Genetic Mutations in FKS1 Gene Associated with Acquired Echinocandin Resistance in Candida parapsilosis Complex.

Candida parapsilosis complex has recently received special attention due to naturally occurring FKS1 polymorphism associated with high minimal inhibitory concentrations for echinocandin and the increase of clonal outbreaks of strains resistant to commonly used antifungals such as fluconazole. Despite the previous fact, little is known about the genetic mechanism associated with echinocandin resistance. Therefore, the present study was designed to investigate the mechanism of acquired echinocandin resistance in C. parapsilosis complex strains. A total of 15 clinical C. parapsilosis complex isolates were sub-cultured for 30 days at a low concentration of micafungin at ½ the lowest MIC value of the tested isolates (0.12 µg/ml). After culturing, all the isolates were checked phenotypically for antifungal resistance and genotypically for echinocandin resistance by checking FKS1 gene hot spot one (HS1) and HS2 mutations. In vitro induction of echinocandin resistance confirmed the rapid development of resistance at low concentration micafungin, with no difference among C. parapsilosis, C. metapsilosis, and C. orthopsilosis in the resistance development. For the first time we identified different FKS1 HS1 and or HS2 mutations responsible for echinocandin resistance such as R658S and L1376F in C. parapsilosis, S656X, R658X, R658T, W1370X, X1371I, V1371X, and R1373X (corresponding to their location in C. parapsilosis) in C. metapsilosis, and L648F and R1366H in C. orthopsilosis. Our results are of significant concern, since the rapid development of resistance may occur clinically after short-term exposure to antifungals as recently described in other fungal species with the potential of untreatable infections.

Taxonomy of Candida parapsilosis complex isolated from neonates and the role of Hsp90 inhibitors to enhanced the antifungal activity of micafungin.

Species from Candida parapsilosis complex are frequently found in neonatal candidemia. The antifungal agents to treat this infection are limited and the occurrence of low in vitro susceptibility to echinocandins such as micafungin has been observed. In this context, the chaperone Hsp90 could be a target to reduce resistance. Thus, the objective of this research was to identify isolates from the C. parapsilosis complex and verify the action of Hsp90 inhibitors associated with micafungin. The fungal identification was based on genetic sequencing and mass spectrometry. Minimal inhibitory concentrations were determined by broth microdilution method according to Clinical Laboratory and Standards Institute. The evaluation of the interaction between micafungin with Hsp90 inhibitors was realized using the checkerboard methodology. According to the polyphasic taxonomy, C. parapsilosis sensu stricto was the most frequently identified, followed by C. orthopsilosis and C. metapsilosis, and one isolate of Lodderomyces elongisporus was identified by genetic sequencing. The Hsp90 inhibitor geladanamycin associated with micafungin showed a synergic effect in 31.25% of the isolates, a better result was observed with radicicol, which shows synergic effect in 56.25% tested yeasts. The results obtained demonstrate that blocking Hsp90 could be effective to reduce antifungal resistance to echinocandins.

Structure-guided engineered urethanase from Candida parapsilosis with pH and ethanol tolerance to efficiently degrade ethyl carbamate in Chinese rice wine.

Urethane hydrolase can degrade the carcinogen ethyl carbamate (EC) in fermented food, but its stability and activity limit its application. In this study, a mutant G246A and a double mutant N194V/G246A with improved cpUH activity and stability of Candida parapsilosis were obtained by site-directed mutagenesis. The catalytic efficiency (Kcat/Km) of mutant G246A and double mutant N194V/G246A are 1.95 times and 1.88 times higher than that of WT, respectively. In addition, compared with WT, the thermal stability and pH stability of mutant G246A and double mutant N194V/G246A were enhanced. The ability of mutant G246A and double mutant N194V/G246A to degrade EC in rice wine was also stronger than that of WT. The mutation increased the stability of the enzyme, as evidenced by decreased root mean square deviation (RMSD) and increased hydrogen bonds between the enzyme and substrate by molecular dynamics simulation and molecular docking analysis. The molecule modification of new cpUH promotes the industrial process of EC degradation.

Recurrent copy number variations in the human fungal pathogen Candida parapsilosis.

Candida parapsilosis is an opportunistic fungal pathogen with increasing incidence in hospital settings worldwide; however, we lack a comprehensive understanding of the mechanisms promoting its virulence and drug resistance. Bergin et al. systematically quantify the frequency and effect of copy number variation (CNV) across 170 diverse clinical and environmental isolates of C. parapsilosis (Bergin SA, Zhao F, Ryan AP, Müller CA, Nieduszynski CA, Zhai B, Rolling T, Hohl TM, Morio F, Scully J, Wolfe KH, Butler G, 2022, mBio, https://doi.org/10.1128/mbio.01777-22). Using a combination of both short- and long-read whole genome sequencing techniques, they determine the structure and copy number of two CNVs that arose recurrently throughout the evolution of these isolates. Each CNV predominantly amplifies one coding sequence (ARR3 or RTA3); however, the amplitude and recombination breakpoints are variable across the isolates. Amplification of RTA3 correlates with drug resistance and deletion causes drug susceptibility. This study highlights the need for further research into the mechanisms and dynamics of CNV formation and the impact of these CNVs on virulence and drug resistance across diverse fungal pathogens.

Decreased echinocandin susceptibility in Candida parapsilosis causing candidemia and emergence of a pan-echinocandin resistant case in China.

Candida parapsilosis is becoming a predominant non-albicans cause of invasive candidiasis (IC). Echinocandins are the preferred choice for IC treatment and prophylaxis. Resistance to echinocandins in C. parapsilosis has emerged in several countries, but little is known about the susceptibility profile in China or about mechanisms of resistance. Here, we investigated the echinocandin susceptibilities of 2523 C. parapsilosis isolates collected from China and further explored the resistance mechanism among echinocandin-resistant isolates. Anidulafungin exhibited the highest MICs (MIC50/90, 1 and 2 µg/mL; GM, 0.948 µg/mL), while caspofungin showed better activity (0.5 and 1 µg/mL; 0.498 µg/mL). Significantly higher echinocandin MICs were observed among blood-derived isolates compared to others, especially for caspofungin (GM, 1.348 µg/mL vs 0.478 µg/mL). Isolates from ICU and surgical wards also showed higher MICs. Twenty isolates showed intermediate phenotypes for at least one echinocandin. One was resistant to all three echinocandins, fluconazole and voriconazole, which caused breakthrough IC during long-term exposure to micafungin. WGS revealed this isolate carried a mutation S656P in hotspot1 region of Fks1. Bioinformatics analyses suggested that this mutation might lead to an altered protein conformation. CRISPR Cas9-mediated introduction of this mutation into a susceptible reference C. parapsilosis strain increased MICs of all echinocandins 64-fold, with similar results found in the subspecies, C. orthopsilosis and C. metapsilosis. This is the first report of a multi-azole resistant and pan-echinocandin resistant C. parapsilosis isolate, and the identification of a FKS1S656P conferring pan-echinocandin resistance. Our study underscores the necessity of rigorous management of antifungal use and of monitoring for antifungal susceptibility.

Systematic Analysis of Copy Number Variations in the Pathogenic Yeast Candida parapsilosis Identifies a Gene Amplification in RTA3 That is Associated with Drug Resistance.

We analyzed the genomes of 170 C. parapsilosis isolates and identified multiple copy number variations (CNVs). We identified two genes, RTA3 (CPAR2_104610) and ARR3 (CPAR2_601050), each of which was the target of multiple independent amplification events. Phylogenetic analysis shows that most of these amplifications originated only once. For ARR3, which encodes a putative arsenate transporter, 8 distinct CNVs were identified, ranging in size from 2.3 kb to 10.5 kb with 3 to 23 copies. For RTA3, 16 distinct CNVs were identified, ranging in size from 0.3 kb to 4.5 kb with 2 to ~50 copies. One unusual amplification resulted in a DUP-TRP/INV-DUP structure similar to some human CNVs. RTA3 encodes a putative phosphatidylcholine (PC) floppase which is known to regulate the inward translocation of PC in Candida albicans. We found that an increased copy number of RTA3 correlated with resistance to miltefosine, an alkylphosphocholine drug that affects PC metabolism. Additionally, we conducted an adaptive laboratory evolution experiment in which two C. parapsilosis isolates were cultured in increasing concentrations of miltefosine. Two genes, CPAR2_303950 and CPAR2_102700, coding for putative PC flippases homologous to S. cerevisiae DNF1 gained homozygous protein-disrupting mutations in the evolved strains. Overall, our results show that C. parapsilosis can gain resistance to miltefosine, a drug that has recently been granted orphan drug designation approval by the United States Food and Drug Administration for the treatment of invasive candidiasis, through both CNVs or loss-of-function alleles in one of the flippase genes. IMPORTANCE Copy number variations (CNVs) are an important source of genomic diversity that have been associated with drug resistance. We identify two unusual CNVs in the human fungal pathogen Candida parapsilosis. Both target a single gene (RTA3 or ARR3), and they have occurred multiple times in multiple isolates. The copy number of RTA3, a putative floppase that controls the inward translocation of lipids in the cell membrane, correlates with resistance to miltefosine, a derivative of phosphatidylcholine (PC) that was originally developed as an anticancer drug. In 2021, miltefosine was designated an orphan drug by the United States Food and Drug Administration for the treatment of invasive candidiasis. Importantly, we find that resistance to miltefosine is also caused by mutations in flippases, which control the outward movement of lipids, and that many C. parapsilosis isolates are prone to easily acquiring an increased resistance to miltefosine.

Candida parapsilosis Mdr1B and Cdr1B Are Drivers of Mrr1-Mediated Clinical Fluconazole Resistance.

Candida parapsilosis is a common cause of invasive candidiasis worldwide and is the most commonly is7olated Candida species among pediatric and neonatal populations. Previous work has demonstrated that nonsynonymous mutations in the gene encoding the putative transcription factor CpMrr1 can influence fluconazole susceptibility. However, the direct contribution of these mutations and how they influence fluconazole resistance in clinical isolates are poorly understood. We identified 7 nonsynonymous CpMRR1 mutations in 12 isolates from within a collection of 35 fluconazole-resistant clinical isolates. The mutations leading to the A854V, R479K, and I283R substitutions were further examined and found to be activating mutations leading to increased fluconazole resistance. In addition to CpMDR1, we identified two other genes, one encoding a major facilitator superfamily (MFS) transporter (CpMDR1B, CPAR2_603010) and one encoding an ATP-binding cassette (ABC) transporter (CpCDR1B, CPAR2_304370), as being upregulated in isolates carrying CpMRR1-activating mutations. Overexpression of CpMDR1 in a susceptible strain and disruption in resistant clinical isolates that overexpress CpMDR1 had little to no effect on fluconazole susceptibility. Conversely, overexpression of either CpMDR1B or CpCDR1B increased resistance, and disruption in clinical isolates overexpressing these genes decreased fluconazole resistance. Our findings suggest that activating mutations in CpMRR1 represent important genetic determinants of fluconazole resistance in clinical isolates of C. parapsilosis, and unlike what is observed in Candida albicans, this is primarily driven by upregulation of both MFS (CpMdr1B) and ABC (CpCdr1B) transporters.

Efficacy of antifungal agents against fungal spores: An in vitro study using microplate laser nephelometry and an artificially infected 3D skin model.

Dermal fungal infections seem to have increased over recent years. There is further a shift from anthropophilic dermatophytes to a growing prevalence of zoophilic species and the emergence of resistant strains. New antifungals are needed to combat these fungi and their resting spores. This study aimed to investigate the sporicidal effects of sertaconazole nitrate using microplate laser nephelometry against the microconidia of Trichophyton, chlamydospores of Epidermophyton, blastospores of Candida, and conidia of the mold Scopulariopsis brevicaulis. The results obtained were compared with those from ciclopirox olamine and terbinafine. The sporicidal activity was further determined using infected three-dimensional full skin models to determine the antifungal effects in the presence of human cells. Sertaconazole nitrate inhibited the growth of dermatophytes, molds, and yeasts. Ciclopirox olamine also had good antifungal activity, although higher concentrations were needed compared to sertaconazole nitrate. Terbinafine was highly effective against most dermatophytes, but higher concentrations were required to kill the resistant strain Trichophyton indotineae. Sertaconazole nitrate, ciclopirox olamine, and terbinafine had no negative effects on full skin models. Sertaconazole nitrate reduced the growth of fungal and yeast spores over 72 h. Ciclopirox olamine and terbinafine also inhibited the growth of dermatophytes and molds but had significantly lower effects on the yeast. Sertaconazole nitrate might have advantages over the commonly used antifungals ciclopirox olamine and terbinafine in combating resting spores, which persist in the tissues, and thus in the therapy of recurring dermatomycoses.

Structure-Guided Discovery of the Novel Covalent Allosteric Site and Covalent Inhibitors of Fructose-1,6-Bisphosphate Aldolase to Overcome the Azole Resistance of Candidiasis.

Fructose-1,6-bisphosphate aldolase (FBA) represents an attractive new antifungal target. Here, we employed a structure-based optimization strategy to discover a novel covalent binding site (C292 site) and the first-in-class covalent allosteric inhibitors of FBA from Candida albicans (CaFBA). Site-directed mutagenesis, liquid chromatography-mass spectrometry, and the crystallographic structures of APO-CaFBA, CaFBA-G3P, and C157S-2a4 revealed that S268 is an essential pharmacophore for the catalytic activity of CaFBA, and L288 is an allosteric regulation switch for CaFBA. Furthermore, most of the CaFBA covalent inhibitors exhibited good inhibitory activity against azole-resistant C. albicans, and compound 2a11 can inhibit the growth of azole-resistant strains 103 with the MIC80 of 1 µg/mL. Collectively, this work identifies a new covalent allosteric site of CaFBA and discovers the first generation of covalent inhibitors for fungal FBA with potent inhibitory activity against resistant fungi, establishing a structural foundation and providing a promising strategy for the design of potent antifungal drugs.

Clinical features of invasive fungal disease in children with no underlying disease.

There is limited research into Invasive fungal disease (IFD) in children with no underlying disease. We undertook a retrospective study of children with IFD who did not suffer from another underlying disease, from June 2010 to March 2018 in Changsha, China. Nine children were identified. Eosinophil counts were elevated in six cases. The level of procalcitonin (PCT) was elevated in six cases. Fungal culture was positive in all patients, including eight cases of Cryptococcus neoformans and one case of Candida parapsilosis. 8.33 days following antifungal treatment, the body temperature of the eight patients affected by cryptococcal disease had returned to normal. Our study indicates that the primary pathogen in IFD was Cryptococcus neoformans in children who had no other underlying disease. Eosinophils can be considered to be indicators of cryptococcal infection. IFD in children with no other underlying disease has a satisfactory prognosis.

In vitro activity of ibrexafungerp against Candida species isolated from blood cultures. Determination of wild-type populations using the EUCAST method.

OBJECTIVES: Ibrexafungerp is a new oral glucan synthase inhibitor with in vivo and in vitro activity against Candida spp., including echinocandin- and azole-resistant isolates. We studied the in vitro activity of ibrexafungerp against Candida species isolated from blood cultures and assessed wild-type upper limits against the five Candida species most frequently associated to candidaemia. METHODS: Isolates (n = 958) causing incident episodes of candidaemia in patients admitted to Gregorio Marañón hospital (Madrid, Spain) between January 2007 and April 2021 were studied. Antifungal susceptibility to ibrexafungerp, fluconazole, micafungin and anidulafungin was tested (EUCAST E.Def 7.3.2) and wild-type upper limits determined against C. albicans (n = 462), C. glabrata (n = 120), C. parapsilosis (n = 249), C. tropicalis (n = 73) and C. krusei (n = 24). fksgene sequencing was carried out in non-wild-type isolates. RESULTS: Ibrexafungerp showed antifungal in vitro activity against the studied isolates. Wild-type upper limits for ibrexafungerp were >0.25 mg/L against C. albicans, >1 mg/L against C. parapsilosis, C. glabrata, and C. tropicalis, and >2 mg/L against C. krusei. Percentages of ibrexafungerp non-wild-type isolates were low (C. parapsilosis and C. krusei, 0%; C. albicans, 0.22% (1/462); C. glabrata, 0.83% (1/120); and C. tropicalis, 1.37% (1/73)). Ibrexafungerp proved in vitro activity against fluconazole- or echinocandin-resistant isolates. DISCUSSION: We show in vitro activity of ibrexafungerp against the tested Candida species. Furthermore, we provide ibrexafungerp wild-type upper limits, which allows defining the wild-type populations of the five most relevant Candida species.

Photophysicochemical, sonochemical, and biological properties of novel hexadeca-substituted phthalocyanines bearing fluorinated groups.

This study presents the preparation of a novel tetra-substituted phthalonitrile (1), namely, 3,6-bis(hexyloxy)-4,5-bis(4-(trifluoromethoxy)phenoxy)phthalonitrile (1) and its metal-free (2)/metal {M = Zn (3), Cu (4), Co (5), Lu(CH3COO) (6), Lu (7)} phthalocyanines. A series of various spectroscopic methods (UV-vis, FT-IR, mass, and 1H NMR spectroscopy) were performed for the characterization of the newly synthesized compounds. The potential of compounds 2, 3, and 6 as photosensitizing materials for photodynamic and sonophotodynamic therapies was evaluated by photophysical, photochemical, and sonochemical methods. The highest singlet quantum yields were obtained for the zinc phthalocyanine derivative 3 by performing photochemical and sonochemical methods. In addition, several biological activities of the new compounds 1-7 were investigated. The newly synthesized phthalocyanines exhibited excellent DPPH scavenging activity and also DNA nuclease activity. The antimicrobial activity of the new compounds was evaluated by the disc diffusion assay. Effective microbial cell viability inhibition was observed with phthalocyanine macromolecules. The photodynamic antimicrobial therapy of the phthalocyanines showed 100% bacterial inhibition when compared to the control. They also exhibited significant biofilm inhibition activity against S. aureus and P. aeruginosa. These results indicate that new phthalocyanines are promising photodynamic antimicrobial therapies for the treatment of infectious diseases.

Green synthesis of novel antifungal 1,2,4-triazoles effective against γ-irradiated Candida parapsilosis.

This study reports the green synthesis of 11 novel 3-substituted-4-amino-5-mercapto-1,2,4-triazole derivatives using water as a readily available nontoxic solvent. Evaluation of their antimicrobial potential against several clinical pathogenic microorganisms was carried out. The newly synthesized cysteine derivative 6 showed promising antifungal activity against both γ-irradiated and nonirradiated Candida parapsilosis 216, with the lowest MIC (minimum inhibitory concentration) value of 3.125 µg/ml, probably through inhibition of 14α-demethylase. In addition, compound 6 showed complete inhibition of gelatinase, a virulence enzyme of C. parapsilosis. Also, scanning electron microscopy was carried out. Interestingly, compound 6 acted as a dual agent as it also showed good antibacterial activity against strains of Gram-positive bacteria used in the study. The synthesized compounds showed no cytotoxicity.

Successful fluconazole combined with caspofungin treatment of candida bloodstream infection in preterm infant: A case report.

RATIONALE: Candida bloodstream infection continues to be a significant cause of mortality in premature infants. Amphotericin B has been recommended as the primary treatment; however, its use is limited due to drug-induced nephrotoxicity and amphotericin B-resistant candidemia. PATIENT CONCERNS: The gestational age was 29 (+6) weeks, and birth weight was 1760 g. DIAGNOSIS: The infant was diagnosed with Candida parapsilosis bloodstream infection. INTERVENTIONS: Fluconazole, 12 mg/kg/day, combined with caspofungin (loading dose 3 mg/kg, at a maintenance dose of 2 mg/kg every 24 h) therapy was administered to premature infant with Candida bloodstream infection. When fluconazole or caspofungin was used to treat Candida bloodstream infection in preterm infants, the blood cultures of the infant remained positive for Candida parapsilosis. OUTCOMES: All persistent candidemia resolved on fluconazole combined with caspofungin therapy. There were no adverse effects, hepatotoxicity, nephrotoxicity, anemia, or thrombocytopenia. LESSONS: Fluconazole combined with caspofungin successfully treated Candida bloodstream infection in premature infants at 29 + 6 weeks' gestational age, but large-scale clinical trials are required.

The Influence of Tea Tree Oil on Antifungal Activity and Pharmaceutical Characteristics of Pluronic® F-127 Gel Formulations with Ketoconazole.

Fungal skin infections are currently a major clinical problem due to their increased occurrence and drug resistance. The treatment of fungal skin infections is based on monotherapy or polytherapy using the synergy of the therapeutic substances. Tea tree oil (TTO) may be a valuable addition to the traditional antifungal drugs due to its antifungal and anti-inflammatory activity. Ketoconazole (KTZ) is an imidazole antifungal agent commonly used as a treatment for dermatological fungal infections. The use of hydrogels and organogel-based formulations has been increasing for the past few years, due to the easy method of preparation and long-term stability of the product. Therefore, the purpose of this study was to design and characterize different types of Pluronic® F-127 gel formulations containing KTZ and TTO as local delivery systems that can be applied in cases of skin fungal infections. The influence of TTO addition on the textural, rheological, and bioadhesive properties of the designed formulations was examined. Moreover, the in vitro release of KTZ, its permeation through artificial skin, and antifungal activity by the agar diffusion method were performed. It was found that obtained gel formulations were non-Newtonian systems, showing a shear-thinning behaviour and thixotropic properties with adequate textural features such as hardness, compressibility, and adhesiveness. Furthermore, the designed preparations with TTO were characterized by beneficial bioadhesive properties. The presence of TTO improved the penetration and retention of KTZ through the artificial skin membrane and this effect was particularly visible in hydrogel formulation. The developed gels containing TTO can be considered as favourable formulations in terms of drug release and antifungal activity.

Aneuploidy Underlies Tolerance and Cross-Tolerance to Drugs in Candida parapsilosis.

Candida species are the most common human fungal pathogens worldwide. Although C. albicans remains the predominant cause of candidiasis, infections caused by non-albicans Candida species, including C. parapsilosis, are increasing. In C. albicans, genome plasticity has been shown to be a prevalent strategy of adaptation to stresses. However, the role of aneuploidy in C. parapsilosis is largely unknown. In this study, we found that six different aneuploid karyotypes conferred adaptation to the endoplasmic reticulum stress inducer tunicamycin (TUN) in C. parapsilosis. Interestingly, a specific aneuploidy including trisomy of chromosome 6 (Chr6x3) also enabled cross-tolerance to aureobasidin A (AbA), a sphingolipid biosynthesis inhibitor. Consistent with this, selection on AbA identified adaptors with three different aneuploid karyotypes, including Chr6x3, which also enabled cross-tolerance to both AbA and TUN. Therefore, as in other Candida species, recurrent aneuploid karyotypes enable the adaptation of C. parapsilosis to specific stresses, and specific aneuploidies enable cross-adaptation to different stresses. IMPORTANCE Candida parapsilosis is an emerging human fungal pathogen, especially prevalent in neonates. Aneuploidy, having uneven numbers of chromosomes, is a well-known mechanism for adapting to stress in Candida albicans, the most common human fungal pathogen. In this study, we exposed C. parapsilosis to two very different drugs and selected for rare cells that grew in one of the drugs. We found that the majority of isolates that grew in the drugs had acquired an extra copy of one of several aneuploid chromosomes and that specific aneuploid chromosomes appeared in several independent cell clones. Importantly, an extra copy of chromosome 6 was detected following selection in either one of the drugs, and this extra chromosome conferred the ability to grow in both drugs, a property called cross-adaptation, or cross-tolerance. Thus, this study highlights the genome plasticity of C. parapsilosis and the ability of an extra copy of a single chromosome to promote cell growth in the presence of more than one drug.

Sintered and 3D-Printed Bulks of MgB2-Based Materials with Antimicrobial Properties.

Pristine high-density bulk disks of MgB2 with added hexagonal BN (10 wt.%) were prepared using spark plasma sintering. The BN-added samples are machinable by chipping them into desired geometries. Complex shapes of different sizes can also be obtained by the 3D printing of polylactic acid filaments embedded with MgB2 powder particles (10 wt.%). Our present work aims to assess antimicrobial activity quantified as viable cells (CFU/mL) vs. time of sintered and 3D-printed materials. In vitro antimicrobial tests were performed against the bacterial strains Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Enterococcus faecium DSM 13590, and Enterococcus faecalis ATCC 29212; and the yeast strain Candida parapsilosis ATCC 22019. The antimicrobial effects were found to depend on the tested samples and microbes, with E. faecium being the most resistant and E. coli the most susceptible.

Clinical efficacy and safety of antifungal drugs for the treatment of Candida parapsilosis infections: a systematic review and network meta-analysis.

Antifungal drugs have already been established as an effective treatment option for Candida parapsilosis infections, but there is no universal consensus on the ideal target for clinical efficacy and safety of antifungal drugs for the treatment of C. parapsilosis infections. Few studies have directly compared the efficacies of antifungal drugs for the treatment of C. parapsilosis infections. We hypothesize that different antifungal drugs offer differing clinical efficacy and safety for the treatment of C. parapsilosis infections. We performed a comprehensive network meta-analysis on different strategies for C. parapsilosis infection treatment and compared the clinical efficacy and safety of antifungal drugs as interventions for C. parapsilosis infections. The Cochrane Database of Systematic Reviews, Medline, Embase, PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), Technology of Chongqing VIP database, Wan Fang Data, and SinoMed databases were searched to identify appropriate randomized trials. Among the extracted C. parapsilosis cases, the survival and death rates with treatment of C. parapsilosis infection were compared among groups treated with different antifungal drugs. According to the evidence-network analysis, echinocandins were a better choice than other drugs for treating C. parapsilosis infections, and more importantly, caspofungin showed a more preferable effect for decreasing the risk of 30 day mortality. In conclusion, this study systematically evaluated the effectiveness and safety of antifungal drugs for the purpose of helping clinicians choose the most appropriate antifungal drugs. Future studies with larger samples are needed to evaluate the effects of patient factors on the clinical efficacy and safety of antifungal drugs for C. parapsilosis infections.

Physically cross-linked chitosan/dextrin cryogels entrapping Thymus vulgaris essential oil with enhanced mechanical, antioxidant and antifungal properties.

Herein, we entrapped Thymus vulgaris essential oil (EO) within the physically cross-linked sponge-like architecture of cryogels by ice template-assisted freeze-drying. Their 3D cryogenically-structured network was built through hydrogen bonding formed by blending two naturally-derived polysaccharides, chitosan and dextrin. The embedment of EOs within the cryogel matrix generates porous films with an increased elasticity that allows their fast shape recovery after full compression. Thus, the swollen EOs-loaded cryogel films exhibited an elastic modulus of 3.00 MPa, which is more than 40 times higher than that of polysaccharide films without EOs (an elastic modulus of only 0.07 MPa). In addition, the encapsulation of bioactive compounds endows the bio-based films with both antioxidant and antifungal properties, showing a radical scavenging activity of 65% and a zone inhibition diameter of 40 mm for Candida parapsilosis fungi. Our results recommend the entrapment of EOs into bio-based cryogel carriers as a straightforward approach to provide 'green' polysaccharide-based films having both improved physicochemical properties and remarkable antifungal activity.

Species distribution, azole resistance and related molecular mechanisms in invasive Candida parapsilosis complex isolates: Increase in fluconazole resistance in 21 years.

BACKGROUND: Candida parapsilosis complex consists of three species, the prevalence and geographical distribution of which might vary. Increasing rates of fluconazole resistance among C. parapsilosis complex were reported from various centres. OBJECTIVES: Aim of this study was to identify invasive C. parapsilosis complex strains up to species level, explore rates and molecular mechanisms of azole resistance and analyse temporal changes at a single centre. METHODS: Isolates from blood cultures from 1997 to 2017 were included. Species were identified using RFLP of the SADH gene and confirmed with ITS sequencing when needed. In vitro susceptibility to fluconazole, voriconazole and posaconazole was tested and evaluated using EUCAST guidelines. Sequences of ERG11 and MRR1 genes were analysed for fluconazole non-susceptible isolates. RESULTS: A total of 283 isolates from 181 patients were tested for azole susceptibility. All were C. parapsilosis sensu stricto, except one C. orthopsilosis. All three azoles were effective against 213 of the isolates from 135 patients, including one C. orthopsilosis. Fluconazole resistance was 13.3% (24/181 patients). While the first fluconazole-resistant isolates were detected in 2004, increase was evident after 2011. In ERG11, Y132F mutation was the most common among fluconazole non-susceptible isolates (71.7%), followed by G458S (10.9%) and D421N (4.3%). In MRR1, R405K (56.5%) and G927C (8.7%) were detected. However, association of these mutations to azole resistance is yet to be investigated. CONCLUSIONS: Rising azole resistance rates in C. parapsilosis sensu stricto isolates particularly after 2011 were of concern. The well-known Y132F mutation was the predominant mechanism of azole resistance while accompanied with other genetic mutations.