RESUMO
Candida albicans and other pathogenic Candida species can develop resistance to clinical fungicides through active drug export mediated by multidrug efflux pumps, in particular by members of the drug:H(+) antiporter family 1 (DHA1). The DHA1 proteins encoded in the genomes of 31 hemiascomycetous strains from 25 species were identified and homology relationships between these proteins and the functionally characterised DHA1 in the model yeast Saccharomyces cerevisiae were established. Gene neighbourhood analysis allowed the reconstruction of sixteen DHA1 lineages conserved during the CTG complex species evolution. The evolutionary history of C. albicans MDR1 and FLU1 genes and Candida dubliniensis, Candida tropicalis and Candida parapsilosis MDR1 genes was detailed. Candida genomes show an abundant number of MDR1 and FLU1 homologues but the chromosome environment where MDR1 homologues reside was poorly conserved during evolution. Gene duplication and loss are major mechanisms underlying the evolution of the DHA1 genes in Candida species.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/genética , Candida/genética , Resistência a Múltiplos Medicamentos/genética , Evolução Molecular , Proteínas Fúngicas/genética , Filogenia , Sintenia , Candida/classificaçãoRESUMO
INTRODUCTION: Resistance to azole antifungals is considered as a significant problem in Candida albicans infections. Several molecular mechanisms of fluconazole resistance including alterations in the gene encoding the target enzyme ERG11 or overexpression of efflux pump genes including CDR1, CDR2, MDR1, MDR2 and FLU1 have been reported. The aim of this study was to investigate overexpression of efflux pump genes including CDR1, CDR2, MDR1, MDR2 and FLU1 in fluconazole- resistant C. albicans. MATERIAL AND METHODS: In this study, a total of 97 clinical isolates of C. albicans were isolated from hospitalized children in Children medical center, an Iranian referral hospital. Fluconazole susceptibility testing of C. albicans was performed using the broth microdilution method according to the CLSI guideline. Expression of CDR1, CDR2, MDR1, MDR2 and FLU1 genes was measured using quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) and 18SrRNA gene was used as a housekeeping gene. RESULTS: Among 97 C. albicans isolates, 5 strains were categorized as fluconazoleresistant. Overexpression of CDR1, CDR2 and MDR2 genes was found in all isolates. MDR1 overexpression was observed in four resistant isolates. None of the resistant strains displayed increases in FLU1 transcript levels. CONCLUSION: Overexpression of the CDR1, CDR2, MDR1 and MDR2 genes might play an important role in fluconazole-resistant C. albicans. No link between expression of FLU1 and fluconazole resistance was found.
Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Fluconazol/farmacologia , Proteínas Fúngicas/genética , Proteínas de Membrana Transportadoras/genética , Transportadores de Cassetes de Ligação de ATP/genética , Candida albicans/isolamento & purificação , Candida albicans/metabolismo , Candidíase/microbiologia , Criança , Farmacorresistência Fúngica , Resistência a Múltiplos Medicamentos/genética , Expressão Gênica , Humanos , Irã (Geográfico) , Testes de Sensibilidade Microbiana , RNA Ribossômico 18S/genética , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Candidiasis caused by primarily Candida albicans poses serious threat due to dry pipeline and ineffective antifungal strategy against resistance. In this study we propose to target genes involved in efflux mediated Multi drug resistance. The main objective of this study was to understand the regulatory interactions responsible for activating a major MFS transporter gene of Candida albicans. Another aim was to identify the docking effect of certain antifungal compounds upon the transcription factor effectively controlling FLU1. The in silico study carried out here aims at control of gene expression at initial levels. This approach helps to understand regulatory control of FLU1 based on which a predictive map was generated. This data focused on factors with major control that could be suitable target for antifungal agents. The docking results confirm the agreeable effect on the target transcription factor. Broadly this sort of study would account for understanding and targeting any significant gene which in turn would help in adjusting therapeutics accordingly. Further in silico ADMET analysis reported positive values that are indicative of a good antifungal compound with respect to pharmacokinetics. These tests are essential in assessment of good drug candidates because they not only help in refining better drug candidates but weeding out the unsuitable ones too.