Physicochemical and Anti-fungal Studies of the Pharmaceutical Co-crystal/Salt of Fluconazole

Crystal engineering is one green alternative to organic synthesis that can be used to manipulate molecular behavior promptly and economically. We report the preparation and characterization of the pharmaceutical organic salt (FLC-C) of fluconazole (FLC) and organosulfonate (NDSA-2H), based on the sulfonate-pyridinium supramolecular synthon. Structural studies validate the crystallization of the two-component stoichiometric crystal with two molecules of water in the triclinic P1̅ space group. The anticipated proton transfer between the crystal forms leads to ionic interactions, augmenting the organic salt's thermal stability. Hirshfeld studies of FLC-C help to understand the role and significance of different types of intermolecular interactions responsible for crystal packing. The structural and theoretical studies indicate the absence of π-π interactions in FLC-C, which account for the incipience of solid-state emission in the product. The solubility studies establish augmented aqueous solubility of FLC-C over pristine FLC at physiological pH values of 2 and 7. Interestingly, in in vitro studies, FLC-C appears to serve as a potential alternative to FLC, displaying a wide spectrum of antifungal activity. FLC-C is active against several human pathogenic yeast strains, including the leading and emerging Candida strains (Candida albicans and Candida auris, respectively), at comparable and/or lower drug concentrations without showing any enhanced host cell toxicity. Interestingly, the pharmaceutical co-crystal also displays fluorescence properties inside the Candida cells.

Fluconazole Resistance and Virulence in In Vitro Induced-Fluconazole Resistant Strains and in Clinical Fluconazole Resistant Strain of Cryptococcus deuterogattii

Neuromeningeal cryptococcosis is a life-threatening infection of the central nervous system, caused by encapsulated yeast belonging to the Cryptococcus neoformans and Cryptococcus gattii species complexes. Recent data showed that virulence and antifungal resistance are variable for yeasts belonging to the C. gattii species complex. There is an increase in resistance to fluconazole for yeasts of the C. gattii species complex and the virulence is variable according to the genotype. In the present study, (i) we explored and compared the mechanisms of resistance to fluconazole between C. deuterogattii clinically resistant strains and induced fluconazole-resistant strains by exposure to fluconazole in vitro, and (ii) we studied their virulence in the Galleria mellonella study model. We demonstrated that the fluconazole resistance mechanisms involved were different between clinically resistant strains and induced resistant strains. We also demonstrated that fluconazole-induced resistant strains are less virulent when compared to the original susceptible strains. On the contrary, the clinically resistant strain tested maintains its virulence compared to fluconazole-susceptible strains of the same sequence type.

Antifungal Susceptibility of Oral Candida Isolates from Mother-Infant Dyads to Nystatin, Fluconazole, and Caspofungin

The carriage of Candida albicans in children's oral cavities is associated with a higher risk for early childhood caries, so controlling this fungus in early life is essential for preventing caries. In a prospective cohort of 41 mothers and their children from 0 to 2 years of age, this study addressed four main objectives: (1) Evaluate in vitro the antifungal agent susceptibility of oral Candida isolates from the mother-child cohort; (2) compare Candida susceptibility between isolates from the mothers and children; (3) assess longitudinal changes in the susceptibility of the isolates collected between 0 and 2 years; and (4) detect mutations in C. albicans antifungal resistance genes. Susceptibility to antifungal medications was tested by in vitro broth microdilution and expressed as the minimal inhibitory concentration (MIC). C. albicans clinical isolates were sequenced by whole genome sequencing, and the genes related to antifungal resistance, ERG3, ERG11, CDR1, CDR2, MDR1, and FKS1, were assessed. Four Candida spp. (n = 126) were isolated: C. albicans, C. parapsilosis, C. dubliniensis, and C. lusitaniae. Caspofungin was the most active drug for oral Candida, followed by fluconazole and nystatin. Two missense mutations in the CDR2 gene were shared among C. albicans isolates resistant to nystatin. Most of the children's C. albicans isolates had MIC values similar to those from their mothers, and 70% remained stable on antifungal medications from 0 to 2 years. For caspofungin, 29% of the children's isolates showed an increase in MIC values from 0 to 2 years. Results of the longitudinal cohort indicated that clinically used oral nystatin was ineffective in reducing the carriage of C. albicans in children; novel antifungal regimens in infants are needed for better oral yeast control.

Resistance to Fluconazole of Candida albicans in Vaginal Isolates: a 10-Year Study in a Clinical Referral Center

Review of vaginal isolates of Candida albicans that caused clinical failure in a 10-year collection of vaginal C. albicans specimens obtained in a university vaginitis referral clinic indicated an increase in fluconazole resistance. Factors contributing to azole resistance are discussed, including treatment choice associated with fluconazole-resistant C. albicans vaginal infection.

Anti-Candidal Activity of Reboxetine and Sertraline Antidepressants: Effects on Pre-Formed Biofilms

Reboxetine (REB) and sertraline (SER) are antidepressants. The antifungal potential of these drugs against planktonic Candida has been recently reported with limited data about their effects on Candidal biofilms. Biofilms are self-derived extracellular matrixes produced by the microbial population that is attached to biotic surfaces, such as vaginal and oral mucosa, or abiotic surfaces, such as biomedical devices, resulting in persistent fungal infections. The commonly prescribed antifungals, azoles, are usually less effective when biofilms are formed, and most of the prescribed antifungals are only fungistatic. Therefore, the current study investigates the antifungal potentials of REB and SER, alone and in combination with fluconazole (FLC) and itraconazole (ITR) against Candidal biofilms. Using proper controls, Candida species (Candida albicans, C. albicans; Candida krusei, C. krusei; and Candida glabrata, C. glabrata) were used to form biofilms in 96-well microplates. Serial dilutions corresponding to concentrations ranging from 2 to 4096 µg/mL of the target drugs (REB, SER, FLC, ITR) were prepared and added to the plates. Impairment of the biofilm biomass and biofilm metabolic viability was detected using the crystal violet (CV) assay and 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, respectively. In the checkerboard assay, the sessile fractional inhibitory concentration index (SFICI) was calculated to evaluate the effects of drug combinations. SER was more effective in reducing the biomass than REB for C. albicans and C. glabrata, but both were equal for C. krusei. For the reduction in metabolic activity in C. albicans and C. glabrata, SER had a slight advantage over REB. In C. krusei, REB was slightly more potent. Overall, FLC and ITR were almost equal and produced more significant reductions in metabolic activity when compared to SER and REB, except for C. glabrata, where SER was almost equal to FLC. Synergism was detected between REB + FLC and REB + ITR against biofilm cells of C. albicans. Synergism was detected between REB + ITR against biofilm cells of C. krusei. Synergism was detected between REB + FLC and REB + ITR against biofilm cells of C. albicans, C. krusei, and C. glabrata. The results of the present study support the potential of SER and REB as anti-Candidal biofilm agents that are beneficial as a new antifungal to combat Candidal resistance.

Quality of life in women with chronic recurrent vulvovaginal candidosis: A sub-analysis of the prospective multicentre phase IIb/III Prof-001 study

BACKGROUND

Chronic recurrent vulvovaginal candidosis (RVVC), defined as three or more episodes of vulvovaginal candidosis per year, significantly impairs quality of life (QoL) and sexual health.

OBJECTIVES

The primary objective of this study was to assess health-related QoL in women with RVVC using validated questionnaires before and after treatment. The secondary objective was to analyse the effect of RVVC on women's sexual health.

PATIENTS/METHODS

This was a sub-analysis of a randomised, controlled, double-blinded study titled 'A phase IIb/III, parallel-arm, randomized, active-controlled, double-blind, double-dummy, multicenter, non-inferiority study in patients with recurrent vulvovaginal candidosis to compare the clinical efficacy, safety and tolerability of topically administered ProF-001 (Candiplus®) to oral fluconazole, which was conducted at 35 study sites in Austria, Poland and Slovakia. QoL was assessed using the European Quality of Life (EQ) five-dimension five-level scale (EQ-5D-5L) and visual analogue scale (EQ-VAS) questionnaires, followed by specific questions regarding sexuality.

RESULTS

From 2019 to 2021, 360 of 432 (83.3%) women with RVVC had accomplished a 6-months maintenance treatment and were enrolled in this sub-analysis. The EQ-5D-5L and EQ-VAS scores demonstrated improved QoL in 137 (65.2%) and 159 (75.4%) women after 6 months of maintenance treatment. Each individual aspect of sexual health significantly improved (all p < .05). A reduction in pain frequency during or after sexual intercourse in the 6-month period occurred in 124 (66.3%) women.

CONCLUSIONS

Women with RVVC had high QoL and sexual health impairment; however, a 6-months maintenance treatment resulted in effective improvement in QoL and sexual health.

Interplay of the microbiome and antifungal therapy in recurrent vulvovaginal candidiasis (RVVC): A narrative review

Recurrent vulvovaginal candidiasis (RVVC) is a microbial, immune and sexual health disorder impacting up to 10 % of the adult female population. Fluconazole is a well-established antifungal drug commonly utilized for acute and long-term RVVC treatment. This insight review provides an overview of known vaginal and gastrointestinal microbiota characteristics in RVVC, presents the potential impacts of fluconazole therapy on multi-microbiome relationships and discusses implications for future research and clinical practice. Next-generation sequencing (NGS) and molecular methods to accurately define vaginal microbiota trends in RVVC are not comprehensively available, limiting understanding of microbiota roles in RVVC. Inconsistencies and variances in Lactobacillus profiles in RVVC women suggest poorly understood disease implications on the bacterial and fungal microbiomes. Investigations of environmental conditions like vaginal pH, drug therapy's impact, especially fluconazole maintenance therapy, and the elucidation of multi-microbiome relationships in RVVC are required to further investigate disease pathogenesis and responsible antimicrobial prescribing.

Evaluation of Fluconazole versus Echinocandins for Treatment of Candidemia Caused by Susceptible Common Candida Species: A Propensity Score Matching Analysis

This study aimed to evaluate the effectiveness of fluconazole and echinocandins in the treatment of candidemia caused by both fluconazole- and echinocandin-susceptible common Candida species. A retrospective study which enrolled adult candidemia patients ≥19 years diagnosed at a tertiary care hospital in the Republic of Korea from 2013 to 2018 was conducted. Common Candida species were defined as C. albicans, C. tropicalis, and C. parapsilosis. Cases of candidemia were excluded based on the following exclusion criteria: (1) candidemia showed resistance to either fluconazole or echinocandins, or (2) candidemia was caused by other Candida species than common Candida species. In order to compare the mortality rates between patients who receive fluconazole or echinocandins, the propensity scores on variables of baseline characteristics using the multivariate logistic regression analysis were employed to balance the antifungal treatment groups, and a Kaplan-Meier survival analysis was performed. Fluconazole and echinocandins were used in 40 patients and in 87 patients, respectively. The propensity score matching included 40 patients in each treatment group. After matching, the rates of 60-day mortality after candidemia were 30% in the fluconazole group and 42.5% in the echinocandins group, and a Kaplan-Meier survival analysis showed no significant difference between antifungal treatment groups, p = 0.187. A multivariable analysis demonstrated that septic shock was significantly associated with the 60-day mortality, whereas fluconazole antifungal treatment was not associated with an excess 60-day mortality. In conclusion, our study results suggest that fluconazole use in the treatment of candidemia caused by susceptible common Candida species may be not associated with increased 60-day mortality compared to echinocandins.

Exposure of Cryptococcus neoformans to Seven Commonly Used Agricultural Azole Fungicides Induces Resistance to Fluconazole as Well as Cross-Resistance to Voriconazole, Posaconazole, Itraconazole and Isavuconazole

BACKGROUND

Cross-resistance to medical azoles by exposure to azole pesticides is well documented for Aspergillus family fungi but is poorly evaluated for other environmental pathogen fungi, particularly for yeasts belonging to the Cryptococcus neoformans/Cryptococcus gattii species complexes.

METHODS

One thousand C. neoformans yeast were exposed to various concentrations of seven different commonly used azole pesticides. Clones surviving exposure were picked randomly, and their minimal inhibitory concentrations (MICs) of fluconazole, voriconazole, posaconazole, itraconazole and isavuconazole were assessed.

RESULTS

Depending on the pesticide used for exposure, up to 13.3% of selected Cryptococcus colonies showed a phenotype of resistance to fluconazole, and among them, several showed cross-resistance to another or several other medical azoles. Molecular mechanisms involved in the resistance setups seem to be dependent on ERG11 and AFR1 gene overexpression.

CONCLUSION

Exposure to any of the seven azole pesticides tested is capable of increasing the MIC of fluconazole in C. neoformans, including up to the level of the fluconazole-resistant phenotype, as well as generating cross-resistance to other medical azoles in some cases.

Pharmacokinetics and Bioequivalence of Fluconazole Capsules Manufactured in France and China in Healthy Chinese Participants: Open-Label, Randomized, Single-Dose, 2-Way, Crossover Bioequivalence Study Under Fasted and Fed Conditions

This was an open-label, randomized study in healthy Chinese participants to assess the bioequivalence of 2 fluconazole 150-mg capsules under fasted and fed conditions. The study consisted of 2 treatment periods, separated by a 14-day washout period. Thirty-six participants were enrolled, with 18 participants each in the fasted and fed groups. In each treatment period, participants received a single oral dose of the test or reference fluconazole 150-mg capsule. After washout, participants received the alternate treatment. Blood samples for pharmacokinetic analysis were collected from 1 hour before dosing to 72 hours after dosing. The median plasma concentration-time profiles were similar for both treatments under fasted and fed conditions. Bioequivalence of fluconazole between the 2 capsules was demonstrated as 90% confidence intervals of the geometric mean ratios for the maximum plasma concentration and area under the plasma concentration-time curve from time 0 to 72 hours after dosing under fasted and fed conditions were within the acceptable range of 80%-125%. Overall, 7 participants reported at least 1 treatment-emergent adverse event; all were mild in severity. No serious adverse events or deaths were reported. The test fluconazole capsule was bioequivalent to the reference capsule, and a single dose was well tolerated. Clinicaltrials.gov ID: NCT03621072.

Antifungal Tolerance and Resistance Emerge at Distinct Drug Concentrations and Rely upon Different Aneuploid Chromosomes

Antifungal drug tolerance is a response distinct from resistance, in which cells grow slowly above the MIC. Here, we found that the majority (69.2%) of 133 Candida albicans clinical isolates, including standard lab strain SC5314, exhibited temperature-enhanced tolerance at 37°C and 39°C, and were not tolerant at 30°C. Other isolates were either always tolerant (23.3%) or never tolerant (7.5%) at these three temperatures, suggesting that tolerance requires different physiological processes in different isolates. At supra-MIC fluconazole concentrations (8 to 128 μg/mL), tolerant colonies emerged rapidly at a frequency of ~10^-3. In liquid passages over a broader range of fluconazole concentrations (0.25 to 128 μg/mL), tolerance emerged rapidly (within one passage) at supra-MICs. In contrast, resistance appeared at sub-MICs after 5 or more passages. Of 155 adaptors that evolved higher tolerance, all carried one of several recurrent aneuploid chromosomes, often including chromosome R, alone or in combination with other chromosomes. Furthermore, loss of these recurrent aneuploidies was associated with a loss of acquired tolerance, indicating that specific aneuploidies confer fluconazole tolerance. Thus, genetic background and physiology and the degree of drug stress (above or below the MIC) influence the evolutionary trajectories and dynamics with which antifungal drug resistance or tolerance emerges. IMPORTANCE Antifungal drug tolerance differs from drug resistance: tolerant cells grow slowly in drug, while resistant cells usually grow well, due to mutations in a few known genes. More than half of Candida albicans clinical isolates have higher tolerance at body temperature than they do at the lower temperatures used for most lab experiments. This implies that different isolates achieve drug tolerance via several cellular processes. When we evolved different strains at a range of high drug concentrations above inhibitory levels, tolerance emerged rapidly and at high frequency (one in 1,000 cells) while resistance appeared only later at very low drug concentrations. An extra copy of all or part of chromosome R was associated with tolerance, while point mutations or different aneuploidies were seen with resistance. Thus, genetic background and physiology, temperature, and drug concentration all influence how drug tolerance or resistance evolves.

How Applicable Is the Single-Dose AMBITION Regimen for Human Immunodeficiency Virus-Associated Cryptococcal Meningitis to High-Income Settings?

The AmBisome Therapy Induction Optimization (AMBITION-cm) trial, conducted in eastern and southern Africa, showed that a single, high dose (10 mg/kg) of liposomal amphotericin B, given with an oral backbone of fluconazole and flucytosine, was noninferior to the World Health Organization (WHO)-recommended regimen of 7 days of amphotericin B deoxycholate plus flucytosine for treatment of human immunodeficiency virus (HIV)-associated cryptococcal meningitis and has been incorporated into WHO treatment guidelines. We believe that the trial also has important implications for the treatment of HIV-associated cryptococcal meningitis in high-income settings. We advance the arguments, supported by evidence where available, that the AMBITION-cm trial regimen is likely to be as fungicidal as the currently recommended 14-day liposomal amphotericin-based treatments, better tolerated with fewer adverse effects, and confer significant economic and practical benefits and, therefore, should be included as a treatment option in guidance for HIV-associated cryptococcal treatment in high-income settings.

A longitudinal study on fluconazole resistance in Candida albicans vaginal isolates

BACKGROUND

Recurrent vulvovaginal candidiasis (RVVC), despite its worldwide prevalence, has limited treatment options; and a long-term prophylactic regimen utilising fluconazole is the dominant choice.

OBJECTIVES

An increase in fluconazole resistance is reported, and little information is available about the reversibility of resistance status following the withdrawal of fluconazole.

METHODS

Repeated antifungal susceptibility tests (ASTs) for fluconazole at a median interval of 3 months between them were evaluated in women with refractory or recurrent VVC patients at the Vaginitis clinic from 2012 to 2021 (10 years) and performed at pH 7 and pH 4.5 using the broth microdilution tests based on the CLSI M27-A4 reference method.

RESULTS

Of 38 patients with long-term follow-up with repeat ASTs, 13 patients (13/38, 34.2%) tested at pH 7.0 remained susceptible to fluconazole with MIC ≤2 μg/mL. Nineteen patients (19/38, 50%) remained resistant to fluconazole with MIC ≥8 μg/mL, whereas four (4/38, 10.5%) changed from susceptible to resistant and two (2/38, 5.2%) changed from resistant to susceptible over time. At pH 4.5, among the 37 patients with repeated MIC values, nine (9/37, 24.3%) remained susceptible to fluconazole and 22 (22/37, 59.5%) remained resistant. Three isolates (3/37, 8.1%) changed from susceptible to resistant, while 3 (3/37, 8.1%) changed from resistant to susceptible over time.

CONCLUSION

Fluconazole susceptibility in Candida albicans vaginal isolates obtained longitudinally in women with RVVC remains stable with rare reversal of resistance despite azole avoidance.

Species and antifungal susceptibility profile of agents causing vulvovaginal candidiasis in a military population: a cross-sectional study

Military women on active duty are exposed to constant physical and mental demands, which may predispose them to some infection risks, including vulvovaginal candidiasis (VVC), a pathology considered a global public health problem. To monitor the prevalent and emerging pathogens in VVC, this study aimed to evaluate the distribution of yeast species and their in vitro antifungal susceptibility profile. We studied 104 vaginal yeast specimens obtained during routine clinical examinations. The population was attended at the Medical Center of the Military Police, São Paulo, Brazil, and was divided into two groups: infected patients (VVC) and colonised patients. Species were identified by phenotypic and proteomic methods (MALDI-TOF MS) and susceptibility to eight antifungal drugs, including azoles, polyenes, and echinocandins, was determined using microdilution broth. Candida albicans stricto sensu was found to be the most frequently isolated species (55%), but we observed a considerable rate of other Candida species isolates (30%), including Candida orthopsilosis stricto sensu only in the infected group. There were also other rare genera such as Rhodotorula, Yarrowia, and Trichosporon (15%), of which Rhodotorula mucilaginosa was the most prevalent in both groups. Fluconazole and voriconazole had the highest activity against all species in both groups. Candida parapsilosis was the most susceptible species, except for amphotericin-B in the infected group. Of note, we observed unusual resistance in C. albicans. Our results have allowed us to compile an epidemiological database on the etiology of VVC to support the empirical treatment and improve the health care of military women.

Real-life comparison of posaconazole versus fluconazole for primary antifungal prophylaxis during remission-induction chemotherapy for acute leukemia

BACKGROUND

Patients undergoing remission-induction intensive chemotherapy for acute leukemia are at high risk for life-threatening invasive fungal infections (IFIs). Primary antifungal prophylaxis with posaconazole has been shown to reduce the incidence of IFI compared to fluconazole, but real-life data are limited and the effect on mortality remains unclear.

METHODS

This retrospective cohort study compared fluconazole and posaconazole as primary prophylaxis in real-life practice over a 10-year period, in a Canadian hospital.

RESULTS

A total of 299 episodes were included (fluconazole, n = 98; posaconazole, n = 201), of which 68% were first inductions. The underlying hematologic malignancy was acute myeloid leukemia or myelodysplastic syndrome in 88% of episodes and acute lymphoblastic leukemia in 9%. Overall, 20 cases of IFI occurred (aspergillosis, n = 17; candidiasis, n = 3) and 14 were considered as breakthrough IFI. IFI incidence was significantly lower in the posaconazole group (3.5% versus 13.2%; p = 0.001). Empirical or targeted antifungal therapy was also reduced in the posaconazole cohort. Mortality was similar in both groups.

CONCLUSIONS

In a real-life setting in Canada, primary posaconazole prophylaxis reduces the incidence of IFI during remission-induction chemotherapy, compared to fluconazole.

Current Trends in Antifungal Prophylaxis for High-Risk Neonates in Neonatal Intensive Care Units in India: A Nationwide Survey

Background Prophylactic antifungals are often used in high-risk babies in neonatal intensive care units (NICUs) to reduce invasive fungal infections (IFIs). However, existing guidelines regarding prophylactic antifungal usage do not clearly define the high-risk population. This study aimed to assess the practices related to prophylactic antifungal use in NICUs in India. Methods For this cross-sectional study, an online structured questionnaire was completed by neonatologists who worked in level 3 NICUs in 12 states in India during the period June 2022 to August 2022. Results Data from 151 NICUs were analyzed. 71.7% of respondents were from private hospitals, and 28.3% were from government hospitals. Nearly one-fourth of the units (28.5%) used antifungal prophylaxis in all extremely low birth weight (ELBW) babies, while another one-fourth (25.8%) used a case-based approach. The remaining NICUs (45.7%) did not use prophylactic antifungals. Among the users, the preferred antifungal was fluconazole; 3 mg/kg and 6 mg/kg were the dosage regimens used. The commonly used interval for administering fluconazole was 72 hours (69.2% of units). The intravenous route was the preferred route of administration (84.1%). Factors that influenced the non-users were the low incidence of fungal infections in their NICUs and concern about the development of resistance. It was noted that the users felt strongly about the need for further recommendations from pediatric societies and more studies on the efficacy of antifungals. Conclusion There is considerable variation in the use of prophylactic antifungals across NICUs in India. Among the users, uniformity in the choice of antifungal and interval of administration was observed. Further recommendations from pediatric societies, including the definitions of neonates at-risk of fungal infections, are required to ensure consistency in practice and help clinicians decide whether or not to use prophylactic antifungals.

Oral fluconazole has variable pharmacokinetics in dogs

The purpose of this study was to assess the effects of food and manufacturer on the oral bioavailability of fluconazole in dogs. We hypothesized feeding would decrease fluconazole bioavailability and large variability between manufacturers would occur. Six healthy purpose-bred dogs aged 2-3 years, weighing 9.5-13.7 kg, were enrolled. Each dog was administered a 100 mg fluconazole tablet from three FDA approved manufacturers (1-Glenmark, 2-Citron, 3-Harris) in a randomized crossover block study, fasted for 12 h (fasted) or 15 min after feeding (fed); each dog had 6 treatments. Blood was collected for 72 h after dosing with a 10-day washout between treatments. Fluconazole plasma concentrations were determined with mass spectrometry. Overall variability in dose-normalized drug exposure (AUC/dose) was large (range 1.9-2.9x) within each treatment, while the overall range across all treatments was 3.3-fold. The inter-dog variability in the terminal half-life was also large, 3.1-fold. The mean fed relative oral bioavailability was lower (82%-90%) compared to fasted for each formulation. Due to the large variability, the formulations were not bioequivalent. These data suggest the variability in the half-life was a major contributor to the large variability in fluconazole pharmacokinetics in dogs, while the feeding status and manufacturer were minor contributors.

Comparative cardiac effects of antimalarial drug halofantrine with or without concomitant administration of kolanut or fluconazole in healthy volunteers

BACKGROUND

There is rekindled interest in the cardiotoxicity of antimalarial medicines. Halofantrine is associated with QT interval prolongation. Fluconazole and kolanut alter the pharmacokinetics of halofantrine.

OBJECTIVES

The study assessed the electrocardiographic changes of concomitant administration of kolanut or fluconazole with halofantrine and the effects on the QTc interval.

METHODS

Eighteen healthy volunteers received a single oral dose of halofantrine, halofantrine with kolanut or halofantrine with fluconazole in a crossover study. Twelve lead electrocardiography (ECG) was performed to measure the PR and QT interval (QTc). Statistical analysis was with SPSS at 5% level of significance.

RESULTS

PR intervals were shortened by halofantrine alone and halofantrine with kolanut (169.29 28.67 to 165.29 28.007 and 172.73 29.843 to 163.00 18.336ms) but was prolonged by halofantrine with fluconazole (177.70 27.394 to 186.59 44.434ms). There was prolongation of QTc (384.76 21.727 to 394.12 21.525; 381.36 22.29 to 388.30 17.26 and 382.35 20.08 to 390.84 21.97) in all the three treatment groups at 6 hours, p>0.05. One subject on halofantrine and fluconazole had QTc >440ms. Pre-treatment PR interval (PR0) correlated well with post-treatment PR6, and with PR14 r= 0.519, p= 0.014; r=0.664, p=0.013.

CONCLUSION

Concomitant intake of kolanut with halofantrine was significantly decrease cardiac effect of halofantrine.

Aneuploidy Mediates Rapid Adaptation to a Subinhibitory Amount of Fluconazole in Candida albicans

Candida albicans is a prevalent, opportunistic, human fungal pathogen. Antifungal drug resistance and tolerance are two distinct mechanisms of adaptation to drugs. Studies of mechanisms of drug resistance are limited to the applications of high doses of drugs. Few studies have investigated the effects of subinhibitory amounts of drugs on the development of drug resistance or tolerance. In this study, we found that growth in a subinhibitory amount of fluconazole (FLC), a widely used antifungal drug, for just a short time was sufficient to induce aneuploidy in C. albicans. Surprisingly, the aneuploids displayed fitness loss in the presence of subinhibitory FLC, but a subpopulation of cells could tolerate up to 128 μg/mL FLC. Particular aneuploidy (ChrR trisomy) caused tolerance, not resistance, to FLC. In the absence of FLC, the aneuploids were unstable. Depending on the karyotype, aneuploids might become completely euploid or maintain particular aneuploidy, and, accordingly, the tolerance would be lost or maintained. Mechanistically, subinhibitory FLC was sufficient to induce the expression of several ERG genes and as well as the drug efflux gene MDR1. Aneuploids had a constitutive high-level expression of genes on and outside the aneuploid chromosomes, including most of the ERG genes as well as the drug efflux genes MDR1 and CDR2. Therefore, aneuploids were prepared for FLC challenges. In summary, aneuploidy provides a rapid and reversible strategy of adaptation when C. albicans is challenged with subinhibitory concentrations of FLC. IMPORTANCE Genome instability is a hallmark of C. albicans. Aneuploidy usually causes fitness loss in the absence of stress but confers better fitness under particular stress conditions. Therefore, aneuploidy is considered to be a double-edged sword. Here, we extend the understanding of aneuploidy. We found that aneuploidy arose under weak stress conditions but that it did not confer better fitness to the stress. Instead, it was less fit than its euploid counterparts. If the stress was withdrawn, aneuploidy spontaneously reverted to euploidy. If the stress became stronger, aneuploidy enabled subpopulation growth in a dose-independent manner of the stress. Therefore, we posit that aneuploidy enables the rapid and reversible development of drug tolerance in C. albicans. Further studies are required to investigate whether this is a general mechanism in human fungal pathogens.

[New opportunities for complex treatment of oropharyngeal candidiasis in HIV-infected patients in the later stages of the disease]

Treatment of recurrent oropharyngeal candidiasis (OPC) in HIV-infected patients is a serious clinical problem due to the emergence of resistant Candida strains, the risk of invasive disease, and high economic costs, which warrants the need for new treatment regimens.

AIM

To improve the treatment regimen of OPC in the later stages of HIV infection by combining the complex herbal medicinal product Tonsilgon^® N with fluconazole and evaluate the effectiveness of this combination.

MATERIALS AND METHODS

A comparative randomized clinical study included 65 patients divided into observation and comparison groups, receiving fluconazole plus Tonsilgon^® H and fluconazole monotherapy, respectively, for 7 days. On days 1 and 8, the severity of OPC clinical signs was assessed using a visual analog scale. The secretory immunoglobulin A in saliva was measured as a criterion for changing the level of local mucosal protection of the oral cavity and pharynx.

CONCLUSION

This treatment regimen for oropharyngeal candidiasis in patients with HIV infection in the later stages of the disease (IVB-IVC) with fluconazole and Tonsilgon^® N is effective, which is confirmed by a significantly more pronounced regression of clinical signs (p^M-U<0.01), as well as an increase in the level of secretory immunoglobulin A in the oral fluid (from 0.62±0.33 g/L to 0.81±0.18 g/L; p<0.05).

Inflammatory invasion on human vaginal mucosa correlated with combined drug treatment and recurrence in recurrent vulvovaginal candidiasis

AIM

Recurrent vulvovaginal candidiasis (RVVC) is a chronic, difficult to treat vaginal infection, caused by Candida species, which affects women of all ages and ethnic and social background. Most RVVC studies use animal models, and there is still a lack of observation on human tissue samples and effective therapy to reduce recurrence.

MATERIALS AND METHODS

We observed CD163⁺ macrophages and NLRP3 expression by immunohistochemistry, also investigated bacteria and fungi co-invasion by fluorescence in situ hybridization from 144 human vaginal biopsy tissues (48 RVVC, 48 VVC, 48 healthy volunteers), and we also explored the effect of combining metronidazole in the treatment of RVVC.

RESULTS

A large number of neutrophils, lymphocytes and plasma cells infiltrated the mucosa, basement membrane and submucosa, accompanied by significantly overexpressed NLRP3 inflammasome. While CD163⁺ macrophages often infiltrated under the basement membrane in patients with RVVC, 29.2% of cases were found Gardnerella and fungi jointly invaded the vaginal mucosas. RVVC vaginal mucosal histopathology revealed mucosal inflammatory responses dominated by neutrophils, which may involve activation of NLRP3 and immune tolerance of M2 macrophages (CD163⁺ ). Fluconazole combined with metronidazole can achieve higher efficiency (95.8% vs. 70.8%) and reduce the recurrence rate more (8.3% vs. 37.5%) at 6-month follow-up.

CONCLUSION

Inflammatory invasion on human vaginal mucosa correlated with combined drug treatment and recurrence in RVVC. The combined medication will need to further evaluate in future.

Lack of Association between YEASTONE Antifungal Susceptibility Tests and Clinical Outcomes of Cryptococcus Meningitis

The relation between antifungal susceptibility and treatment outcomes is not well-characterized. There is paucity of surveillance data for cerebrospinal fluid (CSF) isolates of cryptococcus investigated with YEASTONE colorimetric broth microdilution susceptibility testing. A retrospective study of laboratory-confirmed cryptococcus meningitis (CM) patients was conducted. The antifungal susceptibility of CSF isolates was determined using YEASTONE colorimetric broth microdilution. Clinical parameters, CSF laboratory indices, and antifungal susceptibility results were analyzed to identify risk factors for mortality. High rates of resistance to fluconazole and flucytosine were observed in this cohort. Voriconazole had the lowest MIC (0.06 µg/mL) and lowest rate of resistance (3.8%). In a univariate analysis, hematological malignancy, concurrent cryptococcemia, high Sequential Organ Failure Assessment (SOFA) score, low Glasgow coma scale (GCS) score, low CSF glucose level, high CSF cryptococcal antigen titer, and high serum cryptococcal antigen burden were associated with mortality. In a multivariate analysis, meningitis with concurrent cryptococcemia, GCS score, and high CSF cryptococcus burden, were independent predictors of poor prognosis. Both early and late mortality rates were not significantly different between CM wild type and non-wild type species.

Sustained Release of Antifungal and Antibacterial Agents from Novel Hybrid Degradable Nanofibers for the Treatment of Polymicrobial Osteomyelitis

This study aimed to develop a drug delivery system with hybrid biodegradable antifungal and antibacterial agents incorporated into poly lactic-co-glycolic acid (PLGA) nanofibers, facilitating an extended release of fluconazole, vancomycin, and ceftazidime to treat polymicrobial osteomyelitis. The nanofibers were assessed using scanning electron microscopy, tensile testing, water contact angle analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The in vitro release of the antimicrobial agents was assessed using an elution method and a high-performance liquid chromatography assay. The in vivo elution pattern of nanofibrous mats was assessed using a rat femoral model. The experimental results demonstrated that the antimicrobial agent-loaded nanofibers released high levels of fluconazole, vancomycin, and ceftazidime for 30 and 56 days in vitro and in vivo, respectively. Histological assays revealed no notable tissue inflammation. Therefore, hybrid biodegradable PLGA nanofibers with a sustainable release of antifungal and antibacterial agents may be employed for the treatment of polymicrobial osteomyelitis.

Carbonic Anhydrase II Activators in Osteopetrosis Treatment: A Review

Osteopetrosis is a rare hereditary illness generated by failure in osteoclasts resulting in elevated bone densities. Patients with osteopetrosis possess several complications, like dental caries, earlier teeth loss, delayed eruption, malformed crowns and roots, and lamina dura thickening. Since deficiency of carbonic anhydrase II is a major cause behind osteopetrosis, carbonic anhydrase II activators have a large number of applications in osteopetrosis treatment. There is a lack of a comprehensive review on osteopetrosis, pathogenesis of dental abnormalities, and the role of carbonic anhydrase II activators in osteopetrosis treatment. To address this research gap, the authros perfomed a comprehensive review on osteopetrosis and its types, pathogenesis of dental abnormalities, and the role of carbonic anhydrase II activators in osteopetrosis treatment. A brief introduction to the pathogenesis of dental abnormalities and regeneration is provided in this survey. A discussion of types of osteopetrosis depending on genetic inheritance, such as autosomal dominant, autosomal recessive, and X-linked inheritance osteopetrosis, is presented in this survey. The paper also focuses on the importance of carbonic anhydrase II activators as a potential drug therapy for dental osteopetrosis. In addition, a brief note on the role of azole and fluconazole in treating osteopetrosis is given. Finally, future directions involving gene therapy for dental osteopetrosis are described.