Candida Parapsilosis Isolates Research Articles

Inhibitory effect of Nigella sativa oil loaded to liposomal nanocarriers on Candida parapsilosis isolates.

Candida parapsilosis is the second most common species causing infectious diseases and can lead to biofilm resistance. This study aims to adjust and synthesize a liposomal compound of Nigella sativa and evaluate its antifungal properties against C. parapsilosis isolates. The liposomal formulation of N. sativa was optimized through the utilization of transmission electron microscopy (TEM), particle size analysis, zeta potential measurement, and UV-visible spectrophotometry. Furthermore, an MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay was conducted on peripheral blood mononuclear cells (PBMCs). The antifungal efficacy was evaluated in accordance with the M27-A3 guideline. The minimum inhibitory concentrations (MICs) of N. sativa oil and the liposomal formulation on C. parapsilosis isolates ranged from 128 to 8 µg/mL and from 250 to 31.25 µg/mL, respectively. The MIC50 and MIC90 values of N. sativa oil and the liposomal formulation were 125, 187, and 32, 96 µg/mL, respectively. The viability percentage of cells treated with the liposomal formulation and free N. sativa oil was 91% and 85%, respectively. The cytotoxicity of free N. sativa was significantly reduced when using nanoliposomes. The liposomal form of N. sativa showed greater antifungal properties compared to the free N. sativa extract against C. parapsilosis isolates.

Epidemiology of Candidemia in Mashhad, Northeast Iran: A Prospective Multicenter Study (2019-2021).

Candidemia is a major cause of morbidity and mortality in health care settings, and its epidemiology is changing. In the last two decades, the proportion of non-albicans Candida (NAC) yeasts in candidemia has increased. These yeasts more often display resistance to common antifungals. In many western countries, candidemia is mainly caused by susceptible C. albicans, while in resource-limited countries, including Iran, the candidemia species distribution is studied less often. Here, we investigated the species distribution, resistance levels, and characteristics of patients with candidemia in five hospitals in Mashhad (northeast Iran) for two years (2019-2021). Yeast isolates from blood were identified with MALDI-TOF MS and subjected to antifungal susceptibility testing (AFST) using the broth microdilution method, while molecular genotyping was applied to Candida parapsilosis isolates. In total, 160 yeast isolates were recovered from 160 patients, of which the majority were adults (60%). Candidemia was almost equally detected in men (48%) and women (52%). Almost half of patients (n = 67, 49%) were from intensive care units (ICUs). C. parapsilosis (n = 58, 36%) was the most common causative agent, surpassing C. albicans (n = 52, 33%). The all-cause mortality rate was 53%, with C. albicans candidemia displaying the lowest mortality with 39%, in contrast to a mortality rate of 59% for NAC candidemia. With microbroth AFST, nearly all tested isolates were found to be susceptible, except for one C. albicans isolate that was resistant to anidulafungin. By applying short tandem repeat (STR) genotyping to C. parapsilosis, multiple clusters were found. To summarize, candidemia in Mashhad, Iran, from 2019 to 2021, is characterized by common yeast species, in particular C. parapsilosis, for which STR typing indicates potential nosocomial transmission. The overall mortality is high, while resistance rates were found to be low, suggesting that the high mortality is linked to limited diagnostic options and insufficient medical care, including the restricted use of echinocandins as the first treatment option.

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.

The fungicidal effectiveness of 2-Chloro-3-hydrazinylquinoxaline, a newly developed quinoxaline derivative, against Candida species.

Candida represents a prevalent fungal infection, notable for its substantial implications on morbidity and mortality rates. In the landscape of prospective treatments, quinoxaline derivatives emerge as a category of compact compounds exhibiting notable potential in addressing infections. These derivatives showcase promising antimicrobial efficacy coupled with favorable pharmacokinetic and safety characteristics. The central aim of this investigation was to examine the antifungal characteristics of 2-Chloro-3-hydrazinylquinoxaline against diverse strains of Candida and Aspergillus in vitro. Additionally, we endeavored to assess the in vivo efficacy of 2-Chloro-3-hydrazinylquinoxaline using a murine model for oral candidiasis induced by C. albicans cells ATCC 10231. 2-Chloro-3-hydrazinylquinoxaline demonstrated noteworthy effectiveness when tested against various reference strains of Candida species. It exhibited heightened efficacy, particularly against Candida krusei isolates. However, its performance against Candida albicans, Candida tropicalis, Candida glabrata, Candida parapsilosis, and Candida auris isolates exhibited variability. Notably, 2-Chloro-3-hydrazinylquinoxaline manifests variable efficacy against Aspergillus fumigatus, Aspergillus niger, Aspergillus terreus and Aspergillus flavus and no effect against Aspergillus brasiliensis. In a murine model, 2-Chloro-3-hydrazinylquinoxaline exhibited significant efficacy in combating the C. albicans cells ATCC 10231 strain, underscoring its potential as a viable treatment option. 2-Chloro-3-hydrazinylquinoxaline has demonstrated substantial potential in effectively addressing various Candida and Aspergillus species, showcasing dual attributes of antifungal and anti-inflammatory properties. However, to attain a more comprehensive understanding of its therapeutic capabilities, further investigations, incorporating additional tests and experiments, are imperative.

Analysis of clinical Candida parapsilosis isolates reveals copy number variation in key fluconazole resistance genes.

We used whole-genome sequencing to analyze a collection of 35 fluconazole-resistant and 7 susceptible Candida parapsilosis isolates together with coverage analysis and GWAS techniques to identify new mechanisms of fluconazole resistance. Phylogenetic analysis shows that although the collection is diverse, two persistent clinical lineages were identified. We identified copy number variation (CNV) of two genes, ERG11 and CDR1B, in resistant isolates. Two strains have a CNV at the ERG11 locus; the entire ORF is amplified in one, and only the promoter region is amplified in the other. We show that the annotated telomeric gene CDR1B is actually an artifactual in silico fusion of two highly similar neighboring CDR genes due to an assembly error in the C. parapsilosis CDC317 reference genome. We report highly variable copy numbers of the CDR1B region across the collection. Several strains have increased the expansion of the two genes into a tandem array of new chimeric genes. Other strains have experienced a deletion between the two genes creating a single gene with a reciprocal chimerism. We find translocations, duplications, and gene conversion across the CDR gene family in the C. parapsilosis species complex, showing that it is a highly dynamic family.

Antifungal Activity of 3-Hydrazinoquinoxaline-2-Thiol, a Novel Quinoxaline Derivative against Candida Species

Candida ranks as among the most frequently encountered fungal infections that associated with high morbidity and mortality. Quinoxaline derivatives are a group of small molecules that showed a promising antimicrobial activity. This study aimed to investigate the fungicidal effects of 3-hydrazinoquinoxaline-2-thiol against Candida in comparison with Amphotericin B in vitro as a reference. Also, we aim to assess the efficacy of 3-hydrazinoquinoxaline-2-thiol in vivo using mice oral candidiasis model. Fifty-six Candida isolates were subjected to susceptibility testing by broth microdilution method for 3-hydrazinoquinoxaline-2-thiol and Amphotericin B. Therefore, Minimal inhibitory concentrations (MIC) were assessed and compared. The oral candidiasis mice model was used to evaluate the activity of 3-hydrazinoquinoxaline-2-thiol in vivo. Microbiological evaluation of progression and ELISA were used in this study. 3-hydrazinoquinoxaline-2-thiol was more effective than Amphotericin B against most clinical isolates of Candida albicans. Higher effectiveness was seen against Candida glabrata and Candida parapsilosis isolates. However, the efficiency against Candida tropicalis isolates varies. 3-hydrazinoquinoxaline-2-thiol was also effective against Pichia kudriavzevii and Clavispora lusitaniae. 3-hydrazinoquinoxaline-2-thiol showed a good efficacy in mice model against C. albicans cells ATCC 10231. 3-hydrazinoquinoxaline-2-thiol has shown promising antifungal and anti-inflammatory activity against different Candida species. More tests and experiments are needed.

The Fourier-transform infrared spectroscopy-based method as a new typing tool for Candida parapsilosis clinical isolates.

The Fourier-transform infrared spectroscopy-based IR Biotyper is a straightforward typing tool for bacterial species, but its use with Candida species is limited. We applied IR Biotyper to Candida parapsilosis, a common cause of nosocomial bloodstream infection (BSI), which is aggravated by the intra-hospital spread of fluconazole-resistant isolates. Of 59 C. parapsilosis isolates studied, n = 56 (48 fluconazole-resistant and 8 fluconazole-susceptible) and n = 3 (2 fluconazole-resistant and 1 fluconazole-susceptible) isolates, respectively, had been recovered from BSI episodes in 2 spatially distant Italian hospitals. The latter isolates served as an outgroup. Of fluconazole-resistant isolates, n = 40 (including one outgroup) harbored the Y132F mutation alone and n = 10 (including one outgroup) harbored both Y132F and R398I mutations in the ERG11-encoded azole-target enzyme. Using a microsatellite typing method, which relies on the amplification of genomic short tandem repeats (STR), two major clusters were obtained based on the mutation(s) (Y132F or Y132F/R398I) present in the isolates. Regarding IR Biotyper, each isolate was analyzed in quintuplicate using an automatic (i.e., proposed by the manufacturer's software) or tentative (i.e., proposed by us) cutoff value. In the first case, four clusters were identified, with clusters I and II formed by Y132F or Y132F/R398I isolates, respectively. In the second case, six subclusters (derived by the split of clusters I and II) were identified. This allowed to separate the outgroup isolates from other isolates and to increase the IR Biotyper typeability. The agreement of IR Biotyper with STR ranged from 47% to 74%, depending on type of cutoff value used in the analysis. IMPORTANCE Establishing relatedness between clinical isolates of Candida parapsilosis is important for implementing rapid measures to control and prevent nosocomial transmission of this Candida species. We evaluated the FTIR-based IR Biotyper, a new typing method in the Candida field, using a collection of fluconazole-resistant C. parapsilosis isolates supposed to be genetically related due to the presence of the Y132F mutation. We showed that IR Biotyper was discriminatory but not as much as the STR method, which is still considered the method of choice. Further studies on larger series of C. parapsilosis isolates or closely related Candida species will be necessary to confirm and/or extend the results from this study.

In vitro activity of sanitizers against mono- and polymicrobial biofilms of C. parapsilosis and S. aureus.

The emergence of disinfectant-resistant microorganisms poses a significant threat to public health. These resilient pathogens can survive and thrive in hospital settings despite routine disinfection practices, leading to persistent infections and the potential for outbreaks. In this study, we investigated the impact of 11 different commercial sanitizers at various concentrations and exposure times on biofilms consisting of clinical and nosocomial environmental isolates of Candida parapsilosis and Staphylococcus aureus. Among the sanitizers tested, 0.5% and 2.0% chlorhexidine (CLX), 10% polyvinyl pyrrolidone (PVP-I), a disinfectant based on quaternary ammonium compound (QAC), 2% glutaraldehyde, and 0.55% orthophthalaldehyde (OPA) demonstrated efficacy against both C. parapsilosis and S. aureus in monospecies and mixed biofilms. Analysis showed that 0.5% CLX and 10% PVP-I had fungicidal and bactericidal activity against all biofilms. However, the sanitizer based on QAC and 0.55% OPA proved to be bacteriostatic and fungicidal against both monospecies and mixed biofilms. In mixed biofilms, despite the last four sanitizers exerting fungicidal action, the reduction of fungal cells was approximately 4 log10 CFU/mL compared to monospecies biofilms, showing that the interaction provided more resistance of the yeast to the sanitizer. Formation of mixed biofilms in hospital settings can create an ecological niche that enhances the survival of pathogens against routine sanitization procedures. Therefore, effective sanitization practices, including regular cleaning with effective sanitizers, should be implemented to prevent C. parapsilosis/S. aureus biofilm formation in healthcare settings.

Does repeated exposure to hydrogen peroxide induce Candida auris resistance?

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

Mutations in TAC1 and ERG11 are major drivers of triazole antifungal resistance in clinical isolates of Candida parapsilosis

ObjectivesThe aim of this study was to determine how mutations in CpERG11 and CpTAC1 contribute to fluconazole resistance in a collection of clinical isolates. MethodsSequences of CpERG11 and CpTAC1 were determined for 35 resistant Candida parapsilosis clinical isolates. A plasmid-based CRISPR-Cas9 system was used to introduce mutations leading to amino acid substitution in CpTac1 and CpErg11. Triazole susceptibility was determined by broth microdilution and E-test. Differential expression of genes mediated by CpTAC1 mutation was determined by RNA sequencing, and relative expression of individual transporter genes was assessed with RT-qPCR. ResultsSix isolates carried a mutation in CpTAC1 in combination with the CpERG11 mutation, leading to the CpErg11Y132F substitution. When introduced into susceptible isolates, this CpERG11 mutation led to a 4- to 8-fold increase in fluconazole minimum inhibitory concentrations (MIC; 0.125 μg/mL vs. 0.5 μg/mL, 0.125 μg/mL vs. 0.5 μg/mL, and 0.5 μg/mL vs. 4 μg/mL). When introduced into a susceptible isolate, the CpTAC1 mutation leading to the G650E substitution resulted in an 8-fold increase in fluconazole MIC (0.25 μg/mL vs. 2 μg/mL), whereas correction of this mutation in resistant isolates led to a 16-fold reduction in MIC (32 μg/mL vs. 2 μg/mL). CpCDR1, CpCDR1B, and CpCDR1C were overexpressed in the presence CpTac1G650E. Disruption of these genes in combination resulted in a 4-fold reduction in fluconazole MIC (32 μg/mL vs. 8 μg/mL). DiscussionThese results define the specific contribution made by the Y132F substitution in CpERG11 and demonstrate a role for activating mutations in CpTAC1 in triazole resistance in C. parapsilosis.

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

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

Candida parapsilosis isolates carrying mutations outside FKS1 hotspot regions confer high echinocandin tolerance and facilitate the development of echinocandin resistance

Candida parapsilosis is a significant cause of candidemia worldwide. Echinocandin-resistant (ECR) and echinocandin-tolerant (ECT) C. parapsilosis isolates have been reported in various countries but are rare. Resistance and tolerance are predominantly caused by mutations related to the hotspot (HS) regions of the FKS1 gene. A relatively high proportion of clinical C. parapsilosis isolates carrying mutations outside the HS regions has been noted in some studies, but an association with echinocandin (EC) resistance or tolerance was not explored. Herein, CRISPR-Cas9 was used and the association between amino acid substitution in FKS1 outside HS 1/2 (V595I, S745L, M1328I, F1386S, and A1422G) with EC susceptibility profile was delineated. None of the mutations conferred EC resistance, but they resulted in a significantly higher level of EC tolerance than the parental isolate, ATCC 22019. When incubated on agar plates containing ECs, specifically caspofungin and micafungin, ECR colonies were exclusively observed among ECT isolates, particularly mutants carrying V595I, S745L, and F1386S. Additionally, mutants had significantly better growth rates in yeast extract peptone dextrose (YPD) and YPD containing agents inducing membrane and oxidative stresses. The mutants had a trivial fitness cost in the Galleria mellonella model relative to ATCC 22019. Collectively, this study supports epidemiological studies to catalog mutations occurring outside the HS regions of FKS1, even if they do not confer EC resistance. These mutations are important as they potentially confer a higher level of EC tolerance and a higher propensity to develop EC resistance, therefore unveiling a novel mechanism of EC tolerance in C. parapsilosis. The identification of EC tolerance in C. parapsilosis may have direct clinical benefit in patient management.

Rational Design of New Monoterpene-Containing Azoles and Their Antifungal Activity.

Azole antifungals, including fluconazole, have long been the first-line antifungal agents in the fight against fungal infections. The emergence of drug-resistant strains and the associated increase in mortality from systemic mycoses has prompted the development of new agents based on azoles. We reported a synthesis of novel monoterpene-containing azoles with high antifungal activity and low cytotoxicity. These hybrids demonstrated broad-spectrum activity against all tested fungal strains, with excellent minimum inhibitory concentration (MIC) values against both fluconazole-susceptible and fluconazole-resistant strains of Candida spp. Compounds 10a and 10c with cuminyl and pinenyl fragments demonstrated up to 100 times lower MICs than fluconazole against clinical isolates. The results indicated that the monoterpene-containing azoles had much lower MICs against fluconazole-resistant clinical isolates of Candida parapsilosis than their phenyl-containing counterpart. In addition, the compounds did not exhibit cytotoxicity at active concentrations in the MTT assay, indicating potential for further development as antifungal agents.

Recent increase in fluconazole-nonsusceptible Candida parapsilosis in a global surveillance with the expansion of the Erg11 Y132F genotype and a rapid detection method for this alteration

We evaluated the rates of fluconazole nonsusceptibility among 1103 Candida parapsilosis isolates collected globally from 2018 to 2021. These rates were <10.3% until 2020 but increased to 15.4% in 2021. Fluconazole-nonsusceptible C. parapsilosis rates were highest in Europe (96/466 isolates; 20.6%) followed by the US (23/386; 6.0%). As the Erg11 Y132F alteration has been a common fluconazole nonsusceptibility mechanism in C. parapsilosis, we developed a PCR assay to detect this mutation. This assay displayed 100% sensitivity and specificity when tested against 56 isolates previously submitted to whole genome sequencing. The Erg11 Y132F alteration was detected in 83.2% of the isolates (104/125) collected during 2018 to 2021 using the PCR assay. The highest rates of the Erg11 Y132F genotype were observed among fluconazole-nonsusceptible isolates from Europe (93.8%), followed by the US (60.9%). An increase in fluconazole-nonsusceptible C. parapsilosis was documented in 2021. Most isolates from Europe and the US carried the Y132F Erg11 alteration that has been reported in various countries.

Improved RAPD Method for Candida parapsilosis Fingerprinting

Recently, methods based on the analysis of arbitrarily amplified target sites of genome microorganisms have been extensively applied in microbiological studies, and especially in epidemiological studies. The range of their application is limited by problems with discrimination and reproducibility resulting from a lack of standardized and reliable methods of optimization. The aim of this study was to obtain optimal parameters of the Random Amplified Polymorphic DNA (RAPD) reaction by using an orthogonal array as per the Taguchi and Wu protocol, modified by Cobb and Clark for Candida parapsilosis isolates. High Simpson's index values and low Dice coefficients obtained in this study indicated a high level of interspecies DNA polymorphism between C. parapsilosis strains, and the optimized RAPD method proved useful in the microbiological and epidemiological study.

Hospital Clonal Outbreak of Fluconazole-Resistant Candida parapsilosis Harboring the Y132F ERG11p Substitution in a French Intensive Care Unit.

We report the first identification of a fluconazole-resistant Candida parapsilosis (FR-Cp) strain in our hospital, which subsequently caused an outbreak involving 17 patients (12 deaths) within a 26-bed French intensive care unit. Microsatellite genotyping confirmed that all FR-Cp isolates belonged to the same clone. Given recent reports of rapid dissemination of these emerging clones, routine testing of azole susceptibility for all Candida parapsilosis isolates should be encouraged, at least in ICU patients.

Draft Genome Sequence of a Preterm Infant-Derived Isolate of Candida parapsilosis.

Candida parapsilosis is a human fungal pathogen of increasing incidence and causes invasive candidiasis, notably in preterm or low-birthweight neonates. Here, we present the genome sequence of C. parapsilosis NCYC 4289, a fecal isolate from a preterm male infant.

Hydrolytic Enzyme Production and Susceptibility to Antifungal Compounds of Opportunistic Candida parapsilosis Strains Isolated from Cucurbitaceae and Rosaceae Fruits

Endophytic yeast species were studied in the internal tissues of ripe cultivated vegetables and fruits. A total of 19 yeast species, 11 ascomycete species, and 8 basidiomycete species were observed in the internal tissues of all fruits examined. The opportunistic yeast Candida parapsilosis was present in all plants studied. Several virulence factors (production of hydrolytic enzymes and sensitivity to antifungal agents) were examined in all 107 isolates of C. parapsilosis from the internal tissues of fruits. The most virulent isolates were found in vegetables. C. parapsilosis is widespread in nature and is often isolated from a variety of non-human sources. It is frequently involved in invasive infections that seriously affect human health. This species poses a high risk to immunocompromised individuals, such as HIV patients and surgical patients or children whose immune systems are not sufficiently mature. Since virulent isolates of Candida parapsilosis have been found in vegetables and fruits; their raw consumption may not be safe. Finally, we emphasize the importance of ongoing phenotypic and genetic studies of endophytic isolates of Candida parapsilosis and their comparison with clinical isolates.

P027 Early warning bells: emergence of fluconazole resistance in Candida parapsilosis

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PMPreeti S. Ajapuje¹, Parikshit S. Prayag¹, Bharat D. Purandare¹, Sampada A. Patwardhan², Shweta P. Panchakshari¹, Rajeev N. Soman¹Department of Infectious Diseases, Deenanath Mangeshkar Hospital, Pune 2Department of Microbiology, Deenanath Mangeshkar Hospital, PuneObjectivesTo study the susceptibility patterns in blood isolates of Candida parapsilosis at a tertiary care center.MethodsThis was a retrospective observational study of nine cases of candidemia due to C. Parapsilosis over a period of 1 year. Data were collected using the hospital’s electronic health records. Species identification was done using Matrix-Assisted Laser Desorption and Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS) (Bruker Biotyper Sirius-Bruker Daltonics, Bremen, Germany). Antifungal susceptibility was performed by broth microdilution method using Sensititre™ YeastOne™ YO1O AST Plates (Thermofisher Scientific, USA).ResultsAll patients with C. parapsilosis bloodstream infection had central venous access and all patients had received broad-spectrum antibiotics at the time of developing candidemia. Four patients developed C. parapsilosis candidemia in the post coronavirus disease 2019 (COVID 19) setting. Out of the 9 isolates, 7 (77.7%) were resistant to fluconazole, 2 were resistant to voriconazole and posaconazole, and 1 isolate was resistant to amphotericin. A total of 4/9 patients were started on fluconazole prior to antifungal susceptibility testing; 3 of these needed to be switched to an echinocandin due to fluconazole resistance.ConclusionFluconazole resistance in this study was seen in 7/9 (77.7%) isolates which is more than what has been previously described for C. parapsilosis. This makes fluconazole a poor choice for the treatment of C. parapsilosis in our institute. These findings may have an implication in the selection or de-escalation of antifungal treatment for C. parapsilosis.

Antifungal activity of 2-chloro-N-phenylacetamide, docking and molecular dynamics studies against clinical isolates of Candida tropicalis and Candida parapsilosis.

This study evaluated the antifungal, antibiofilm and molecular docking of 2-chloro-N-phenylacetamide against clinical isolates of Candida tropicalis and Candida parapsilosis. Minimum inhibitory concentration (MIC) of the test drugs was determined by microdilution. A1Cl obtained MIC values ranging from 16 and 256μg/ml. Fluconazole MIC ranging from 16 and 512μg/ml. MIC of A1Cl showed fungicide activity, emphasizing the solid antifungal potential of this drug. An association study was performed with A1Cl and fluconazole (checkerboard), revealing indifference by decreasing. Thus, we conducted this study using A1Cl isolated. In the micromorphological assay, the test drugs reduced the production of virulence structures compared to the control (concentration-dependent effect). A1Cl inhibited in vitro biofilm formation at all concentrations tested (1/4MIC to 8×MIC) (p<0.05) and reduced mature biofilm biomass (p<0.05) against C. tropicalis and C. parapsilosis. In the ex vivo biofilm susceptibility testing (human nails fragments), A1Cl inhibited biofilm formation and reduced mature biofilm biomass (p<0.05) more than 50% at MIC. Fluconazole had a similar effect at 4×MIC. In silico studies suggest that the mechanism of antifungal activity of A1Cl involves the inhibition of the enzyme dihydrofolate reductase (DHFR) rather than geranylgeranyltransferase-I. The results suggest that A1Cl is a promising antifungal agent. Furthermore, this activity is related to attenuation of expression of virulence factors and antibiofilm effects against C. tropicalis and C. parapsilosis. Our study provides the first evidence that A1Cl, a novel synthetic drug, has fungicidal effects against C. tropicalis and C. parapsilosis. Furthermore, in vitro and ex vivo biofilms assays have demonstrated the potential antibiofilm of A1Cl. The mechanism of action involves inhibiting the enzyme DHFR, which was supported by in silico analyses. Therefore, this potential can be explored as a therapeutic alternative for onychomycosis and, at the same time, contribute to decreasing the resistance of clinical isolates of C. tropicalis and C. parapsilosis.