RESUMEN
Abstract INTRODUCTION: Candidiasis is the most frequent opportunistic mycosis in humans and can cause mortality, particularly in immunodeficient patients. One major concern is the increasing number of infections caused by drug-resistant Candidas trains, as these cannot be efficiently treated with standard therapeutics. The most common mechanism of fluconazole resistance in Candida is mutation of ERG11, a gene involved in the biosynthesis of ergosterol, a compound essential for cell integrity and membrane function. METHODS: Based on this knowledge, we investigated polymorphisms in the ERG11 gene of 3 Candida species isolated from immunocompromised and immunocompetent patients. In addition, we correlated the genetic data with the fluconazole susceptibility profile of the Candida isolates. RESULTS: A total of 80 Candida albicans, 8 Candida tropicalis and 6 Candida glabrata isolates were obtained from the saliva of diabetic, kidney transplant and immunocompetent patients. Isolates were considered susceptible to fluconazole if the minimum inhibitory concentration was lower than 8 μg/mL. The amino acid mutations F105L, D116E, K119N, S137L, and K128T were observed in C. albicans isolates, and T224C and G263A were found in C. tropicalis isolates. CONCLUSIONS: Despite the high number of polymorphisms observed, the mutations occurred in regions that are not predicted to interfere with ergosterol synthesis, and therefore are not related to fluconazole resistance.
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Anciano , Polimorfismo Genético/efectos de los fármacos , Candida/efectos de los fármacos , Candida/genética , Fluconazol/farmacología , Trasplante de Riñón , Diabetes Mellitus/microbiología , Antifúngicos/farmacología , Valores de Referencia , Saliva/microbiología , Candida/aislamiento & purificación , ADN de Hongos/genética , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Farmacorresistencia Fúngica/genética , Inmunocompetencia , Persona de Mediana Edad , Mutación/efectos de los fármacosRESUMEN
Yeasts of the genus Candida have high genetic variability and are the most common opportunistic pathogenic fungi in humans. In this study, we evaluated the genetic diversity among 120 isolates of Candida spp. obtained from diabetic patients, kidney transplant recipients and patients without any immune deficiencies from Paraná state, Brazil. The analysis was performed using the ITS1-5.8S-ITS2 region and a partial sequence of 28S rDNA. In the phylogenetic analysis, we observed a consistent separation of the species C. albicans, C. dubliniensis, C. glabrata, C. tropicalis, C. parapsilosis, C. metapsilosis and C. orthopsilosis, however with low intraspecific variability. In the analysis of the C. albicans species, two clades were formed. Clade A included the largest number of isolates (91.2%) and the majority of isolates from GenBank (71.4%). The phylogenetic analysis showed low intraspecific genetic diversity, and the genetic polymorphisms between C. albicans isolates were similar to genetic divergence found in other studies performed with isolates from Brazil. This low genetic diversity of isolates can be explained by the geographic proximity of the patients evaluated. It was observed that yeast colonisation was highest in renal transplant recipients and diabetic patients and that C. albicans was the species most frequently isolated.
Asunto(s)
Humanos , Masculino , Femenino , Candida/genética , Candidiasis Invasiva/genética , Diabetes Mellitus/microbiología , Variación Genética , Trasplante de Riñón , Brasil/epidemiología , Candida/clasificación , Candida/aislamiento & purificación , Candidiasis Invasiva/clasificación , Candidiasis Invasiva/epidemiología , Candidiasis Invasiva/microbiología , Estudios de Casos y Controles , Complicaciones de la Diabetes , ADN de Hongos/análisis , ADN Ribosómico/genética , Pruebas de Sensibilidad MicrobianaRESUMEN
Um dos maiores problemas de Saúde Pública das últimas décadas foi o agravamento da resistência a antimicrobianos; a qual em estafilococos é resultado de genes cromossômicos que codificam modificações no receptor de ação dos lactâmicos, as proteínas ligadoras de penicilinas (PBPs), havendo a produção PBPs a, essa modificação é devido ao gene mecA, onde uma seqüência de DNA de origem não estafilocócica é incorporado ao cromossomo. O Objetivo do presente estudo foi avaliar o perfil de resistência dos Staphylococcus aureus a, β-lactâmicos em uruculturas, devido a presença de gene mecA. A metodologia consistiu, em semear a urina no meio BP. Após o crescimento realizou-se provas bioquímicas para identificação de S. aureus (Gram, catalase e coagulase); após a confirmação, realizou-se o antibiograma com oxacilina 1µg, considerando resistentes halos menores que 13 mm, para confirmar o gene mecA, inoculou-se as colônias resistentes em meio MH, com oxacilina à 6µg/mL. Foi considerado positivo o crescimento microbiano. Com os resultados foi possível isolar 388 colônias, sendo 36 ,β-lactamases positiva, resistentes a oxacilina, ou seja, 9,27%, dessas 69,44% (26 colônias) foram identificadas como portadoras do gene mecA, a qual sugere a probabilidade de transferência horizontal de genes entre espécies distintas.