Non-albicans Candida spp. causing fungaemia: pathogenicity and antifungal resistance

Utilizing the subtractive proteomics approach to design ensemble vaccine against Candida lusitaniae for immune response stimulation; a bioinformatics study

Vaccines have always been one of the promising therapeutic sources against many pathogens including infectious fungi. Candida lusitaniae is also one of those fungi which is responsible for different infections in human beings including vaginitis, endocarditis, endophthalmitis and blood stream infections. There is thus, a need to adopt effective therapeutic strategies to tackle such infections. Vaccine is one of those efficient therapeutic agents which stimulates immune response and prevents a certain infection to get hazardous. Keeping in view this very important concept, we have designed in-silico vaccine against C. lusitaniae by following the subtractive proteomics approach. Initially, the screening of therapeutic targets was performed to identify potent vaccine candidates from the whole proteome of C. lusitaniae. Several significant factors were taken into account in this context, such as stability index, IFN status, allergenicity, and antigenicity. As a result, four distinct proteins that were both antigenic and non-allergenic, were selected from the whole proteome. Furthermore, physiochemical investigation revealed that these vaccine candidates were stable and that their IFN status was positive. Notably, each of these proteins was non-homologous to human beings. This particular attribute of the selected proteins i.e., to be non-homologous, was made in order to possess the ability to trigger an immunological response in host (humans). Furthermore, the whole proteome (WP) vaccine was constructed accordingly. The structural modelling of all the selected vaccine candidates was then performed to proceed them further for docking with the human toll-like receptor 2 (TLR2). Afterwards, the codon optimization was executed, followed by in-silico cloning of the final vaccine construct. The pet28A plasmid was incorporated for this purpose while, the SnapGene tool was utilized for this particular analysis. Ultimately, the immune simulations were executed to assess the immune response of the designed vaccine (WP). Upon final results, it was found that highest count of IgG and IgM was achieved i.e., up to 700000 between the days 8 to 13 and then slowly neutralized till the day 30. These results signified that the designed vaccine possessed the potential to stimulate the required immune response.

The Antimicrobial Resistance of Candida: A 5-Year Retrospective Analysis at a Tertiary Hospital in Jordan

Candida infections are a global health concern, increasingly complicated by rising antimicrobial resistance (AMR). This study analyzed the prevalence and AMR patterns of circulating Candida species in Amman, Jordan, using electronic records from a tertiary teaching hospital's microbiology lab (from 2017 to 2022). Complete records of Candida isolates (n = 2673) were assessed by sample type, species, and AMR. Among positive blood samples, C. albicans accounted for the majority (38.7%), followed by C. tropicalis (19.0%), C. parapsilosis (18.3%), Nakaseomyces glabratus (14.6%), and Pichia kudriavzevii (9.5%). Non-albicans species demonstrated higher resistance to Caspofungin, notably P. kudriavzevii (23.1%), N. glabratus (30.0%), and C. parapsilosis (32.0%), compared to C. albicans (1.9%). In high vaginal swabs, C. albicans was most prevalent (63.7%), with N. glabratus also notable (28.6%); Fluconazole resistance in C. albicans remained low (2.0%). Across all pooled isolates, AMR was similar between inpatients and outpatients, except for Micafungin, where inpatient resistance was significantly higher. In conclusion, non-albicans species predominated in blood infections and demonstrated pronounced AMR. Micafungin resistance was notably higher among inpatients. Variations in Candida species and AMR by sample type suggest that aggregating samples in registry studies may obscure critical patterns.

Dual Mechanisms of Action: Anti-Candida and Anti-Inflammatory Potential of Lactobacillus Fermentation Broth in Treating Vulvovaginal Candidiasis

Vulvovaginal candidiasis (VVC), a condition predominantly caused by Candida albicans, affects millions of women worldwide, prompting the need for alternative treatments due to the side effects and increasing resistance associated with conventional imidazole antifungals. This study investigated VAGINNE®, a novel fermentation broth derived from Lactobacillus species, as a potential VVC treatment. Using a BALB/c mouse model of C. albicans infection, we evaluated VAGINNE®'s effects on vaginal microbiome composition, inflammatory markers, and tissue integrity. Our findings revealed that VAGINNE® treatment enhanced the growth of beneficial Lactobacillus species while suppressing C. albicans proliferation, leading to a more balanced vaginal microbiome. Additionally, VAGINNE® significantly reduced pro-inflammatory cytokines (IL-17A, IL-22, IL-23) in vaginal tissues and systemic inflammatory markers (IL-6, IL-1β) in plasma. Histological analysis showed minimal fungal invasion and preserved vaginal epithelial integrity in VAGINNE®-treated mice compared to untreated controls. These results suggest that VAGINNE® could serve as an effective anti-Candida and anti-inflammatory agent for managing VVC, offering a promising alternative to traditional antifungal treatments. By promoting a healthy vaginal microbiome, reducing inflammation, and maintaining tissue health, this probiotic-based approach presents a novel strategy for addressing VVC, particularly in cases of drug resistance or adverse reactions to standard therapies. This study underscores the potential of microbiome-modulating strategies in managing vaginal infections, paving the way for more targeted and side-effect-free VVC treatments.

Biodetection Strategies for Selective Identification of Candidiasis

Fungi are among the predominant pathogens seen in a greater proportion of infections acquired in healthcare settings. A common fungus that causes infections in medical settings is Candida species. Hospitalized patients who suffer from fungal diseases such as candidiasis and candidemia often have elevated rates of mortality and morbidity. It is evident that longer hospital stays have the possibility of bacterial and fungal recurrence and also have a negative economic impact. If left untreated, a Candida infection can spread to other organs and cause a systemic infection that can result in sepsis. Clinicians can treat patients quickly when fungal infections are timely detected, this enhances the results of clinical trials. Developing novel, sensitive, and quick methods for detecting Candida species is imperative. Conventional detection techniques are unsuitable for clinical settings and point-of-care systems as they require expensive equipment and take a longer detection time. This review examines a few of the most widely used biosensor systems for the detection of Candida species, their sensitivity, and the limit of detection. It focuses on various biorecognition elements used and follows utilization and advances in nanotechnology in the context of sensing. In addition to enabling general analysis and quick real-time analysis, crucial for detecting Candida species, biosensors provide an intriguing alternative to more conventional techniques.

Development and evaluation of a loop-mediated isothermal amplification (LAMP) method for Candida glabrata detection

PURPOSE

Loop-mediated isothermal amplification (LAMP) is a simple and rapid nucleic acid method for DNA amplification at a constant temperature. The "gold standard" culture method for yeast detection, has low sensitivity with severe consequences, increasing morbidity and mortality rates. Here, we report the development of a LAMP method for the specific detection of C. glabrata.

METHODOLOGY

The specific LAMP primers for C. glabrata detection were designed and evaluated.

RESULTS

The LAMP assay accurately detected C. glabrata with no cross-reactivity with other Candida species.

CONCLUSION

The developed molecular method would be a promising tool in the management of invasive candidiasis.

Distribution and antifungal susceptibility profiles of Candida species isolated from candidemia patients admitted to Egyptian tertiary hospitals: a cross-sectional study

BACKGROUND

Candidemia is a widespread threat that can lead to significant complications in healthcare settings.

OBJECTIVES

Our study aimed to identify isolates of Candida isolated from blood culture bottles of patients with candidemia and assess their antifungal susceptibility profiles.

METHODS

We conducted a cross-sectional study at Cairo University tertiary care hospitals over 16 months including 90 patients. Candida isolates were collected from blood culture bottles, and identified using MALDI-TOF MS technology of VITEK MS PRIME (bioMérieux) with the corresponding database VITEK IVD Database 3.2. followed by antifungal susceptibility testing using VITEK 2 Compact system.

RESULTS

Candida albicans was the most common species isolated from both pediatric and adult patients with percentages of 47.3% and 36.4% respectively, followed by Candida parapsilosis with percentages of 32.6% and 25.0% respectively. Voriconazole showed the highest antifungal activity at 90.9% of isolates in adults and 95.7% in pediatrics, followed by caspofungin and micafungin. The mean hospital stays for adults ranged from 8 to 30 days and from 10 to 42 days in the pediatric group.

CONCLUSIONS

C. albicans remains the predominant species isolated from both pediatric and adult candidemia patients, despite a notable increase in other species. C. tropicalis and C. parapsilosis are considered the most common non-albicans Candida (NAC) species. The rise in Candida species other than albicans highlights the urgent need for effective antifungal stewardship programs. Voriconazole exhibited the higher antifungal activity followed by caspofungin and micafungin.

Unveiling the Chemical Constituents and Inhibitory Roles of Extracts from Pinus Pinea L. Nut and Nutshell: A Novel Source for Pharmaceutical Antimicrobials

Antibiotic resistance in infectious diseases has been a serious problem for the last century, and scientists have focused on discovering new natural antimicrobial agents. Pinus pinea has been used as a natural pharmacotherapeutic agent with antimutagenic, anticarcinogenic, and high antioxidant properties. In this study, GC-MS and LC-HR/MS were employed to analyze Pinus pinea L. nut and nutshell extracts. DPPH radical scavenging assay was performed to analyze the antioxidant properties of the extracts, but no activity was determined. GC-MS analysis showed that linoleic, oleic, and palmitic acids were the three most dominant fatty acids in nut and nutshell extracts, with ratios between 6.75 % and 47.06 % (v/v). LC-HR/MS revealed that the nutshell methanol extract had a higher phenolic content than other extracts, with vanillic acid (1.4071 mg/g). Antimicrobial activity assays showed that the minimum inhibitory concentrations (MIC) of the extracts varied between 5.94 and 190 mg/mL, and the most significant inhibition was seen in the nutshell methanol extract (MICs: between 5.94 and 47.5 mg/mL). Consequently, the antimicrobial activity of the extracts can be attributed to the dense fatty acids they contain, and the nutshell methanol extract showed the most potent inhibition related to the abundance of phenolic compounds in the extract.

Fungal Enzyme-Responsive Hydrogel Drug Delivery Platform for Triggered Antifungal Release

Fungal infections can lead to debilitating consequences if they are not treated effectively. Antifungal drugs used to treat these infections can be toxic and overuse contributes to growing antifungal resistance. Candida spp., particularly C. albicans, are implicated in a majority of these infections. Virulent C. albicans produce secreted aspartic proteases (Saps) that aid in pathogen tissue invasion and proliferation at an infected site. Here, fungi-responsive hydrogels are developed that degrade in the presence of Saps to provide a triggered release of encapsulated liposomal antifungals. The hydrogel backbone incorporates a Sap-cleavable peptide sequence enabling Sap-responsive degradation. Hydrogels are found to effectively degrade in the presence of Saps extracted from C. albicans. Encapsulated liposomal antifungals show similar release kinetics as hydrogel degradation products in the presence of Saps, supporting a degradation-dependent release mechanism. Antifungal liposome-loaded responsive hydrogels exhibit successful eradication of C. albicans cultures and remain stable in sterile murine wound fluid. Finally, no significant cytotoxicity is observed for murine fibroblast cells and red blood cells exposed to hydrogel degradation products. These fungi-responsive hydrogels have the potential to be used for local, on-demand delivery of antifungal drugs, for effective treatment of fungal infections while helping to limit unnecessary exposure to these therapeutics.

Antifungal drug resistance in Candida: a special emphasis on amphotericin B

Invasive fungal infections in humans caused by several Candida species, increased considerably in immunocompromised or critically ill patients, resulting in substantial morbidity and mortality. Candida albicans is the most prevalent species, although the frequency of these organisms varies greatly according to geographic region. Infections with C. albicans and non-albicans Candida species have become more common, especially in the past 20 years, as a result of aging, immunosuppressive medication use, endocrine disorders, malnourishment, extended use of medical equipment, and an increase in immunogenic diseases. Despite C. albicans being the species most frequently associated with human infections, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei also have been identified. Several antifungal drugs with different modes of action are approved for use in clinical settings to treat fungal infections. However, due to the common eukaryotic structure of humans and fungi, only a limited number of antifungal drugs are available for therapeutic use. Furthermore, drug resistance in Candida species has emerged as a result of the growing use of currently available antifungal drugs against fungal infections. Amphotericin B (AmB), a polyene class of antifungal drugs, is mainly used for the treatment of serious systemic fungal infections. AmB interacts with fungal plasma membrane ergosterol, triggering cellular ion leakage via pore formation, or extracting the ergosterol from the plasma membrane inducing cellular death. AmB resistance is primarily caused by changes in the content or structure of ergosterol. This review summarizes the antifungal drug resistance exhibited by Candida species, with a special focus on AmB.

Regulatory role of Mss11 in Candida glabrata virulence: adhesion and biofilm formation

Introduction

Candida glabrata has emerged as a fungal pathogen with high infection and mortality rates, and its primary virulence factors are related to adhesion and biofilm formation. These virulence factors in C.glabrata are primarily mediated by epithelial adhesins (Epas), most of which are encoded in subtelomeric regions and regulated by subtelomeric silencing mechanisms. The transcription factor Mss11, known for its regulatory role in adhesion, biofilm formation, and filamentous growth in Saccharomyces cerevisiae and Candida albicans, has also been implicated in the expression of EPA6, suggesting its potential influence on C.glabrata virulence. The present study aims to determine the regulatory role of Mss11 in the virulence of C. glabrata.

Methods

In this work, a Δmss11 null mutant and its complemented strain were constructed from a C.glabrata standard strain. The impact of the transcription factor Mss11 on the virulence of C.glabrata was investigated through a series of phenotypic experiments, including the microbial adhesion to hydrocarbons (MATH) test, adherence assay, biofilm assay, scanning electron microscopy and Galleria mellonella virulence assay. Furthermore, transcriptome sequencing, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and chromatin immunoprecipitation sequencing (ChIP-seq) were employed to investigate the molecular mechanisms behind the regulation of Mss11.

Results

In C.glabrata, the loss of MSS11 led to a significant reduction in several virulence factors including cell surface hydrophobicity, epithelial cell adhesion, and biofilm formation. These observations were consistent with the decreased virulence of the Δmss11 mutant observed in the Galleria mellonella infection model. Further exploration demonstrated that Mss11 modulates C. glabrata virulence by regulating EPA1 and EPA6 expression. It binds to the upstream regions of EPA1 and EPA6, as well as the promoter regions of the subtelomeric silencing-related genes SIR4, RIF1, and RAP1, indicating the dual regulatory role of Mss11.

Conclusion

Mss11 plays a crucial role in C. glabrata adhesion and biofilm formation, and thus has a broad influence on virulence. This regulation is achieved by regulating the expression of EPA1 and EPA6 through both promoter-specific regulation and subtelomeric silencing.

Investigation of Luliconazole-Loaded Mucoadhesive Electrospun Nanofibers for Anticandidal Activity in the Management of Vaginal Candidiasis

In this study, we fabricated and evaluated luliconazole-loaded electrospun nanofibers for anticandidal activity in the management of vaginal candidiasis. Polycaprolactone (PCL)/gelatin nanofibers were designed by the electrospinning technique, and the Box-Behnken design (BBD) was adopted for optimization to get tailored fibers. The luliconazole (LCZ) drug was mixed into different concentrations (2.5, 5, 7.5, and 10%) of tea tree oil (TT oil) and loaded into the PCL/gelatin nanofibrous mats. The effective anticandidal potential of nanofiber samples were analyzed by the disk-diffusion method. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), XRD analysis, and in silico study were performed. The entrapment efficiency, swelling degree, mechanical strength, contact angle, mucoadhesion, drug release, and permeation study were assessed. The average diameter of the PCL/gelatin-optimized nanofiber was 153 nm. SEM reflected that the fabricated nanofibers were uniform and bead-free. FTIR and DSC analyzed the interaction and physical entrapment of the drug in the polymeric fibers. The entrapment efficiency of the drug-loaded nanofiber was found to be 89.2 ± 0.8%. Maximum swelling percentages at 4 h were 40.8, 18.9, and 14.0% and contact angles were 46.5°, 62.95°, and 65.78° for the blank, TT oil-loaded, and drug-loaded nanofiber, respectively, which indicated the hydrophilic nature of the fibers. The drug-loaded nanofiber had a high tensile strength with satisfactory mucoadhesive property that led to its adhesion to the vaginal mucosa with no tear. The drug-loaded nanofiber had a cumulative drug release of 67.7 ± 3.4% in 48 h, and the 12.8 ± 0.53 mm of zone of inhibition (ZOI) in 48 h illustrated an effective anticandidal activity. The TT oil-loaded nanofiber also exhibited a small ZOI of 4.3 ± 0.30 mm, indicating a synergistic effect to the antifungal activity of the drug-loaded nanofiber. LCZ-loaded nanofibers can emerge as a novel approach for vaginal drug delivery in the treatment of candida infection. Thus, this pharmaceutical investigation can help in formulating preclinical and clinical models.

Antifungal resistance, combinations and pipeline: oh my!

Invasive fungal infections are a strong contributor to healthcare costs, morbidity and mortality, especially amongst hospitalized patients. Historically, Candida was responsible for approximately 15% of all nosocomial bloodstream infections. In the past 10 years, the epidemiology of Candida species has altered, with increasing prevalence of resistant species. With rising fungal resistance, especially in Candida spp., the demand for novel antifungal therapies has exponentially increased over the last decade. Newer antifungal agents have become an attractive option for patients needing long-term therapy for infections or those requiring antifungal prophylaxis. Despite advances in coverage of non-Candida pathogens with newer agents, clinical scenarios involving multidrug-resistant fungal pathogens continue to arise in practice. Combination antifungal therapy can lead to a host of side-effects, some of which can be drug limiting. Additional antifungal therapies with enhanced fungal spectrum of activity and decreased rates of adverse effects are warranted. Fosmanogepix, ibrexafungerp, olorofim and rezafungin may help fill some of these gaps in the antifungal armamentarium. This article is part of the Challenges and strategies in the management of invasive fungal infections Special Issue: https://www.drugsincontext.com/special_issues/challenges-and-strategies-in-the-management-of-invasive-fungal-infections.

Presence and implication of Candida spp. in patients with peri-implantitis enrolled in a supportive peri-implant therapy program of the Basque Country (Spain). A case-control study

INTRODUCTION

The peri-implant sulcus is a good niche for infectious colonization such as Candida spp. In this study, the level of Candida spp. fungal colonization is analyzed in patients with peri-implantitis under supportive peri-implant therapy, as well as its correlation with the main clinicopathological data.

METHODS

A case-control study was carried out on 161 patients treated with dental implants, 80 with PI and 81 without PI, which corresponded to 91 women and 70 men, whose mean age was 60.90 years. A specific protocol was completed for the clinical and implant data. Microbiological samples were taken by oral rinse and with paper tips from the peri-implant sulcus. For the quantitative and qualitative analysis Candida Chromogenic Agar/CONDA plates were incubated for 72 h at 36 + 1°C. Fungal growth was considered active when having more than 50 CFU. Specific Candida spp. cultures were later confirmed by API ID 32C and PCR.

RESULTS

Fungal growth was achieved in 28% of oral rinse and 6.75% of peri-implant fluid samples. No significant differences were recognized between study groups. Most of the cultures (>65%) showed more than 50 CFU. The most frequent species were Candida albicans and Candida parapsilosis. There was no association between different PI risk factors and fungal data. The presence of Candida spp. in the oral cavity of patients with dental implants was related to total edentulism and the use of implant-fixed complete prosthesis implant-retained removable prosthesis.

CONCLUSIONS

These results suggest that there is no link between PI and presence of Candida in patients with dental implants undergoing regular supportive periodontal therapy.

Pseudomonas aeruginosa increases the susceptibility of Candida albicans to amphotericin B in dual-species biofilms

BACKGROUND

Biofilms are the leading cause of nosocomial infections and are hard to eradicate due to their inherent antimicrobial resistance. Candida albicans is the leading cause of nosocomial fungal infections and is frequently co-isolated with the bacterium Pseudomonas aeruginosa from biofilms in the cystic fibrosis lung and severe burn wounds. The presence of C. albicans in multispecies biofilms is associated with enhanced antibacterial resistance, which is largely mediated through fungal extracellular carbohydrates sequestering the antibiotics. However, significantly less is known regarding the impact of polymicrobial biofilms on antifungal resistance.

RESULTS

Here we show that, in dual-species biofilms, P. aeruginosa enhances the susceptibility of C. albicans to amphotericin B, an effect that was biofilm specific. Transcriptional analysis combined with gene ontology enrichment analysis identified several C. albicans processes associated with oxidative stress to be differentially regulated in dual-species biofilms, suggesting that P. aeruginosa exerts oxidative stress on C. albicans, likely through the secretion of phenazines. However, the mitochondrial superoxide dismutase SOD2 was significantly down-regulated in the presence of P. aeruginosa. Monospecies biofilms of the sod2Δ mutant were more susceptible to amphotericin B, and the susceptibility of these biofilms was further enhanced by exogenous phenazines.

CONCLUSIONS

We propose that in dual-species biofilms, P. aeruginosa simultaneously induces mitochondrial oxidative stress, while down-regulating key detoxification enzymes, which prevents C. albicans mounting an appropriate oxidative stress response to amphotericin B, leading to fungal cell death. This work highlights the importance of understanding the impact of polymicrobial interactions on antimicrobial susceptibility.

Antifungal Susceptibility Pattern of Candida glabrata from a Referral Center and Reference Laboratory: 2012-2022

The prevalence of invasive candidiasis caused by non-Candida albicans has rapidly increased. Candida glabrata (Nakaseomyces glabrata) is an important pathogen associated with substantial mortality. Our study examined the antifungal temporal susceptibility of C. glabrata and cross-resistance/non-wild-type patterns with other azoles and echinocandins. Laboratory data of all adult patients with C. glabrata isolated from clinical specimens at the Mayo Clinic, Rochester, from 2012 to 2022 were collected. Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints were used. We obtained 1046 C. glabrata isolates from 877 patients. Using CLSI and EUCAST breakpoints, 187 (17.9%) isolates and 256 (24.5%) isolates were fluconazole-resistant, respectively. Focusing on C. glabrata bloodstream infections, fluconazole-resistance ranged from 16 to 22%. Among those 187 fluconazole-resistant isolates, 187 (100%) and 184 (98.4%) isolates were also voriconazole and posaconazole non-wild-type, respectively, with 97 (51.9%) isolates deemed non-wild type for itraconazole. The fluconazole susceptibility pattern has not changed over the past decade. The proportion of fluconazole-resistant C. glabrata is relatively high, which could be due to the complexity of patients and fluconazole exposure. Itraconazole appears to be a compelling step-down therapy for fluconazole-resistant C. glabrata, given the high proportion of wild-type isolates. Further research to examine clinical outcomes is warranted.

Emerging Role of Sphingolipids in Amphotericin B Drug Resistance

Invasive fungal infections in humans are common in people with compromised immune systems and are difficult to treat, resulting in high mortality. Amphotericin B (AmB) is one of the main antifungal drugs available to treat these infections. AmB binds with plasma membrane ergosterol, causing leakage of cellular ions and promoting cell death. The increasing use of available antifungal drugs to combat pathogenic fungal infections has led to the development of drug resistance. AmB resistance is not very common and is usually caused by changes in the amount or type of ergosterol or changes in the cell wall. Intrinsic AmB resistance occurs in the absence of AmB exposure, whereas acquired AmB resistance can develop during treatment. However, clinical resistance arises due to treatment failure with AmB and depends on multiple factors such as the pharmacokinetics of AmB, infectious fungal species, and host immune status. Candida albicans is a common opportunistic pathogen that can cause superficial infections of the skin and mucosal surfaces, thrush, to life-threatening systemic or invasive infections. In addition, immunocompromised individuals are more susceptible to systemic infections caused by Candida, Aspergillus, and Cryptococcus. Several antifungal drugs with different modes of action are used to treat systemic to invasive fungal infections and are approved for clinical use in the treatment of fungal diseases. However, C. albicans can develop a variety of defenses against antifungal medications. In fungi, plasma membrane sphingolipid molecules could interact with ergosterol, which can lead to the alteration of drug susceptibilities such as AmB. In this review, we mainly summarize the role of sphingolipid molecules and their regulators in AmB resistance.

In vitro evaluation of biofilm formation by Candida parapsilosis and Enterobacter cloacae. Scanning electron microscopy and efficacy of antimicrobial combinations study

Fungal-bacterial infections are being increasingly recognized in clinical settings, and the interaction between these species in polymicrobial biofilms often lead to infections that are highly resistant to treatment. In this in vitro study, we analyzed the formation of mixed biofilms using clinically isolated Candida parapsilosis and Enterobacter cloacae. Additionally, we assessed the potential of conventional antimicrobials, both alone and in combination, for treating polymicrobial biofilms built by these human pathogens. Our results demonstrate that C. parapsilosis and E. cloacae are capable of forming mixed biofilms, as confirmed by scanning electron microscopy. Interestingly, we found that colistin alone or in combination with antifungal drugs was highly effective reducing up to 80% of the total biomass of polymicrobial biofilms.

Efficacy of adjunct photodynamic therapy on Candida growth and oral health quality of life in denture stomatitis patients with type 2 diabetes mellitus wearing implant-retained overdentures: a randomized clinical study

AIM

The aim of the present clinical trial was to study the efficacy of combined miconazole and PDT in the improvement of quality of life and levels of Candida species in chronic hyperglycemic patients with denture stomatitis (DS).

METHODS

One hundred patients were randomly divided into five groups; 20 each in the miconazole, PDT, miconazole+ PDT, CHX and distilled water groups. Methylene blue mediated irradiation was conducted using 600nm diode laser with power, energy density and radiance as 100 mW, 3527 mW/cm2 and 9 J, respectively. Patients were advised to apply 2.5 ml of 2% topical miconazole four times a day. The existence of Candida spp. was detected by means of microbiological culture technique. Candida colony counts from the palates and dentures surfaces, quantified as colony forming unit (CFU)/mL were evaluated at baseline, end of 14 days, 28 days and 60 days. Oral health related quality of life was assessed with the help of a questionnaire.

RESULTS

The quality of life showed significant improvement in the group where combination treatment was executed. The overall CFU/mL values were greater in the dentures in comparison to those from the palates of the patients of all the five groups. During all time periods of the study, the CFU/mL values obtained from combination treatment group showed significant differences. Candida albicans was the most predominant yeast.

CONCLUSION

This study showed the effectiveness of methylene blue- PDT in combination with miconazole in improving oral health related quality of life and significantly reducing Candida CFU counts to resolve palatal inflammation in diabetic individuals with implant-supported complete dentures.

Characterization of the Trr/Trx system in the fungal pathogen Candida glabrata

C. glabrata, an opportunistic fungal pathogen, can adapt and resist to different stress conditions. It is highly resistant to oxidant stress compared to other Candida spp and to the phylogenetically related but non-pathogen Saccharomyces cerevisiae. In this work, we describe the Trx/Trr system of C. glabrata composed of Trr1 and Trr2 (thioredoxin reductases) and Trx2 (thioredoxin) that are localized in the cytoplasm and Trx3 present in the mitochondrion. The transcriptional induction of TRR2 and TRX2 by oxidants depends on Yap1 and Skn7 and TRR1 and TRX3 have a low expression level. Both TRR2 and TRX2 play an important role in the oxidative stress response. The absence of TRX2 causes auxotrophy of methionine and cysteine. Trr1 and Trr2 are necessary for survival at high temperatures and for the chronological life span of C. glabrata. Furthermore, the Trx/Trr system is needed for survival in the presence of neutrophils. The role of TRR1 and TRX3 is not clear, but in the presence of neutrophils, they have non-overlapping functions with their TRR2 and TRX2 paralogues.

P4-ATPase subunit Cdc50 plays a role in yeast budding and cell wall integrity in Candida glabrata

BACKGROUND

As highly-conserved types of lipid flippases among fungi, P4-ATPases play a significant role in various cellular processes. Cdc50 acts as the regulatory subunit of flippases, forming heterodimers with Drs2 to translocate aminophospholipids. Cdc50 homologs have been reported to be implicated in protein trafficking, drug susceptibility, and virulence in Saccharomyces cerevisiae, Candida albicans and Cryptococcus neoformans. It is likely that Cdc50 has an extensive influence on fungal cellular processes. The present study aimed to determine the function of Cdc50 in Candida glabrata by constructing a Δcdc50 null mutant and its complemented strain.

RESULTS

In Candida glabrata, the loss of Cdc50 led to difficulty in yeast budding, probably caused by actin depolarization. The Δcdc50 mutant also showed hypersensitivity to azoles, caspofungin, and cell wall stressors. Further experiments indicated hyperactivation of the cell wall integrity pathway in the Δcdc50 mutant, which elevated the major cell wall contents. An increase in exposure of β-(1,3)-glucan and chitin on the cell surface was also observed through flow cytometry. Interestingly, we observed a decrease in the phagocytosis rate when the Δcdc50 mutant was co-incubated with THP-1 macrophages. The Δcdc50 mutant also exhibited weakened virulence in nematode survival tests.

CONCLUSION

The results suggested that the lipid flippase subunit Cdc50 is implicated in yeast budding and cell wall integrity in C. glabrata, and thus have a broad influence on drug susceptibility and virulence. This work highlights the importance of lipid flippase, and offers potential targets for new drug research.

Clinical Features and Outcomes of Persistent Candidemia Caused by Candida albicans versus Non-albicans Candida Species: A Focus on Antifungal Resistance and Follow-Up Blood Cultures

The clinical distinctions among variations in Candida species, antifungal resistance (AFR), and clearance status of hospital-acquired persistent candidemia (HA-PC) remain uncertain. This secondary analysis of a retrospective cohort study aimed to assess the differences in HA-PC based on different Candida species, AFR, and persistent candidemia (PC) clearance status. A retrospective review was conducted using medical records from Tohoku University Hospital of patients for whom blood cultures were performed between January 2012 and December 2021. PC cases were categorized into groups based on Candida species, azole, or echinocandin resistance, as well as PC-clearance status, and the respective characteristics were analyzed. The HA-PC non-clearance group had a tendency toward higher 30–90-day and 90-day mortality rates compared to the HA-PC-clearance group in both the susceptible and resistant strain groups, with the former group demonstrating a statistically significant difference (odds ratio = 19, p = 0.028). The high mortality rate observed in the Candida non-albicans and resistant strain groups necessitates a more meticulous therapeutic management approach for PC. Follow-up blood cultures and confirmation of PC clearance are useful for improving the survival rates of both the HA-PC-susceptible and -resistant strain groups.

Fungemia in Hospitalized Adult Patients with Hematological Malignancies: Epidemiology and Risk Factors

Fungemia in hematologic malignancies (HM) has high mortality. This is a retrospective cohort of adult patients with HM and fungemia between 2012 and 2019 in institutions of Bogotá, Colombia. The epidemiological, clinical, and microbiological characteristics are described, and risk factors related to mortality are analyzed. One hundred five patients with a mean age of 48 years (SD 19.0) were identified, 45% with acute leukemia and 37% with lymphomas. In 42%, the HM was relapsed/refractory, 82% ECOG > 3, and 35% received antifungal prophylaxis; 57% were in neutropenia, with an average duration of 21.8 days. In 86 (82%) patients, Candida spp. was identified, and other yeasts in 18%. The most frequent of the isolates were non-albicans Candida (61%), C. tropicalis (28%), C. parapsilosis (17%), and C. krusei (12%). The overall 30-day mortality was 50%. The survival probability at day 30 in patients with leukemia vs. lymphoma/multiple myeloma (MM0 group was 59% (95% CI 46-76) and 41% (95% CI 29-58), p = 0.03, respectively. Patients with lymphoma or MM (HR 1.72; 95% CI 0.58-2.03) and ICU admission (HR 3.08; 95% CI 1.12-3.74) were associated with mortality. In conclusion, in patients with HM, non-albicans Candida species are the most frequent, and high mortality was identified; moreover, lymphoma or MM and ICU admission were predictors of mortality.

Effects of Euterpe oleracea Mart. extract on Candida spp. biofilms

PROBLEM OF RESEARCH

Candida spp. biofilms are complex microbial communities that have been associated with increasing resistance to clinically available antifungal drugs. Hence, novel pharmacological approaches with ability to inhibit biofilm formation have been investigated.

AIM OF STUDY

The aim was to analyze in vitro antifungal activity of Euterpe oleracea Mart. (açaí berry) extract on biofilm strains of Candida albicans, C. parapsilosis, and C. tropicalis that were formed on abiotic surfaces.

REMARKABLE METHODOLOGY

Biofilms of C. albicans, C. parapsilosis, and C. tropicalis were grown in vitro. They were then treated with E. oleracea Mart. extract at different concentrations (7.8, 15.6, 31.2, 62.5, 125, 250, 500, and 1000 μg/mL) for evaluation of both biofilm removal and anti-biofilm activity.

REMARKABLE RESULTS

All Candida species analyzed formed biofilms on abiotic surfaces. Yet, increased biofilm formation was displayed for C. tropicalis in comparison with the other two species. E. oleracea Mart. extract was shown to inhibit biofilm formation at all concentrations used when compared to no treatment (p < 0.05).

SIGNIFICANCE OF THE STUDY

In the current study, the extract of E. oleracea Mart. demonstrated antifungal activity against Candida albicans, C. parapsilosis, and C. tropicalis biofilms, regardless of the dose utilized. These results are important to evaluate a natural product as antifungal for Candida species.

The first case of Wickerhamomyces anomalus fungemia in Iran in an immuneodeficient child, a review on the literature

The incidence of invasive candidiasis in pediatric patients is increasing and is associated with significant morbidity and mortality. C. pelliculosa has been rarely reported as a human pathogen, however, it has been associated with serious nosocomial infections and clonal outbreaks with poor clinical outcomes in immunocompromised children were reported. Here, we describe the first case of candidemia due to Candida pelliculosa in a 5-year-old immunocompromised male suffered from Griscelli syndrome with hemophagocytic syndrome hospitalized in the pediatric intensive care unit (PICU), Tehran, Iran. In addition, the history of reported cases or case-series due to C. pelliculosa is reviewed.

Novel Intravenous Immunoglobulin Therapy for the Prevention and Treatment of Candida auris and Candida albicans Disseminated Candidiasis

Disseminated candidiasis is a life-threatening disease and remains the most common bloodstream infection in hospitalized patients in the United States. Despite the availability of modern antifungal therapy, the crude mortality rate in the last decade has remained unacceptably high. Novel approaches are urgently needed to supplement or replace current antifungal therapies. In our study, we show that human intravenous immunoglobulin (IVIG) can provide protection against Candida auris and Candida albicans disseminated infections in A/J and C57BL/6 mouse models. The protective efficacy of IVIG is evidenced by the prolonged survival of mice with invasive candidiasis that were treated with human IVIG alone or in combination with amphotericin B. Our previous studies have led to the identification of a panel of Candida cell surface peptide and glycan epitopes, which are targeted by protective mouse monoclonal antibodies (mAbs) against invasive candidiasis. Of interest, the peptide- and glycan-specific IgGs could be detected in all 18 human IVIG samples. In particular, the specific IVIG lots with the highest protective peptide- and glycan-related IgGs provided the best protection. The combination of IVIG and amphotericin B had enhanced efficacy in protection compared to monotherapy against both multidrug-resistant (MDR) C. auris and C. albicans, with evidence of significantly prolonged survival and lower fungal burdens in targeted organs. This study provides evidence that the protective effects of IVIG were associated with the protective antibodies found in normal human donor sera against pathogenic Candida, and IVIG can be a novel therapy or adjunctive therapy with modern antifungal drugs against disseminated candidiasis. IMPORTANCE Since current antifungal treatments are ineffective in the immunocompromised population and no vaccine is available for humans, hope remains that antibody preparations selected for specific fungal antigens may make it possible to reduce the incidence and mortality of invasive candidiasis. Intravenous immunoglobulin (IVIG) has long been approved as a standard treatment for patients with immunodeficiency disorders who are also susceptible to fungal infection. IVIG has been widely used as prophylaxis or supplemental treatment for sepsis and septic shock; however, this form of adjunctive therapy lacks convincing data to establish its efficacy. In this study, 18 samples from commercial IVIG preparations were screened and evaluated by enzyme-linked immunosorbent assays (ELISAs); Candida peptide- and glycan-specific IgGs were detected with various titers among all IVIG lots. Importantly, significantly reduced organ fungal burdens and mortality were demonstrated in IVIG-treated mouse models of invasive candidiasis. IVIG lots with higher titers of Candida-specific IgGs provided better protection. These findings are important in (i) selecting Candida-specific IVIG therapy that may overcome several shortcomings of conventional IVIG therapy by targeting specific antigens responsible for disease pathogenesis, (ii) enhancing protective efficacy, and (iii) validating data from our previous studies and those of others showing that antibodies combined with conventional antifungal drugs provided enhanced resistance to disease. To our knowledge, this study is the first to demonstrate that human IVIG samples contain protective IgGs targeting Candida cell surface antigens and can be a novel therapy or adjunctive therapy with modern antifungal drugs against disseminated candidiasis.

Candida species and oral mycobiota of patients clinically diagnosed with oral thrush

Overgrowth of Candida yeasts in the oral cavity may result in the development of oral thrush in immunocompromised individuals. This study analyzed the diversity and richness of the oral mycobiota of patients clinically diagnosed with oral thrush (OT), follow-up of oral thrush patients after antifungal therapy (AT), and healthy controls (HC). Oral rinse and oral swab samples were collected from 38 OT patients, 21 AT patients, and 41 healthy individuals (HC). Pellet from the oral rinse and oral swab were used for the isolation of oral Candida yeasts on Brilliance Candida Agar followed by molecular speciation. ITS1 amplicon sequencing using Illumina MiSeq was performed on DNA extracted from the oral rinse pellet of 16 OT, 7 AT, and 7 HC oral rinse samples. Trimmed sequence data were taxonomically grouped and analyzed using the CLC Microbial Genomics Module workflow. Candida yeasts were isolated at significantly higher rates from oral rinse and swab samples of OT (68.4%, p < 0.001) and AT (61.9%, p = 0.012) patients, as compared to HC (26.8%). Predominance of Candida albicans specifically, was noted in OT (60.5%, p < 0.001) and AT (42.9%, p = 0.006) vs. HC (9.8%), while non-albicans Candida species was dominant in HC. Analysis of oral mycobiota from OT patients showed the presence of 8 phyla, 222 genera, and 309 fungal species. Low alpha diversity (Shannon index, p = 0.006; Chao-1 biased corrected index, p = 0.01), varied beta diversity (Bray-Curtis, p = 0.01986; Jaccard, p = 0.02766; Weighted UniFrac, p = 0.00528), and increased relative abundance of C. albicans (p = 3.18E-02) was significantly associated with the oral mycobiota of OT vs. HC. This study supported that C. albicans is the main etiological agent in oral thrush and highlights the association of fungal biodiversity with the pathophysiology of oral thrush.

Distribution of candida species and risk factors for invasive candidiasis

Aim: The aim of this study was to investigate the Candida species isolated from the clinical samples of patients in the pediatric intensive care unit and to determine the risk factors for invasive candidiasis. Materials and Methods: Patients with Candida species detected in clinical samples between January 2013 and December 2018 were included in this study. The demographic characteristics of the patients, the use of broad-spectrum antibiotics and immunosuppressive drugs, underlying diseases, blood transfusions, history of surgical operations, whether there is bacterial growth with Candida species in the same clinical sample, parenteral nutrition and invasive interventions were retrospectively analyzed and their relationship with invasive candidiasis was investigated. Results: A total of 91 patients were included in the study. The mean age was 72.3 ± 70.1 months. Among the patients 48.4% had Candida albicans while 51.6% had non-albicans Candida. Candida parapsilosis (n = 18, 19.8%) and Candida tropicalis (n = 14, 15.4%) were the most common non-albicans Candida species. The most common antifungal treatment was fluconazole (n = 34, 59.6%). There was no statistically significant relationship between invasive candidiasis and the underlying disease, central venous and / or urinary catheter, broad-spectrum antibiotic, corticosteroid, gender and surgical operation (p&gt; 0.05). On the other hand, there was a statistically significant relationship between invasive candidiasis and parenteral nutrition, blood transfusion and bacterial growth with Candida species in the same clinical sample (p &lt;0.05). Conclusions: Non-albicans Candida species are more common than Candida albicans in the pediatric intensive care units. Candida parapsilosis is the most common among non-albicans Candida species. Parenteral nutrition, blood transfusion and bacterial growth with Candida species in the same clinical sample increased the risk of invasive candidiasis.

Meyerozyma guilliermondii species complex: review of current epidemiology, antifungal resistance, and mechanisms

Meyerozyma guilliermondii has been accepted as a complex composed of Meyerozyma guilliermondii, Meyerozyma carpophila, and Meyerozyma caribbica. M. guilliermondii is a saprophyte detected on human mucosa and skin. It can lead to serious infections in patients with risk factors like chemotherapy, immunodeficiency, gastrointestinal or cardiovascular surgery, and oncology disorders. Most deaths related to M. guilliermondii infections occur in individuals with malignancy. In recent decades, incidence of M. guilliermondii infections is increased. Sensitivity of this microorganism to conventional antifungals (e.g., amphotericin B, fluconazole, micafungin and anidulafungin) was reduced. Prophylactic and empirical uses of these drugs are linked to elevated minimal inhibitory concentrations (MICs) of M. guilliermondii. Drug resistance has concerned many researchers across the world. They are attempting to discover appropriate solution to combat this challenge. This study reviews the most important mechanisms of resistance to antifungals developed by in M. guilliermondii species complex.

Clinical Challenges of Emerging and Re-Emerging Yeast Infections in the Context of the COVID-19 Pandemic

During the geological eras, some fungi, through adaptation and/or environmental/ecological pressure, interacted directly and indirectly with humans, through occasionally harmful interaction interdependent on the individual's immunological condition. Infections caused by yeasts are underreported, subjugated, and underdiagnosed, and treatment is restricted to a few drugs, even after the significant progress of medicine and pharmacology. In the last centuries, antagonistically, there has been an exponential increase of immunocompromised individuals due to the use of immunosuppressive drugs such as corticosteroids, increased cases of transplants, chemotherapeutics, autoimmune diseases, neoplasms, and, more recently, coronavirus disease 2019 (COVID-19). This review aims to survey emerging and re-emerging yeast infections in the current clinical context. Currently, there is an immense clinical challenge for the rapid and correct diagnosis and treatment of systemic mycoses caused by yeasts due to the terrible increase in cases in the current context of COVID-19.

Overview on the Infections Related to Rare Candida Species

Atypical Candida spp. infections are rising, mostly due to the increasing numbers of immunocompromised patients. The most common Candida spp. is still Candida albicans; however, in the last decades, there has been an increase in non-Candida albicans Candida species infections (e.g., Candida glabrata, Candida parapsilosis, and Candida tropicalis). Furthermore, in the last 10 years, the reports on uncommon yeasts, such as Candida lusitaniae, Candida intermedia, or Candida norvegensis, have also worryingly increased. This review summarizes the information, mostly related to the last decade, regarding the infections, diagnosis, treatment, and resistance of these uncommon Candida species. In general, there has been an increase in the number of articles associated with the incidence of these species. Additionally, in several cases, there was a suggestive antifungal resistance, particularly with azoles, which is troublesome for therapeutic success.

Recombinant polymerase amplification combined with lateral flow strips for the detection of deep-seated Candida krusei infections

The incidence of Candida infections in intensive care units (ICU) has significantly increased in recent years, and these infections have become one of the most serious complications threatening the lives of ICU patients. The proportion of non-Candida albicans infections, such as Candida krusei and Candida glabrata infections, which are resistant to fluconazole, is increasing each year. Early identification of the strains causing Candida infections is important for the timely implementation of targeted treatments to save patients’ lives. However, the current methods of direct microscopy, culture, and histopathology, as well as other diagnostic methods, have many shortcomings, such as their low sensitivity and long assay times; therefore, they cannot meet the needs for early clinical diagnosis. Recombinant polymerase amplification (RPA) is a promising isothermal amplification technique that can be performed without sophisticated instruments and equipment, and is suitable for use in resource-poor areas. RPA combined with lateral flow strips (LFS) can be used to rapidly amplify and visualize target genes within 20 min. In this study, RPA-LFS was used to amplify the internal transcribed spacer 2 (ITS2) region of C. krusei. The primer-probe design was optimized by introduction of base mismatches (probe modification of five bases) to obtain a specific and sensitive primer-probe combination for the detection of clinical specimens. Thirty-five common clinical pathogens were tested with RPA-LFS to determine the specificity of the detection system. The RPA-LFS system specifically detected C. krusei without cross-reaction with other fungi or bacteria. A gradient dilution of the template was tested to explore the lower limit of detection and sensitivity of the assay. The sensitivity was 10 CFU/50 µL per reaction, without interference from genomic DNA of other species. The RPA-LFS and qPCR assays were performed on 189 clinical specimens to evaluate the detection performance of the RPA-LFS system. Seventy-six specimens were identified as C. krusei, indicating a detection rate of 40.2%. The results were consistent with those of qPCR and conventional culture methods. The RPA-LFS system established in our study provides a reliable molecular diagnostic method for the detection of C. krusei, thus meeting the urgent need for rapid, specific, sensitive, and portable clinical field testing.

Establishment of a rapid diagnosis method for Candida glabrata based on the ITS2 gene using recombinase polymerase amplification combined with lateral flow strips

Candida glabrata is the second or third most common Candida-associated species isolated from hospital-acquired infections, surpassing even C. albicans in some hospitals. With the rapid progression of the disease course of C. glabrata infections, there is an urgent need for a rapid and sensitive on-site assay for clinical diagnosis. Isothermal amplification is a recently developed method for rapid nucleic acid detection that is being increasingly used for on-site detection, especially recombinase polymerase amplification (RPA). RPA combined with lateral flow strips (LFS) can rapidly amplify and visually detect the target gene within 20 min. The whole detection process can be controlled within 30–60 min by rapid sample pre-treatment. In this study, RPA-LFS was used to amplify the internal transcribed spacer region 2 gene of C. glabrata. The primer–probe design was optimized by introducing base mismatches (probe modification of one base) to obtain a highly specific and sensitive primer–probe combination for clinical sample detection. RPA-LFS was performed on 23 common clinical pathogens to determine the specificity of the assay system. The RPA-LFS system specifically detected C. glabrata without cross-reaction with other fungi or bacteria. Gradient dilutions of the template were tested to explore the lower limit of detection of this detection system and to determine the sensitivity of the assay. The sensitivity was 10 CFU/µL, without interference from genomic DNA of other species. The RPA-LFS and qPCR assays were performed on 227 clinical samples to evaluate the detection performance of the RPA-LFS system. Eighty-five samples were identified as C. glabrata, representing a detection rate of 37.5%. The results were consistent with qPCR and conventional culture methods. The collective findings indicate a reliable molecular diagnostic method for the detection of C. glabrata, and to meet the urgent need for rapid, specific, sensitive, and portable clinical field-testing.

Synbiotic Musa acuminata skin extract and Streptococcus salivarius K12 inhibit candida species biofilm formation

This study aimed to determine the effect of synbiotic Musa acuminata skin extract (MASE) and Streptococcus salivarius K12 (K12) on Candida species biofilm formation. Liquid chromatography quadrupole time-of-flight (LC-Q-TOF-MS) was conducted to characterize MASE. To determine the effect of synbiotic on Candida biofilm, 200 µL of RPMI-1640 containing Candida, K12, and MASE were pipetted into the same well and incubated at 37 °C for 72 h. A similar protocol was repeated with K12 or MASE to determine the probiotic and prebiotic effects, respectively. Dimorphism, biofilm biomass, and Candida total cell count (TCC) were determined. A total of 60 compounds were detected in MASE. C. albicans (ALT5) and Candida lusitaniae exhibited the highest reduction in biofilm biomass when co-cultured with prebiotic (77.70 ± 7.67%) and synbiotic (97.73 ± 0.28%), respectively. All Candida spp. had decreased TCC and hyphae when co-cultured with synbiotic. In conclusion, MASE and K12 inhibit Candida biofilm formation.

Characteristics of Biofilms Formed by C. parapsilosis Causing an Outbreak in a Neonatal Intensive Care Unit

Background: We dealt with the occurrence of an outbreak of Candida parapsilosis in a neonatal intensive care unit (NICU) in September 2020. There have been several reports of C. parapsilosis outbreaks in NICUs. In this study we describe our investigation into both the transmission route and the biofilm of C. parapsilosis. Methods: C. parapsilosis strains were detected in three inpatients and in two environmental cultures in our NICU. One environmental culture was isolated from the incubator used by a fungemia patient, and another was isolated from the humidifier of an incubator that had been used by a nonfungemia patient. To prove their identities, we tested them by micro satellite analysis. We used two methods, dry weight measurements and observation by electron microscopy, to confirm biofilm. Results: Microsatellite analysis showed the five C. parapsilosis cultures were of the same strain. Dry weight measurements and electron microscopy showed C. parapsilosis formed biofilms that amounted to clumps of fungal cells. Conclusions: We concluded that the outbreak happened due to horizontal transfer through the humidifier of the incubator and that the C. parapsilosis had produced biofilm, which promoted an invasive and infectious outbreak. Additionally, biofilm is closely associated with pathogenicity.

Risk Factors for Candida Infection among Children Admitted to a Pediatric Intensive Care Unit in a Tertiary Care Centre in Southern India

Background

To describe the clinical profile, risk factors, and outcomes that are associated with candida infection among critically ill children.

Patients and methods

A retrospective case-control study wherein 109 children admitted to the pediatric intensive care unit (PICU) in the years between 2015 and 2017 with the growth of candida from blood, urine, endotracheal (ET) aspirate, and pus swabs were included and compared to 97 age and sex-matched controls chosen from the same time period.

Results

Of the 124 candida isolates from 109 children, 37% were from blood, 24% from urine, and 14% in pus; 40% of the isolates were from ET aspirate. Candida non-albicans types (70%) predominated with Candida tropicalis causing 50% of the infections. Risk factors for candida infection were neutropenia [OR 20.01, 95% CI (0.94–422.32)], mechanical ventilation [OR 5.97, 95% CI (2.44–14.62)], peritoneal dialysis [OR 5.81, 95% CI (1.27–26.50)], institution of amino acids [OR 5.41, 95% CI (0.85–34.13)], presence of central venous catheter [OR 3.83, 95% CI (1.59–9.19)], antibiotic use >5 days [OR 3.58, 95% CI (1.38–9.29)]. Candida Cases (95.4%) had a septic shock with acute kidney injury in 34% and had significantly lower survival than controls [72 (66%) of 109 vs. 74 (80%) of 92] (p = 0.023).

Conclusions

The rate of candida infection in our PICU was 4.2% of PICU admissions. The most common species was C. tropicalis. The independent risk factors for candida infection were neutropenia, antibiotic duration >5 days, peritoneal dialysis, amino acid administration, mechanical ventilation, and presence of a central venous catheter (CVC).

How to cite this article

Rajeshwari R, Vyasam S, Chandran J, Porwal S, Ebenezer K, Thokchom M, et al. Risk Factors for Candida Infection among Children Admitted to a Pediatric Intensive Care Unit in a Tertiary Care Centre in Southern India. Indian J Crit Care Med 2022;26(6):717–722.

Prevalence and Antifungal Susceptibility Profile of Oral Candida spp. Isolates from a Hospital in Slovakia

Oral fungal infections are a worldwide healthcare problem. Although Candida albicans is still the most common yeast involved in the infections of oral cavity, non-Candida albicans Candida species (NCACs) have been highly related to these infections, particularly in older, immunosuppressed or patients with long exposure to antimicrobial drugs. The goal of this work was to perform a quick epidemiological and mycological study on the oral samples collected from a laboratory of a hospital in Slovakia, for 60 days. The samples’ identification was performed by Germ-tube formation test, CHROMID® Candida, Auxacolor 2, ID 32C automated method, and the antifungal susceptibility testing determined by E-test®. Results confirm that comparing with bacteria, yeasts still occur in the lower number, but there is a high rate of antifungal resistance (81.6%)—to, at least one drug—among the collected samples, particularly to azoles and 5′-FC, which is clinically noteworthy.

Systemic Infection by Non-albicans Candida Species Affects the Development of a Murine Model of Multiple Sclerosis

Candidiasis may affect the central nervous system (CNS), and although Candida albicans is predominant, non-albicans Candida species can also be associated with CNS infections. Some studies have suggested that Candida infections could increase the odds of multiple sclerosis (MS) development. In this context, we investigated whether systemic infection by non-albicans Candida species would affect, clinically or immunologically, the severity of experimental autoimmune encephalomyelitis (EAE), which is an animal model used to study MS. For this, a strain of C. glabrata, C. krusei, and C. parapsilosis was selected and characterized using different in vitro and in vivo models. In these analysis, all the strains exhibited the ability to form biofilms, produce proteolytic enzymes, and cause systemic infections in Galleria mellonella, with C. glabrata being the most virulent species. Next, C57BL/6 mice were infected with strains of C. glabrata, C. krusei, or C. parapsilosis, and 3 days later were immunized with myelin oligodendrocyte glycoprotein to develop EAE. Mice from EAE groups previously infected with C. glabrata and C. krusei developed more severe and more prevalent paralysis, while mice from the EAE group infected with C. parapsilosis developed a disease comparable to non-infected EAE mice. Disease aggravation by C. glabrata and C. krusei strains was concomitant to increased IL-17 and IFN-γ production by splenic cells stimulated with fungi-derived antigens and with increased percentage of T lymphocytes and myeloid cells in the CNS. Analysis of interaction with BV-2 microglial cell line also revealed differences among these strains, in which C. krusei was the strongest activator of microglia concerning the expression of MHC II and CD40 and pro-inflammatory cytokine production. Altogether, these results indicated that the three non-albicans Candida strains were similarly able to reach the CNS but distinct in terms of their effect over EAE development. Whereas C. glabrata and C. Krusei aggravated the development of EAE, C. parapsilosis did not affect its severity. Disease worsening was partially associated to virulence factors in C. glabrata and to a strong activation of microglia in C. krusei infection. In conclusion, systemic infections by non-albicans Candida strains exerted influence on the experimental autoimmune encephalomyelitis in both immunological and clinical aspects, emphasizing their possible relevance in MS development.

Plausible Mechanistic Insights in Biofilm Eradication Potential against Candida spp. Using In Situ-Synthesized Tyrosol-Functionalized Chitosan Gold Nanoparticles as a Versatile Antifouling Coating on Implant Surfaces

In the present study, tyrosol-functionalized chitosan gold nanoparticles (Chi-TY-AuNPs) were prepared as an alternative treatment strategy to combat fungal infections. Various biophysical techniques were used to characterize the synthesized Chi-TY-AuNPs. The antifungal and antibiofilm activities of Chi-TY-AuNPs were evaluated against Candida albicans and C. glabrata, and efforts have been made to elucidate the possible mechanism of action. Chi-TY-AuNPs showed a high fungicidal effect against both sessile and planktonic cells of Candida spp. Additionally, Chi-TY-AuNPs completely eradicated (100%) the mature biofilms of both the Candida spp. FESEM analysis highlighted the morphological alterations in Chi-TY-AuNP-treated Candida biofilm cells. The effect of Chi-TY-AuNPs on the ECM components showed significant reduction in protein content in the C. glabrata biofilm and substantial decrease in extracellular DNA content of both the Candida spp. ROS generation analysis using DCFDA-PI staining showed high ROS levels in both the Candida spp., whereas pronounced ROS production was observed in the Chi-TY-AuNP-treated C. glabrata biofilm. Biochemical analysis revealed decreased ergosterol content in Chi-TY-AuNP-treated C. glabrata cells, while inconsequential changes were observed in C. albican s. Furthermore, the transcriptional expression of selected genes (ergosterol biosynthesis, efflux, sterol importer, and glucan biogenesis) was reduced in C. glabrata in response to Chi-TY-AuNPs except ERG11 and CDR1. Conclusively, the result showed the biofilm inhibition and biofilm eradication efficacy of Chi-TY-AuNPs in both the Candida spp. Findings of the present study manifest Chi-TY-AuNPs as a potential therapeutic solution to Candida biofilm-related chronic infections and overcome biofilm antifungal resistance.

Synergistic activity of dobutamine combined with azoles and its mechanism of action against strains of Candida glabrata

Aims: To evaluate the antifungal effect of dobutamine against Candida glabrata as well as its synergism with azoles and its action on biofilm. Methods: The M27-A3 protocol and flow cytometry were used for elucidation of the possible mechanism of action. Results: The tested isolates presented MICs ranging from 2 to 32 μg/ml for dobutamine, with fungistatic effect. A total of 82% of the strains showed synergism with fluconazole, with 90% showing synergism with itraconazole. The effect on biofilm formation was nonsignificant. Cytometry tests showed that dobutamine induced mitochondrial depolarization. Conclusion: Dobutamine has an antifungal effect on strains of C. glabrata and synergistic activity with azoles. This effect is probably mediated by increased oxidative damage to the membrane.

FLO8 deletion leads to decreased adhesion and virulence with downregulated expression of EPA1, EPA6, and EPA7 in Candida glabrata

BACKGROUND

The Candida glabrata does not develop into a pathogenic hiphal form; however, it has become the second most common pathogen of fungal infections in humans, partly because of its adhesion ability and virulence.

OBJECTIVES

The present study aimed to determine whether Flo8, a transcription factor that plays an important role in the virulence and drug resistance in Candida albicans, has a similar role in C. glabrata.

METHODS

We constructed FLO8 null strains of a C. glabrata standard strain and eight clinical strains from different sources, and a FLO8 complemented strain. Real-time quantitative PCR, biofilm formation assays, hydrophobicity tests, adhesion tests, Caenorhabditis elegans survival assay, and drug-susceptibility were then performed.

RESULTS

Compared with the wild-type strains, the biofilm formation, hydrophobicity, adhesion, and virulence of the FLO8-deficient strains decreased, accompanied by decreased expression of EPA1, EPA6, and EPA7. On the other hand, it showed no changes in antifungal drug resistance, although the expression levels of CDR1, CDR2, and SNQ2 increased after FLO8 deletion.

CONCLUSIONS

These results indicated that Flo8 is involved in the adhesion and virulence of C. glabrata, with FLO8 deletion leading to decreased expression of EPA1, EPA6, and EPA7 and decreased biofilm formation, hydrophobicity, adhesion, and virulence.

The association of air pollutants (CO2, MTBE) on Candida albicans and Candida glabrata drug resistance

Introduction

Therapeutic methods are very important in the prevalence of opportunistic fungal infections, which are an important cause of human diseases. In this study, air pollution agents that are in direct contact with microorganisms, and the effects of carbon sources using CO2 and MTBE on growth of fungi, and particularly the evaluation of changes in the expression of interfering genes in susceptibility and drug resistance in these fungi, were investigated.

Materials and Methods

Collecting samples and isolating Candida glabrata and Candida albicans with phenotypic methods were accomplished. We then evaluated the minimum inhibitory concentration (MIC) with the M27A4 protocol of CLSI. We adjusted 20 strains of C. albicans and 10 strains of C. glabrata whose sensitivity was evaluated in the MIC test with 5% CO2 and 5mg/ml methyl tert-butyl ether (MTBE) considered as air pollutants, and followed by re-evaluating MIC testing to separate azole-resistant strains. Interfering agents were also considered.

Results

Upregulation of some genes on the two mentioned yeasts had led to drug resistance in them; they were previously sensitive to both drugs. Correspondingly, 41% of C. glabrata samples in sputum showed sensitivity to these drugs. Upregulation of ERG11 (71%) and EPA1 (90%) were observed in resistant strains. Upregulation of genes associated with aspartate proteins and downregulation of SAP3 genes were recognized in C. glabrata in sputum and a 15% downregulation of bronchoalveolar lavage (BAL) isolate and 50% upregulation of SAP1 gene in C. albicans sensitive samples were observed and compared to fluconazole and itraconazole with the oral and joint sources. Remarkably, decreased SAP2 expression in oral sources and a 60% increase in resistant strains in C. albicans were observed. The downregulation of SAP3 expression showed in the joint samples. An increase in HWP1 expression (30%) was noted in isolated and drug-sensitive samples at the sputum and BAL source. CDR1 expression was increased in MTBE-affected species; however, it decreased in the vicinity of CT.

Conclusions

Air pollutants such as CO2 and MTBE eventually caused drug resistance in Candida, which can be one of the causes of drug resistance in candidiasis infections.

The Flo Adhesin Family

The first step in the infection of fungal pathogens in humans is the adhesion of the pathogen to host tissue cells or abiotic surfaces such as catheters and implants. One of the main players involved in this are the expressed cell wall adhesins. Here, we review the Flo adhesin family and their involvement in the adhesion of these yeasts during human infections. Firstly, we redefined the Flo adhesin family based on the domain architectures that are present in the Flo adhesins and their functions, and set up a new classification of Flo adhesins. Next, the structure, function, and adhesion mechanisms of the Flo adhesins whose structure has been solved are discussed in detail. Finally, we identified from Pfam database datamining yeasts that could express Flo adhesins and are encountered in human infections and their adhesin architectures. These yeasts are discussed in relation to their adhesion characteristics and involvement in infections.

Silver nanoparticles, a promising treatment against clinically important fluconazole-resistant Candida glabrata

Resistance to azole antifungal agents is a challenging limitation in Candida glabrata treatment. It is associated with decreased intracellular concentrations of antifungal agents as a result of overexpression of efflux pumps on the cellular plasma membranes. This work evaluates the potential of silver nanoparticles (AgNPs) to reverse the resistance of fungal cells to fluconazole. Silver nanoparticles were prepared using wet chemical method and characterised by UV-Vis spectrophotometry, dynamic light scattering, and zeta potential. Broth microdilution and pour plates methods were used to study the anticandidal activity using two C. glabrata fluconazole-resistant strains (DSY565 and CBS138) known to overexpress active efflux pumps, and a standard fluconazole sensitive strain ATCC 22553. Silver nanoparticles-fluconazole combinations decreased concentrations of fluconazole substantially without compromising the activity. These findings suggest that AgNPs enhance the efficacy of fluconazole and offer a promising application in therapy of C. glabrata infections.

Update on Candida krusei, a potential multidrug-resistant pathogen

Although Candida albicans remains the main cause of candidiasis, in recent years a significant number of infections has been attributed to non-albicans Candida (NAC) species, including Candida krusei. This epidemiological change can be partly explained by the increased resistance of NAC species to antifungal drugs. C. krusei is a diploid, dimorphic ascomycetous yeast that inhabits the mucosal membrane of healthy individuals. However, this yeast can cause life-threatening infections in immunocompromised patients, with hematologic malignancy patients and those using prolonged azole prophylaxis being at higher risk. Fungal infections are usually treated with five major classes of antifungal agents which include azoles, echinocandins, polyenes, allylamines, and nucleoside analogues. Fluconazole, an azole, is the most commonly used antifungal drug due to its low host toxicity, high water solubility, and high bioavailability. However, C. krusei possesses intrinsic resistance to this drug while also rapidly developing acquired resistance to other antifungal drugs. The mechanisms of antifungal resistance of this yeast involve the alteration and overexpression of drug target, reduction in intracellular drug concentration and development of a bypass pathway. Antifungal resistance menace coupled with the paucity of the antifungal arsenal as well as challenges involved in antifungal drug development, partly due to the eukaryotic nature of both fungi and humans, have left researchers to exploit alternative therapies. Here we briefly review our current knowledge of the biology, pathophysiology and epidemiology of a potential multidrug-resistant fungal pathogen, C. krusei, while also discussing the mechanisms of drug resistance of Candida species and alternative therapeutic approaches.

Species Distribution, Antifungal Susceptibility, and Molecular Epidemiology of Candida Species Causing Candidemia in a Tertiary Care Hospital in Bangkok, Thailand

Candida species represent a common cause of bloodstream infection (BSI). Given the emergence of non-albicans Candida (NAC) associated with treatment failure, investigations into the species distribution, fungal susceptibility profile, and molecular epidemiology of pathogens are necessary to optimize the treatment of candidemia and explore the transmission of drug resistance for control management. This study evaluated the prevalence, antifungal susceptibility, and molecular characteristics of Candida species causing BSI in a tertiary-level hospital in Bangkok, Thailand. In total, 54 Candida isolates were recovered from 49 patients with candidemia. C. tropicalis was the most prevalent species (33.3%), followed by C. albicans (29.6%). Most Candida species were susceptible to various antifungal agents, excluding C. glabrata and C. tropicalis, which had increased rates of non-susceptibility to azoles. Most C. glabrata isolates were non-susceptible to echinocandins, especially caspofungin. The population structure of C. albicans was highly diverse, with clade 17 predominance. GoeBURST analysis of C. tropicalis revealed associations between genotype and fluconazole resistance in a particular clonal complex. The population structure of C. glabrata appeared to have a low level of genetic diversity in MLST loci. Collectively, these data might provide a fundamental database contributing to the development of novel antifungal agents and diagnostic tests.

Yeasts Associated with the Small-Intestinal Contents and Epithelium of Pon Yang Kham (Charolais Crossbred) Fattening Beef Cattle

Yeast diversity in the pia and small-intestinal epithelium of Pon Yang Kham fattening cattle in Thailand was studied using a culture-dependent method. A total of 701 yeasts were isolated from the pia of the duodenum, jejunum, and ileum of the small intestine, while 425 isolates were obtained from the epithelium of all three parts of the small intestine. Yeast identification was performed and ascomycetous yeasts were found at levels of 96.9% and 86.8% in the pia and small intestine, respectively, whereas basidiomycetous yeasts were found at levels of 2.3% and 12.7%. Candida parapsilosis was the species with the highest occurrence in the duodenal and jejunal pia, with an 83.3% and 77.8% frequency of occurrence (FO), respectively. Both C. parapsilosis and C. tropicalis were species with the highest occurrence in the ileum, with a 61.1% FO. Moreover, C. parapsilosis was the species with the highest occurrence in the epithelium of the duodenum, jejunum, and ileum, with FOs of 88.2%, 87.5%, and 87.2%, respectively. Principal coordinate analysis revealed no marked differences in yeast communities from either the pia or epithelium of all three parts of the small intestine. An estimation of the expected richness of the species showed that the observed species richness was lower than the predicted richness.

Comparison of risk factors and outcomes of Candida auris candidemia with non-Candida auris candidemia: A retrospective study from Pakistan

Candida auris has emerged as a nosocomial multi-drug resistant pathogen. This study aimed to compare the risk factors and outcomes of C. auris candidemia patients with non-C. auris candidemia, at a single center in Pakistan. A retrospective study compared 38 C. auris with 101 non-C. auris (36 C. albicans, 38 C. tropicalis, and 27 C. parapsilosis) candidemia patients between September 2014 and March 2017 at the Aga Khan University Hospital, Pakistan. Demographics, clinical history, management and outcomes were studied. Prior history of surgery (adjusted odds ratio [aOR] 4.9, 95% confidence interval [CI]: 1.4-17.5), antifungals exposure (aOR 38.3, 95% CI: 4.1-356) and prior MDR bacteria isolation (aOR 5.09, 95% CI: 1.6-15.9) were associated with C. auris candidemia. On survival analysis both groups of patients had similar outcome in terms of mortality (62.6% vs. 52.54%, hazard ratio [HR] 1.45, 95% CI: 0.84-2.4, P-value = .17) and microbiological failure rates (42.3% vs. 32.2%, HR 0.65, 95% CI: 0.35-1.2, P-value = .17) however, C. auris patients had a higher mean hospital stay (36.32 days vs. 14.8 days, P-value = <.001) and higher >15-day in-hospital stay from positive culture (HR 2.68, 95% CI: 1.1-6.3, P-value = .025). Antifungal susceptibility was different, with C. auris more often resistant to voriconazole (29.6% vs. 0%) and amphotericin (3.7 vs. 0%); though no echinocandin resistance was detected in either group. As opposed to other Candida species, C. auris candidemia occurred after nosocomial exposure, and its source was most commonly an indwelling line. Although these patients had a higher in-hospital stay, but there was no excess mortality when compared to other Candida species.