GILDA MARIA BARBARO DEL NEGRO
Projetos de Pesquisa
Unidades Organizacionais
LIM/53 - Laboratório de Micologia, Hospital das Clínicas, Faculdade de Medicina
3 resultados
Resultados de Busca
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- An Azole-Resistant Candida parapsilosis Outbreak: Clonal Persistence in the Intensive Care Unit of a Brazilian Teaching Hospital(2018) THOMAZ, Danilo Yamamoto; ALMEIDA JR., Joao Nobrega de; LIMA, Glaucia Moreira Espindola; NUNES, Maina de Oliveira; CAMARGO, Carlos Henrique; GRENFELL, Rafaella de Carvalho; BENARD, Gil; NEGRO, Gilda M. B. DelThe incidence of candidemia by the Candida parapsilosis complex has increased considerably in recent decades, frequently related to use of indwelling intravascular catheters. The ability of this pathogen to colonize healthcare workers (HCW)' hands, and to form biofilm on medical devices has been associated with the occurrence of nosocomial outbreaks and high mortality rates. Fluconazole has been the leading antifungal drug for the treatment of invasive candidiasis in developing countries. However, azole-resistant C. parapsilosis isolates are emerging worldwide, including in Brazil. Few studies have correlated outbreak infections due to C. parapsilosis with virulence factors, such as biofilm production. We thus conducted a microbiological investigation of C. parapsilosis complex isolates from a Brazilian teaching hospital. Additionally, we identified a previously unrecognized outbreak caused by a persistent azole-resistant C. parapsilosis (sensu stricto) clone in the intensive care unit (ICU), correlating it with the main clinical data from the patients with invasive candidiasis. The molecular identification of the isolates was carried out by PCR-RFLP assay; antifungal susceptibility and biofilm formation were also evaluated. The genotyping of all C. parapsilosis (sensu stricto) was performed by microsatellite analysis and the presence of ERG11 mutations was assessed in the azole non-susceptible isolates. Fourteen C. parapsilosis (sensu stricto) isolates were recovered from patients with invasive candidiasis, eight being fluconazole and voriconazole-resistant, and two intermediate only to fluconazole (FLC). All non-susceptible isolates showed a similar pattern of biofilm formation with low biomass and metabolic activity. The A395T mutation in ERG11 was detected exclusively among the azole-resistant isolates. According to the microsatellite analysis, all azole non-susceptible isolates from the adult ICU were clustered together indicating the occurrence of an outbreak. Regarding clinical data, all patients infected by the clonal non-susceptible isolates and none of the patients infected by the susceptible isolates had been previously exposed to corticosteroids (p=0.001), while the remaining characteristics showed no statistical significance. The current study revealed the persistence of an azole non-susceptible C. parapsilosis clone with low capacity to form biofilm over two years in the adult ICU. These results reinforce the need of epidemiological surveillance and monitoring antifungal susceptibility of C. parapsilosis isolates in hospital wards.
- Identification of Candida haemulonii Complex Species: Use of ClinProTools (TM) to Overcome Limitations of the Bruker Biotyper (TM), VITEK MS (TM) IVD, and VITEK MS (TM) RUO Databases(2016) GRENFELL, Rafaella C.; SILVA JUNIOR, Afonso R. da; NEGRO, Gilda M. B. Del; MUNHOZ, Regina B.; GIMENES, Viviane M. F.; ASSIS, Diego M.; ROCKSTROH, Anna C.; MOTTA, Adriana L.; ROSSI, Flavia; JULIANO, Luiz; BENARD, Gil; ALMEIDA JUNIOR, Joao N. deCandida haemulonli is now considered a complex of two species and one variety: C. haemulonii sensu strict, Candida duobushaemulonii and the variety C. haemulonii var. vulnera. Identification (ID) of these species is relevant for epidemiological purposes and for therapeutic management, but the different phenotypic commercial systems are unable to provide correct species ID for these emergent pathogens. Hence, we evaluated the MALDI-TOF MS performance for the ID of C. haemulonli species, analyzing isolates/strains of C. haemulonli complex species, Candida pseudohaemulonii and Candida auris by two commercial platforms, their databases and softwares. To differentiate C. haemulonli sensu sctricto from the variety vulnera, we used the ClinProTools (TM) models and a single-peak analysis with the software FlexAnalysis (TM). The Biotyper (TM) database gave 100% correct species ID for C. haemulonii sensu strict, C. pseudohaemulonii and C. auris, with 69% of correct species ID for C. duobushaemulonii. Vitek MS (TM) IVD database gave 100% correct species ID for C. haemulonii sensu stricto, misidentifying all C. duobushaemulonii and C. pseudohaemulonii as C. haemulonii, being unable to identify C. auris. The Vitek MS (TM) RUO database needed to be upgraded with in-house SuperSpectra to discriminate C. haemulonii sensu stricto, C. duobushaemulonii, C. pseudohaemulonii, and C. auris strains/isolates. The generic algorithm model from ClinProTools (TM) software showed recognition capability of 100% and cross validation of 98.02% for the discrimination of C. haemulonli sensu stricto from the variety vulnera. Single-peak analysis showed that the peaks 5670, 6878, or 13750 m/z can distinguish C. haemulonli sensu stricto from the variety vulnera.
- Polymorphism in Mitochondrial Group I Introns among Cryptococcus neoformans and Cryptococcus gattii Genotypes and Its Association with Drug Susceptibility(2018) GOMES, Felipe E. E. S.; ARANTES, Thales D.; FERNANDES, Jose A. L.; FERREIRA, Leonardo C.; ROMERO, Hector; BOSCO, Sandra M. G.; OLIVEIRA, Maria T. B.; NEGRO, Gilda M. B. Del; THEODORO, Raquel C.Cryptococcosis, one of the most important systemic mycosis in the world, is caused by different genotypes of Cryptococcus neoformans and Cryptococcus gattii, which differ in their ecology, epidemiology, and antifungal susceptibility. Therefore, the search for new molecular markers for genotyping, pathogenicity and drug susceptibility is necessary. Group I introns fulfill the requisites for such task because (i) they are polymorphic sequences; (ii) their self-splicing is inhibited by some drugs; and (iii) their correct splicing under parasitic conditions is indispensable for pathogen survival. Here, we investigated the presence of group I introns in the mitochondrial LSU rRNA gene in 77 Cryptococcus isolates and its possible relation to drug susceptibility. Sequencing revealed two new introns in the LSU rRNA gene. All the introns showed high sequence similarity to other mitochondrial introns from distinct fungi, supporting the hypothesis of an ancient non-allelic invasion. Intron presence was statistically associated with those genotypes reported to be less pathogenic (p < 0.001). Further virulence assays are needed to confirm this finding. In addition, in vitro antifungal tests indicated that the presence of LSU rRNA introns may influence the minimum inhibitory concentration (MIC) of amphotericin B and 5-fluorocytosine. These findings point to group I introns in the mitochondrial genome of Cryptococcus as potential molecular markers for antifungal resistance, as well as therapeutic targets.