Genotyping of candida albicans isolates obtained from vulvovaginal candidiasis patients in Zanjan, Iran, based on ABC and RPS typing systems.

Background and Purpose: Genotyping of pathogenic microorganisms is important for epidemiological studies and the adoption of appropriate strategies to control infectious diseases. In this regard, the present study aimed to genotype Candida albicans strains isolated from vulvovaginal candidiasis (VVC) patients using combined ABC type (25SrDNA) and repetitive sequence (RPS) typing systems. using combined typing systems of ABC type (25SrDNA) and repetitive sequence (RPS). Materials and Methods: In total, 140 patients with VVC were investigated. Vaginal discharges were collected on Sabouraud dextrose agar and identified by CHROMagar. After species identification, a polymerase chain reaction system targeting 25S rDNA as well as ALT repeats in the RPS was designed to determine C. albicans genotypes. The dendrogram was constructed by zero-one matrix data based on the combination of ABC and RPS typing systems. Statistical analysis of data was performed in SPSS software (version 23). Results: In total, 41 (29.3%) Candida isolates were obtained from 140 VVC patients. The most common Candida species that were identified included C. glabrata (56.1%) and C. albicans (39%). Genotype A3 with five isolates (31.25%) had the highest frequency, followed by B2/3 with three isolates (18.3%), A3/4, C3/4, and B3/4 with two isolates (12.5%), and C2/3 and C3 with one isolate (6.25%), respectively. No significant association was found between the genotypes and antifungal resistance (P<0.05). Conclusion: The results showed that non-albicans Candida species are more prevalent in VVC patients, compared to C. albicans. The results also indicated that ABC and RPS typings are useful for rapid genotyping and differentiation of C. albicans isolates in regional and small-scale studies.

The Effectiveness of Nigella Sativa Alcoholic Extract on the Inhibition of Candida Albicans Colonization and Formation of Plaque on Acrylic Denture Plates: an In Vitro Study.

STATEMENT OF THE PROBLEM: Due to growing concerns on complications of chemical drugs, the use of herbal extracts has been considered as denture cleaning solutions. PURPOSE: The aim of this study was to evaluate the in-vitro effects of Nigella sativa on the cleansing of the formation of Candida albicans plaque on the acrylic resin pieces. MATERIALS AND METHOD: In this experimental study, 30 pieces of acrylic resin were contaminated by Candida albicans suspension. Then, the acrylic pieces were randomly divided into six groups and treated with 0.2, 0.4, 20, and 200 mg/ml of Nigella sativa, 100,000 units of nystatin (positive control), and distilled water (negative control) for 8 hours. At the end of the exposure period of the drugs, the rinse solution from acrylic pieces was cultured in Sabouraud Dextrose Agar and the average of the colonies from each group was compared. RESULTS: The average number of colonies obtained at concentrations of 0.2, 0.4, 20, and 200 mg/ml of Nigella sativa were 122.6, 117.8, 73.4, and 14.4 colonies, respectively, as compared to distilled water (141.6) and nystatin (0) that had a significant difference (p< 0.001). CONCLUSION: Nigella sativa extract at definite concentration is capable of clearing dental prosthesis, but compared to nystatin, it is weaker. However, due to the indirect immune-regulatory effects of Nigella sativa, it is suggested that other studies be conducted to investigate the therapeutic properties of Nigella sativa from the aspects of antimicrobial, anti-inflammatory, and oral ulcer healing in candida oral lesions.

Drug susceptibility profile of Candida glabrata clinical isolates from Iran and genetic resistant mechanisms to caspofungin.

BACKGROUND: Candida glabrata is a yeast that can cause hazardous fungal infections with high mortality and drug resistance. AIMS: The aim of this study was to determine the profile of drug susceptibility in clinical isolates of C. glabrata and review the resistance mechanisms to caspofungin. METHODS: A total of 50 C. glabrata clinical isolates from Iran were tested for in vitro susceptibilities to amphotericin B, caspofungin, fluconazole and voriconazole. To investigate the mechanism of resistance to caspofungin, hotspot areas of FKS1 and FKS2 genes were sequenced and gene expression profile was evaluated. RESULTS: All the isolates were susceptible to amphotericin B and caspofungin. Fluconazole resistance was exhibited in four isolates. In addition, only one isolate was resistant to voriconazole. FKS2 with 12 point mutations showed more mutations compared to FKS1 that had only two mutations. All substitutions were synonymous. FKS genes were expressed at comparable levels (no statistical significance) in caspofungin-treated and non-treated cultures. CONCLUSIONS: The silent mutations in the hotspot areas of FKS genes and inconsiderable changes in gene expression were not associated with increased MIC (0.25µg/ml). Other mechanisms of resistance which include mutations outside the hotspot area of FKS genes could be involved in a slight increase of MIC, and they should be identified through complete FKS gene sequencing.

Genotyping of clinical isolates of Candida glabrata from Iran by multilocus sequence typing and determination of population structure and drug resistance profile.

Candida glabrata is often the second most common causative agent for candidiasis following Candida albicans. Despite the importance of C. glabrata infections, few epidemiological studies have been conducted on this issue. The goal of this study was genotyping of clinical isolates of C. glabrata by multilocus sequence typing (MLST) technique for determination of the endemic prevalent genotypes and any association between isolation source and drug resistance. A total of 50 C. glabrata clinical isolates from Iran were analyzed by MLST and tested for in-vitro susceptibilities to amphotericin-B, caspofungin, fluconazole, and voriconazole according to the Clinical Laboratory Standards Institute (CLSI) M27-A4 document guidelines. Among these isolates, 16 distinct STs were identified, indicating a discriminatory power index of 0.9029. The three major sequence types (STs) were ST-59, ST-74, and ST-7 with 10, 8, and 7 isolates, respectively. Furthermore, a total of 11 new sequences were found, to which no allele numbers were assigned in the MLST database. All the isolates were susceptible to amphotericin B and caspofungin. Fluconazole resistance was shown in four isolates. Also, a sole isolate was voriconazole resistant. This study shows that the population structure of C. glabrata in Iran consists of groups closely related to the global database as well as to some new clonal clusters and STs. Regarding the high prevalence of 11 new sequences found in this study, it can be concluded that, these new alleles are among the endemic genotypes of Iran. The genotypes or STs were independent of drug susceptibility and anatomic sources.