Elucidation of the mechanisms of fluconazole resistance and repurposing treatment options against urinary Candida spp. isolated from hospitalized patients in Alexandria, Egypt.

BACKGROUND: The incidence of fungal urinary tract infections (UTIs) has dramatically increased in the past decades, with Candida arising as the predominant etiological agent. Managing these infections poses a serious challenge to clinicians, especially with the emergence of fluconazole-resistant (FLC-R) Candida species. In this study, we aimed to determine the mechanisms of fluconazole resistance in urinary Candida spp. isolated from hospitalized patients in Alexandria, Egypt, assess the correlation between fluconazole resistance and virulence, and explore potential treatment options for UTIs caused by FLC-R Candida strains. RESULTS: Fluconazole susceptibility testing of 34 urinary Candida isolates indicated that 76.5% were FLC-R, with a higher prevalence of resistance recorded in non-albicans Candida spp. (88.9%) than in Candida albicans (62.5%). The calculated Spearman's correlation coefficients implied significant positive correlations between fluconazole minimum inhibitory concentrations and both biofilm formation and phospholipase production. Real-time PCR results revealed that most FLC-R isolates (60%) significantly overexpressed at least one efflux pump gene, while 42.3% significantly upregulated the ERG11 gene. The most prevalent mutation detected upon ERG11 sequencing was G464S, which is conclusively linked to fluconazole resistance. The five repurposed agents: amikacin, colistin, dexamethasone, ketorolac, and sulfamethoxazole demonstrated variable fluconazole-sensitizing activities in vitro, with amikacin, dexamethasone, and colistin being the most effective. However, the fluconazole/colistin combination produced a notable reduction (49.1%) in bladder bioburden, a 50% decrease in the inflammatory response, and tripled the median survival span relative to the untreated murine models. CONCLUSIONS: The fluconazole/colistin combination offers a promising treatment option for UTIs caused by FLC-R Candida, providing an alternative to the high-cost, tedious process of novel antifungal drug discovery in the battle against antifungal resistance.

Resistance and virulence genes characteristic of a South Asia Clade (I) Candida auris strain isolated from blood in Beijing.

INTRODUCTION: Candida auris is a globally disseminated invasive ascomycetous yeast, that imposes a substantial burden on healthcare systems. It has been documented to have spread to over 40 countries across six continents, necessitating in-depth comprehension through advanced techniques like Whole-Genome Sequencing. METHOD: This study entailed the isolation and Whole-Genome Sequencing of a fluconazole-resistant C. auris strain (CA01) obtained from a patient's blood in Beijing. Genome analysis was conducted to classify the strain, and molecular docking was performed to understand the impact of mutations on drug resistance. RESULTS: Genome analysis revealed that CA01 belongs to the South Asia Clade (I) and shares the closest genetic relationship with previously reported strains BJCA001 and BJCA002. Notably, unlike BJCA001, CA01 exhibits significant resistance to fluconazole primarily due to the A395T mutation in the ERG11 gene. Molecular docking studies demonstrated that this mutation leads to geometric changes in the active site where fluconazole binds, resulting in decreased binding affinity. Additionally, the present findings have identified several core virulence genes in C. auris, such as RBF1. DISCUSSION: The findings from this study expand the understanding of the genetic diversity and adaptive mechanisms of C. auris within the South Asia Clade (I). The observed fluconazole resistance driven by the ERG11 mutation A395T highlights the need for heightened awareness and adaptation in clinical treatment strategies in China. This study provides critical insights into drug resistance and virulence profiles at a genetic level, which could guide future therapeutic and management strategies for C. auris infections.

Neonatal Fungemia by Non-Candida Rare Opportunistic Yeasts: A Systematic Review of Literature.

Fungal colonization poses a significant risk for neonates, leading to invasive infections such as fungemia. While Candida species are the most commonly identified pathogens, other rare yeasts are increasingly reported, complicating diagnosis and treatment due to limited data on antifungal pharmacokinetics. These emerging yeasts, often opportunistic, underscore the critical need for early diagnosis and targeted therapy in neonates. This systematic review aims to comprehensively analyze all published cases of neonatal fungemia caused by rare opportunistic yeasts, examining geographical distribution, species involved, risk factors, treatment approaches, and outcomes. Searching two databases (PubMed and SCOPUS), 89 relevant studies with a total of 342 cases were identified in the 42-year period; 62% of the cases occurred in Asia. Pichia anomala (31%), Kodamaea ohmeri (16%) and Malassezia furfur (15%) dominated. Low birth weight, the use of central catheters, prematurity, and the use of antibiotics were the main risk factors (98%, 76%, 66%, and 65%, respectively). 22% of the cases had a fatal outcome (80% in Asia). The highest mortality rates were reported in Trichosporon beigelii and Trichosporon asahii cases, followed by Dirkmeia churashimamensis cases (80%, 71%, and 42% respectively). Low birth weight, the use of central catheters, the use of antibiotics, and prematurity were the main risk factors in fatal cases (84%, 74%, 70%, and 67%, respectively). 38% of the neonates received fluconazole for treatment but 46% of them, died. Moreover, the rare yeasts of this review showed high MICs to fluconazole and this should be taken into account when planning prophylactic or therapeutic strategies with this drug. In conclusion, neonatal fungemia by rare yeasts is a life-threatening and difficult-to-treat infection, often underestimated and misdiagnosed.

Changes in fluconazole pharmacokinetics can impact on antifungal effectiveness in critically ill burn patients: a Pharmacokinetic-Pharmacodynamic (PK/PD) approach.

OBJECTIVES: The Fluconazole pharmacokinetic-pharmacodynamic relationship was investigated in a few clinical settings and only limited studies regarding burned patients are available. Thus, the authors aimed to investigate fluconazole pharmacokinetics changes and its impact on antifungal therapy coverage against dose-dependent Candida spp. applying the PK/PD approach in critically ill severely burned patients. METHODS: Fluconazole was administered as a one-hour intravenous infusion of 200 mg q12h. Doses were increased according to the coverage based on the PK/PD approach. Blood samples were collected at the end of the infusion (1st hour), two hours after (3rd hour), and before the next dose (12th or 24th hour). Serum concentrations were obtained by HPLC-UV. Pharmacokinetic parameters were estimated by noncompartmental analysis and compared with data described in healthy subjects. The effectiveness predictive index was based on the AUCss0-24h/MIC ratio, with a target above 25. RESULTS: Every pharmacokinetic parameter was reduced throughout all three sets of the study. Compared to healthy subjects, the volume of distribution was decreased about 3‒7 times, biological half-life was 2‒3 times shorter and total body clearance was slightly altered but statistically significant. Both half-life and total body clearance were correlated to the volume of distribution. Consequently, an increase in fluconazole daily dose was necessary to improve empiric coverage. CONCLUSIONS: Fluconazole pharmacokinetics is altered in critically ill severely burned patients, mainly related to the volume of distribution. Doses higher than usual may be necessary to reach the PK/PD target and guarantee antifungal coverage against dose-dependent Candida spp. up to MIC 32 mg/L.

Best Practices in Treatment of Fungal Urinary Tract Infections.

Fungal pathogens within the urine, specifically Candida species, are a common finding amongst hospitalized patients. Risk factors for the development of candiduria involve patients with indwelling urinary drainage devices, surgical patients, patients undergoing urologic instrumentation, and diabetic patients. Candiduria often presents with an asymptomatic course but can also be a severe life-threatening process. This article will review the epidemiology and risk factors associated with fungal urinary tract infections, and the diagnosis and categorization of these infections along with a review of current medical and surgical treatments for this condition.

Higher doses of fluconazole are needed to ensure target attainment in critically ill adults on continuous Veno-venous hemodialysis.

BACKGROUND: Critically ill patients undergoing Continuous Renal Replacement Therapy (CRRT) are treated with higher doses of fluconazole based on the literature recommendations. However, clinical follow-up data demonstrating the effectiveness of this approach are lacking. PURPOSE: A retrospective cohort study was conducted to evaluate whether target attainment was achieved with higher doses of fluconazole. Additionally, the study focused on identifying factors that may contribute to variability in fluconazole exposure in these patients. METHODS: Critically ill patients undergoing Continuous Veno-Venous Hemodialysis (CVVHD) who received either standard or higher doses of intravenous fluconazole were included. Evaluation of target attainment was conducted for each dose regimen. RESULTS: Administering higher doses resulted in target attainment in 100 % of the patients, indicating that starting with at least 400 mg twice daily is an adequate dosing guideline. In this study, only the dose of fluconazole was found to significantly influence target attainment (p < 0.001), with no other predefined factors identified as having a significant impact. CONCLUSION: According to the results of the study, increasing the fluconazole dose to at least 400 mg twice daily is sufficient to reach the desired target in critically ill patients undergoing CVVHD.

Parametric and nonparametric population pharmacokinetic analysis of fluconazole in critically ill patients and dosing simulations for Candida infections.

Large pharmacokinetic (PK) variability of fluconazole has been reported in critically ill patients, but the implications for fluconazole dosing remain unclear. The objectives of this study were to evaluate the population PK of fluconazole and identify appropriate dosage regimens by simulations. This was a retrospective analysis of fluconazole PK data from patients hospitalized in critical care and infectious disease departments. Both parametric and nonparametric population approaches were used. Various loading and maintenance fluconazole doses were evaluated by simulations, with computation of the probabilities of PK/pharmacodynamic (PD) target attainment (PTA) and cumulative fractions of response (CFR) based on international and local minimum inhibitory concentration (MIC) distributions of Candida sp. Data from 36 critically ill patients and 16 non-critically ill patients were available for model building (n = 202 concentrations). The final model adequately described the data, including the external data set (13 patients). After 24 h of therapy, 65% and 74% of patients had trough and area under the concentration-time curve values below the usual targets. Standard dosages were associated with low PTA for MIC >1 mg/L at 24 h. Higher loading doses administered two times daily improved PTA. CFR were >90% for C. albicans with standard dosages, while they were very low for C. glabrata, even with high dosages. Candida species and associated MIC distributions strongly influence fluconazole dosage requirements. Higher loading doses may be necessary for the achievement of PK/PD targets up to MIC breakpoints. The use of fluconazole for invasive C. glabrata infection should be discouraged because of poor PK/PD target attainment.

UPLC-MS/MS method for fluconazole determination in plasma and its application in Mexican patients with candidaemia.

Aim: An accurate and fast ultra-high performance liquid chromatography coupled with tandem mass spectrometry analytical method was developed and validated for quantifying fluconazole levels in human plasma according to the US FDA guidelines.Materials & methods: A simple protein precipitation by acetonitrile was employed for the sample preparation. The chromatographic separation was carried out using isocratic elution of water (0.1% formic acid) and acetonitrile on an Acquity ultra-high performance liquid chromatography HSS T3 column. Samples from ten adult patients diagnosed with candidemia who received fluconazole treatment were analyzed.Results & conclusion: The method demonstrated excellent linearity and stability within the 1-50 µg/ml range (r2 >0.999). The intraday and interday precision were determined with coefficient of variation values ranging from 1.4 to 4.38% and 2.8 to 6.6%, respectively. This rapid and selective method has successfully analyzed 27 plasma samples. The straightforward sample preparation in a single step and the reduced analysis time make this method suitable for adult patients with candidemia, leading to improved clinical outcomes.

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Evaluation of amlodipine against strains of Candida spp. in planktonic cells, developing biofilms and mature biofilms.

Aim: To evaluate the antifungal activity of amlodipine against strains of Candida spp. and to its possible mechanism of action.Methods: Broth microdilution tests were used to determine the minimum inhibitory concentration, while the synergistic activity was evaluated by calculating the fractional inhibitory concentration index. The action of amlodipine against biofilms was determined using the MTT assay and its possible mechanism of action was investigated through flow cytometry tests.Results: Amlodipine showed MICs ranging from 62.5 to 250 µg/ml, in addition to action against pre-formed and forming biofilms, with reductions between 50 and 90%. Amlodipine increases the externalization of phosphatidylserine and reduces the cell viability of fungal cells, suggesting apoptosis.Conclusion: Amlodipine had good antifungal activity against planktonic cells and biofilms of Candida spp., by leading the cells to apoptosis.

Candida is a type of fungus that can cause diseases. This fungus became stronger over time and drugs can no longer kill them easily, so it is important to find new drugs. We decided to study whether amlodipine, a drug used for heart disease, has action against Candida. We discovered that amlodipine make fungi weaker. We still need to do more studies to find out if amlodipine can help prevent Candida diseases.

Now that griseofulvin is not available, what to do with tinea capitis treatments?

INTRODUCTION: Griseofulvin, discovered in 1939 and commercially available since 1959, was the first oral antifungal agent effective against dermatophytosis, particularly tinea capitis. Although it was eventually superseded by azole antifungals due to its long treatment duration and reliance on keratopoiesis, griseofulvin remains notable for its effectiveness and safety in treating tinea capitis, especially when caused by Microsporum canis. However, due to a decline in cases and commercial unavailability, alternative treatments are now required. AREAS COVERED: The following topics regarding to other treatments were discussed: (I) The efficacy of alternative antifungal agents such as terbinafine, itraconazole, and fluconazole, in the treatment of tinea capitis. (II) The use and role of topical therapies. (III) Experience in the management of tinea capitis. EXPERT OPINION: The usefulness of oral terbinafine as a replacement for griseofulvin in the treatment of tinea capitis and why it is the preferred drug in elderly patients was discussed. Challenges with Microsporum spp. and the use of fluconazole in pediatric patients were also analyzed. Support for the use of topical treatment as an adjunctive treatment for tinea capitis was highlighted.