A review of Candida species causing blood stream infection

Antifungal activity of Cinnamaldehyde derivatives against fluconazole-resistant Candida albicans

BACKGROUND

Candida albicans is an opportunistic pathogen commonly found in human mucous membranes. In light of the escalating challenge posed by antibiotic resistance of C. albicans strains worldwide, it is an urgently necessary to explore alternative therapeutic options.

OBJECTIVE

This study aims to assess the efficacy of two Cinnamaldehyde derivatives, 2-Cl Cinnamaldehyde (2-Cl CA) and 4-Cl Cinnamaldehyde (4-Cl CA), against C. albicans through both in vitro experiments and in vivo murine models and to evaluate their potential as new drug candidates for treating C. albicans.

METHODS AND RESULTS

The minimum inhibitory concentrations (MICs) of Cinnamaldehyde 2-Cl and 4-Cl benzene ring derivatives against C. albicans were 25 μg/mL. Time-killing experiments revealed that both Cinnamaldehyde derivatives exhibited fungicidal activity against C. albicans at concentrations of 5 MIC and 10 MIC. In the checkerboard experiment, 4-Cl CA did not show any antagonistic effect when combined with first-line antifungal drugs. Instead, it exhibited additive effects in combination with nystatin. Both 2-Cl and 4-Cl CA demonstrated inhibitory activity against C. albicans biofilm formation, especially at 8 MIC and 16 MIC concentrations. In C. albicans biofilm eradication experiments, although high drug concentrations of 2-Cl and 4-Cl CA were unable to eradicate the biofilm completely, they were still effective in killing C. albicans cells within the biofilm. Moreover, sub-inhibitory concentrations of 4-Cl CA (ranging from 5 to 20 μg/mL) significantly inhibited cell aggregation and hyphal formation. Furthermore, 4-Cl CA effectively inhibited intracellular C. albicans infection in macrophages. Lastly, the effectiveness of 4-Cl CA was evaluated in a mouse model of hematogenous disseminated candidiasis caused by C. albicans, which revealed that 4-Cl CA significantly reduced fungal burden and improved mouse survival compared to the untreated controls.

CONCLUSION

The 4-Cl CA exhibited inhibitory effects against C. albicans through both in vivo and in vitro models, demonstrating its therapeutic potential as a promising new drug candidate for treating drug-resistant candidiasis albicans.

Drug delivery based on a supramolecular chemistry approach by using chitosan hydrogels

Microbial infections are a serious healthcare related problem, causing several complications and even death. That is why, the development of new drug delivery systems with prolonged effect represents an interesting research topic. This study presents the synthesis and characterization of new hydrogels based on chitosan and three halogenated monoaldehydes. Further, the hydrogels were used as excipients for the development of drug delivery systems (DDS) by the incorporation of fluconazole, an antifungal drug. The systems were structurally characterized by Fourier Transformed Infrared Spectroscopy and Nuclear Magnetic Resonance, both methods revealing the formation of the imine linkages between chitosan and the aldehydes. The samples presented a high degree of ordering at supramolecular level, as demonstrated by WXRD and POM and a good water-uptake, reaching a maximum of 1.6 g/g. The obtained systems were biodegradable, loosing between 38 and 49 % from their initial mass in the presence of lysozyme in 21 days. The ability to release the antifungal drug in a sustained manner for seven days, along with the high values of the inhibition zone diameter, reaching a maximum of 64 mm against Candida parapsilosis for the chlorine containing sample, recommend these systems as promising materials for bioapplications.

Antifungal drug susceptibility profiles and molecular mechanisms of azole resistance in Candida blood stream isolates

PURPOSE

The purpose of this study was to determine the activity of fluconazole, voriconazole, posaconazole, amphotericin B, micafungin and caspofungin against Candida blood stream isolates and to investigate the molecular mechanisms of azole resistance in fluconazole resistant isolates.

METHODS

The in vitro susceptibilities of Candida isolates to fluconazole, voriconazole, posaconazole, amphotericin B, micafungin and caspofungin were tested by E-test ERG11, CDR1, CDR2 and MDR1 genes expression of fluconazole resistant, fluconazole (S-DD) and fluconazole intermediate resistant isolates were investigated by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR).

RESULTS

C. albicans (41%) was the most frequently isolated fungal species from blood stream infections followed by C. parapsilosis (22%). All C. albicans isolates except one and all C. tropicalis isolates were found to be susceptible to fluconazole. Overall, 21% of C. glabrata isolates were resistant to fluconazole. None of the Candida isolates were found to be resistant to caspofungin except 2 ​C. glabrata isolates. Overexpression of ERG11 and CDR1 genes were detected in all fluconazole S-DD and fluconazole resistant C. glabrata isolates, while CDR2 overexpression was observed in 91% fluconazole S-DD and 67 of % fluconazole resistant C.glabrata isolates. The overexpression of MDR1, ERG11 and CDR1 genes were found 100%, 80% and 80%, respectively, in fluconazole resistant C. parapsilosis isolates.

CONCLUSION

Most of the Candida isolates were susceptible to posaconazole and caspofungin. Our data also highlighted that overexpression of efflux pump genes major cause of azole resistance.

Naturally Occurring Organohalogen Compounds-A Comprehensive Review

The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.

Adsorption of Candida albicans on Ti-6Al-4V surface and its corrosion effects in artificial saliva

In this study, the corrosion behavior and mechanism of Ti-6Al-4V in artificial saliva with Candida albicans were investigated using electrochemical and surface analysis techniques. Fluorescence microscopy (FM) and confocal laser scanning microscopy (CLSM) showed that C. albicans could easily adsorb on the surface of Ti-6Al-4V alloy to form non-dense biofilm. The non-compact biofilm provided necessary conditions for pitting corrosion on Ti-6Al-4V alloys by scanning electron microscopy (SEM) observation. The potentiodynamic polarization (PDP) curves and electrochemical impedance spectroscopy (EIS) revealed that C. albicans significantly reduced the corrosion resistance of Ti-6Al-4V alloys. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) results indicated that C. albicans biofilm promoted electron transfer from the anodic sites to cathodic depolarizer during the corrosion process, showing that the role of oral fungi must be considered when evaluating the performance of oral materials. This study may provide a new clue for evaluating the corrosion resistance of dental implant materials in the oral environment.

Antifungal Activity of N-(4-Halobenzyl)amides against Candida spp. and Molecular Modeling Studies

Fungal infections remain a high-incidence worldwide health problem that is aggravated by limited therapeutic options and the emergence of drug-resistant strains. Cinnamic and benzoic acid amides have previously shown bioactivity against different species belonging to the Candida genus. Here, 20 cinnamic and benzoic acid amides were synthesized and tested for inhibition of C. krusei ATCC 14243 and C. parapsilosis ATCC 22019. Five compounds inhibited the Candida strains tested, with compound 16 (MIC = 7.8 µg/mL) producing stronger antifungal activity than fluconazole (MIC = 16 µg/mL) against C. krusei ATCC 14243. It was also tested against eight Candida strains, including five clinical strains resistant to fluconazole, and showed an inhibitory effect against all strains tested (MIC = 85.3–341.3 µg/mL). The MIC value against C. krusei ATCC 6258 was 85.3 mcg/mL, while against C. krusei ATCC 14243, it was 10.9 times smaller. This strain had greater sensitivity to the antifungal action of compound 16. The inhibition of C. krusei ATCC 14243 and C. parapsilosis ATCC 22019 was also achieved by compounds 2, 9, 12, 14 and 15. Computational experiments combining target fishing, molecular docking and molecular dynamics simulations were performed to study the potential mechanism of action of compound 16 against C. krusei. From these, a multi-target mechanism of action is proposed for this compound that involves proteins related to critical cellular processes such as the redox balance, kinases-mediated signaling, protein folding and cell wall synthesis. The modeling results might guide future experiments focusing on the wet-lab investigation of the mechanism of action of this series of compounds, as well as on the optimization of their inhibitory potency.

A Study on Prevalence and Characterization of Candida Species in Immunocompromised Patients

Candida spp. is one among the major causes of nosocomial infection, with candidemia gaining increasing prevalence worldwide in parallel with mortality rates ranging from 10-49%. Epidemiology and predisposing factors of candidemia have changed since the number of patients receiving transplants and immunosuppressive therapy, the use of broadspectrum antimicrobials, and the number of AIDS patients have increased. Candidemia is more common among patients with subcutaneous and cutaneous candida infections, through percutaneous inoculation. Major predisposing factors for invasive candidiasis includes neutropenia, haematological malignancies, bone marrow transplantation, total parenteral nutrition, chemotherapy, invasive procedures, and immune-suppressive agents. This study analyses the risk factors of immunocompromised patients with candidemia and antibiogram of Candida spp. isolated from ICU patients. To evaluate the prevalence, distribution and antibiogram of Candida spp., associated risk factors, and outcome in candidemia patients. Blood samples received from patients with clinically suspected fungal infections were subjected to gram staining, culture, sugar assimilation & fermentation, Candida Chrome agar (CCA) & Corn meal agar for identification and speciation. Antifungal susceptibility tests were performed by disk-diffusion tests. Among a total of 337 samples received, 22 (6.5%) samples were positive for candida infections, of which Candida tropicalis 9 (41%) was the predominant isolate followed by C. albicans 5 (23%), Candida glabrata 4 (18%), Candida parapsilosis 2 (9%) and Candida krusei 2 (9%). Male patients had a higher prevalence of candidemia 15 (68.2%). Among the age group of 51-70 years, uncontrolled DM(Diabetes mellitus) and CKD (chronic kidney disease) were found to be the predominant co-morbidities with candidemia.

Risk Factors of Candida parapsilosis Catheter-Related Bloodstream Infection

Catheter-related bloodstream infection (CRBSI) is an important healthcare-associated infection caused by various nosocomial pathogens. Candida parapsilosis has emerged as a crucial causative agent for the CRBSI in the last two decades. Many factors have been associated with the development of CRBSI including, demography, pre-maturity, comorbidities (diabetes mellitus, hypertension, heart diseases, neuropathy, respiratory diseases, renal dysfunction, hematological and solid organ malignancies, and intestinal dysfunction), intensive care unit (ICU) admission, mechanical ventilation (MV), total parenteral nutrition (TPN), prior antibiotic and/or antifungal therapy, neutropenia, prior surgery, immunosuppressant, and type, site, number, and duration of catheters. This study aims to determine C. parapsilosis CRBSI risk factors. A retrospective study has been performed in an 853-bedded tertiary-care hospital in north-eastern Malaysia. All inpatients with C. parapsilosis positive blood cultures from January 2006 to December 2018 were included, and their medical records were reviewed using a standardized checklist. Out of 208 candidemia episodes, 177 had at least one catheter during admission, and 31 cases had not been catheterized and were excluded. Among the 177 cases, 30 CRBSI cases were compared to 147 non-CRBSI cases [81 bloodstream infections (BSIs), 66 catheter colonizers]. The significance of different risk factors was calculated using multivariate analysis. Multivariate analysis of potential risk factors shows that ICU admission was significantly associated with non-CRBSI as compared to CRBSI [OR, 0.242; 95% CI (0.080-0.734); p = 0.012], and TPN was significantly positively associated with CRBSI than non-CRBSI [OR, 3.079; 95%CI (1.125-8.429); p = 0.029], while other risk factors were not associated significantly. Patients admitted in ICU were less likely to develop C. parapsilosis CRBSI while patients receiving TPN were more likely to have C. parapsilosis CRBSI when compared to the non-CRBSI group.

Investigation of the Anti-Methicillin-Resistant Staphylococcus aureus Activity of (+)-Tanikolide- and (+)-Malyngolide-Based Analogues Prepared by Asymmetric Synthesis

Herein, we report antibacterial and antifungal evaluation of a series of previously prepared (+)-tanikolide analogues. One analogue, (4S,6S)-4-methyltanikolide, displayed promising anti-methicillin-resistant Staphylococcus aureus activity with a MIC of 12.5 µg/mL. Based on the antimicrobial properties of the structurally related (-)-malyngolide, two further analogues (4S,6S)-4-methylmalyngolide and (4R,6S)-4-methylmalyngolide bearing a shortened n-nonyl alkyl side chain were prepared in the present study using a ZrCl₄-catalysed deprotection/cyclisation as the key step in their asymmetric synthesis. When these were tested for activity against anti-methicillin-resistant Staphylococcus aureus, the MIC increased to 50 µg/mL.

Recent Advances and a Roadmap to Aptamer-Based Sensors for Bloodstream Infections

The present review is intended to describe bloodstream infections (BSIs), the major pathogens responsible for BSIs, conventional tests and their limitations, commercially available methods used, and the aptamer and nanomaterials-based approaches developed so far for the detection of BSIs. The advantages associated with aptamers and the aptamer-based sensors, the comparison between the aptamers and the antibodies, and the various types of aptasensors developed so far for the detection of bloodstream infections have been described in detail in the present review. Also, the future outlook and roadmap toward aptamer-based sensors and the challenges associated with the aptamer development have also been concluded in this review.

Evaluation of Rapid Sepsityper® protocol and specific MBT-Sepsityper module (Bruker Daltonics) for the rapid diagnosis of bacteremia and fungemia by MALDI-TOF-MS

During bloodstream infections, rapid adaptation of empirical treatment according to the microorganism identified is essential to decrease mortality. The aim of the present study was to assess the microbiological performances of a new rapid version of the Sepsityper® kit (Bruker Daltonics) allowing identification of bacteria and yeast by MALDI-TOF mass spectrometry directly from positive blood cultures in 10 min and of the specific MBT-Sepsityper module for spectra analysis, designed to increase identification performance. Identification rates were determined prospectively on 350 bacterial and 29 fungal positive blood cultures, and compared to conventional diagnostic method. Our rapid diagnosis strategy (Rapid Sepsityper® protocol: one spot with and one without formic acid extraction step) combined to MBT-Sepsityper module provided 65.4%, 78.9% and 62% reliable identification to the species level of monomicrobial positive blood cultures growing respectively Gram-positive, Gram-negative bacteria or yeast. Importantly, identification rates of Gram-positive bacteria were higher in anaerobic than in aerobic bottles (77.8% vs 22.2%; p = 0.004), if formic acid extraction step was performed (60.8% vs 39.2%; p = 1.8e⁻⁶) and if specific MBT-Sepsityper module was used (76.2% vs 61.9%, p = 0.041) while no significant differences were observed for Gram-negative bacteria. For yeasts identification, formic acid extraction step improved rapid identification rate by 37.9% while the specific MBT-Sepsityper module increased overall performances by 38%, providing up to 89.7% reliable identification if associated with the standard Sepsityper® protocol. These performances, associated with a reduce turnaround time, may help to implement a rapid identification strategy of bloodstream infections in the routine workflow of microbiology laboratories.

Multilocus Sequence Typing Reveals Clonality of Fluconazole-Nonsusceptible Candida tropicalis: A Study From Wuhan to the Global

Candida tropicalis is a globally distributed human pathogenic yeast, and its increasing resistance to azoles makes clinical treatment difficult. In this study, we investigated the clinical features, azole resistance and genetic relatedness of 87 C. tropicalis isolates from central China and combined with the global database to explore the relationship between genetic information and fluconazole susceptibility. Of the 55 diploid sequence types (DSTs) identified by multilocus sequence typing (MLST), 27 DSTs were new to the C. tropicalis MLST database. Fluconazole-nonsusceptible (FNS) isolates were genetically closely related. goeBURST analysis showed that DST225, DST376, DST506, and DST546 formed a distinct and unique FNS clonal complex (CC) in Wuhan. The local FNS CC belongs to the large FNS CC (CC2) in China, in which the putative founder DST225 has been reported from the environment. The three most prevalent types (DST506, DST525, and DST546) in Wuhan had high minimum inhibitory concentrations (MICs) for antifungal azoles, and the six possible nosocomial transmissions we captured were all FNS strains, most of which were from CC2. Unique FNS CCs have been found in Singapore (CC8) and India (CC17) and are close to China's CC2 in the minimum spanning tree. There were no FNS CCs outside Asia. This study is the first to reveal a significant correlation between genetic information and fluconazole susceptibility worldwide and to trace geographical locations, which is of great value for molecular epidemiological surveillance and azole-resistance study of C. tropicalis globally.

Successful in-vivo treatment of mice infected with Candida glabrata using silver nanoparticles

The current study describes the production of silver nanoparticles (AgNPs) to treat Candida glabrata infections. The method involved incubation of silver nitrate (AgNO3) with Aspergillus terreus using a green and straightforward route. The production of AgNPs was confirmed through a color change from transparent yellow to brown as well as by ultraviolet-visible (UV-VIS) spectroscopy. The surface morphology of AgNPs was assessed using a scanning electron microscope. The antifungal activity of AgNPs against C. glabrata was investigated in the serum of 20 infected mice. The mice were divided into four groups, and the level of cytokines: IL-4 and IFN-γ were examined after 21 days. The atomic force microscopy confirmed that the average diameter of AgNPs was 25.1 nm, which is appropriate for delivering silver nanoparticles to treat animals' infection. The concentration of cytokines IL-4 and IFN-γ were significantly (P < 0.05) higher in the C. glabrata-infected group than in the control group. While the cytokines level remained close to average concentration in mice administrated with AgNPs, such a result was comparable with the fourth group of mice (Candida-treated Aspergillus) after treatment with AgNPs.

Structural Insights into the Interactions of Candidal Enolase with Human Vitronectin, Fibronectin and Plasminogen

Significant amounts of enolase—a cytosolic enzyme involved in the glycolysis pathway—are exposed on the cell surface of Candida yeast. It has been hypothesized that this exposed enolase form contributes to infection-related phenomena such as fungal adhesion to human tissues, and the activation of fibrinolysis and extracellular matrix degradation. The aim of the present study was to characterize, in structural terms, the protein-protein interactions underlying these moonlighting functions of enolase. The tight binding of human vitronectin, fibronectin and plasminogen by purified C. albicans and C. tropicalis enolases was quantitatively analyzed by surface plasmon resonance measurements, and the dissociation constants of the formed complexes were determined to be in the 10⁻⁷–10⁻⁸ M range. In contrast, the binding of human proteins by the S.cerevisiae enzyme was much weaker. The chemical cross-linking method was used to map the sites on enolase molecules that come into direct contact with human proteins. An internal motif ₂₃₅DKAGYKGKVGIAMDVASSEFYKDGK₂₅₉ in C. albicans enolase was suggested to contribute to the binding of all three human proteins tested. Models for these interactions were developed and revealed the sites on the enolase molecule that bind human proteins, extensively overlap for these ligands, and are well-separated from the catalytic activity center.

Coadministration of liposomal methylglyoxal increases the activity of amphotericin B against Candida albicans in leukopoenic mice

In this study, we investigated the therapeutic efficacy of a combination of liposomal amphotericin B (Lip-Amp B) and Methylglyoxal (Lip-MG) against Candida albicans in the leukopoenic mice. The antifungal efficacy of Lip-Amp B or Lip-MG or a combination of Lip-Amp B and Lip-MG was evaluated by the analysis of the survival rate and the fungal load in the treated mice. The immune-stimulatory effect of Lip-MG on macrophages was evaluated by analysing the secretion of proinflammatory cytokines. C. albicans infected mice treated at the doses of 1 and 2 mg/kg of Lip-Amp B showed 20% and 50% survival rates, respectively. Whereas the mice treated with free Amp B at the same doses died within 40 days of treatment. Interestingly, C. albicans infected mice treated with a combination of Lip-Amp B and Lip-MG had 70% survival rate on day 40 postinfection. Moreover, treatment of macrophages with Lip-MG increased their fungicidal activity and the secretion of proinflammatory cytokines, including TNF-α and IL-1β. These findings suggested that co-treatment with Lip-Amp B and Lip-MG had a synergistic effect and could be effective against C. albicans in immunocompromised subjects.

Potential of Methylglyoxal-Conjugated Chitosan Nanoparticles in Treatment of Fluconazole-Resistant Candida albicans Infection in a Murine Model

Background

Fungal infections are becoming more prevalent and threatening because of the continuous emergence of azole-resistant fungal infections. The present study was aimed to assess the activity of free Methylglyoxal (MG) or MG-conjugated chitosan nanoparticles (MGCN) against fluconazole-resistant Candida albicans.

Materials and Methods

A novel formulation of MGCN was prepared and characterized to determine their size, shape and polydispersity index. Moreover, the efficacy of fluconazole or MG or MGCN was determined against intracellular C. albicans in macrophages and the systematic candidiasis in a murine model. The safety of MG or MGCN was tested in mice by analyzing the levels of hepatic and renal toxicity parameters.

Results

Candida albicans did not respond to fluconazole, even at the highest dose of 20 mg/kg, whereas MG and MGCN effectively eliminated C. albicans from the macrophages and infected mice. Mice in the group treated with MGCN at a dose of 10 mg/kg exhibited a 90% survival rate and showed the lowest fungal load in the kidney, whereas the mice treated with free MG at the same dose exhibited 50% survival rate. Moreover, the administration of MG or MGCN did not induce any liver and kidney toxicity in the treated mice.

Conclusion

The findings of the present work suggest that MGCN may be proved a promising therapeutic formulation to treat azole-resistant C. albicans infections.

Assessment of antifungal resistance and associated molecular mechanism in Candida albicans isolates from different cohorts of patients in North Indian state of Haryana

The present study examines the trend in distribution of Candida species and their antifungal resistance patterns in hospitals across Haryana, a North Indian state with poorly addressed epidemiology of fungal infections. In our collection of 228 Candida isolates, Candida albicans dominated in both high vaginal swab (HVS) and urine samples while Candida glabrata and Candida tropicalis were the second-highest non-albicans Candida species (NAC), respectively. Of note, in blood samples, C. tropicalis and C. albicans were present in equal numbers. All 228 isolates were subjected to antifungal susceptibility tests, whereby 51% of C. albicans recovered from HVS samples displayed fluconazole resistance. To understand its mechanistic basis, expression profiling of efflux pump genes CDR1, CDR2, MDR1 and azole drug target, ERG11 was performed in 20 randomly selected resistant isolates, wherein many isolates elicited higher expression. Further, ERG11 gene sequencing suggested that most of the isolates harbored mutations, which are not reported with azole resistance. However, one isolate, RPCA9 (MIC 64 μg/mL) harbored triple mutation (Y132C, F145L, A114V), wherein Y132 and F145 sites were previously implicated in azole resistance. Interestingly, one isolate, (RPCA61) having MIC > 128 μg/mL harbored a novel mutation, G129R. Of note, HVS isolates RPCA 21, RPCA 22, and RPCA 44 (MICs 64 to > 128 μg/mL) did not show any change in alteration in ERG11 or overexpression of efflux pump genes. Together, this study presents a first report of Candida infections in selected hospitals of Haryana State.

Extracellular hydrolytic enzyme activities of the different Candida spp. isolated from the blood of the Intensive Care Unit-admitted patients

BACKGROUND

Candida spp. secretes various extracellular hydrolytic enzymes. These enzymes are the important virulence factor for the pathogenesis of Candida. We assessed four different enzymatic activities of Candida isolates obtained from bloodstream infections.

MATERIALS AND METHODS

We isolated 79 strains of different Candida species from the blood of the Intensive Care Unit-admitted patients. Species were identified by conventional methods including culture characteristic, germ tube, sugar assimilation, and Dalmau's culture technique. Phospholipase, proteinase, hemolysin, and esterase enzymatic activities were determined by the Plate method.

RESULTS

Non albicans candida were the most common isolates from the blood of the ICU admitted patient with a predominance of Candida tropicalis. Hemolytic activity was the most prominent enzyme activity followed by the proteinase activity. Candida albicans (89.86%) was the major proteinase producer, while 95.8% of C. tropicalis produced hemolysin. No esterase activity was shown by the Candida glabrata and Candida krusei.

CONCLUSION

No significant difference was observed between the two most common causative agents of candidemia: C. albicans and C. tropicalis.

Necessity to identify candida species accurately with minimum inhibitory concentration determination in each case of bloodstream infections

BACKGROUND

Bloodstream Candida infection is a life-threatening event among ICU admitted patients. This infection is caused by a diverse range of Candida species having varied minimum inhibitory concentrations.

OBJECTIVES

To identify Candida species causing bloodstream infections with their antifungal susceptibility determination.

METHODS

Candida species isolated from the blood of ICU admitted patients were identified by phenotypic as well as by molecular methods including PCR-RFLP using MspI restriction enzyme and MALDI TOF MS. The minimum inhibitory concentration of fluconazole, voriconazole, amphotericin B and caspofungin was determined against isolated Candida species by CLSI M27A₃ guidelines.

RESULTS

A total of 119 Candida species were isolated. Among them, C. tropicalis(n=29) was the predominant isolate followed by C. parapsilosis(n=18), C. glabrata (n=12), C. krusei (n=11) and C. albicans(n=11). Uncommon Candida species isolated were; Wickerhamomyces anomalus(n=15), Kodaemia ohmeri(n=8), C. lusitaniae (n=5) and C. auris (n=2). A varied antifungal MIC values were observed. Caspofungin had the lowest MIC among the tested antifungals. Increased fluconazole MIC was observed against the isolated Candida species including C. tropicalis. All the isolated C. lusitaniae and C. auris strains have ≥1mcg/ml amphotericin B MIC. In comparison to fluconazole, voriconazole was more effective when tested in vitro.

CONCLUSION

Emergence of uncommon Candida species having varied antifungal MIC warns the physicians to have a prompt, accurate identification with antifungal MIC determination in each case of bloodstream Candida infections.

The Overlooked Immune State in Candidemia: A Risk Factor for Mortality

Lymphopenia has been related to increased mortality in septic patients. Nonetheless, the impact of lymphocyte count on candidemia mortality and prognosis has not been addressed. We conducted a retrospective study, including all admitted patients with candidemia from 2007 to 2016. We examined lymphocyte counts during the first 5 days following the diagnosis of candidemia. Multivariable logistic regression analysis was performed to determine the relationship between lymphocyte count and mortality. Classification and Regression Tree analysis was used to identify the best cut-off of lymphocyte count for mortality associated with candidemia. From 296 cases of candidemia, 115 died, (39.8% 30-day mortality). Low lymphocyte count was related to mortality and poor outcome (p < 0.001). Lymphocyte counts <0.703 × 10⁹ cells/L at diagnosis (area under the curve (AUC)-ROC, 0.783 ± 0.042; 95% confidence interval (CI), 0.700-0.867, p < 0.001), and lymphocyte count <1.272 × 10⁹ cells/L five days later (AUC-ROC, 0.791 ± 0.038; 95%CI, 0.716-0.866, p < 0.001) increased the odds of mortality five-fold (odds ratio (OR), 5.01; 95%CI, 2.39-10.93) at time of diagnosis, and three-fold (OR, 3.27; 95%CI, 1.24-8.62) by day 5, respectively. Low lymphocyte count is an independent predictor of mortality in patients with candidemia and might serve as a biomarker for predicting candidemia-associated mortality and poor outcome.

Therapeutic potential of thymoquinone liposomes against the systemic infection of Candida albicans in diabetic mice

The present study was aimed to develop a liposomal formulation of thymoquinone (Lip-TQ) to treat Candida albicans infection in diabetic mice. Streptozotocin (STZ) was injected to induce hyperglycemia and on day 3 post STZ administration, mice were intravenously infected with C. albicans. Various doses (2, 5 and 10 mg/kg) of Free or Lip-TQ were administered in C. albicans infected diabetic mice. The effect of Lip-TQ was also determined on the organ indices, liver and kidney function parameters. Lip-TQ at a dose of 10 mg/kg significantly reduced the level of the blood glucose and alleviated the systemic C. albicans infection in diabetic mice. C. albicans infected diabetic mice treated with Lip-TQ at a dose of 10 mg/kg showed the survival rate of 70% as compared to that of 20% in the group treated with free TQ. The treatment with Lip-TQ resulted in the recovery of the organ indices, liver inflammation, kidney functioning and pancreas regeneration in diabetic mice. Moreover, TQ formulations also showed the direct therapeutic effect against candidiasis in the untreated or metformin-treated diabetic mice. Therefore, the findings of the present study support the use of Lip-TQ in the treatment of candidiasis in the diabetic patients.

Influence of phosphatidylserine and phosphatidylethanolamine on farnesol tolerance in Candida albicans

Candida albicans is among the most common human fungal pathogens. The ability to undergo the morphological transition from yeast to hyphal growth is critical for its pathogenesis. Farnesol, a precursor in the isoprenoid/sterol pathway, is a quorum-sensing molecule produced by C. albicans that inhibits hyphal growth in this polymorphic fungus. Interestingly, C. albicans can tolerate farnesol concentrations that are toxic to other fungi. We hypothesized that changes in phospholipid composition are one of the factors contributing to farnesol tolerance in C. albicans. In this study, we found that loss of enzymes that synthesize the phospholipids phosphatidylserine (PS) and/or phosphatidylethanolamine (PE) compromise the tolerance of C. albicans to farnesol. Compared with wild type, the phospholipid mutant cho1∆/∆ (loss of PS and decreased PE synthesis) shows greater inhibition of growth, loss of ATP production, increased consumption of oxygen, and increased formation of reactive oxygen species in the presence of farnesol. The cho1∆/∆ mutant also exhibits decreased sensitivity to mitochondrial ATPase inhibition, suggesting that cells lacking PS and/or downstream PE rely less on mitochondrial function for ATP synthesis. These data reveal that PS and PE play roles in farnesol tolerance and maintaining mitochondrial respiratory function.

Extracellular proteinases of Candida species pathogenic yeasts

The increased incidence of severe disseminated infections caused by the opportunistic yeast-like fungi Candida spp. highlights the urgent need for research into the major virulence factors of these pathogens-extracellular aspartic proteinases of the candidapepsin and yapsin families. Classically, these enzymes were considered to be generally destructive factors that damage host tissues and provide nutrients for pathogen propagation. However, in recent decades, novel and more specific functions have been suggested for extracellular candidal proteinases. These include contributions to cell wall maintenance and remodeling, the formation of polymicrobial biofilms, adhesion to external protective barriers of the host, the deregulation of host proteolytic cascades (such as the complement system, blood coagulation and the kallikrein-kinin system), a dysregulated host proteinase-inhibitor balance, the inactivation of host antimicrobial peptides, evasion of immune responses and the induction of inflammatory mediator release from host cells. Only a few of these activities recognized in Candida albicans candidapepsins have been also confirmed in other Candida species, and characterization of Candida glabrata yapsins remains limited.

Antifungal Compounds against Candida Infections from Traditional Chinese Medicine

Infections caused by Candida albicans, often refractory and with high morbidity and mortality, cause a heavy burden on the public health while the current antifungal drugs are limited and are associated with toxicity and resistance. Many plant-derived molecules including compounds isolated from traditional Chinese medicine (TCM) are reported to have antifungal activity through different targets such as cell membrane, cell wall, mitochondria, and virulence factors. Here, we review the recent progress in the anti-Candida compounds from TCM, as well as their antifungal mechanisms. Considering the diverse targets and structures, compounds from TCM might be a potential library for antifungal drug development.

An Update on Candida tropicalis Based on Basic and Clinical Approaches

Candida tropicalis has emerged as one of the most important Candida species. It has been widely considered the second most virulent Candida species, only preceded by C. albicans. Besides, this species has been recognized as a very strong biofilm producer, surpassing C. albicans in most of the studies. In addition, it produces a wide range of other virulence factors, including: adhesion to buccal epithelial and endothelial cells; the secretion of lytic enzymes, such as proteinases, phospholipases, and hemolysins, bud-to-hyphae transition (also called morphogenesis) and the phenomenon called phenotypic switching. This is a species very closely related to C. albicans and has been easily identified with both phenotypic and molecular methods. In addition, no cryptic sibling species were yet described in the literature, what is contradictory to some other medically important Candida species. C. tropicalis is a clinically relevant species and may be the second or third etiological agent of candidemia, specifically in Latin American countries and Asia. Antifungal resistance to the azoles, polyenes, and echinocandins has already been described. Apart from all these characteristics, C. tropicalis has been considered an osmotolerant microorganism and this ability to survive to high salt concentration may be important for fungal persistence in saline environments. This physiological characteristic makes this species suitable for use in biotechnology processes. Here we describe an update of C. tropicalis, focusing on all these previously mentioned subjects.

Functional analysis of selected deletion mutants in Candida glabrata under hypoxia

Increased drug resistance in Candida glabrata (a model non-albicans Candida) calls for the identification of potential molecular targets for the development of effective drugs. Hypoxia (a state of low oxygen) is an important host factor, which affects the virulence of the pathogen and efficacy of drugs. In the present study, in vitro characterization of 13 null mutants of C. glabrata were done under hypoxic condition (1% O₂). These mutants have a major role to play in cellular pathways, viability and pathogenesis (cell wall biosynthesis, ergosterol synthesis, calcium-calcineurin, etc.). The in vitro growth, biofilm formation and susceptibility of biofilm to antifungal drugs of these mutants were compared with the control. Hypoxia reduced the susceptibility of planktonic cells to fluconazole. The mutants ecm33Δ, kre1Δ, rox1Δ, and kre2Δ showed maximum reductions in their biofilm activities (>20%). The selected mutants (upc2BΔ, kre2 Δ, ecm7Δ, rox1 Δ, mid1Δ, ecm33Δ, cch1Δ, kre1Δ) showed reduced biofilm activities (>30%) in the presence of 16 μg ml^-1 fluconazole under hypoxia. Functional analysis revealed that Kre1, Ecm33, Upc2B, Kre2, Ecm7, Cch1, Mid1 and Rox1 can be explored as a potential drug target for developing novel antifungal drugs.

Development of a CRISPR-Cas9 System for Efficient Genome Editing of Candida lusitaniae

Candida lusitaniae is a member of the Candida clade that includes a diverse group of fungal species relevant to both human health and biotechnology. This species exhibits a full sexual cycle to undergo interconversion between haploid and diploid forms. C. lusitaniae is also an emerging opportunistic pathogen that can cause serious bloodstream infections in the clinic and yet has often proven to be refractory to facile genetic manipulations. In this work, we develop a clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated gene 9 (Cas9) system to enable genome editing of C. lusitaniae. We demonstrate that expression of CRISPR-Cas9 components under species-specific promoters is necessary for efficient gene targeting and can be successfully applied to multiple genes in both haploid and diploid isolates. Gene deletion efficiencies with CRISPR-Cas9 were further enhanced in C. lusitaniae strains lacking the established nonhomologous end joining (NHEJ) factors Ku70 and DNA ligase 4. These results indicate that NHEJ plays an important role in directing the repair of DNA double-strand breaks (DSBs) in C. lusitaniae and that removal of this pathway increases integration of gene deletion templates by homologous recombination. The described approaches significantly enhance the ability to perform genetic studies in, and promote understanding of, this emerging human pathogen and model sexual species. IMPORTANCE The ability to perform efficient genome editing is a key development for detailed mechanistic studies of a species. Candida lusitaniae is an important member of the Candida clade and is relevant both as an emerging human pathogen and as a model for understanding mechanisms of sexual reproduction. We highlight the development of a CRISPR-Cas9 system for efficient genome manipulation in C. lusitaniae and demonstrate the importance of species-specific promoters for expression of CRISPR components. We also demonstrate that the NHEJ pathway contributes to non-template-mediated repair of DNA DSBs and that removal of this pathway enhances efficiencies of gene targeting by CRISPR-Cas9. These results therefore establish important genetic tools for further exploration of C. lusitaniae biology.

Multilocus sequence analyses reveal extensive diversity and multiple origins of fluconazole resistance in Candida tropicalis from tropical China

Candida tropicalis is among the most prevalent human pathogenic yeast species, second only to C. albicans in certain geographic regions such as East Asia and Brazil. However, compared to C. albicans, relatively little is known about the patterns of genetic variation in C. tropicalis. This study analyzed the genetic diversity and relationships among isolates of C. tropicalis from the southern Chinese island of Hainan. A total of 116 isolates were obtained from seven geographic regions located across the Island. For each isolate, a total of 2677 bp from six gene loci were sequenced and 79 (2.96%) polymorphic nucleotide sites were found in our sample. Comparisons with strains reported from other parts of the world identified significant novel diversities in Hainan, including an average of six novel sequences (with a range 1 to 14) per locus and 80 novel diploid sequence types. Most of the genetic variation was found within individual strains and there was abundant evidence for gene flow among the seven geographic locations within Hainan. Interestingly, our analyses identified no significant correlation between the diploid sequence types at the six loci and fluconazole susceptibility, consistent with multiple origins of fluconazole resistance in the Hainan population of C. tropicalis.

Candida albicans outbreak associated with total parenteral nutrition in the neonatal unit

BACKGROUND

The most frequently isolated fungi in patients using TPN belongs to the Candida genus. Various infections including venous catheter infections, fungemia, endocarditis and ophthalmitis may be encountered.

OBJECTIVE

Upon growth of Candida in the blood cultures from the pediatric (neonatal) unit of our hospital, a surveillance was performed in this unit and involving the health care workers. Clonal relationships of the isolates were investigated with molecular tests.

METHODS

Blood samples obtained from the patients in pediatric neonatal unit were studied with automatized blood culture [BacT/Alert (Bio Mιrioux, France)]. Yeast isolates from environmental surveillance cultures (TPN solutions, hands of healthcare personnel, ιtagθre, etc) and patients were identified as C. albicans with conventional methods and ID 32 C and ATB TM Fungus 3 (Biomerieux, France) kits. Clonal similarity was determined by using AP-PCR as initial method and we have also typified all strains by the method of REP-PCR (diversilab system,bioMιrieux). Finally; Pulsed Field Gel Electrophoresis (PFGE) was used for confirmation.

RESULTS

C. albicans was isolated in blood cultures of seven patients. Similar antifungal susceptibility patterns were observed in all isolates. AP-PCR and REP-PCR showed that the C. albicans isolates grown in the TPN solution and from the patients' blood cultures were clonally same strains. PFGE analysis further confirmed this clonality.

CONCLUSION

According to results of the molecular methods, we thought that a C. albicans outbreak had occurred in the neonatal pediatric unit, due to contamination of TPN solution.

Siderophores; iron scavengers: the novel & promising targets for pathogen specific antifungal therapy

INTRODUCTION

The recent emergence of resistance, toxicity paradigm and limited efficacy of conventional antifungal drugs necessitate the identification of de novo targets in fungal metabolism. One of the most critical physiological processes during in vivo pathogenesis is maintenance of iron homeostasis. The most life threatening opportunistic human fungal pathogens like Aspergillus, Candida and Cryptococcus exploit the siderophore mediated iron uptake mechanism either for survival, virulence, propagation or resistance to oxidative stress envisaged in vivo during infection. Areas covered: In this review, we will highlight the metabolic pathways; specifically siderophore biosynthesis, uptake and utilisation, triggered in the fungal pathogens in iron starving conditions and the various putative targets viable in these pathways to be recruited as novel therapeutic antidotes either via biosynthetic enzymes catalytic site inhibitors or as drug conjugates through trojan horse approach and further role in the development of fungal specific reliable diagnostic markers. Expert opinion: Siderophores are the weapons released by a pathogen to conquer the battle for iron acquisition. Hence, the fungal siderophore biosynthetic pathways along with their uptake and utilisation mechanisms represent an ideal target for pathogen specific, host friendly therapeutic strategy which would block the proliferation of parasite without causing any harm to the mammalian host.

Epidemiology of Blood Stream Infection due to Candida Species in a Tertiary Care Hospital in Japan over 12 Years: Importance of Peripheral Line-Associated Candidemia

BACKGROUND

Candidemia is an important cause of mortality in healthcare settings. Peripheral lines are a source of candidemia, yet few studies have reported on the clinico-epidemiological features of candidemia due to peripheral-line associated blood stream infection (PLABSI).

METHODS

We conducted a single-centre retrospective cohort study of all patients with candidemia between 2002 and 2013. PLABSI was defined as the presence of at least one of the following: the presence of phlebitis or the resolution of clinical symptoms after peripheral-line withdrawal, with careful exclusion of an alternative explanation for bacteraemia. We described the epidemiology of candidemia and assessed predictive factors of PLABSI due to Candida spp., peripheral line-associated candidemia (PLAC), compared with non-PLAC.

RESULTS

A total of 301 episodes of candidemia, including 37 of PLAC, were diagnosed during the study period. Central-line associated blood stream infection, intra-abdominal infection, and infection of unknown source accounted for the remaining 233, 14, and 17 cases, respectively. The overall incidence rate of candidemia was 0.11/1000 patient-days. In multivariate analysis, cephalosporin exposure (odds ratio [OR] = 2.22, 95% CI 1.04-4.77), polymicrobial bacteraemia/fungaemia (OR = 2.87, 95% CI 1.02-8.10), and ID specialist consultation (OR = 2.40, 95% CI 1.13-5.13) were identified as independent predictors of PLAC. Although non-PLAC had a higher mortality, the length of hospital stay after candidemia was similar between the two groups and candidemia duration was longer in the PLAC group.

CONCLUSION

PLACs are an important cause of candidemia in hospitalized patients. Appropriate identification and management of PLAC are crucial.

The Candida Genome Database (CGD): incorporation of Assembly 22, systematic identifiers and visualization of high throughput sequencing data

The Candida Genome Database (CGD, http://www.candidagenome.org/) is a freely available online resource that provides gene, protein and sequence information for multiple Candida species, along with web-based tools for accessing, analyzing and exploring these data. The mission of CGD is to facilitate and accelerate research into Candida pathogenesis and biology, by curating the scientific literature in real time, and connecting literature-derived annotations to the latest version of the genomic sequence and its annotations. Here, we report the incorporation into CGD of Assembly 22, the first chromosome-level, phased diploid assembly of the C. albicans genome, coupled with improvements that we have made to the assembly using additional available sequence data. We also report the creation of systematic identifiers for C. albicans genes and sequence features using a system similar to that adopted by the yeast community over two decades ago. Finally, we describe the incorporation of JBrowse into CGD, which allows online browsing of mapped high throughput sequencing data, and its implementation for several RNA-Seq data sets, as well as the whole genome sequencing data that was used in the construction of Assembly 22.

Study of the prevalence and association of ocular chlamydial conjunctivitis in women with genital infection by Chlamydia trachomatis, Mycoplasma genitalium and Candida albicans attending outpatient clinic

AIM

To determine the association between chlamydial conjunctivitis and genital infection by Chlamydia trachomatis, Mycoplasma genitalium and Candida albicans, in addition to the possible relationship between cultured bacterial pathogens and oculogenital chlamydial infection.

METHODS

This study was performed on 100 (50 symptomatic and 50 asymptomatic) women attending the Gynecological and Obstetric outpatient clinic of Alzahra hospital, Alazhar University. Simultaneously a conjunctival swab was taken from these patients. Polymerase chain reaction (PCR) was done on DNA extracted from both vaginal and conjunctival swab samples. Culture for both vaginal and conjunctival swabs was also done.

RESULTS

Candida albicans was the predominant organism isolated by culture in 20% and 40% of conjunctival and vaginal swabs respectively. By the PCR method, ocular Chlamydia trachomatis was present in 60% of symptomatic women, while genital Chlamydia trachomatis infection was present in 30% of symptomatic women. The results of this method also indicated that 25/50 (50%) vaginal swabs were positive with PCR for Candida albicans versus 15/50 (30%) were PCR positive in conjunctival swab. Mycoplasma genitalium was present in only 10% of vaginal swabs. Concomitant oculogenital PCR positive results for Chlamydia trachomatis and Candida albicans were 30% and 28% respectively.

CONCLUSION

Ocular Chlamydia trachomatis was associated with genital Chlamydia trachomatis in a high percentage of women followed by Candida albicans. Cultured bacterial organisms do not play a role in enhancement of Chlamydia trachomatis infection.

Antifungal Activity of Cinnamon Oil and Olive Oil against Candida Spp. Isolated from Blood Stream Infections

INTRODUCTION

Recently non-albicans Candida has emerged as a major cause of morbidity and mortality in blood stream infections. Some species of the Candida are becoming increasingly resistant to first line and second line antifungals such as echinocandins and fluconazole. In view of increasing global antifungal resistance, role of alternative and better antifungals like natural plant products need to be explored. Essential oils are known to exhibit antimicrobial activity against various fungi. Hence, we evaluated the efficacy of cinnamon oil and olive oil against Candida spp.

AIM

To evaluate the invitro antifungal activity of olive oil and cinnamon oil against blood stream Candida isolates.

MATERIALS AND METHODS

The present prospective observational study was conducted in the Department of Microbiology at a tertiary care teaching hospital during one year June 2011-July 2012. Blood samples were collected from 1376 patients clinically suspected to have fungal septicaemia, out of which 100 (7.2%) Candida isolates obtained, were speciated by conventional methods. Antifungal susceptibility testing of all the isolates was done against fluconazole, voriconazole as per NCCL (M27-A2) and against olive oil and cinnamon oil by agar well diffusion method.

RESULTS

Prevalence of Candidemia was 7.26%. C. albicans (85.3%) and C. parapsilosis (85.7%) were most sensitive to fluconazole followed by C. tropicalis (67.4%). All isolates were 100% sensitive to voriconazole. Both oils were found to be effective against nearly 50% of the Candida isolates. About 55.5% of fluconazole resistant C. krusei strains were sensitive to olive and cinnamon oil.

CONCLUSION

Fluconazole resistant non-albicans Candida has emerged as major cause of Candidemia. Cinnamon and olive oil show marked sensitivity against albicans and non-albicans spp.

Antifungal Properties of Cationic Phenylene Ethynylenes and Their Impact on β-Glucan Exposure

Candida species are the cause of many bloodstream infections through contamination of indwelling medical devices. These infections account for a 40% mortality rate, posing a significant risk to immunocompromised patients. Traditional treatments against Candida infections include amphotericin B and various azole treatments. Unfortunately, these treatments are associated with high toxicity, and resistant strains have become more prevalent. As a new frontier, light-activated phenylene ethynylenes have shown promising biocidal activity against Gram-positive and -negative bacterial pathogens, as well as the environmental yeast Saccharomyces cerevisiae In this study, we monitored the viability of Candida species after treatment with a cationic conjugated polymer [poly(p-phenylene ethynylene); PPE] or oligomer ["end-only" oligo(p-phenylene ethynylene); EO-OPE] by flow cytometry in order to explore the antifungal properties of these compounds. The oligomer was found to disrupt Candida albicans yeast membrane integrity independent of light activation, while PPE is able to do so only in the presence of light, allowing for some control as to the manner in which cytotoxic effects are induced. The contrast in killing efficacy between the two compounds is likely related to their size difference and their intrinsic abilities to penetrate the fungal cell wall. Unlike EO-OPE-DABCO (where DABCO is quaternized diazabicyclo[2,2,2]octane), PPE-DABCO displayed a strong propensity to associate with soluble β-glucan, which is expected to inhibit its ability to access and perturb the inner cell membrane of Candida yeast. Furthermore, treatment with PPE-DABCO unmasked Candida albicans β-glucan and increased phagocytosis by Dectin-1-expressing HEK-293 cells. In summary, cationic phenylene ethynylenes show promising biocidal activity against pathogenic Candida yeast cells while also exhibiting immunostimulatory effects.

The identification and differentiation of the Candida parapsilosis complex species by polymerase chain reaction-restriction fragment length polymorphism of the internal transcribed spacer region of the rDNA

Currently, it is accepted that there are three species that were formerly grouped under Candida parapsilosis: C. para- psilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. In fact, the antifungal susceptibility profiles and distinct virulence attributes demonstrate the differences in these nosocomial pathogens. An accurate, fast, and economical identification of fungal species has been the main goal in mycology. In the present study, we searched sequences that were available in the GenBank database in order to identify the complete sequence for the internal transcribed spacer (ITS)1-5.8S-ITS2 region, which is comprised of the forward and reverse primers ITS1 and ITS4. Subsequently, an in silico polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to differentiate the C. parapsilosis complex species. Ninety-eight clinical isolates from patients with fungaemia were submitted for analysis, where 59 isolates were identified as C. parapsilosis sensu stricto, 37 were identified as C. orthopsilosis, and two were identified as C. metapsilosis. PCR-RFLP quickly and accurately identified C. parapsilosis complex species, making this method an alternative and routine identification system for use in clinical mycology laboratories.

Management of Candida biofilms: state of knowledge and new options for prevention and eradication

Biofilms formed by Candida species (spp.) on medical devices represent a potential health risk. The focus of current research is searching for new options for the treatment and prevention of biofilm-associated infections using different approaches including modern nanotechnology. This review summarizes current information concerning the most relevant resistance/tolerance mechanisms to conventional drugs and a role of additional factors contributing to these phenomena in Candida spp. (mostly Candida albicans). Additionally, it provides an information update in prevention and eradication of a Candida biofilm including experiences with 'lock' therapy, potential utilization of small molecules in biomedical applications, and perspectives of using photodynamic inactivation in the control of a Candida biofilm.

Aging does not affect the ability of human monocyte-derived dendritic cells to phagocytose Candida albicans

BACKGROUND

Dendritic cells (DCs) are the most potent antigen-presenting cells, playing a key role in induction of both innate and adaptive immunity. Immunosenescence refers to age-associated changes in the immune system, which may be associated with susceptibility to infections and their clinical complications. The precise effects of aging on DCs in immunity to infections are not well understood. Among the common pathogenic microorganisms, the fungus Candida albicans is an important pathogen for the development of invasive infections, especially in immunocompromised individuals, as well as during aging.

AIMS

To make a comparative in vitro evaluation of the immunomodulatory function of DCs challenged with C. albicans, by phagocytosis of the fungal cells, and determine the involvement of TLR2 and TLR4 receptors. For this purpose, DCs were generated with the use of peripheral blood monocytes from healthy young and aged subjects.

RESULTS

The phagocytosis of C. albicans is developed by DCs in TLR2- and TLR4-dependent way. This mechanism is not affected by aging.

CONCLUSION

Given the important role of the DCs in responses against the fungus, it is evident that if changes in phagocytosis occurred with aging, impairment in the elderly could develop. However, the evidence that phagocytosis of this fungus by DCs is not impaired with aging, brings us to the question of which are the mechanisms truly associated with the prevalence of certain diseases in the elderly.

Biological Activity of Recently Discovered Halogenated Marine Natural Products

This review presents the biological activity-antibacterial, antifungal, anti-parasitic, antiviral, antitumor, antiinflammatory, antioxidant, and enzymatic activity-of halogenated marine natural products discovered in the past five years. Newly discovered examples that do not report biological activity are not included.

Csr1/Zap1 Maintains Zinc Homeostasis and Influences Virulence in Candida dubliniensis but Is Not Coupled to Morphogenesis

The supply and intracellular homeostasis of trace metals are essential for every living organism. Therefore, the struggle for micronutrients between a pathogen and its host is an important determinant in the infection process. In this work, we focus on the acquisition of zinc by Candida dubliniensis, an emerging pathogen closely related to Candida albicans. We show that the transcription factor Csr1 is essential for C. dubliniensis to regulate zinc uptake mechanisms under zinc limitation: it governs the expression of the zinc transporter genes ZRT1, ZRT2, and ZRT3 and of the zincophore gene PRA1. Exclusively, artificial overexpression of ZRT2 partially rescued the growth defect of a csr1Δ/Δ mutant in a zinc-restricted environment. Importantly, we found that, in contrast to what is seen in C. albicans, Csr1 (also called Zap1) is not a major regulator of dimorphism in C. dubliniensis. However, although a csr1Δ/Δ strain showed normal germ tube formation, we detected a clear attenuation in virulence using an embryonated chicken egg infection model. We conclude that, unlike in C. albicans, Csr1 seems to be a virulence factor of C. dubliniensis that is not coupled to filamentation but is strongly linked to zinc acquisition during pathogenesis.

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.

A systematic evaluation of high-dimensional, ensemble-based regression for exploring large model spaces in microbiome analyses

BACKGROUND

Microbiome studies incorporate next-generation sequencing to obtain profiles of microbial communities. Data generated from these experiments are high-dimensional with a rich correlation structure but modest sample sizes. A statistical model that utilizes these microbiome profiles to explain a clinical or biological endpoint needs to tackle high-dimensionality resulting from the very large space of variable configurations. Ensemble models are a class of approaches that can address high-dimensionality by aggregating information across large model spaces. Although such models are popular in fields as diverse as economics and genetics, their performance on microbiome data has been largely unexplored.

RESULTS

We developed a simulation framework that accurately captures the constraints of experimental microbiome data. Using this setup, we systematically evaluated a selection of both frequentist and Bayesian regression modeling ensembles. These are represented by variants of stability selection in conjunction with elastic net and spike-and-slab Bayesian model averaging (BMA), respectively. BMA ensembles that explore a larger space of models relative to stability selection variants performed better and had lower variability across simulations. However, stability selection ensembles were able to match the performance of BMA in scenarios of low sparsity where several variables had large regression coefficients.

CONCLUSIONS

Given a microbiome dataset of interest, we present a methodology to generate simulated data that closely mimics its characteristics in a manner that enables meaningful evaluation of analytical strategies. Our evaluation demonstrates that the largest ensembles yield the strongest performance on microbiome data with modest sample sizes and high-dimensional measurements. We also demonstrate the ability of these ensembles to identify microbiome signatures that are associated with opportunistic Candida albicans colonization during antibiotic exposure. As the focus of microbiome research evolves from pilot to translational studies, we anticipate that our strategy will aid investigators in making evaluation-based decisions for selecting appropriate analytical methods.

Candida glabrata and Candida tropicalis in an immunocompetent patient: a case report

OBJECTIVE

To report a case of Candida glabrata and tropicalis pneumonia in an immunocompetent patient.

CASE SUMMARY

A 72-year-old male was transferred from an outside institution due to worsening respiratory status, acute kidney injury secondary to intravenous contrast media, sepsis, and pneumonia with fever and leukocytosis. Upon admission, he was initiated on treatment for hospital-acquired pneumonia, but was also concomitantly tested for many other opportunistic infections due to his recent month-long trip to Ecuador where he participated in a tribal treatment for neuropathy that involved direct exposure to dead guinea pigs. With completion of cultures and bronchoalveolar lavage, C. glabrata was identified in the blood culture and C. glabrata and C. tropicalis in the bronchoalveolar lavage specimen. One month later, he was admitted due to recurrent pneumonia. The patient unfortunately expired during the second admission, due to complications from chronic respiratory pulmonary disease and pneumonia.

DISCUSSION

Initially, this patient was treated for hospital-acquired pneumonia, but due to a recent trip to Ecuador, it was soon discovered that this patient had developed an invasive Candida pneumonia. His pulmonary biopsies showed growth of invasive C. glabrata and C. tropicalis, while his blood culture showed C. glabrata. Candida-related lower respiratory tract infections are exceptionally rare in immunocompetent patients and require histopathologic evidence to confirm the diagnosis. A second blood culture showed that the C. glabrata was still present and the patient had worsening leukocytosis, so micafungin was added to his antimicrobial therapy.

CONCLUSION

It is understood that pneumonia is rarely caused by Candida species in patients who are admitted to the hospital. However, health care professionals should be aware that Candida pneumonia should be suspected as part of the differential diagnosis even in immunocompetent patients, particularly if they have recently traveled outside the United States.

Cutaneous, Subcutaneous and Systemic Mycology

The first description of dermatophytosis was recorded by Celsus, a Roman encyclopaedist who described a suppurative infection of scalp (‘porrigo’ or ‘kerion of Celsus’) in De Re Medicina (30 A.D.). Throughout the middle ages, several descriptions of dermatophytosis were produced where it is described as ‘tinea’. The keratin-destroying moths which made circular holes in the woollen garments are known as Tinea. Due to similarity in the structure of circular lesion of dermatophytosis on the smooth skin with the circular hole made by moth, Cassius Felix introduced the term ‘tinea’ to describe the lesions. In 1806, Alibert used the term ‘favus’ to describe the honey-like exudate in some scalp infections. However, the fungal aetiology of tinea was first detected by Robert Remak, a Polish physician who first observed the presence of hyphae in the crusts of favus. This detection is also a landmark in medical history because this is the first description of a microbe causing a human disease. He himself did not publish his work, but he permitted the reference of his observations in a dissertation by Xavier Hube in 1837. Remak gave all the credits of his discovery to his mentor Schoenlein who first published the fungal etiological report of favus in 1839. He observed the infectious nature of the favus by autoinoculation into his own hands and also successfully isolated the fungus later (1945) and named Achorion schoenleinii (Trichophyton schoenleinii) in honour of his mentor. In 1844, Gruby described the etiologic agent of tinea endothrix, later became known as Trichophyton tonsurans. The genus Trichophyton was created and described by Malmsten (1845) with its representative species T. tonsurans. Charles Robin identified T. mentagrophytes in 1847 and T. equinum was identified by Matruchot and Dassonville in 1898. Raymond Jacques Adrien Sabouraud (France) first compiled the description of Trichophyton in his book (Les Teignes) in 1910 which was based on his observation in artificial culture. The sexual state of dermatophyte was described by Nannizzi (1927). Emmons (1934) first reported the classification of dermatophytes based on vegetative structures and conidia. Gentles (1958) established the successful treatment of tinea capitis with griseofulvin.

Forazoline A: marine-derived polyketide with antifungal in vivo efficacy

Forazoline A, a novel antifungal polyketide with in vivo efficacy against Candida albicans, was discovered using LCMS-based metabolomics to investigate marine-invertebrate-associated bacteria. Forazoline A had a highly unusual and unprecedented skeleton. Acquisition of (13)C-(13)C gCOSY and (13)C-(15)N HMQC NMR data provided the direct carbon-carbon and carbon-nitrogen connectivity, respectively. This approach represents the first example of determining direct (13)C-(15)N connectivity for a natural product. Using yeast chemical genomics, we propose that forazoline A operated through a new mechanism of action with a phenotypic outcome of disrupting membrane integrity.

Candida albicans endophthalmitis in a patient with a non-functioning pituitary adenoma evolving into Cushing׳s disease: A case report

A 53-year-old woman presented with complaints of blurred vision in the left eye. She had been treated for recurrent non-functioning pituitary adenoma (NFPA). A vitreous biopsy followed by histopathologic examination showed the presence of Candida albicans. Meanwhile, Cushing׳s disease was diagnosed and gamma knife surgery was performed. Vitrectomy and antifungal treatment improved ocular infection and inflammation. Herein, we describe the first case of C. albicans endophthalmitis in a patient with NFPA evolving into Cushing׳s disease.