ABSTRACT
BACKGROUND: Candida albicans remains the main cause of candidiasis in most clinical settings. Available drugs for candidiasis treatment have many side effects. In this work, novel nitroglycerin derivatives were synthesized and their cytotoxic and antifungal effects evaluated against fluconazole susceptible and resistant clinical C. albicans isolates. METHODS: This experimental study was performed in Tehran University of Medical Sciences and Baqiatallah University of Medical Sciences, Tehran, Iran between Feb to Dec 2019. The in vitro activities of two novel nitroglycerin derivatives (1b and 2b) against 25 clinical fluconazole-susceptible and resistant C. albicans isolates and four standard C. albicans strains were determined according to CLSI reference M27-A3 documents. The cytotoxicity of chemical compounds was investigated near the SNL76/7 cells by colorimetric assay. Real-time PCRs were performed to evaluate the alterations in the regulation of ERG11 and CDR1 genes under nitroglycerin derivatives-treated and untreated conditions. RESULTS: The derivatives 1b and 2b exhibited potent antifungal activity against C. albicans isolates; MICs and MFCs varied from 18 µg/ml to 72 µg/ml and 36 µg/ml to 144 µg/ml, respectively. The cell viability evaluation demonstrated that both chemical compounds are safe within 24h. The nitroglycerin derivatives were able to reduce the transcription level of CDR1 and ERG11 genes in all susceptible and resistant C. albicans isolates. CONCLUSION: Considering the potential and efficacy of these compounds against clinical C. albicans isolates, the complementary in vivo and clinical trials should be investigated.
ABSTRACT
BACKGROUND: Global reports have highlighted the increasing prevalence of Candida tropicalis infections as well as organism(') s drug resistance. This study aimed at identifying azole resistance markers in clinical isolates of C. tropicalis, which will be a great resource for developing new drugs. METHODS: Two susceptible and resistant isolates of C. tropicalis were recovered from an epidemiological investigation of candidiasis in immunocompromised patients. C. tropicalis ATCC 750 was used as reference strain. Antifungal susceptibility to fluconazole and itraconazole was determined using Clinical and Laboratory Standards Institute (CLSI) method. Complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) technology and real-time reverse-transcriptase (RT) PCR were used for identification of potential genes involved in azole resistance of C. tropicalis clinical isolates. RESULTS: Five genes encoding the following enzymes were identified as superoxide dismutase (SOD) implicated in antioxidant defense, ornithine aminotransferase (OAT), acetyl ornithine aminotransferase (ACOAT), adenosylmethionine-8-amino-7-oxononanoate aminotransferase (DAPA AT), and 4-aminobutyrate aminotransferase (ABAT)-belonging to pyridoxal phosphate (PLP) dependent enzymes and acting in an important physiological role in many fungal-cell cycles. Real-time RT-PCR confirmed mRNA level of the aforementioned genes. CONCLUSION: Our findings showed that factors such as PLP-dependent enzymes and SOD might be implicated in drug resistance in C. tropicalis clinical isolate. Therefore, further studies are required to explore the accurate biological functions of the mentioned genes that would be helpful for effective drug development.
