Clinical Isolates Of Candida Albicans Research Articles

Pore-forming peptide C14R exhibits potent antifungal activity against clinical isolates of Candida albicans and Candida auris.

Invasive candidiasis is a global public health problem as it poses a significant threat in hospital-settings. The aim of this study was to evaluate C14R, an analog derived from peptide BP100, as a potential antimicrobial peptide against the prevalent opportunistic yeast Candida albicans and the emergent multidrug-resistant yeast Candida auris. Antifungal susceptibility testing of C14R against 99C. albicans and 105C. auris clinical isolates from Colombia, was determined by broth microdilution. Fluconazole was used as a control antifungal. The synergy between C14R and fluconazole was assessed in resistant isolates. Assays against fungal biofilm and growth curves were also carried out. Morphological alterations of yeast cell surface were evaluated by scanning electron microscopy. A permeability assay verified the pore-forming ability of C14R. C. albicans and C. auris isolates had a geometric mean MIC against C14R of 4.42 µg/ml and 5.34 µg/ml, respectively. Notably, none of the isolates of any species exhibited growth at the highest evaluated peptide concentration (200 µg/ml). Synergistic effects were observed when combining the peptide and fluconazole. C14R affects biofilm and growth of C. albicans and C. auris. Cell membrane disruptions were observed in both species after treatment with the peptide. It was confirmed that C14R form pores in C. albicans' membrane. C14R has a potent antifungal activity against a large set of clinical isolates of both C. albicans and C. auris, showing its capacity to disrupt Candida membranes. This antifungal activity remains consistent across isolates regardless of their clinical source. Furthermore, the absence of correlation between MICs to C14R and resistance to fluconazole indicates the peptide's potential effectiveness against fluconazole-resistant strains. Our results suggest the potential of C14R, a pore-forming peptide, as a treatment option for fungal infections, such as invasive candidiasis, including fluconazole and amphotericin B -resistant strains.

Antibiofilm Activity of Curcumin and Piperine and Their Synergistic Effects with Antifungals against Candida albicans Clinical Isolates.

Candidiasis is the common name for diseases caused by yeast of the genus Candida. Candida albicans is one of the most implicated species in superficial and invasive candidiasis. Antifungals, polyenes, and azoles have been used to treat candidiasis. However, due to the development of antifungal resistance, research of natural substances with potential antifungal effects at low concentrations or combined is also a possibility. The broth microdilution method was used to evaluate the antifungal activity. The biofilm formation was assessed using the microtiter plate method. The antibiofilm activities were assessed using micro plaque tetrazolium salt assay (MTT). The combination effect of antifungal with natural substances was made using the checkerboard method. Among our isolates, clotrimazole was the most resistant, but amphotericin B was the most effective antifungal. The biofilm was formed by all isolates of C. albicans. Curcumin and piperine displayed antibiofilm activity with minimum biofilm inhibitory concentration (MBIC) and minimum eradicating concentration (MBEC) ranging from 64 to 1024 μg/mL and 256 to 2048 μg/mL. In combination, piperine presented double synergistic effects compared to curcumin with all antifungals tested. Curcumin shows more synergistic effect when combined with polyenes than with azoles. However, piperine shows a more synergistic effect when combined with azoles compared to polyenes. C. albicans was susceptible to curcumin and piperine both on planktonic cells and biofilm. The combination of curcumin and piperine with antifungals has shown synergistic effects against multiresistant clinical isolates of Candida albicans representing an alternative drug research for the treatment of clinical candidiasis.

Enhancing Antibiotic Efficacy: Exploring Synergistic Interactions between Plant Extracts and Conventional Antibiotics

Medicinal herbs including Senna alata, Ricinus communis, and Lannea barteri have been utilized for centuries to cure a variety of illnesses caused by microbial infections. This study looked at the synergistic effects of these drugs with traditional antibiotics on clinical isolates of Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. The test bacteria were chosen based on their minimal potential for monotherapy and susceptibility to at least one antibiotic with a known genetic basis. The interactions of plant extracts with antibiotics against the chosen pathogenic microorganisms were investigated using the agar well diffusion, broth microdilution, and checkerboard methods. Calculated fractional inhibitory concentration index (FICI) values were used to describe how the extracts and antibiotics interacted. All the extracts from the three plants combined with fluconazole exhibited a synergistic interaction against C. albicans (FICI < 0.5). The minimum inhibitory concentration (MIC) of ampicillin against E. coli was demonstrated to be reduced by the combination of the ethanol extract of S. alata with ampicillin, with a FICI value of 0.4 indicating a synergistic effect. With a synergistic action (FICI ˂ 0.5) against P. aeruginosa, the ethanol extract of S. alata and amoxicillin were successful in reducing the MIC of amoxicillin from 0.32 to 0.17 mg/mL. Aqueous L. barteri extract combined with amoxicillin exhibited synergism (FICI < 0.2) against S. aureus with a reduction of MIC from 0.20 to 0.03 mg/mL. The current study is the first to investigate the aforementioned plants in combination with conventional antibiotics for their antimicrobial activities. The findings of this study could be used to create a useful, applicable, feasible, and alternative source of novel antimicrobial agents.

Extracellular Vesicles from a Biofilm of a Clinical Isolate of Candida albicans Negatively Impact on Klebsiella pneumoniae Adherence and Biofilm Formation.

The opportunistic human fungal pathogen Candida albicans produces and releases into the surrounding medium extracellular vesicles (EVs), which are involved in some processes as communication between fungal cells and host-pathogen interactions during infection. Here, we have conducted the isolation of EVs produced by a clinical isolate of C. albicans during biofilm formation and proved their effect towards the ability of the Gram-negative bacterial pathogen Klebsiella pneumoniae to adhere to HaCaT cells and form a biofilm in vitro. The results represent the first evidence of an antagonistic action of fungal EVs against bacteria.

A Novel Mitochondrial Targeted Compound Phosundoxin Showing Potent Antifungal Activity against Common Clinical Pathogenic Fungi.

The current increase in resistance to antifungal drugs indicates that there is an urgent need to explore novel antifungal drugs with different mechanisms of action. Phosundoxin is a biphenyl aliphatic amide using a TPP-targeting strategy which targets mitochondria. To provide insights into the antifungal activities of phosundoxin, the antifungal susceptibility testing of phosundoxin was conducted on 158 pathogenic fungi and compared to that of traditional azole drugs. Phosundoxin displayed a broad-spectrum antifungal activity on all the tested yeast-like and filamentous fungi ranging from 2 to 16 mg/L. In particular, azole-resistant clinical isolates of Candida albicans were susceptible to phosundoxin with the same MICs as azole-susceptible C. albicans. Transcriptome analysis on azole-resistant C. albicans identified 554 DEGs after treatment with phosundoxin. By integrating GO and KEGG pathway enrichment analysis, the antifungal activity of phosundoxin was related to impairment of mitochondrial respiratory chain function. Acute oral and percutaneous toxicity of phosundoxin to rats showed that the compound phosundoxin were mild toxicity and LD50 was above 5000 mg/kg body weight in rats. This study demonstrated the potential of phosundoxin as an antifungal agent for the treatment of common fungal infection and contributed to providing insights into the mechanisms of action of phosundoxin against C. albicans.

Variation in transcription regulator expression underlies differences in white-opaque switching between the SC5314 reference strain and the majority of Candida albicans clinical isolates.

Candida albicans, a normal member of the human microbiome and an opportunistic fungal pathogen, undergoes several morphological transitions. One of these transitions is white-opaque switching, where C. albicans alternates between 2 stable cell types with distinct cellular and colony morphologies, metabolic preferences, mating abilities, and interactions with the innate immune system. White-to-opaque switching is regulated by mating type; it is repressed by the a1/α2 heterodimer in a/α cells, but this repression is lifted in a/a and α/α mating type cells (each of which are missing half of the repressor). The widely used C. albicans reference strain, SC5314, is unusual in that white-opaque switching is completely blocked when the cells are a/α; in contrast, most other C. albicans a/α strains can undergo white-opaque switching at an observable level. In this paper, we uncover the reason for this difference. We show that, in addition to repression by the a1/α2 heterodimer, SC5314 contains a second block to white-opaque switching: 4 transcription regulators of filamentous growth are upregulated in this strain and collectively suppress white-opaque switching. This second block is missing in the majority of clinical strains, and, although they still contain the a1/α2 heterodimer repressor, they exhibit a/α white-opaque switching at an observable level. When both blocks are absent, white-opaque switching occurs at very high levels. This work shows that white-opaque switching remains intact across a broad group of clinical strains, but the precise way it is regulated and therefore the frequency at which it occurs varies from strain to strain.

Does repeated exposure to hydrogen peroxide induce Candida auris resistance?

BackgroundTo minimize environmental colonization by microorganisms that may persist and thrive in healthcare settings, thus reducing healthcare-associated infections (HAIs), new insights over already known biocides are certainly of relevance. Although the efficacy of hydrogen peroxide (H2O2) against the emergent yeast Candida auris is moderately documented, concerns over the potential induction of resistance after repeated exposure do persist. The main objective of the present study was to evaluate the hypothetical induction of Candida auris resistance following 30 days of consecutive exposure to lethal and sublethal concentrations of H2O2. Furthermore, the authors aimed to elucidate about the rank of efficacy of H2O2 against C. auris comparing to other Candida species and whether different strains of C. auris may display different susceptibilities to H2O2.MethodsDuring the induction of resistance assays, both type strains and clinical isolates of Candida auris, Candida albicans and Candida parapsilosis were exposed repeatedly to defined concentrations of H2O2, for 30 days.ResultsAfter that period, no significant differences were found when comparing the minimal inhibitory concentration values of H2O2 in case of the induced strains versus each respective positive control. Moreover, H2O2 displayed similar effectiveness against all the tested Candida species and no differences were demonstrated among the distinct strains of C. auris.ConclusionsThe adoption of H2O2 solutions in routine protocols in order to promote disinfection standards against Candida auris, improving patient safety and reducing healthcare costs, is certainly welcomed.

Combining the Peptide RWQWRWQWR and an Ethanolic Extract of Bidens pilosa Enhances the Activity against Sensitive and Resistant Candida albicans and C. auris Strains.

The antifungal activity of palindromic peptide RWQWRWQWR and its derivatives was evaluated against clinical isolates of Candida albicans and C. auris. Also, Bidens pilosa ethanolic extracts of leaves and stem were evaluated. Furthermore, combinations of peptide, extract, and/or fluconazole (FLC) were evaluated. The cytotoxicity of peptides and extracts in erythrocytes and fibroblasts was determined. The original palindromic peptide, some derivative peptides, and the ethanolic extract of leaves of B. pilosa exhibited the highest activity in some of the strains evaluated. Synergy was obtained between the peptide and the FLC against C. auris 435. The combination of the extract and the original palindromic peptide against C. albicans SC5314, C. auris 435, and C. auris 537 decreased the minimal inhibitory concentrations (MICs) by a factor of between 4 and 16. These mixtures induced changes in cell morphology, such as deformations on the cell surface. The results suggest that the combination of RWQWRWQWR and B. pilosa extract is an alternative for enhancing antifungal activity and decreasing cytotoxicity and costs and should be considered to be a promising strategy for treating diseases caused by Candida spp.

Evaluation of Tamarix nilotica Fractions in Combating Candida albicans Infections

ABSTRACT Objectives Evaluation of the antifungal properties of Tamarix nilotica fractions against Candida albicans clinical isolates. Methods The in vitro antifungal potential was evaluated by agar well diffusion and broth microdilution methods. The antibiofilm potential was assessed by crystal violet, scanning electron microscopy (SEM), and qRT-PCR. The in vivo antifungal activity was evaluated by determining the burden in the lung tissues of infected mice, histopathological, immunohistochemical studies, and ELISA. Results Both the dichloromethane (DCM) and ethyl acetate (EtOAc) fractions had minimum inhibitory concentration (MIC) values of 64–256 and 128–1024 μg/mL, respectively. SEM examination showed that the DCM fraction decreased the biofilm formation capacity of the treated isolates. A significant decline in biofilm gene expression was observed in 33.33% of the DCM-treated isolates. A considerable decline in the CFU/g lung count in infected mice was observed, and histopathological examinations revealed that the DCM fraction maintained the lung tissue architecture. Immunohistochemical investigations indicated that the DCM fraction significantly (p < 0.05) decreased the expression of pro-inflammatory and inflammatory cytokines (TNF-α, NF-kB, COX-2, IL-6, and IL-1β) in the immunostained lung sections. The phytochemical profiling of DCM and EtOAc fractions was performed using Liquid chromatography-mass spectrometry (LC-ESI-MS/MS). Conclusion T. nilotica DCM fraction could be a significant source of natural products with antifungal activity against C. albicans infections.

Aqueous spice extracts as alternative antimycotics to control highly drug resistant extensive biofilm forming clinical isolates of Candida albicans.

Candida albicans form biofilm by associating with biotic and abiotic surfaces. Biofilm formation by C. albicans is relevant and significant as the organisms residing within, gain resistance to conventional antimycotics and are therefore difficult to treat. This study targeted the potential of spice-based antimycotics to control C. albicans biofilms. Ten clinical isolates of C. albicans along with a standard culture MTCC-3017 (ATCC-90028) were screened for their biofilm-forming ability. C. albicans M-207 and C. albicans S-470 were identified as high biofilm formers by point inoculation on Trypticase Soy Agar (TSA) medium as they formed a lawn within 16 h and exhibited resistance to fluconazole and caspofungin at 25 mcg and 8 mcg respectively. Aqueous and organic spice extracts were screened for their antimycotic activity against C. albicans M-207 and S-470 by agar and disc diffusion and a Zone of Inhibition was observed. Minimal Inhibitory Concentration was determined based on growth absorbance and cell viability measurements. The whole aqueous extract of garlic inhibited biofilms of C. albicans M-207, whereas whole aqueous extracts of garlic, clove, and Indian gooseberry were effective in controlling C. albicans S-470 biofilm within 12 h of incubation. The presence of allicin, ellagic acid, and gallic acid as dominant compounds in the aqueous extracts of garlic, clove, and Indian gooseberry respectively was determined by High-Performance Thin Layer Chromatography and Liquid Chromatography-Mass Spectrometry. The morphology of C. albicans biofilm at different growth periods was also determined through bright field microscopy, phase contrast microscopy, and fluorescence microscopy. The results of this study indicated that the alternate approach in controlling high biofilm-forming, multi-drug resistant clinical isolates of C. albicans M-207 and S-470 using whole aqueous extracts of garlic, clove, and Indian gooseberry is a safe, potential, and cost-effective one that can benefit the health care needs with additional effective therapeutics to treat biofilm infections.

In-vitro and In-vivo Anti-Candidal Effect of Cnidoscolus aconitifolius Leaves Extracts

Candidiasis is an opportunistic infection caused by pathogens of the genus Candida. Due to the increase in antifungal resistance by Candida species, there is a need for alternatives in its treatment. Cnidoscolus aconitifolius is a medicinal plant with vast nutritional and antimicrobial properties. This study evaluated the in-vitro and in-vivo anti-candidal effect of Cnidoscolus aconitifolius (spinach tree) leaves extract. Clinical isolates of Candida albicans, Candida krusei, Candida tropicalis, Candida dublinensis, Candida glabrata, and Candida parapsilosis were used in this study and Cold maceration technique was employed in the plant extraction process, to obtain its ethanolic, methanolic, and aqueous extract. The agar well diffusion method and 2-fold dilution process -to obtain 250 mg/ml to 15.625mg/ml of the extracts -were used for the antimicrobial sensitivity test and three weeks old female Wistar rats infected with 20µl of standardized C. albicans were used for the in-vivo evaluation. Statistical analysis was done using Statistical package for Social Sciences (SPSS) version 22. In-vitro assay revealed ethanolic extract as the most potent extract with the highest inhibition zone diameter of 12.67±1.15c, 11.67±1.15c, and 12.33±0.58c at 250mg/ml against C. tropicalis, C. krusei2, and C. parapsilosis respectively. C. parapsilosis was the most sensitive to all the extracts. In-vivo, the disappearance of disease symptoms and progressive decrease in rats Candida burden- from 6.35×103 CFU/ml obtained after infection to 2.15×103CFU/ml after treatment revealed the ability of the plant to treat candidiasis. The study suggests that extract of Cnidoscolus aconitifolius leaves could act individually or synergistically as effective drug candidates in the treatment of candidiasis; thus if its individual antifungal constituents are purified, this plant could be the next major anti-candidal agent.

Phenotypes characterization and ABC genotypes distribution of clinical Candida albicans isolates.

Candidemia and vaginitis are the most common types of candidiasis mostly caused by Candida albicans species. C. albicans has several genotypes and the potential ability to form different phenotype colonies on specific media. This study aimed to evaluate the genotype distribution of blood and vaginal C. albicans isolates and phenotype characteristics on Spider and yeast peptone dextrose agar medium. A total of 40 clinical Candida albicans isolates comprising vagina (20) and blood (20) were used. ABC typing using CA-INT-R and CA-INT-L primers was performed to span the transposable group I intron of the 25S rDNA gene. For colony phenotypic characteristics, the Spider and YPDA media were used. Among the blood and vaginal isolates, genotype A (12/60%) and genotype C (10/50%) were the most common types, respectively. The highest phenotype shape frequency of the colonies in blood and vaginal samples was the ring and the lowest was the hat/ring. The dominant color phenotype in blood and vaginal samples was gray. There was a significant relationship between genotype and phenotype forms in the blood sample on YPDA medium (p = 0.02). In the Spider medium, there were no significant differences between genotypes and phenotypes. In this study, genotype A and genotype C were predominant in blood and vaginal samples, respectively. In both groups, YPD agar medium demonstrated the most variety of phenotypes that was related to genotypes A and C. The variety of phenotypes in both groups was the same in genotypes A and C on the Spider medium.

Anti-Biofilm Activity of Phenyllactic Acid against Clinical Isolates of Fluconazole-Resistant Candida albicans

Commonly found colonizing the human microbiota, Candida albicans is a microorganism known for its ability to cause infections, mainly in the vulvovaginal region, and is responsible for 85% to 90% of vulvovaginal candidiasis (VVC) cases. The development of drug resistance in C. albicans isolates after long-term therapy with fluconazole is an important complication to solve and new therapeutic strategies are required to target this organism and its pathogenicity. In the present study, phenyllactic acid (PLA) an important broad-spectrum antimicrobial compound was investigated for its antifungal and antivirulence activities against clinical isolates of C. albicans. Previously characterized strains of C. albicans isolates from women with VVC and C. albicans ATCC90028 were used to evaluate the antimicrobial and time dependent killing assay activity of PLA showing a MIC 7.5 mg mL-1 and a complete reduction of viable Candida cells detected by killing kinetics after 4 h of treatment with PLA. Additionally, PLA significantly reduced the biomass and the metabolic activity of C. albicans biofilms and impaired biofilm formation also with changes in ERG11, ALS3, and HWP1 genes expression as detected by qPCR. PLA eradicated pre-formed biofilms as showed also with confocal laser scanning microscopy (CLSM) observations. Furthermore, the compound prolonged the survival rate of Galleria mellonella infected by C. albicans isolates. These results indicate that PLA is a promising candidate as novel and safe antifungal agents for the treatment of vulvovaginal candidiasis.

Antifungal Activity of Efinaconazole Compared to Fluconazole, Itraconazole, and Terbinafine against Terbinafine- and Itraconazole-Resistant and -Susceptible Clinical Isolates of Dermatophytes, Candida, and Mold.

Recently, an increasing number of resistant-to-terbinafine dermatophytosis cases have been reported. Thus, identifying an alternative antifungal agent that possesses a broad-spectrum activity, including against resistant strains, is needed. In this study, we compared the antifungal activity of efinaconazole to fluconazole, itraconazole, and terbinafine against clinical isolates of dermatophyte, Candida, and molds using in vitro assays. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of each antifungal was quantified and compared. Both susceptible and resistant clinical isolates of Trichophyton mentagrophytes (n=16), T. rubrum (n=43), T. tonsurans (n=18), T. violaceum (n=4), Candida albicans (n=55), C. auris (n=30), Fusarium sp., Scedosporium sp., and Scopulariopsis sp. (n=15 for each) were tested. Our data shows that efinaconazole was the most active antifungal, compared to the other agents tested, against dermatophytes with MIC50 and MIC90 (Concentration that inhibited 50% and 90% of strains tested, respectively) values of 0.002 and 0.03 μg/ml, respectively. Fluconazole, itraconazole and terbinafine showed MIC50 and MIC90 values of 1 and 8 μg/ml, 0.03 and 0.25 μg/ml, and 0.031 and 16 μg/ml, respectively. Against Candida isolates, efinaconazole MIC50 and MIC90 values were 0.016 and 0.25 μg/ml, respectively, whereas fluconazole, itraconazole and terbinafine had MIC50 and the MIC90 values of 1 and 16 μg/ml, 0.25 and 0.5 μg/ml, and 2 and 8 μg/ml, respectively. Against various mold species, efinaconazole MIC values ranged from 0.016 and 2 μg/ml, compared to 0.5 to greater than 64 μg/ml for the comparators. efinaconazole showed superior potent activity against a broad panel of susceptible and resistant dermatophyte, Candida, and mold isolates.

Antimicrobial Potential of Moringa peregrina Against Some Causative Agents of Urogenital Infections

Abstract&#x0D; Aim: To evaluate and compare the antimicrobial effectiveness of aqueous and methanol extracts from Moringa peregrina leaves against standard strains of microorganisms and clinical isolates.&#x0D; Study Design: An experimental study which was carried out at the microbiology laboratory, Medicinal and Aromatic Plants Research Institute (MAPRI), Khartoum, Sudan, during the period from September 2012 to March 2013.&#x0D; Methodology: Aqueous and methanol extracts of Moringa peregrina at concentration of 100 mg/ml were subjected to antimicrobial screening against six standard strains include Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (ATCC 53657), Proteus vulgaris (ATCC 6380), Staphylococcus aureus (ATCC 25923), Candida albicans (ATCC 7596) and 133 clinical isolates including bacterial and fungal species. Screening for antimicrobial activity of extracts, standard antibiotics and antifungal drug were detected by the agar well diffusion method. The Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) for the tested extracts were determined by using the broth dilution method. The MDIZs of clinical isolates were analyzed statistically using One-Way analysis of variance.&#x0D; Results: Methanol extract of Moringa peregrina leaves revealed prominent activity against standard strains compared to the aqueous extract of the same plant where the diameter of inhibition zone (DIZ) was ranged from 18 mm to 21 mm. The aqueous extract exhibited moderate activity which was ranged from 16 mm to 17 mm. The MIC of leaves methanol extract of Moringa peregrina for standard bacterial strains was ranged from ˂6.25 to 12.50 mg/ml, while the MBC was ranged from 6.25 mg/ml to 50 mg/ml. Standard strain and clinical isolates of Candida albicans was inhibited by 25 mg/ml from methanol extract, while the MFC was 50 mg/ml. The highest MDIZs obtained by the leaves methanol extract of Moringa peregrina on the clinical isolates was 18.93±3.07 mm for Escherichia coli, 18.50±2.07 mm for Pseudomonas aeruginosa, 18.62±2.72 mm for Proteus mirabilis and 18.11±2.47 mm for Staphylococcus saprophyticus. The antifungal activity of leaves methanol extract of Moringa peregrina on clinical isolates of Candida albicans was 16.56±1.62 mm which was lower than activity of Candizole 5 mg/ml. Moringa peregrina leaves extract showed varied MICs values towards clinical isolates which was ranged from 6.25 mg/ml to 25 mg/ml, while the MBC of the same isolates was from 25 mg/ml to 50 mg/ml.&#x0D; Finally, Methanol extract of Moringa peregrina was found to be effective against both the standard strains and clinical isolates compared to the aqueous extract.

Analysis of Microsatellite Length Polymorphism for Clinical Isolates of Candida albicans from Animals

Background: Candida albicans has been shown as the most common species of Candida collected from different animals. Objectives: This study aimed to evaluate the genetic diversity and genetic relationships among C. albicans isolates collected from clinical specimens of animals suffering from candidiasis using microsatellite length polymorphism (MLP). Methods: We used MLP for a group of 60 C. albicans strains isolated from various animal species (dog: 16, cat: 10, horse: 10, cow: 14, chicken: 10), previously defined as animal clinical isolates. Three loci, including EF3, CDC3, and HIS3, were amplified, and the products ran onto an ABI XL 370 genetic analyzer, and fragment sizes were determined. Results: Of the 60 clinical strains illustrated, 49 different genotypes were identified with a discriminatory power index of 0.991. A total of 17 alleles and 26 different combinations were identified for EF3 locus, six alleles and 13 combinations for CDC3 locus, and 17 alleles and 27 combinations for HIS3 locus. The most common genotypes were GP9 (four strains) and GP1 and GP33 (three strains). Wright’s fixation index (FST) values were calculated to assess inter-group genetic diversity for all pairwise combinations of the five sub-populations of C. albicans isolated from the different animal hosts. The highest FST values related to C. albicans isolated from chicken to three sub-populations of cats (FST: 0.1397), cows (FST: 0.0639), and horses (FST: 0.0585). Conclusions: The results indicated a moderate genetic differentiation (0.05 &lt; FST &lt; 0.15) between C. albicans strains isolated from cats, cows, and horses as a mammal vs. chickens.

Antifungal activity of Thymus kotschyanus extract: An in vitro study on the expression of CDR1 and CDR2 genes in clinical isolates of Candida albicans

IntroductionThymus kotschyanus (T. kotschyanus) belongs to the Lamiaceae family that are medicinal plants used in traditional medicine. In this study, the aim was to evaluate the antifungal activity of T. kotschyanus extract and its effects on the expression of CDR1 and CDR2 genes associated with drug resistance genes of Candida albicans (C. albicans). MethodsT. kotschyanus crude extract was prepared using percolation method. Different concentrations of the extract (2–500 mg/ml) were utilized for determination of the minimal inhibitory concentrations (MICs) and minimal fungicidal concentration (MFC) of T. kotschyanus using broth microdilution method. The expression level of CDR1 and CDR2 genes was evaluated in C. albicans isolates before and after the treatment with MIC concentration, using Quantitative real-time PCR (qRT-PCR). ResultsT. kotschyanus extract showed an inhibitory effect on Candida growth with MIC and MFC of 75 and 125 mg/ml, respectively. Real-time PCR findings indicated that mRNA expression level of CDR1 and CDR2 genes were significantly reduced after exposure to MIC concentration of T. kotschyanus (p < 0.01). ConclusionThe findings demonstrate that T. kotschyanus extract has anti-Candida activity and reduces mRNA levels of CDR1 and CDR2 genes as drug-resistance genes of clinical isolates of C. albicans.

Antifungal Resistance of Clinical Candida albicans Isolates in Iran: A Systematic Review and Meta-Analysis.

The present systematic review aimed to investigate the drug susceptibility patterns of Iranian clinical Candida albicans isolates to antifungal drugs (azoles, polyenes, and echinocandins). Six electronic databases including "PubMed," "Scopus," "Web of Science," "IranDoc", "SID", and "Magiran" were searched from May 2000 to June 2021. The susceptibility of 6322 C. albicans strains from 19967 patients against 14 antifungal drugs was evaluated according to CLSI method. The pooled prevalence of antifungal resistance ranged from 0% to 26%. The lowest resistance levels among azoles were observed in luliconazole with a frequency of 0% and voriconazole of 3.94%. Due to the emergence of multi-drug resistant C. albicans, rational drug prescription based on the anti-fungal stewardship strategy and therapeutic drug monitoring is warranted.

Effect of Probiotic Lactobacillus plantarum on Streptococcus mutans and Candida albicans Clinical Isolates from Children with Early Childhood Caries.

Probiotics interfere with pathogenic microorganisms or reinstate the natural microbiome. Streptococcus mutans and Candida albicans are well-known emerging pathogenic bacteria/fungi for dental caries. In this study, three probiotic Lactobacilli strains (Lactobacillus plantarum 8014, L. plantarum 14917, and Lactobacillus salivarius 11741) were tested on S. mutans and C. albicans clinical isolates using a multispecies biofilm model simulating clinical cariogenic conditions. The ten pairs of clinical isolates of S. mutans and C. albicans were obtained from children with severe early childhood caries. Our study findings show a remarkable inhibitory effect of L. plantarum 14917 on S. mutans and C. albicans clinical isolates, resulting in significantly reduced growth of S. mutans and C. albicans, a compromised biofilm structure with a significantly smaller microbial and extracellular matrix and a less virulent microcolony structure. FurTre, plantaricin, an antimicrobial peptide produced by L. plantarum, inhibited the growth of S. mutans and C. albicans. The mechanistic assessment indicated that L. plantarum 14917 had a positive inhibitory impact on the expression of S. mutans and C. albicans virulence genes and virulent structure, such as C. albicans hypha formation. Future utilization of L. plantarum 14917 and/or its antimicrobial peptide plantaricin could lead to a new paradigm shift in dental caries prevention.

Antifungal drug concentration impacts the spectrum of adaptive mutations in Candida albicans.

Invasive fungal infections are a leading global cause of human mortality. Only three major classes of antifungal drugs are widely used, and resistance to all three classes can arise rapidly. The most widely prescribed antifungal drug, fluconazole, disseminates rapidly and reaches a wide range of concentrations throughout the body. The impact of drug concentration on the spectrum and effect of mutations acquired during adaptation is not known for any fungal pathogen, and how the specific level of a given stress influences the distribution of beneficial mutations has been poorly explored in general. We evolved 144 lineages from three genetically distinct clinical isolates of Candida albicans to four concentrations of fluconazole (0, 1, 8, and 64 μg/ml) and performed comprehensive phenotypic and genomic comparisons of ancestral and evolved populations. Adaptation to different fluconazole concentrations resulted in distinct adaptive trajectories. In general, lineages evolved to drug concentrations close to their MIC50 (the level of drug that reduces growth by 50% in the ancestor) tended to rapidly evolve an increased MIC50 and acquired distinct segmental aneuploidies and copy number variations. By contrast, lineages evolved to drug concentrations above their ancestral MIC50 tended to acquire a different suite of mutational changes and increased in drug tolerance (the ability of a subpopulation of cells to grow slowly above their MIC50). This is the first evidence that different concentrations of drug can select for different genotypic and phenotypic outcomes in vitro and may explain observed in vivo drug response variation.