Determination of antimicotic susceptibility pattern of Candida species isolated from patients with symptomatic candiduria

Comparison of antifungal and cytotoxicity activities of titanium dioxide and zinc oxide nanoparticles with amphotericin B against different Candida species: In vitro evaluation

BACKGROUND

Candida species are known to cause serious fungal infections that produce cutaneous, mucosal, and systemic infections. Nowadays, mortality and morbidity candidiasis in immunocompromised patients have increased. Nanotechnology is a new world-known technology and includes particles ranging from about 1 to 100 nanometers. The purpose of this study was to evaluate the antifungal and cytotoxicity activities of titanium dioxide nanoparticles (TiO2-NPs) and zinc oxide nanoparticles (ZnO-NPs) compared to amphotericin B (AmB) on different Candida spp in in vitro conditions.

METHODS

In the present study, susceptibility of different Candida species to TiO2-NPs and ZnO-NPs compared to AmB was determined by broth microdilution (BMD) and agar well diffusion methods. Cytotoxicity of TiO2-NPs and ZnO-NPs and amphotericin B was measured by MTT (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide) assay.

RESULTS

The results indicated that the TiO2-NPs and ZnO-NPs showed antifungal activities against pathogenic Candida spp. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of TiO2-NP ranges against Candida spp. were 128-256 µg/mL and 256-512 µg/mL, respectively. The MIC and MFC values of ZnO-NPs were 64-128 µg/mL and 256-512 µg/mL, respectively. However, MICs and MFCs of AmB were 8-16 µg/mL and 16-32 µg/mL, respectively. The MTT assay results showed that the CC50% belonged to ZnO-NPs 706.2 μg/mL, for TiO2-NPs 862.1 μg/mL, and for AmB 70.19 μg/mL, respectively.

CONCLUSION

Our findings showed that TiO2-NPs and ZnO-NPs had antifungal effects against all Candida species, yet the antifungal properties of TiO2-NPs and ZnO-NPs were significantly less than those of AmB. The CC50% of AmB was significantly lower than ZnO-NPs and TiO2-NPs.

Candidemia and its Risk Factors in Neonates and Children

Objectives: The present study was conducted to raise attention to the frequency of Candida spp. and evaluation of risk factors of candidemia in hospitalized neonates and children. Methods: Identification of Candida at species level was done using the PCR-RFLP method. The Candida albicans complex and Candida parapsilosis complex were differentiated using the HWP1 gene amplification and PCR-RFLP with NlaIII restriction enzyme, respectively. Results: Out of 75 blood culture specimens, 42 (84%) cases were positive for Candida spp. of whom 30 (71.42%) and 12 (28.57%) cases were female and male, respectively. Thirty-two (76%) candidemia were presented in pediatrics with 6 years up to 12 years, 10 (23.80%) in neonates of one month or less. In the present study, Candida parapsilosis (n =25; 59.52%) was the most prevalent isolated species followed by C. albicans (n =11; 26.19%), C. tropicalis (n =4; 9.52%), and Candida glabrata (n =2; 4.76%). Conclusions: According to potentially dangerous complications of bloodstream infection by Candida spp. in neonates and children, it is necessary to identify and eliminate the underlying conditions and risk factors of this disease.

Molecular identification of Candida isolates by Real-time PCR-high-resolution melting analysis and investigation of the genetic diversity of Candida species

BACKGROUND

Candida species are considered as the cause of one of the most important opportunistic fungal diseases. Accurate identification of Candida species is important because of antifungal susceptibility patterns are different among these species, so proper identification helps in the selection of antifungal drugs for the prevention and treatment. Phenotypic methods for identification of Candida species, which are widely used in clinical microbiology laboratories, have some limitations. Real-time PCR followed by the high-resolution melting analysis (HRMA) is a novel approach for the rapid recognition of pathogenic fungi. Molecular phylogeny is essential for obtaining a better understanding of the evolution of the genus Candida and the identification of the relative degree of the Candida species. The purpose of this study was molecular identification of Candida isolates by Real-time PCR-high-resolution melting analysis and investigation of the genetic diversity of Candida species.

METHODS

Two hundred and thirty-two Candida isolates including 111 Candida isolates obtained from 96 HIV/AIDS patients and 121 Candida isolates obtained from 98 non-HIV persons were identified by real-time PCR and high-resolution melting curve analysis. To evaluate genetic diversity and relationships among Candida species, PCR products of nine clinical Candida isolates, as a representative of each kind of species, were randomly selected for DNA sequence analysis.

RESULTS

In HIV/AIDS patients, six species of Candida spp. were identified as follows: C albicans (n = 64; 57.7%), C glabrata (n = 31; 27.92%), C parapsilosis (n = 9; 8.1%), C tropicalis (n = 4; 3.6%), C krusei (n = 2; 1.8%), and C kefyr (n = 1; 0.90%). In non-HIV persons, we identified eight species of Candida including C albicans (n = 46; 38.33%) followed by C glabrata and C krusei (each one, n = 18; 15%), C tropicalis (n = 13; 10.83%), C lusitaniae (n = 12; 5.17%), C parapsilosis (n = 10; 4.31%), and C kefyr and C guillermondii (each one, n = 2; 1.66%). Also, the phylogenetic analysis showed the presence of two main clades and six separate subclades. Accordingly, about 88.9% of the isolates were located in clade I and 11.10% of the studied isolates were in clade II.

CONCLUSIONS

Real-time PCR followed by high-resolution melting analysis (HRMA) is known as a reliable, fast, and simple approach for detection and accurate identification of Candida species, especially in clinical samples.

Antifungal effects of Lactobacillus acidophilus and Lactobacillus plantarum against different oral Candida species isolated from HIV/ AIDS patients: an in vitro study

Oropharyngeal Candidiasis (OPC) is an opportunistic fungal infection occurring in immunocompromised  patients such as HIV/AIDS. The purpose of this study was to evaluate the antifungal properties of Lactobacillus acidophilus and Lactobacillus plantarum on different Candida species isolated from oral cavity of HIV/AIDS patients compared to Fluconazole (FLC). In this study, the antifungal effects of both cells and cell-free supernatants (CFSs) of L. acidophilus and L. plantarum were investigated against different oral Candida species by co-aggregation, agar overlay interference and broth microdilution assays, respectively. Our results showed that the highest co-aggregation ratio of the two tested Lactic acid bacteria (LAB) was observed for C. krusei. Both L. acidophilus and L. plantarum at cell concentrations 10¹⁰ to 10² cfu/ml were able to inhibit the growth of most of the oral Candida species, except for C. albicans, and to some C. krusei. In this study, MIC and MFC values for CFS of L. acidophilus ranged from 100 to 200 µl/ml and 100 to 200 µl/ml, respectively, and MIC and MFC values for CFS of L. plantarum were 50 to 200 µl/ml and 50 to 200 µl/ml, respectively. The ranges of MIC and MFC for FLC were 256-1024 µg/ml and 512-2048 µg/ml, respectively. C. albicans and C. parapsilosis displayed the highest and least susceptibility to CFSs of two LAB, respectively. Our findings showed that both cells and CFSs of L. acidophilus and L. plantarum had antifungal effects against oral Candida species.