The impact of ORF19.36.1 in the pathobiology of Candida albicans

BACKGROUND

Our previous proteomics data obtained from Candida albicans recovered after serial passage in a murine model of systemic infection revealed that Orf19.36.1 expression correlates with the virulence of the fungus. Therefore, the impact of ORF19.36.1 upon virulence was tested in this study.

MATERIALS & METHODS

CRISPR-Cas9 technology was used to construct homozygous C. albicans orf19.36.1 null mutants and the phenotypes of these mutants examined in vitro (filamentation, invasion, adhesion, biofilm formation, hydrolase activities) and in vivo assays.

RESULTS

The deletion of ORF19.36.1 did not significantly impact the phenotypes examined or the virulence of C. albicans in two infection models.

CONCLUSION

These results suggest that, although Orf19.36.1 expression correlates with virulence, this protein is not essential for C. albicans pathobiology.

In-vivo efficiency of the novel azole compounds (ATTAF-1 and ATTAF-2) against systemic candidiasis in a murine model

BACKGROUND

Antifungal resistance is the main health concern in the control of invasive fungal infections. This research was designed to further assess the antifungal activity of aryl-1,2,4-triazole-3-ylthio analogs of fluconazole (ATTAFs) against Candida albicans systemic candidiasis in the murine model.

MATERIALS & METHODS

The murine model of systemic candidiasis was designed via the inoculation of 1 × 106 CFU of Candida albicans. The treatment dosages of 3.5 and 35 mg/kg per day were selected for ATTAFs and fluconazole, respectively. The median survival time (MST) was assayed for 30 days post-infection. The quantitative and qualitative (via histopathology staining) fungal burden was also assessed. Furthermore, immunohistochemistry and biochemistry assays were performed to monitor anti-inflammatory activity using the Cyclooxygenase-2 (Cox-2) marker and changes in serum protein levels.

RESULTS

ATTAFs considerably improved the survival of the murine model (P < 0.003). Compared with fluconazole, the antifungal activity of ATTAFs and their MST showed no difference (P > 0.05). However, these compounds decreased the fungal burden in the kidneys, spleen, and liver.

CONCLUSION

Our research indicates that ATTAF-1 and ATTAF-2 are effective therapeutic agents due to their fungal clearing and increasing the MST in the murine model of systemic candidiasis. Although we concluded that these components are novel and promising candidates for the management of invasive candidiasis, further studies are warranted to correlate these findings with clinical outcomes.

Clinical Sensitivity of the (1-3)-β-D-glucan Test for Predicting Candidemia

The sensitivity of the (1-3)-β-D-glucan (BDG) diagnostic test for candidemia varies in different clinical settings, and its usefulness in early diagnosis of candidemia is suboptimal. We evaluated the sensitivity of the test for early candidemia prediction. All adult patients with culture-proven candidemia who underwent a serum Goldstream Fungus (1-3)-β-D-Glucan Test within seven days prior to candidemia onset at a tertiary referral hospital between January 2017 and May 2021 were included. Any-positive BDG results within seven days prior to candidemia onset were obtained in 38 out of 93 (40.9%) patients. The positive rate increased when the test was performed near the day of candidemia onset (P=0.04) but reached only 52% on the day of candidemia onset. We observed no significant differences between BDG-positive and -negative groups in terms of underlying disease, risk factors for candidemia, clinical presentation, origin of candidemia, and 30-day mortality. Candida albicans was significantly associated with positive BDG results than with all-negative BDG results (P=0.04). The Goldstream BDG test is unreliable for candidemia prediction because of its low sensitivity. Negative BDG results in patients with a high risk of invasive candidiasis should be interpreted with caution.

Efficacy and safety of echinocandin monotherapy and combination therapy for immunocompromised patients with systemic candidiasis: A systematic review and meta-analysis

BACKGROUND

Systemic candidiasis is caused by Candida invading the bloodstream. The efficacy and safety of echinocandins in monotherapy and combination therapy regimes have not been adequately compared in immunocompromised patients with Candidiasis, and thus this systematic review aims to do so.

METHODS

A protocol was prepared a priori. PubMed, Embase and Cochrane Library databases were searched systematically (from inception of each database to September 2022) to identify randomized controlled trials. Two reviewers performed screening, quality assessment of trials, and extracted data independently. Pairwise meta-analysis was performed using random-effects model to compare echinocandin monotherapy versus other antifungals. The primary outcomes of interest were treatment success and treatment-related adverse events.

RESULTS

547 records (PubMed=310, EMBASE=210 and Cochrane Library=27) were reviewed. Following our screening criteria, six trials involving 177 patients were included. Risk of bias of four included studies had some concerns due to lack of a pre-specified analysis plan. Meta-analysis shows that echinocandin monotherapy does not have significantly higher rates of "treatment success" compared to other classes of antifungals (RR 1.12, 95%CI 0.80-1.56). However, echinocandins appeared to be significantly safer than other forms of antifungal therapy (RR 0.79, 95%CI 0.73-0.86).

CONCLUSION

Our findings have shown that echinocandin monotherapy (micafungin, caspofungin) given intravenously are just as effective as other antifungals (amphotericin B, itraconazole) in the treatment of systemic candidiasis in immunocompromised patients. There appears to be similar benefits when using echinocandins compared to amphotericin B which has also been used as a broad-spectrum antifungal, while avoiding the severe adverse effects that amphotericin B causes, such as nephrotoxicity.

Candida spp. co-infection in COVID-19 patients with severe pneumonia: Prevalence study and associated risk factors

Background

Invasive fungal infections (IFI) are increasing in prevalence in recent years. In the last few months, the rise of COVID-19 patients has generated a new escalation in patients presenting opportunistic mycoses, mainly by Aspergillus. Candida infections are not being reported yet.

Objectives

We aimed to determine the prevalence of systemic candidiasis in patients admitted to ICUs due to severe pneumonia secondary to SARS-CoV-2 infection and the existence of possible associated risk factors that led these patients to develop candidiasis.

Patients/methods

We designed a study including patients with a confirmed diagnosis of COVID-19.

Results

The prevalence of systemic candidiasis was 14.4%, and the main isolated species were C. albicans and C. parapsilosis. All patients that were tested positive for Candida spp. stayed longer in the ICU in comparison to patients who tested negative. Patients with candidiasis had higher MuLBSTA score and mortality rates and a worse radiological involvement. In our study, Candida spp. isolates were found in patients that were submitted to: tocilizumab, tocilizumab plus systemic steroids, interferon type 1β and Lopinavir-Ritonavir.

Conclusions

Results suggested a high prevalence of systemic candidiasis in severe COVID-19-associated pneumonia patients. Patients with Candidiasis had the worst clinical outcomes. Treatment with tocilizumab could potentialize the risk to develop systemic candidiasis.

Chitosan hydrogel loaded with recombinant protein containing epitope C from HSP90 of Candida albicans induces protective immune responses against systemic candidiasis

We reported previously a recombinant protein (rP-HSP90C) containing epitope C from heat shock protein 90 of Candida albicans mediates protective immune responses against systemic candidiasis. However, it exhibits weak immunogenicity. Therefore, we evaluated the potential and mechanisms of thermosensitive chitosan hydrogel (CH-HG) as an adjuvant in rP-HSP90C vaccine. CH-HG synthesized by ionic cross-linking showed buffering capacity and control-released rP-HSP90C in vitro. In comparison to naked rP-HSP90C, CH-HG-loaded rP-HSP90C (CH-HG/rP-HSP90C) not only evoked a long-lasting rP-HSP90C-specific IgG, but also enhanced Th1, Th2, Th17 responses and the ratio of Th1/Th2 in vivo; Meanwhile, CH-HG/rP-HSP90C provoked a stronger CTL response than rP-HSP90C. Notably, CH-HG increased the protective immune responses against systemic candidiasis in rP-HSP90C-immunized mice since CH-HG/rP-HSP90C enhanced the survival rate of infected mice, and diminished the CFUs in kidneys compared to rP-HSP90C, which were similar to that of QuilA. Further in vitro investigation displayed CH-HG upgraded the expressions of costimulators, MHCs and cytokines in BMDCs compared to rP-HSP90C；CH-HG also promoted cellular uptake, endosomal escape and "cross-presentation" of rP-HSP90C. In addition, it recruited immune cells at the injection site. Our study demonstrated that CH-HG can be an efficient adjuvant in fungal vaccines.

Anti-inflammatory potential of myristic acid and palmitic acid synergism against systemic candidiasis in Danio rerio (Zebrafish)

Nosocomial Candida colonization causes Systemic candidiasis in human with invasive infections in immunocompromised patients. Of all Candida spp., C. albicans is dominant in morbidity of all systemic candidiasis but C. tropicalis is phenomenal in mortality, virulence aspects and resistance development against antifungal drugs. The present study investigated the synergistic anti-virulent activity of myristic acid (MA) and palmitic acid (PA) against insidious dimorphic Candida spp. (C. albicans and C. tropicalis). In vitro and qPCR results revealed the mechanisms of MA-PA combination effectively inhibiting various virulence aspects such as biofilm, hyphal formation, secreted aspartyl proteases, lipases, ergosterol biosynthesis and drug effluxes. Further, in Danio rerio (Zebrafish), the MA-PA treatment increased the survival of animals and also the treated groups showed decreased level of fungal burden compared to the infected controls, after 3^rd day of post infection. Histopathology of vital organs and SEM analysis of skin revealed a drastic recovery and reduced the inflammation of both Candida spp. infections in MA-PA treated animals. In addition, MA-PA treatment reduced the haemolysin and increased the susceptibility of Candida spp. in human blood model. Hence, this study suggested the therapeutic utilization of MA-PA as synergistic combination for their anti-inflammatory potency against systemic candidiasis and candidemia.

RANK-RANKL signaling upregulates Il-10 mRNA expression in mucosal Candida infection in vivo

Osteoprotegerin (OPG) prevents binding of receptor activator of nuclear factor-kappa B ligand (RANKL) to RANK. Recent studies have reported that immune cell RANK-RANKL interactions are critical to the infection process. Candida albicans is an opportunistic pathogenic fungus and a common cause of candidiasis. This study utilized an orally inoculated mouse model of C. albicans infection to determine whether superficial or systemic candidiasis was associated with alterations in RANK/RANKL/OPG expression. Invasive systemic C. albicans infection increased serum OPG levels in mice. In addition, tongue Opg, Rankl, and Rank mRNA expression were upregulated in mice with superficial oral cavity C. albicans infection. Moreover, administration of exogenous soluble RANKL upregulated Rank and interleukin-10 (Il-10) mRNA in superficially infected tissue, suggesting suppression of localized inflammation. Taken together, these findings suggested that RANK/RANKL/OPG signaling contributes to the pathogenesis of candidiasis. This is the first in vivo study to identify a relationship between this opportunistic infection and the RANK/RANKL/OPG axis.

Fluphenazine antagonizes with fluconazole but synergizes with amphotericin B in the treatment of candidiasis

Candida albicans causes a high mortality rate in immunocompromised individuals, but the increased drug resistance challenges the current antifungal therapeutics. Fluphenazine (FPZ), a commonly used antipsychotic medication, can induce the expression of drug efflux pumps in C. albicans and, thus, may interfere with the therapeutic efficacy of antifungals, such as fluconazole (FLC) and amphotericin B (AmB). Here, we investigated the combined effects of FLC/FPZ and AmB/FPZ against C. albicans in vitro and in a systemic candidiasis mouse model. The antifungal activity of FLC was significantly reduced when supplemented with FPZ. The inhibitory effects of FLC on the expression of the Candida virulence-related genes ALS3 and HWP1 were antagonized by FPZ. However, FPZ enhanced the susceptibility of C. albicans to AmB and further downregulated the expression of ALS3 and HWP1 in a synergistic manner with AmB. FPZ also enhanced the gene expression of ERG11, a key gene of the ergosterol biosynthesis pathway that has been associated with the activities of both FLC and AmB. In our mammalian infection model, mice treated with FLC/FPZ showed notably poor living status and increased fungal burden in their kidneys and brains compared with those treated with FLC alone. Conversely, the combined application of AmB/FPZ significantly improved the survival rate, attenuated the weight loss and reduced the organ fungal burdens of the infected mice. These data suggest that FPZ antagonized the therapeutic efficacy of FLC but enhanced the antifungal activity of AmB in the treatment of candidiasis.

In vitro and in vivo antifungal activity of Allium hirtifolium and Allium sativum

OBJECTIVE

One of the major clinical problems is the resistance of Candida species towards most of antifungals. The search for new antifungal drug from plants have helped to overcome this problem. This study evaluated the effects of Allium hirtifolium and Allium sativum extracts on Candida tropicalis both in vitro and in a mouse model of systemic candidiasis.

MATERIALS AND METHODS

In this study, clinical isolates of C. tropicalis were isolated and identified from immunocompromised patients with recurrent candidiasis. Antifungal susceptibilities assessment and time kill study of aqueous and ethanolic extracts of A. hirtifolium and A. sativum extracts were done against C. tropicalis. The in vivo activity of aqueous extracts of A. hirtifolium and A. sativum were evaluated in a mouse model of systemic candidiasis caused by C. tropicalis through estimating the host survival time, fungal burden and histopathologic analyses.

RESULTS

The aqueous and ethanolic extracts of A. hirtifolium and A. sativum exhibited significant antifungal activity against C. tropicalis. In time kill study, A. hirtifolium and A. sativum extracts exhibited significant effects against C. tropicalis (p<0.05). Treatment of BALB/c mice that were systemically infected with C. tropicalis, showed that treatments with A. hirtifolium and A. sativum (at 1 mg/kg/day) were slightly less efficacious than that of fluconazole in terms of the fungal burden reduction and host survival time, it was still effective against C . tropicalis.

CONCLUSION

These findings demonstrate the anticandidal properties of A. hirtifolium and A. sativum extracts in vitro and in vivo and suggest their potential to be used as an adjuvant therapy in the management of Candida infections.

In vitro lymphoproliferative response and cytokine production in mice with experimental disseminated candidiasis

Objective(s):

Systemic candidiasis is an infection of Candida albicans (C. albicans) causing disseminated disease and sepsis, invariably when host defenses are compromised. We investigated the histopathological changes as well as the lymphoproliferative responses and cytokine production of splenic cells after stimulation with Concanavalin A (Con A) and Pokeweed mitogen (PWM) in mice with disseminated candidiasis.

Materials and Methods:

Lymphoproliferative responses were stimulated in vitro with Con A (1 µg/ml) and PWM (1 µg/ml) mitogens in Roswell Park Memorial Institute (RPMI) 1640 media, and the production of interferon (IFN)-γ and interleukin-4 (IL-4) in the supernatants was measured by enzyme-linked immunosorbent assay (ELISA).

Results:

The results revealed that C. albicans organisms multiplied to a greater extent in the kidneys than in the liver and spleen of infected mice. The most predominant forms of C. albicans in different parts of the kidneys were yeast mixed with hyphal forms. Infected mice had a significantly increased proliferative response when splenocytes were stimulated with PWM (2.0±0.16) and Con A (1.9±0.19) (P<0.05). PWM and Con A-stimulated production of IFN-γ significantly tended to be higher in infected mice (PWM: 68.4±14.0 pg/ml; Con A: 53.7±17.3 pg/ml) when compared to controls (P<0.05). Stimulation with PWM and Con A showed no differences in IL-4 production between infected mice and controls.

Conclusion:

These findings demonstrated a significant increase in both cell proliferation and IFN-γ secretion in supernatants of PWM and Con A- stimulated splenocyte cultures obtained from mice with disseminated candidiasis.

Epidemiologic and microbiologic evaluation of nosocomial infections associated with Candida spp in children: A multicenter study from Istanbul, Turkey

BACKGROUND

The purpose of this study was to establish species distribution of Candida isolates from pediatric patients in Istanbul, Turkey, and to determine risk factors associated with nosocomial Candida infections.

METHODS

This study was conducted between June 2013 and June 2014 by participation of 7 medical centers in Istanbul. Candida spp strains isolated from the clinical specimens of pediatric patients were included. Clinical features were recorded on a standardized data collection sheet.

RESULTS

A total of 134 systemic Candida infections were identified in 134 patients. The patients were admitted in pediatric and neonatal intensive care units (41.8% and 9.7%, respectively) and in pediatric wards (48.5%). Candida albicans was the most prevalent species (47%), followed by Candida parapsilosis (13.4%), Candida tropicalis (8.2%), Candida glabrata (4.5%), Candida lusitaniae (3.7%), Candida kefyr (2.2%), Candida guilliermondii (1.5%), Candida dubliniensis (0.7%), and Candida krusei (0.7%). Types of Candida infections were candidemia (50.7%), urinary tract infection (33.6%), surgical site infection (4.5%), central nervous system infection (3.7%), catheter infection (3.7%), and intra-abdominal infection (3.7%). In multivariate analysis, younger age (1-24 months) and detection of non-albicans Candida spp was found to be risk factors associated with candidemia (P = 0.040; odds ratio [OR], 4.1; 95% confidence interval [CI], 1.06-15.86; and P = 0.02; OR, 2.4; 95% CI, 1.10-5.53, respectively).

CONCLUSIONS

This study provides an update for the epidemiology of nosocomial Candida infections in Istanbul, which is important for the management of patients and implementation of appropriate infection control measures.

An investigation of the inhibitory effects of dendrosomal nanocurcumin on Candida albicans and systemic candidiasis in BALB/c mice

Background and Purpose:

Use of curcumin, as a promising antifungal agent, is considered an alternative treatment for fungal infections; however, the low solubility of this agent limits its efficacy. Accordingly, in this study, we aimed to evaluate the in vitro and in vivo antifungal activities of dendrosomal nanocurcumin with improved solubility and bioavailability.

Materials and Methods:

The in vitro antifungal activities of several Candida species, including C. albicans, C. tropicalis, C. krusei, C. parapsilosis , and C. dubliniensis, were evaluated, using the broth microdilution method. In the in vivo study, different doses of nanocurcumin (5, 10, 20, and 40 mg/kg) were administered to mice with systemic C. albicans infection via intraperitoneal injection. All mice were euthanized at 20 days following the administration of different doses of nanocurcumin. Different organs were extracted for organ culture and histopathological investigation.

Results:

Based on the findings, 40 mg/kg of nanocurcumin significantly decreased the fungal load in the evaluated organs; the results were confirmed with histopathological examination. The kidney was found to be the most affected organ with the highest number of severe lesions. Yeasts and pseudohyphae were observed in the blood vessels, kidney, and brain. Also, yeasts were present in the liver, brain, lungs, and heart of the control group.

Conclusion:

Although curcumin is generally an excellent antifungal component, its nano-sized form showed more potent properties. Based on the gathered data, dendrosomal nanocurcumin is an effective antifungal agent with good efficacy against disseminated candidiasis. However, further studies are required to evaluate the effects of dendrosomal nanocurcumin on other fungal infections. Also, this agent could be useful for the prevention of fungal infections, such as candidiasis, particularly in high-risk patients.

[Systemic and localized infection by Candida species in patients with rheumatic diseases receiving anti-TNF therapy]

OBJECTIVE

To evaluate the prevalence of systemic and localized infection by Candida species and its possible association with demographic, clinical and laboratory manifestations and therapy in patients with rheumatic diseases taking TNF blockers.

METHODS

Consecutive patients with rheumatic diseases receiving anti-TNF agents were included. The following risk factors up to four weeks prior to the study were analyzed: use of antibiotics, immunosuppressant drugs, hospitalization and invasive procedures. All subjects were evaluated for clinical complaints, specific blood cultures were obtained for fungi and blood samples were collected for Candida spp. detection by polymerase chain reaction.

RESULTS

194 patients [67 with rheumatoid arthritis (RA), 47 with ankylosing spondylitis (AS), 36 with juvenile idiopathic arthritis (JIA), 28 with psoriatic arthritis and 16 with other conditions] were included. The average age of patients was 42±16 years, with 68 (35%) male and mean disease duration of 15±10 years. Sixty-four (33%) patients were receiving adalimumab, 59 (30%) etanercept and 71 (36%) infliximab. Eighty-one percent of patients were concomitantly taking immunosuppressants drugs. At the time of the study, only one (0.5%) patient had localized fungal infection (vaginal candidiasis). None of the patients included had systemic candidiasis with positive blood cultures for fungi or PCR positive for Candida spp. in peripheral blood sample.

CONCLUSIONS

This was the first study to assess the prevalence of invasive and localized fungal disease by candida in a significant number of patients with rheumatic diseases on anti-TNF therapy, and demonstrated low risk of candidiasis, despite the high prevalence of immunosuppressive drug use.

Liposomal thymoquinone effectively combats fluconazole-resistant Candida albicans in a murine model

The aim of the present study was to develop a novel liposomal formulation of thymoquinone (TQ) to treat fluconazole-susceptible and -resistant Candida albicans (C. albicans) infections. The liposomal preparation of TQ (Lip-TQ) was used against a fluconazole-susceptible or -resistant isolate of C. albicans. Various doses of fluconazole (0, 5, 10, 20 and 40 mg/kg) or free TQ or Lip-TQ (0, 1, 2 and 5mg/kg) were used to treat C. albicans infected mice. Mice were observed for 40 days post C. albicans infection, and their kidneys were assessed for the fungal load. Fluconazole showed anti-fungal activity against the drug-susceptible, but not against the -resistant isolate of C. albicans. Free TQ showed its activity against both fluconazole-susceptible or -resistant C. albicans, however, Lip-TQ was found to be the most effective and imparted ∼ 100% and ∼ 90% survival of mice infected with fluconazole-susceptible and -resistant isolates of C. albicans, respectively. Mice treated with Lip-TQ showed highly reduced severity of infection in their tissue homogenates. Therefore, Lip-TQ may effectively be used in the treatment of C. albicans infections, including those which are not responding to fluconazole.

β-D-Glucan Assay in Diagnosis and Monitoring the Systemic Candidiasis in a Rat Model

BACKGROUND

Determination of β-D-Glucan (BDG) in the serum aids to diagnose the invasive fungal infections. The current study evaluated the diagnostic potential value of BDG assay in monitoring the disease in experimental systemic candidiasis in a rat model. The results can provide a useful preliminary data to improve this approach in developing countries.

OBJECTIVES

The present study aimed to evaluate β-D-Glucan assay in diagnosis and monitoring the systemic candidiasis in a rat model.

MATERIALS AND METHODS

Twenty one rats were infected with 10(6) Candida albicans blastospore per rat. Twelve rats were considered as the negative controls (six immunocompromised rats without infection and six intact rats). During a week, every 24 hours the BDG sera level was determined by both Fungitell and Wako kits. To confirm the systemic infection in each rat, the suspensions of their internal organs were cultivated on agar plates and the number of colony forming units (CFU) of C. albicans was counted.

RESULTS

All the infected rats were positive with BDG tests. An increasing level of BDG was observed during early days after injection. The cutoff value for discrimination of BDG positive sera was obtained from the negative sera by the Fungitell kit. The sensitivity, specificity, positive and negative predictive values assessed for the Fungitell kit were 95%, 66.6%, 90.47% and 80%, respectively. These criteria for those of Wako were 90%, 83.3%, 94.7% and 71.4%, respectively.

CONCLUSIONS

While BDG assay seems to be a sensitive and specific adjunctive tool to diagnose and monitor the experimental systemic candidiasis, it seems that measuring the positive cutoff value in different laboratory conditions is necessary for favorable establishment of these tests.

Comparison of the T2Dx instrument with T2Candida assay and automated blood culture in the detection of Candida species using seeded blood samples

As a delay in the diagnosis and treatment of candidemia is associated with increased mortality and healthcare costs, a more rapid method of detection is urgently needed. The T2Candida assay is a new rapid diagnostic test, which uses T2 magnetic resonance technology to identify Candida spp. directly from whole blood in approximately 3 hours. In this study, the performance of the BACTEC 9050 using Aerobic Plus/F blood culture bottles was compared to that of the T2Candida assay run on the T2Dx Instrument for detection of Candida albicans, Candida tropicalis, Candida parapsilosis, Candida glabrata, and Candida krusei, in seeded blood samples at concentrations between 3.1 and 11 CFU/mL. The BACTEC 9050 detected Candida growth in 100% of bottles (n = 20 replicates) within 5 days for all species (63.23 ± 30.27 hours), with the exception of Candida glabrata (0%). The T2Candida assay had a 100% detection rate for each species (n = 13-20 replicates) within 3 hours including C. glabrata. The sensitivity and specificity of the T2Candida assay were 1 and 0.978, respectively.