Isolates Of Candida Albicans Research Articles

In vitro long-term exposure to chlorhexidine or triclosan induces cross-resistance against azoles in Nakaseomyces glabratus

BackgroundTopical antiseptics are crucial for preventing infections and reducing transmission of pathogens. However, commonly used antiseptic agents have been reported to cause cross-resistance to other antimicrobials in bacteria, which has not yet been described in yeasts. This study aims to assess the in vitro efficacy of antiseptics against clinical and reference isolates of Candida albicans and Nakaseomyces glabratus, and whether prolonged exposure to antiseptics promotes the development of antifungal (cross)resistance.MethodsA high-throughput approach for in vitro resistance development was established to simultaneously expose 96 C. albicans and N. glabratus isolates to increasing concentrations of a given antiseptic – chlorhexidine, triclosan or octenidine. Susceptibility testing and whole genome sequencing of yeast isolates pre- and post-exposure were performed.ResultsLong-term exposure to antiseptics does not result in the development of stable resistance to the antiseptics themselves. However, 50 N. glabratus isolates acquired resistance to azole antifungals after long-term exposure to triclosan or chlorhexidine, revealing newly acquired mutations in the PDR1 and PMA1 genes.ConclusionsChlorhexidine as well as triclosan, but not octenidine, were able to introduce selective pressure promoting resistance to azole antifungals. Although we assessed this phenomenon only in vitro, these findings warrant critical monitoring in clinical settings.Graphical

Antifungal potential of silver nanoparticles stabilized with the flavonoid naringenin.

Introduction. Fungal infections caused by yeast have increased in recent decades, becoming a major threat to public health.Hypothesis/Gap Statement. Antifungal therapy represents a challenging problem because, in addition to presenting many side effects, fungal resistance has been increasing in recent years. As a result, the search for new therapeutic agents has advanced with the use of new technologies such as nanoparticles (NPs).Aim. Synthesize, characterize and evaluate the antifungal potential of naringenin (NAR)-stabilized silver NPs.Methodology. The biosynthesis of NPs was stabilized using the NAR molecule and an aqueous solution of silver nitrate. The characterization of silver nanoparticles (AgNPs) was performed using different methods, which include UV-visible spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy, zeta potential measurements and Fourier transform infrared (FTIR) spectroscopy. Antifungal activity was evaluated against clinical isolates of Candida albicans by determining the MIC and the minimum fungicidal concentration (MFC).Results. The AgNP NAR showed a colloidal appearance with an average size of 14.71 nm and zeta potential measured at -33.3 mV, indicating a highly stable suspension. XRD analysis confirmed the crystal structure. FTIR spectra showed the presence of several functional groups of plant compounds, which play an important role in the coating and bioreduction processes. The antifungal activity against C. albicans showed an MIC of 3.55 µg ml-1 and an MFC of 7.1 µg ml-1. According to the growth kinetic assay in 12 h, there was a reduction of ~50% (<3 log10). Furthermore, AgNP NAR did not show mutagenic potential.Conclusion. The AgNP NAR obtained presented ideal characteristics for biomedical applications, good stability and promising antimicrobial activity.

The impact of Mig1 and Orf19.173 genes on Candida albicans cell wall biosynthesis in different growth conditions

Transcription factors are proteins encoded in an organism's genome that regulate gene expression and control various biological activities. In fungi, many of these transcription factors are proteins with unidentified functions until now, particularly those that regulate genes associated with Candida albicans cell wall biosynthesis. This process is vital for fungal bioactivity and sensitivity to some antifungal agents. This study investigates Mig1 and Orf19.173 transcription factors in response to caspofungin in different environmental conditions as an initial step toward understanding their roles in cell wall biogenesis and drug resistance. A set of C. albicans mutant strains were exposed to caspofungin in Yeast Extract-Peptone-Dextrose (YPD) medium at 25°C and in RPMI 1640 medium (supplemented with 10% serum) at 37°C to simulate host conditions. Transmission electron microscopy (TEM) was used to analyze structural changes in the cell wall of Candida albicans isolates. The study found that mutant strains (mig1Δ/Δ) and (orf19.173Δ/Δ) were susceptible to Caspofungin in RPMI 1640 medium at 37°C but not on YPD medium at 25°C. Additionally, TEM images revealed that the cell wall of these mutant strains exhibited a noticeable thickness and numerous protrusions when exposed to caspofungin. Based on these findings, it was concluded that the transcription factors Mig1 and Orf19.173 promote cell wall biosynthesis in C. albicans when exposed to caspofungin in the host-like environment.

Candida species covered from traditional cheeses: Characterization of C. albicans regarding virulence factors, biofilm formation, caseinase activity, antifungal resistance and phylogeny

This study has provided characterization data (carriage of virulence, antifungal resistance, caseinase activity, biofilm-forming ability and genotyping) of Candida albicans isolates and the occurrence of Candida species in traditional cheeses collected from Kayseri, Türkiye. Phenotypic (E-test, Congo red agar and microtiter plate tests) and molecular tests (identification, virulence factors, biofilm-formation, antifungal susceptibility) were carried out. The phylogenetic relatedness of C. albicans isolates was obtained by constructing the PCA dendrogram from the mass spectra data. Of 102 samples, 13 (12.7%) were found to be contaminated with C. albicans, 15 (14.7%), 10 (9.8%) and five (4.9%) were found to be contaminated with C. krusei, C. lusitane and C. paraplosis, respectively. While seven (16.2%) of 43 Candida spp. isolates were obtained from cheese collected from villages, 36 (83.7%) belonged to cheeses collected from traditional retail stores. The carriage rate of C. albicans isolates belonging to virulence factors HSP90 and PLB1 genes was 30.7%. ALST1, ALST3, BCR, ECE, andHWP (virulence and biofilm-associated) genes were harbored by 30.7%, 23%, 38.4%, 53.8%, and 38.4% of the 13 isolates. According to the microplate test, eight (61.5%) of 13 isolates had strong biofilm production. ERG11 and FKS1 (antifungal resistance genes) were found in 46.1% and 23% of 13 isolates, respectively. Due to missense mutations, K128T, E266D and V488I amino acid changes were detected for some isolates regarding azole resistance. As a result of the E-test, of the 13 isolates, one (7.6%) was resistant to flucytosine, four (30.7%) were resistant to caspofungin, and nine (69.2%) were resistant to fluconazole. The PCA analysis clustered the studied isolates into two major clades. C. albicans isolates of traditional cheese collected from villages were grouped in the same cluster. Among the C. albicans isolates from village cheese, there were those obtained from the same dairy milk at different times. Samples from the same sales points produced at different dairy farms were also contaminated with C. albicans. Concerning food safety standards applied from farm to fork, in order to prevent these pathogenic agents from contaminating cheeses, attention to the hygiene conditions of the sale points, conscious personnel, prevention of cross contamination will greatly reduce public health threats in addition to the application of animal health control, milking hygiene, pasteurization parameters in traditional cheese production.

Batzelladine D, a Marine Natural Product, Reverses the Fluconazole Resistance Phenotype Mediated by Transmembrane Transporters in Candida albicans and Interferes with Its Biofilm: An In Vitro and In Silico Study.

Numerous Candida species are responsible for fungal infections; however, Candida albicans stands out among the others. Treatment with fluconazole is often ineffective due to the resistance phenotype mediated by transmembrane transporters and/or biofilm formation, mechanisms of resistance commonly found in C. albicans strains. A previous study by our group demonstrated that batzelladine D can inhibit the Pdr5p transporter in Saccharomyces cerevisiae. In the present study, our aim was to investigate the efficacy of batzelladine D in inhibiting the main efflux pumps of Candida albicans, CaCdr1p and CaCdr2p, as well as to evaluate the effect of the compound on C. albicans biofilm. Assays were conducted using a clinical isolate of Candida albicans expressing both transporters. Additionally, to allow the study of each transporter, S. cerevisiae mutant strains overexpressing CaCdr1p or CaCdr2p were used. Batzelladine D was able to reverse the fluconazole resistance phenotype by acting on both transporters. The compound synergistically improved the effect of fluconazole against the clinical isolate when tested in the Caenorhabditis elegans animal model. Moreover, the compound disrupted the preformed biofilm. Based on the obtained data, the continuation of batzelladine D studies as a potential new antifungal agent and/or chemosensitizer in Candida albicans infections can be suggested.

Bloodstream infections in cancer patients in central India: pathogens and trends of antimicrobial resistance over a 5-year period.

Introduction. Bloodstream infection (BSI) is a common complication with a high fatality rate in cancer patients. There are notable variations in the epidemiology of BSI over time and among different countries. Infections due to multidrug-resistant organisms (MDROs) such as extended-spectrum beta-lactamases (ESBLs) and carbapenem-resistant Enterobacteriaceae (CRE) are increasing. This may lead to inadequate empirical antibiotic therapy, increasing the antimicrobial resistance (AMR) problem and unfavourable outcomes in these immunocompromised patients. There is paucity of data pertaining to AMR in such vulnerable patients from developing countries such as India. The aim of this study was to investigate the distribution of the bacterial pathogens causing BSI and the AMR trend in cancer patients in central India. Methodology. This single-centre retrospective observational study was conducted in a tertiary care cancer hospital. Patients with solid organ and haematological malignancies, both adults and paediatric, who had blood cultures sent to the microbiology laboratory from January 2018 to December 2022 were included. Blood cultures were processed using the BacT/ALERT 3D system (bioMérieux, France), and the identification of the bacteria and their antimicrobial susceptibility (AST) was performed using the Vitek 2 compact system (bioMérieux, France). Electronic medical records and microbiology lab records were used to retrieve the demographic and microbiological data. Microsoft Excel (RRID:SCR_016137) was used to enter and tabulate the data. Statistical analysis was performed using SPSS version 29 (RRID:SCR_002865). Results. A total of 687 isolates from 524 patients were studied. Gram-negative bacteria (64%) were the commonest cause of BSI in the studied patients, followed by Gram-positive cocci (25%) and fungal isolates (9%). Ten cases were polymicrobial. Escherichia coli (n=140) was the most common among the isolated pathogens, followed by Klebsiella species (n=103), Pseudomonas species (n=102), and coagulase-negative staphylococci (CONS) (n=92). Among the 140 isolates of E. coli, 66% were extended-spectrum β-lactamase (ESBL) producers and 26% were resistant to carbapenem. Among the 103 isolated Klebsiella species, 50% were carbapenem resistant and 36% were ESBL producers. Among enterobacterales, the CRE rate was 34%. Carbapenem resistance was seen in 25% of Pseudomonas species and 53% of Acinetobacter species isolates. Klebsiella species were the most resistant pathogens isolated. CONS comprised 56% of all Gram-positive isolates, followed by Staphylococcus aureus (36%), enterococci species (11%), and streptococci species (3%). Methicillin resistance was 60% in CONS and 64% in S. aureus. One vancomycin-resistant enterococcus was isolated. Non-albicans Candida was the most common fungal pathogen. The sensitivity to fluconazole was 84% in non-albicans Candida species, while only one isolate of Candida albicans was resistant to fluconazole. The trend of pathogens was insignificant over 5 years, with Gram-negative bacteria being the commonest. Further, there was no significant change in the trend of ESBL and CRE resistance pattern over 5 years. Conclusion. Gram-negative bacteria were the most common isolated pathogens from BSI with a higher antimicrobial resistance rate in cancer patients. The CRE rate of 34% is alarming, limiting the choices for empirical antibiotic therapy.

Unveiling the Innate and Adaptive Immunity Interplay: Global Transcriptomic Profiling of the Host Immune Response in Candida albicans Endophthalmitis in a Murine Model.

Intraocular fungal infection poses a significant clinical challenge characterized by chronic inflammation along with vision impairment. Understanding the host defense pathways involved in fungal endophthalmitis will play a pivotal role in identifying adjuvant immunotherapy. Clinical isolates of Candida albicans (15,000 CFU/μL) were intravitreally injected in C57BL/6 mice followed by enucleation at 24 and 72 h postinfection. Histopathological analysis was performed to evaluate the retinal changes and the disease severity. RNA-seq analysis was conducted on homogenized eyeballs to assess the relevant gene profiles and their differentially expressed genes (DEGs). Pathway enrichment analysis was performed to further annotate the functions of the DEGs. Histopathological analysis demonstrated a higher disease severity with increased inflammatory cells at 72 hpi and transcriptome analysis revealed 27,717 DEGs, of which 1493 were significant (adj p value ≤0.05, FC ≥ 1.5). Among these, 924 were upregulated, and 569 were downregulated. Majority of the upregulated genes were associated with the inflammatory/host immune response and signal transduction and enriched in the T-cell signaling pathway, natural killer cell-mediated cytotoxicity, C-type receptor signaling pathway, and NOD-like receptor signaling pathway. Furthermore, inflammation-associated genes such as T-cell surface glycoprotein CD3, cathelicidin antimicrobial peptide, and lymphocyte cell-specific protein tyrosine kinase were enriched, while pathways such as MAPK, cAMP, and metabolic pathways were downregulated. Regulating the T-cell influx could be a potential strategy to modulate excessive inflammation in the retina and could potentially aid in better vision recovery in fungal endophthalmitis.

Using an in vitro pharmacokinetics / pharmacodynamics model to simulate and assess the pharmacodynamic characteristics of voriconazole against some Candida albicans isolates in humans

Using an in vitro pharmacokinetics / pharmacodynamics model to simulate and assess the pharmacodynamic characteristics of voriconazole against some Candida albicans isolates in humans

Synthesis and Characterization of Silver Nanoparticles Stabilized with Biosurfactant and Application as an Antimicrobial Agent.

Surfactants can be used as nanoparticle stabilizing agents. However, since synthetic surfactants are not economically viable and environmentally friendly, biosurfactants are emerging as a green alternative for the synthesis and stabilization of nanoparticles. Nanoparticles have been applied in several areas of industry, such as the production of biomedical and therapeutic components, packaging coating, solar energy generation and transmission and distribution of electrical energy, among others. The aim of this study was to synthesize, in a simple and green way, silver nanoparticles (AgNPs) using the biosurfactant produced by Candida lipolytica UCP 0899 as a stabilizer. AgNPs were examined and morphologically characterized using the techniques of ultraviolet-visible spectroscopy (UV-visible), scanning electron microscopy (SEM), zeta potential and energy dispersive X-ray spectroscopy (EDS). Newly formed silver nanoparticles showed a maximum UV-visible absorption peak at 400 nm, while a shift to 410 nm was observed in those stored for 120 days. SEM micrograph confirmed the formation of nanoparticles with an average size of 20 nm and with a predominant spherical structure, while a zeta potential of -60 mV suggested that the use of the biosurfactant promoted their stability. Stabilized nanoparticles were tested for their antimicrobial activity against bacterial isolates of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Enterobacter sp., as well as fungal isolates of Candida albicans and Aspergillus niger. At a concentration of 16.50 µg/mL, AgNPs inhibited the growth of all target microorganisms according to the following decreasing order: E. coli (95%), S. aureus, C. albicans (90%), A. niger (85%), Enterobacter sp. (75%) and P. aeruginosa (71%). These results suggest the potential use of the biosurfactant as a stabilizer of silver nanoparticles as an antimicrobial agent in different industrial sectors. Furthermore, the in vivo toxicity potential of biosurfactants was evaluated using the Tenebrio molitor model. The larvae were treated with concentrations in the range of 2.5, 5.0 and 10 g/L, and no mortality was observed within the 24 to 72 h period, demonstrating non-toxicity within the tested concentration range. These findings support the safety, efficacy and non-toxicity of biosurfactant-stabilized nanoparticles.

Antifungal Activity of Efinaconazole Compared with Fluconazole, Itraconazole, and Terbinafine Against Terbinafine- and Itraconazole-Resistant/Susceptible Clinical Isolates of Dermatophytes, Candida, and Molds.

Recently, an increasing number of resistant-to-terbinafine dermatophytosis cases have been reported. Thus, identifying an alternative antifungal agent that possesses broad-spectrum activity, including against resistant strains, is needed. We compared the antifungal activity of efinaconazole with that of fluconazole, itraconazole, and terbinafine against clinical isolates of dermatophytes, Candida, and molds using in vitro assays. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of each antifungal agent were quantified and compared. Susceptible and resistant clinical isolates of Trichophyton mentagrophytes (n = 16), Trichophyton rubrum (n = 43), Trichophyton tonsurans (n = 18), Trichophyton violaceum (n = 4), Candida albicans (n = 55), Candida auris (n = 30), Fusarium spp, Scedosporium spp, and Scopulariopsis spp (n = 15 for each) were tested. Efinaconazole was the most active antifungal agent tested against dermatophytes, with MIC50 and MIC90 (concentrations 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 0.03 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 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 to 2 µg/mL versus 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.

Preparing and Assessment of Biocidal La Nano-complex Treated Filter Capacity against Isolated Microbes from Air Conditioning Systems in COVID-19 Rehabilitation Rooms

Mucormycosis is a severe fungal infection which mainly caused by filamentous fungi of the Absidia sp., Rhizopus sp., Cunninghamella sp, Mucor sp., and Rhizomucor sp. Moreover, the pandemic of the SARS-CoV-2 virus expands the need to interfere with spread of the airborne respiratory infections. Accordingly, developing cutting-edge solutions to restrict and/or prevent air contamination by infectious microbes are very warranted. The current work aims to prepare biocidal La-nano complex treated filters and assess their anti-fungal capacity against 20 Rhizopus oryzae, 10 Candida albicans, and 11 Aspergillus fumigatus. These fungi were isolated from the inside parts of the air conditioning systems in the rehabilitation rooms for COVID-19 patients. The obtained results demonstrated that the prepared were able to significantly decrease the invading microbes and eradicate Rhizopus, Aspergillus, Mucor, Candida albicans isolates at 0.64 mg/ml concentration. DFT study compares the electronic properties and reactivity of a ligand in its uncoordinated form with its lanthanum complex. The ligand exhibits lower binding energy, ionization potential, electron affinity, absolute electronegativity, and chemical potential when coordinated with lanthanum. In contrast, the lanthanum complex has a smaller energy gap, absolute hardness, and global softness.

Antifungal Synergy: Mechanistic Insights into the R-1-R Peptide and Bidens pilosa Extract as Potent Therapeutics against Candida spp. through Proteomics.

Previous reports have demonstrated that the peptide derived from LfcinB, R-1-R, exhibits anti-Candida activity, which is enhanced when combined with an extract from the Bidens pilosa plant. However, the mechanism of action remains unexplored. In this research, a proteomic study was carried out, followed by a bioinformatic analysis and biological assays in both the SC5314 strain and a fluconazole-resistant isolate of Candida albicans after incubation with R-1-R. The proteomic data revealed that treatment with R-1-R led to the up-regulation of most differentially expressed proteins compared to the controls in both strains. These proteins are primarily involved in membrane and cell wall biosynthesis, membrane transport, oxidative stress response, the mitochondrial respiratory chain, and DNA damage response. Additionally, proteomic analysis of the C. albicans parental strain SC5314 treated with R-1-R combined with an ethanolic extract of B. pilosa was performed. The differentially expressed proteins following this combined treatment were involved in similar functional processes as those treated with the R-1-R peptide alone but were mostly down-regulated (data are available through ProteomeXchange with identifier PXD053558). Biological assays validated the proteomic results, evidencing cell surface damage, reactive oxygen species generation, and decreased mitochondrial membrane potential. These findings provide insights into the complex antifungal mechanisms of the R-1-R peptide and its combination with the B. pilosa extract, potentially informing future studies on natural product derivatives.

Study the effect of some physical factors on three isolations of Candida albicans isolated from Iraqi patients

Background: The Candida spp. is considered an opportunistic fungi, as the infection increases when the immune system is weakened due to the exposure of the host to diseases or as a result of diabetes, immunodeficiency, cancerous diseases, or organ transplantation. Methods: The phenotypic and microscopic diagnosis methods for three isolates of Candida albicans isolated from different hospitals in Iraq were conducted along with the Vitek2 Compact System, then the diagnosis of isolated yeasts was confirmed based on PCR technology. The physical factors study was conducted to show the effect of temperature, pH concentration, and CO2 ratio on the three isolates of Candida albicans. Results: The three isolates contained one single bundle of extracted DNA. The PCR products using the fungal primer pair (ITS1, ITS4) showed the production of a single band for the three isolates of Candida albicans of 535bp. While the effect of high temperature on isolates, the best rate of growth was at 37°C, whereas isolate K8 recorded the highest growth rate then isolate B17 and T5, and no growth was recorded for the three isolates at 45°C. As for the effect of pH, the results showed that the best growth was at pH 6.2, where the highest growth rate was in isolate K8, followed by isolate T5 and then isolate B17. The results showed that a high percentage of CO2 harmed the growth rate, the best growth rate for all isolates was at a concentration of 0.03% of carbon dioxide. The highest growth rate was recorded in isolates K8, followed by B17 and then T5, while the lowest growth rate of isolates was at a concentration of 15% of carbon dioxide, as isolates recorded K8, followed by B17, then T5. Conclusions: In this study we found that Candida albicans has a gene expression of 535bp and there were effects of some physical factors characteristics on three isolates of pathogenic Candida albicans.

Antifungal susceptibility pattern of Candida species isolated from pregnant women.

Candidaspecies, opportunistic yeast, are the second most common cause of female vulvovaginal candidiasis. This study aimed to evaluate the antifungal susceptibility profile of the isolatedCandidaspecies in pregnant women in Hajjah governorate, Yemen. A hospital-based cross-sectional study was conducted among 396 pregnant women attending Authority AL-Gumhorri Hospital Hajjah between February and July 2023. Vaginal swabs were collected, andCandidaspecies were isolated and identified based on the standard laboratory method. Furthermore, the antifungal drug susceptibility ofCandidaspecies was determined by the Kirby-Bauer technique. The prevalence of vaginal Candida infection among pregnant women was 61.4%. Candida albicanswas the most predominant species (59.26%), followed by Candida krusei(13.58%), Candida Tropicalis (11.12%), Candida Grabata (9.87%), and Candida dubliniensis (6.17%). The highest rate ofCandidainfections was among women aged 24-30 years (71.9%) who finished primary school (77.8%), with the third trimester (80%), multigravida (66.1%), and recurrent infection (67.7%) showing significant differences (P< 0.05). The Candida albicans isolates were resistant to clotrimazole and itraconazole at 34.7% and 23.6%, respectively.In addition, the resistance of Candida krusei, Candida tropicalis, Candida glabrata, and Candida dublinensis isolates to fluconazole, voriconazole, voriconazole, and nystatin was 57.6%, 63%, 43.8%, and 60%, respectively. Additionally, approximately 46.2% of isolated Candida albicans exhibited one kind of antifungal drug resistance, whereas 38.7% of isolated non-albicans exhibited resistance to three different antifungal agents. According to the above findings, Candida infection is highly prevalent in Yemen and quite widespread. Interventions in health education are advised to increase women's knowledge of vaginitis and its prevention. The antifungal susceptibility test may also be helpful in determining the best medication for each patient.

Relationship of biofilm strength levels in Candida albicans isolates with the type of clinical specimens

Relationship of biofilm strength levels in Candida albicans isolates with the type of clinical specimens

UPC2 mutations and development of azole resistance in Candida albicans hospital isolates from Lebanon

ObjectivesThis study evaluated the role of Upc2 in the development of azole resistance in Candida albicans isolates from Lebanese hospitalized patients and determined a correlation between resistance and virulence. MethodsThe UPC2 gene which codes for an ergosterol biosynthesis regulator was sequenced and analysed in two azole-resistant and one azole-susceptible C. albicans isolates. An amino acid substitution screening was carried out on Upc2 with a focus on its ligand binding domain (LBD) known to interact with ergosterol. Then, Upc2 protein secondary structure prediction and homology modelling were conducted, followed by total plasma membrane ergosterol and cell wall chitin quantifications. For virulence, mouse models of systemic infection were generated and an agar adhesion and invasion test was performed. ResultsAzole-resistant isolates harboured novel amino acid substitutions in the LBD of Upc2 and changes in protein secondary structures were observed. In addition, these isolates exhibited a significant increase in plasma membrane ergosterol content. Resistance and virulence were inversely correlated while increased cell wall chitin concentration does not seem to be linked to resistance since even though we observed an increase in chitin concentration, it was not statistically significant. ConclusionsThe azole-resistant C. albicans isolates harboured novel amino acid substitutions in the LBD of Upc2 which are speculated to induce an increase in plasma membrane ergosterol content, preventing the binding of azoles to their target, resulting in resistance.

Anticandidal activity of a wild Bacillus subtilis NAM against clinical isolates of pathogenic Candida albicans

BackgroundResistance to antifungal medications poses a significant obstacle in combating fungal infections. The development of novel therapeutics for Candida albicans is necessary due to the increasing resistance of candidiasis to the existing medications. The utilization of biological control is seen as a more advantageous and less hazardous strategy therefore the objective of this study is to identify the antifungal properties of Bacillus subtilis against pathogenic C. albicans.ResultsWe conducted a study to evaluate the antifungal properties of three bacterial isolates against the human pathogen Candida albicans. One of the bacterial isolates exhibited a potent antifungal activity against this fungal pathogen. This bacterium was identified as Bacillus subtilis based on the 16Sr RNA gene sequence. It exhibited inhibitory efficacy ranging from 33.5 to 44.4% against 15 Candida isolates. The optimal incubation duration for achieving the maximum antifungal activity was determined to be 48 h, resulting in a mean inhibition zone diameter of 29 ± 0.39 mm. The Potato Dextrose agar (PDA) medium was the best medium for the most effective antifungal activity. Incubation temperature of 25oC and medium pH value of 8.0 were the most favorable conditions for maximum antagonistic activity that resulted fungal growth inhibition of 40 ± 0.16 and 36 ± 0.94 mm respectively. Furthermore, the addition of 10.5 mg/ml of bacterial filtrate to C. albicans colonies resulted in 86.51%. decrease in the number of germinated cells. The fungal cell ultrastructural responses due to exposure to B. subtilis filtrate after 48 h were investigated using transmission electron microscopy (TEM). It revealed primary a drastic abnormality that lead to cellular disintegration including folding and lysis of the cell wall, total collapse of the yeast cells, and malformed germ tube following the exposure to the filtrate. However, the control culture treatment had a characteristic morphology of the normal fungal cells featuring a consistently dense central region, a well-organized nucleus, and a cytoplasm containing several components of the endomembrane system. The cells were surrounded by a uniform and intact cell wall.ConclusionThe current study demonstrates a notable antifungal properties of B. subtilis against C. albicans as a result of production of bioactive components of the bacterial exudate. This finding could be a promising natural antifungal agent that could be utilized to combat C. albicans.

Resistant C. albicans implicated in recurrent vulvovaginal candidiasis (RVVC) among women in a tertiary healthcare facility in Kumasi, Ghana

BackgroundVulvovaginal candidiasis is a common fungal infection that affects the female lower genital tract. This study determined the major risk factors associated with vulvovaginal infection (VVI) in the Ashanti region of Ghana and also determined the antifungal resistance patterns of Candida albicans isolates to some antifungals.MethodsThree hundred and fifty (350) high vaginal swab (HVS) samples were collected from women who presented with signs and symptoms of VVI. A structured questionnaire was administered to one hundred and seventy-two (172) of the women. HVS samples were cultured on Sabouraud dextrose agar with 2% chloramphenicol. The polymerase chain reaction was employed to confirm C. albicans. Antifungal susceptibility testing was performed and the susceptibility of C. albicans isolates to fluconazole, clotrimazole, amphotericin B, nystatin, miconazole and 5-flurocytosine were assessed.ResultsVaginal infection was most prevalent amongst females in their reproductive age (21 to 30 years; 63.0%). The study found a significant association between vaginal infections and some risk factors such as sexual practices (p < 0.001), antibiotic misuse (p < 0.05), poor personal hygiene (p < 0.005) and birth control methods (p < 0.049). Out of the 350 HVS samples collected, 112 yielded yeast cells with 65 (58%) identified as C. albicans. The C. albicans isolates were resistant to 5’ flucytosine (100%), fluconazole (70%), voriconazole (69.2%), miconazole (58.5%) and nystatin (49.2%). C. albicans isolates were more susceptible to amphotericin B (53.8%) and clotrimazole (45.1%), although an appreciable number of isolates showed resistance (46.1% and 52.3%, respectively).ConclusionThere should be nationwide education on all associated risk factors of VVI. Also, use of the various antifungal agents in vaginal candidiasis should proceed after antifungal susceptibility testing to ensure efficacious use of these agents.

Efficacy of sodium hypochlorite in overcoming antimicrobial resistance and eradicating biofilms in clinical pathogens from pressure ulcers.

Sodium hypochlorite (NaOCl) is widely recognized for its broad-spectrum antimicrobial efficacy in skin wound care. This study investigates the effectiveness of NaOCl against a range of bacterial and fungal isolates from pressure ulcer (PU) patients. We analyzed 20 bacterial isolates from PU patients, comprising carbapenem-resistant Klebsiella pneumoniae (CRKP), multidrug-resistant Acinetobacter baumannii (MDRAB), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible Staphylococcus aureus (MSSA), along with 5 Candida albicans isolates. Antibiotic resistance profiles were determined using standard susceptibility testing. Whole-genome sequencing (WGS) was employed to identify antimicrobial resistance genes (ARGs) and disinfectant resistance genes (DRGs). Genetic determinants of biofilm formation were also assessed. The antimicrobial activity of NaOCl was evaluated by determining the minimum inhibitory concentration (MIC) and the minimal biofilm eradication concentration (MBEC) for both planktonic and biofilm-associated cells. CRKP and MDRAB showed resistance to fluoroquinolones and carbapenems, while MRSA exhibited resistance to β-lactams and levofloxacin. MSSA displayed a comparatively lower resistance profile. WGS identified significant numbers of ARGs in CRKP and MDRAB, with fewer DRGs compared to MRSA and MSSA. All isolates possessed genes associated with fimbriae production and adhesion, correlating with pronounced biofilm biomass production. NaOCl demonstrated substantial antimicrobial activity against both planktonic cells and biofilms. The MIC90 for planktonic bacterial cells was 0.125 mg/mL, and the MBEC90 ranged from 0.225 to 0.5 mg/mL. For planktonic C. albicans, the MIC90 was 0.150 mg/mL, and the MBEC90 was 0.250 mg/mL. These results highlight the challenge in treating biofilm-associated infections and underscore the potential of NaOCl as a robust antimicrobial agent against difficult-to-treat biofilm infections at concentrations lower than those typically found in commercial disinfectants.

Comparative pharmacodynamics and dose optimization of liposomal amphotericin B against Candida species in an in vitro pharmacokinetic/pharmacodynamic model.

As comparative pharmacokinetic/pharmacodynamic (PK/PD) studies of liposomal amphotericin B (L-AMB) against Candida spp. are lacking, we explored L-AMB pharmacodynamics against different Candida species in an in vitro PK/PD dilution model. Eight Candida glabrata, Candida parapsilosis, and Candida krusei isolates (EUCAST/CLSI AMB MIC 0.125-1 mg/L) were studied in the in vitro PK/PD model simulating L-AMB Cmax = 0.25-64 mg/L and t1/2 = 9 h. The model was validated with one susceptible and one resistant Candida albicans isolate. The Cmax/MIC-log10CFU/mL reduction from the initial inoculum was analyzed with the Emax model, and Monte Carlo analysis was performed for the standard (3 mg/kg with Cmax = 21.87 ± 12.47 mg/L) and higher (5 mg/kg with Cmax = 83 ± 35.2 mg/L) L-AMB dose. A ≥1.5 log10CFU/mL reduction was found at L-AMB Cmax = 8 mg/L against C. albicans, C. parapsilosis, and C. krusei isolates (MIC 0.25-0.5 mg/L) whereas L-AMB Cmax ≥ 32 mg/L was required for C. glabrata isolates. The in vitro PK/PD relationship followed a sigmoidal pattern (R2 ≥ 0.85) with a mean Cmax/MIC required for stasis of 2.1 for C. albicans (close to the in vivo stasis), 24/17 (EUCAST/CLSI) for C. glabrata, 8 for C. parapsilosis, and 10 for C. krusei. The probability of target attainment was ≥99% for C. albicans wild-type (WT) isolates with 3 mg/kg and for wild-type isolates of the other species with 5 mg/kg. L-AMB was four- to eightfold less active against the included non-C. albicans species than C. albicans. A standard 3-mg/kg dose is pharmacodynamically sufficient for C. albicans whereas our data suggest that 5 mg/kg may be recommendable for the included non-C. albicans species.