various sources. Clear differences were found between the susceptibility of clinical and environmental isolates for caspofungin, amphotericin B and posaconazole, with clinical isolates showing overall greater susceptibility, except for caspofungin. In comparison to clinical isolates, hospital environmental isolates showed significantly less susceptibility to amphotericin B and posaconazole. These data indicate that species section identity and the site from which the isolate was recovered influence the antifungal susceptibility profile, which may affect initial antifungal choices.
- Aspergillosis in free-ranging aquatic birdsPublication . Melo, Aryse Martins; Silva-Filho, Rodolfo Pinho da; Poester, Vanice Rodrigues; von Groll, Andrea; Fernandes, Cristina Gevehr; Stevens, David A.; Sabino, Raquel; Xavier, Melissa OrzechowskiDue to the difficulty in the access to free-ranging birds, data regarding Aspergillus infections in wild avian species is rare compared to captive wild and domestic birds. Objective: report three cases of Aspergillus section Fumigati causing fungal disease in free-ranging aquatic birds, with the identification of the causal agent to the species level. Case reports: The diagnosis of aspergillosis was performed by macroscopic lesions found during the necropsy and confirmed by culture. Molecular identification by partial sequencing of the calM and benA genes allowed to confirm Aspergillus fumigatus sensu stricto as the etiological agent of aspergillosis in Procellaria aequinoctialis (White-chinned petrel) (n = 1), Nannopterum brasilianus (Neotropical cormorant) (n = 1) and Chroicocephalus maculipennis (Brown-hooded gull) (n = 1). Conclusion: Larger studies regarding the importance of aspergillosis in free-ranging aquatic birds are necessary, as well as it potential role in the One Heath context.
- Aspergillosis in free-ranging Magellanic penguinsPublication . Melo, Aryse Martins; Poester, Vanice Rodrigues; Trápaga, Mariana Rodrigues; Stevens, David A.; Canabarro, Paula Lima; Adornes, Andréa Corrado; da Silva, Andrine Paiva; Estima, Sérgio Curi; Frere, Esteban; Sabino, Raquel; Xavier, Melissa OrzechowskiWe evaluated the mortality due to aspergillosis in free-ranging Magellanic penguins during their migration and the reproductive season. A total of 98 carcasses of penguins were collected along 370 km of coastline in Southern Brazil, between June 2017 and October 2019, and from reproductive colonies in Patagonian Argentina, in January 2019. All animals were necropsied, and only proven cases were computed. Aspergillosis was diagnosed in 2.5% of the penguins evaluated during their migration route. Our study, of the Southern coast of Brazil, is the first to demonstrate that aspergillosis is an important cause of mortality in free-ranging penguins. The implications of these findings in the One Health context are discussed
- Aspergillus em ambiente hospitalar: um risco para o desenvolvimento de infeções nosocomiais?Publication . Raquel, Sabino; Veríssimo, Cristina; Viegas, Carla; Brandão, João; Parada, Helena; Martins, Carlos; Furtado, Cristina; Clemons, Karl V.; Stevens, David A.
- Completion of the sequence of the Aspergillus fumigatus partitivirus 1 genomePublication . Filippou, Charalampos; Coutts, Robert H. A.; Stevens, David A.; Sabino, Raquel; Kotta-Loizou, IolyA Portuguese isolate of Aspergillus fumigatus was found to contain three double-stranded (ds) RNA elements ranging in size from 1.1 to 1.8 kbp and comprising the genome of a strain of Aspergillus fumigatus partitivirus 1 (AfuPV-1) previously thought to contain only the two largest dsRNA elements. The sequence of the smallest dsRNA element is described here, completing the sequence of the AfuPV-1 genome. Sequence analysis of the element revealed an open reading frame encoding a protein of unknown function similar in size and distantly related to elements previously identified in other members of the family Partitiviridae.
- Initial Results of the International Efforts in Screening New Agents against Candida aurisPublication . Poester, Vanice Rodrigues; Munhoz, Lívia Silveira; Benelli, Jéssica Louise; Melo, Aryse Martins; Al-Hatmi, Abdullah M.S.; Larwood, David J.; Martinez, Marife; Stevens, David A.; Xavier, Melissa OrzechowskiBackground: Candida auris is an emergent fungal pathogen and a global concern, mostly due to its resistance to many currently available antifungal drugs. Objective: Thus, in response to this challenge, we evaluated the in vitro activity of potential new drugs, diphenyl diselenide (PhSe)2 and nikkomycin Z (nikZ), alone and in association with currently available antifungals (azoles, echinocandins, and polyenes) against Candida auris. Methods: Clinical isolates of C. auris were tested in vitro. (PhSe)2 and nikZ activities were tested alone and in combination with amphotericin B, fluconazole, or the echinocandins, micafungin and caspofungin. Results: (PhSe)2 alone was unable to inhibit C. auris, and antagonism or indifferent effects were observed in the combination of this compound with the antifungals tested. NikZ appeared not active alone either, but frequently acted cooperatively with conventional antifungals. Conclusion: Our data show that (PhSe)2 appears to not have a good potential to be a candidate in the development of new drugs to treat C. auris, but that nikZ is worthy of further study.
- Molecular identification of Aspergillus isolates from Magellanic penguinsPublication . Melo, Aryse Martins; da Silva Filho, Rodolfo Pinho; Poester, Vanice Rodrigues; von Groll, Andrea; Stevens, David A.; Sabino, Raquel; Xavier, Melissa OrzechowskiAspergillosis is an important disease in marine birds and has a mortality rate of 50% in Magellanic penguins (Spheniscus magellanicus) in captivity. Molecular biology allows the precise identification of Aspergillus to species level, which is important since cryptic species may show differences in their virulence attributes and in their antifungal susceptibility. This work aimed to perform molecular identification and the itraconazole susceptibility profile of Aspergillus clinical isolates collected from Magellanic penguins with proven aspergillosis.
- Molecular identification of clinical and environmental avian Aspergillus isolatesPublication . Sabino, Raquel; Burco, Julia; Valente, Joana; Veríssimo, Cristina; Clemons, Karl V.; Stevens, David A.; Tell, Lisa A.Aspergillosis causes high morbidity and mortality in avian species. The main goal of this study was to use molecular techniques to identify Aspergillus species collected from different avian species with aspergillosis. A subsample of those isolates was also screened for resistance to itraconazole. Over a 2-year period, clinical samples were recovered from 44 birds with clinical signs of the disease, clinical pathology results suspicious of aspergillosis, or from birds that died from Aspergillus spp. infection. Environmental sampling was also performed in seabird rehabilitation centers and natural seabird environments. Seventy-seven isolates (43 clinical and 34 environmental) were identified as Aspergillus fumigatus sensu stricto. No cryptic species from the Fumigati section were detected. Two environmental isolates were identified as Aspergillus nidulans var. dentatus and Aspergillus spinulosporus. None of the Aspergillus isolates tested were resistant to itraconazole. Our study emphasizes the dominant association of Aspergillus fumigatus sensu stricto in avian mycoses and shows the lack of itraconazole resistance in the studied isolates.