The global epidemiology of invasive Candida infections—is the tide turning?

Diagnosis and Treatment Challenges of Candida guilliermondii in Immunocompromised Patients: A Case Study in a Neutropenic AML Patient

Although fungal infections causing intestinal perforation and necrosis are rare, they can be particularly dangerous in immunosuppressed patients, often leading to increased mortality rates and poor prognoses. Candida species are typically surface fungi, but in patients with compromised immune systems, they can invade the small intestine and cause angioinvasive infections. A case study involving a 30-year-old female with acute myeloid leukemia (AML) illustrates this phenomenon. The patient was presented with symptoms of abdominal pain, fever, diarrhea, recurrent episodes of intestinal necrosis, hematomas due to thrombocytopenia, and subsequent postoperative enterocutaneous fistulas. Extensive testing ruled out other possible causes of intestinal necrosis and enteritis, including Crohn's and CMV diseases. Candida guilliermondi was ultimately identified in blood cultures from the periphery, peritoneal fluid, and intestinal biopsy of respected sections, indicating that it was responsible for intestinal invasion and necrosis. The patient was then treated with amphotericin B, cefepime, and metronidazole. This case highlights the potential severity of fungal infections in immunosuppressed patients, particularly Candida species, and the importance of prompt diagnosis and appropriate treatment.

Non-traditional approaches for control of antibiotic resistance

INTRODUCTION

The drying up of antibiotic pipeline has necessitated the development of alternative therapeutic strategies to control the problem of antimicrobial resistance (AMR) that is expected to kill 10-million people annually by 2050. Newer therapeutic approaches address the shortcomings of traditional small-molecule antibiotics - the lack of specificity, evolvability, and susceptibility to mutation-based resistance. These 'non-traditional' molecules are biologicals having a complex structure and mode(s) of action that makes them resilient to resistance.

AREAS COVERED

This review aims to provide information about the non-traditional drug development approaches to tackle the problem of antimicrobial resistance, from the pre-antibiotic era to the latest developments. We have covered the molecules under development in the clinic with literature sourced from reviewed scholarly articles, official company websites involved in innovation of concerned therapeutics, press releases from the regulatory bodies, and clinical trial databases.

EXPERT OPINION

Formal introduction of non-traditional therapies in general practice can be quick and feasible only if supported with companion diagnostics and used in conjunction with established therapies. Owing to relatively higher development costs, non-traditional therapeutics require more funding as well as well as clarity in regulatory and clinical path. We are hopeful these issues are adequately addressed before AMR develops into a pandemic.

Early Empirical Anidulafungin Reduces the Prevalence of Invasive Candidiasis in Critically Ill Patients: A Case-control Study

Introduction

Invasive candidiasis (IC) in critically ill patients is a serious infection with high rate of mortality. As an empirical therapy, like antibiotics, the use of antifungals is not common in intensive care units (ICUs) worldwide. The empirical use of echinocandins including anidulafungin is a recent trend.

Aim of the study

The objective of this study was to assess the impact of empirical anidulafungin in the development of invasive candidiasis in critically ill patients in ICU.

Methods

This retrospective case-control study was conducted on 149 patients with sepsis with/without septic shock and bacterial pneumonia. All the patients were divided into two groups. The ‘control group’ termed as ‘NEAT group’ received no empirical anidulafungin therapy and the ‘treated group’ termed as ‘EAT group’ received empirical anidulafungin therapy in early hospitalization hours.

Results

Seventy-two and 77 patients were divided into the control and the treated group, respectively. Patients in EAT group showed less incidences of IC (5.19%) than that of the NEAT group (29.17%) (p = 0.001). Here, the relative risk (RR) was 0.175 (95% CI, 0.064-0.493) and the risk difference (RD) rate was 24% (95% CI, 12.36%-35.58%). The 30-day all-cause mortality rate in NEAT group was higher (19.44%) than that of in EAT group (10.39%) (p = 0.04). Within the first 10-ICU-day, patients in the EAT group left ICU in higher rate (62.34%) than that in the NEAT group (54.17%).

Conclusion

Early empirical anidulafungin within 6 h of ICU admission reduced the risk of invasive candidiasis, 30-day all-cause mortality rate and increased ICU leaving rate within 10-day of ICU admission in critically ill patients.

In vivo active organometallic-containing antimycotic agents

Fungal infections represent a global problem, notably for immunocompromised patients in hospital, COVID-19 patient wards and care home settings, and the ever-increasing emergence of multidrug resistant fungal strains is a sword of Damocles hanging over many healthcare systems. Azoles represent the mainstay of antifungal drugs, and their mode of action involves the binding mode of these molecules to the fungal lanosterol 14α-demethylase target enzyme. In this study, we have prepared and characterized four novel organometallic derivatives of the frontline antifungal drug fluconazole (1a-4a). Very importantly, enzyme inhibition and chemogenomic profiling demonstrated that lanosterol 14α-demethylase, as for fluconazole, was the main target of the most active compound of the series, (N-(ferrocenylmethyl)-2-(2,4-difluorophenyl)-2-hydroxy-N-methyl-3-(1H-1,2,4-triazol-1-yl)propan-1-aminium chloride, 2a). Transmission electron microscopy (TEM) studies suggested that 2a induced a loss in cell wall integrity as well as intracellular features ascribable to late apoptosis or necrosis. The impressive activity of 2a was further confirmed on clinical isolates, where antimycotic potency up to 400 times higher than fluconazole was observed. Also, 2a showed activity towards azole-resistant strains. This finding is very interesting since the primary target of 2a is the same as that of fluconazole, emphasizing the role played by the organometallic moiety. In vivo experiments in a mice model of Candida infections revealed that 2a reduced the fungal growth and dissemination but also ameliorated immunopathology, a finding suggesting that 2a is active in vivo with added activity on the host innate immune response.

Computational Drug Repurposing Resources and Approaches for Discovering Novel Antifungal Drugs against Candida albicans N-Myristoyl Transferase

Candida albicans is a yeast that is an opportunistic fungal pathogen and also identified as ubiquitous polymorphic species that is mainly linked with major fungal infections in humans, particularly in the immunocompromised patients including transplant recipients, chemotherapy patients, HIV-infected patients as well as in low-birth-weight infants. Systemic Candida infections have a high mortality rate of around 29 to 76%. For reducing its infection, limited drugs are existing such as caspofungin, fluconazole, terbinafine, and amphotericin B, etc. which contain unlikable side effects and also toxic. This review intends to utilize advanced bioinformatics technologies such as Molecular docking, Scaffold hopping, Virtual screening, Pharmacophore modeling, Molecular dynamics (MD) simulation for the development of potentially new drug candidates with a drug-repurpose approach against Candida albicans within a limited time frame and also cost reductive.

Molecular Docking and QSAR Studies of Coumarin Derivatives as NMT Inhibitors: Simple Structural Features as Potential Modulators of Antifungal Activity

Background:

Treatments of fungal diseases, including Candidiasis, remain not up to scratch in spite of the mounting catalog of synthetic antifungal agents. These have served as the impetus for investigating new antifungal agents based on natural products. Consequently, genetic algorithm-multiple linear regression (GA-MLR) based QSAR (Quantitative Structure-Activity Relationship) studies of coumarin analogues along with molecular docking were carried out.

Methods:

Coumarin analogues with their MIC values were used to generate the training and test sets of compounds for QSAR models development; the analogues were also docked into the binding pocket of NMT (MyristoylCoA: protein N-myristoyltransferase).

Results and Discussion:

The statistical parameters for internal and external validation of QSAR analysis (R2 = 0.830, Q2 = 0.758, R2Pred = 0.610 and R2m overall = 0.683 ), Y Randomization, Ridge trace, VIF, tolerance and model criteria of Golbraikh and Tropsha data illustrate the robustness of the best proposed QSAR model. Most of the analogues bind to the electrostatic, hydrophobic clamp and display hydrogen bonding with amino acid residues of NMT. Interestingly, the most active coumarin analogue (MolDock score of -189.257) was docked deeply within the binding pocket of NMT, thereby displaying hydrogen bonding with Tyr107, Leu451, Leu450, Gln226, Cys393 and Leu394 amino acid residues.

Conclusion:

The combinations of descriptors from various descriptor subsets in QSAR analysis have highlighted the role of atomic properties such as polarizability and atomic van der Waals volume to explain the inhibitory activity. The models and related information may pave the way for important insight into the designing of putative NMT inhibitors for Candida albicans.

The Yin and Yang of Current Antifungal Therapeutic Strategies: How Can We Harness Our Natural Defenses?

Fungal infections have aroused much interest over the last years because of their involvement in several human diseases. Immunocompromission due to transplant-related therapies and malignant cancer treatments are risk factors for invasive fungal infections, but also aggressive surgery, broad-spectrum antibiotics and prosthetic devices are frequently associated with infectious diseases. Current therapy is based on the administration of antifungal drugs, but the occurrence of resistant strains to the most common molecules has become a serious health-care problem. New antifungal agents are urgently needed and it is essential to identify fungal molecular targets that could offer alternatives for development of treatments. The fungal cell wall and plasma membrane are the most important structures that offer putative new targets which can be modulated in order to fight microbial infections. The development of monoclonal antibodies against new targets is a valid therapeutic strategy, both to solve resistance problems and to support the immune response, especially in immunocompromised hosts. In this review, we summarize currently used antifungal agents and propose novel therapeutic approaches, including new fungal molecular targets to be considered for drug development.

Epidemiology and Clinical Features of Invasive Fungal Infection in a US Health Care Network

Background

A better understanding of the epidemiology and clinical features of invasive fungal infection (IFI) is integral to improving outcomes. We describe a novel case-finding methodology, reporting incidence, clinical features, and outcomes of IFI in a large US health care network.

Methods

All available records in the Intermountain Healthcare Enterprise Data Warehouse from 2006 to 2015 were queried for clinical data associated with IFI. The resulting data were overlaid in 124 different combinations to identify high-probability IFI cases. The cohort was manually reviewed, and exclusions were applied. European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group Consensus Group definitions were adapted to categorize IFI in a broad patient population. Linear regression was used to model variation in incidence over time.

Results

A total of 3374 IFI episodes occurred in 3154 patients. The mean incidence was 27.2 cases/100 000 patients per year, and there was a mean annual increase of 0.24 cases/100 000 patients (P = .21). Candidiasis was the most common (55%). Dimorphic fungi, primarily Coccidioides spp., comprised 25.1% of cases, followed by Aspergillus spp. (8.9%). The median age was 55 years, and pediatric cases accounted for 13%; 26.1% of patients were on immunosuppression, 14.9% had autoimmunity or immunodeficiency, 13.3% had active malignancy, and 5.9% were transplant recipients. Lymphopenia preceded IFI in 22.1% of patients. Hospital admission occurred in 76.2%. The median length of stay was 16 days. All-cause mortality was 17.0% at 42 days and 28.8% at 1 year. Forty-two-day mortality was highest in Aspergillus spp. (27.5%), 20.5% for Candida, and lowest for dimorphic fungi (7.5%).

Conclusions

In this population, IFI was not uncommon, affected a broad spectrum of patients, and was associated with high crude mortality.

Helminth eggs as parasitic indicators of fecal contamination in agricultural irrigation water, biosolids, soils and pastures

INTRODUCTION

A very common practice in agriculture is the disposal of wastewater and biosolids from water treatment systems due to their high nutrient content, which substantially improves crop yields. However, the presence of pathogens of fecal origin creates a sanitary risk to farmers and consumers.

OBJECTIVE

To determine the presence and concentration of helminth eggs in irrigation waters, biosolids, agricultural soils, and pastures.

MATERIALS AND METHODS

Water, biosolids, soil, and pasture samples were collected and analyzed for helminth egg detection, total eggs and viable eggs counts. The behavior of helminth eggs was evaluated in irrigation waters and dairy cattle grassland, where biosolids had been used as an organic amendment.

RESULTS

Concentrations between 0.1-3 total helminth eggs/L, and 0.1-1 viable helminth eggs/L were found in water. In biosolids and soil, we found 3-22 total helminth eggs/4 g of dry weight, and 2-12 viable helminth eggs/4 g of dry weight, and in grass, we found <2-9 total helminth eggs/g of fresh weight, and <1-3 viable helminth eggs/g of fresh weight. The presence of helminth eggs in each matrix varied from days to months, which may represent a sanitary risk to farmers as well as to consumers.

CONCLUSIONS

The presence of helminth eggs in the assessed matrixes confirms the sanitary risk of such practices. Therefore, it is important to control and incorporate regulations related to the use of wastewater and biosolids in agriculture.

Vitamin D and Infectious Diseases: Simple Bystander or Contributing Factor?

Vitamin D (VD) is a fat-soluble steroid essential for life in higher animals. It is technically a pro-hormone present in few food types and produced endogenously in the skin by a photochemical reaction. In recent decades, several studies have suggested that VD contributes to diverse processes extending far beyond mineral homeostasis. The machinery for VD production and its receptor have been reported in multiple tissues, where they have a pivotal role in modulating the immune system. Similarly, vitamin D deficiency (VDD) has been in the spotlight as a major global public healthcare burden. VDD is highly prevalent throughout different regions of the world, including tropical and subtropical countries. Moreover, VDD may affect host immunity leading to an increased incidence and severity of several infectious diseases. In this review, we discuss new insights on VD physiology as well as the relationship between VD status and various infectious diseases such as tuberculosis, respiratory tract infections, human immunodeficiency virus, fungal infections and sepsis. Finally, we critically review the latest evidence on VD monitoring and supplementation in the setting of infectious diseases.

Topographical and physiological differences of the skin mycobiome in health and disease

Skin constantly encounters external elements, including microbes. Culture-based studies have identified fungi present on human skin and have linked some species with certain skin diseases. Moreover, modern medical treatments, especially immunosuppressants, have increased the population at risk for cutaneous and invasive fungal infections, emphasizing the need to understand skin fungal communities in health and disease. A major hurdle for studying fungal flora at a community level has been the heterogeneous culture conditions required by skin fungi. Recent advances in DNA sequencing technologies have dramatically expanded our knowledge of the skin microbiome through culture-free methods. This review discusses historical and recent research on skin fungal communities - the mycobiome - in health and disease, and challenges associated with sequencing-based mycobiome research.

ZCF32, a fungus specific Zn(II)2 Cys6 transcription factor, is a repressor of the biofilm development in the human pathogen Candida albicans

As a human fungal pathogen, Candida albicans can cause a wide variety of disease conditions ranging from superficial to systemic infections. Many of these infections are caused by an inherent ability of the pathogen to form biofilms on medical devices resulting in high mortality. Biofilms formed by C. albicans are a complex consortium of yeast and hyphal cells embedded in an extracellular matrix and are regulated by a network of transcription factors. Here, we report the role of a novel Zn(II)2-Cys6 binuclear cluster transcription factor, ZCF32, in the regulation of biofilm formation. Global transcriptome analysis reveals that biofilm development is the most altered pathway in the zcf32 null mutant. To delineate the functional correlation between ZCF32 and biofilm development, we determined the set of genes directly regulated by Zcf32. Our data suggests that Zcf32 regulates biofilm formation by repressing the expression of adhesins, chitinases and a significant number of other GPI-anchored proteins. We establish that there is the lesser recruitment of Zcf32 on the promoters of biofilm genes in biofilm condition compared to the planktonic mode of growth. Taking together, we propose that the transcription factor ZCF32 negatively regulates biofilm development in C. albicans.

Binding Sites in the EFG1 Promoter for Transcription Factors in a Proposed Regulatory Network: A Functional Analysis in the White and Opaque Phases of Candida albicans

In Candida albicans the transcription factor Efg1, which is differentially expressed in the white phase of the white-opaque transition, is essential for expression of the white phenotype. It is one of six transcription factors included in a proposed interactive transcription network regulating white-opaque switching and maintenance of the alternative phenotypes. Ten sites were identified in the EFG1 promoter that differentially bind one or more of the network transcription factors in the white and/or opaque phase. To explore the functionality of these binding sites in the differential expression of EFG1, we generated targeted deletions of each of the 10 binding sites, combinatorial deletions, and regional deletions using a Renillareniformis luciferase reporter system. Individually targeted deletion of only four of the 10 sites had minor effects consistent with differential expression of EFG1, and only in the opaque phase. Alternative explanations are considered.

Evaluation of Fluorescent Capillary Electrophoresis for Rapid Identification of Candida Fungal Infections

Early diagnosis of fungal infection is critical for initiating antifungal therapy and reducing the high mortality rate in immunocompromised patients. In this study, we focused on rapid and sensitive identification of clinically important Candida species, utilizing the variability in the length of the ITS2 rRNA gene and fluorescent capillary electrophoresis (f-ITS2-PCR-CE). The method was developed and optimized on 29 various Candida reference strains from which 26 Candida species were clearly identified, while Candida guilliermondii, C. fermentati, and C. carpophila, which are closely related, could not be distinguished. The method was subsequently validated on 143 blinded monofungal clinical isolates (comprising 26 species) and was able to identify 88% of species unambiguously. This indicated a higher resolution power than the classical phenotypic approach which correctly identified 73%. Finally, the culture-independent potential of this technique was addressed by the analysis of 55 retrospective DNA samples extracted directly from clinical material. The method showed 100% sensitivity and specificity compared to those of the combined results of cultivation and panfungal PCR followed by sequencing used as a gold standard. In conclusion, this newly developed f-ITS2-PCR-CE analytical approach was shown to be a fast, sensitive, and highly reproducible tool for both culture-dependent and culture-independent identification of clinically important Candida strains, including species of the "psilosis" complex.

Sedaxicenes: potential new antifungal ferrocene-based agents?

Novel bifunctional organometallic antifungal agents has been designed from an active organic core and added with a metallocene moiety. Their synthesis and promising mycotoxicity has been presented.

Local, systemic, demographic, and health-related factors influencing pathogenic yeast spectrum and antifungal drug administration frequency in oral candidiasis: a retrospective study

OBJECTIVES

In order to identify oral candidiasis patients being at risk of carrying potentially drug-resistant Candida, the aim of the study was to detect local, systemic, demographic, and health-related factors influencing (I) yeast spectrum composition and (II) antifungal administration frequency. Additionally, the aim was to investigate (III) species shift occurrence.

MATERIALS AND METHODS

Data from 798 patients (496 females, 302 males; mean age 59.7) with oral candidiasis diagnosed based on positive clinical and microbial findings (species identification and CFU count) between 2006 and 2011 were retrospectively analyzed using Pearson's chi(2) test and regression analysis.

RESULTS

Among 958 isolates, Candida albicans was the most frequently detected (76.8 %). Also, species intrinsically resistant to azoles were frequently isolated (15.8 and 17.7 % of isolates and patients). (I) Infections only caused by C. albicans were significantly associated with the use of inhalation steroids (p = 0.001) and antibiotics (p = 0.04), super-infection of lichen planus (p = 0.002), and the absence of removable dentures (p < 0.001). (II) Anti-mycotics were significantly more frequently administered in patients using inhalation steroids (p = 0.001), suffering from asthma/COPD, or smoking heavily (p = 0.003) and if C. albicans and non-albicans species were detected together (p = 0.001). (III) Pathogen composition did not change over time within the examined period (p = 0.239).

CONCLUSIONS

Different variables enhance the presence of certain Candida and the antifungal prescription frequency. No species shift was evident.

CLINICAL RELEVANCE

The major pathogen in oral candidiasis remains C. albicans. Nevertheless, therapeutic problems may be caused by the frequent presence of species intrinsically resistant to azoles, especially in patients wearing dentures.

Alterations of serum cytokine levels and their relation with inflammatory markers in candidemia

The roles of CRP, PCT, serum amyloid A (SAA), and cytokines in the diagnosis of fungal infections have not yet been clearly demonstrated. This study aims to measure the serum levels of interleukin (IL)-23, IL-17, IL-1β, tumor necrosis factor (TNF)-α, IL-10, transforming growth factor (TGF)-β, C-reactive protein (CRP), procalcitonin (PCT), and serum amyloid A (SAA) in cases of candidemia and to compare them with those observed in cases of bacteremia. For this purpose, the serum cytokine levels from 50 patients with candidemia were compared with those of 14 patients with polymicrobial sepsis, 30 patients with bacteremia, and 27 healthy control subjects. The cytokine levels were studied using sandwich ELISAs according to the manufacturer protocol. The serum levels of TGF-β, IL-23, and IL-17 were found to be significantly higher in the candidemia group in comparison with the samples from those with bacteremia and healthy controls. The PCT and SAA levels were higher in samples from the group with bacteremia those from individuals with candidemia and the healthy control group. Assuming an IL-17 level threshold of >38.79 pg/ml, the sensitivity and specificity were 38% and 96.6%, respectively but considering an IL-23 threshold of >59.97 pg/ml, the sensitivity and specificity values were found to be 72% and 60%, respectively. The sensitivity and the specificity of the TGF-ß levels were found to be 85.71% and 53.33%, respectively, when the TGF-ß threshold is >560 pg/ml. PCT and SAA demonstrated a superior performance for the differentiation of candidemia and bacteremia. Our study demonstrates that IL-17, IL-23, TGF-ß, PCT, and SAA levels could be a diagnostic marker for candidemia.

Evaluation of blood culture media for the detection of fungi

The aim of this study was to compare the utility of BACTEC™ Mycosis-IC/F (Mycosis), BACTEC™ Plus Aerobic/F (Aerobic), and BACTEC™ Plus Anaerobic/F (Anaerobic) media in the detection of fungi from simulated (obtained by the inoculation of tested media first with sterile sheep's blood and subsequently with one of 60 clinical yeast isolates) and clinical blood samples, taken during routine diagnostic examination in two hospitals. All tested strains grew on Mycosis as well as Aerobic bottles, and the time to detection obtained for Mycosis was significantly shorter (p < 0.05). The largest differences in the time to positivity was found for Candida glabrata and Cryptococcus neoformans, when Mycosis preceded Aerobic in 20-48 h (mean 35.5 h) and 0.7-64 h (mean 24 h), respectively. On the contrary, C. krusei were detected earlier in Aerobic media. In clinical samples, the detection of C. glabrata was also significantly faster in Mycosis than in Aerobic (29.22 ± 11.48 h compared to 86 ± 40 h). The media complement each other and, in 45% of clinical examination sets, a single positive medium was noted (25% in Mycosis and 19% in Aerobic). The study proved that both Aerobic and Mycosis media serve as the correct condition for the culture of fungi and that they varied significantly in the detection time of clinically important species. This result could suggest that the simultaneous use of Aerobic as well as Mycosis media may improve the time of diagnosis in many patients, especially those infected with C. glabrata or C. neoformans.

Candidaemia in a tertiary hospital in Nigeria

Background

Candidaemia is a widely-studied and reviewed topic in the developed world; however, there is a dearth of information on nosocomial candidaemia in Nigeria, despite the increasing use of more invasive therapeutic modalities, immunosuppressive agents and increasing incidence of immunosuppression as a result of malignancies and HIV.

Objectives

To determine the hospital-based frequency of candidaemia in a tertiary hospital in Ibadan, Nigeria.

Method

This was a prospective descriptive study which included 230 immunosuppressed patients. All isolates were identified to the species level using both conventional and automated methods. Thereafter, all Candida species isolated were tested for antifungal susceptibility using the broth microdilution method.

Results

Candidaemia occurred in 12 (5.21%) of the 230 study patients, with C. tropicalis accounting for 50% of the infections. Four patients (33.3%) presented with C. parapsilosis, one (8.3%) with C. albicans and one (8.3%) with a mixed infection of C. albicans and C. tropicalis. All 12 isolates were sensitive to fluconazole (minimal inhibitory concentration < 8 mg/mL). Univariate analysis revealed that old age, multiple surgeries and long-term hospitalisation were significant contributing factors for the occurrence of candidaemia. Eleven (91.7%) of the 12 patients with candidaemia had Candida colonisation of other sterile sites including the bladder, peritoneum and trachea. Furthermore, bivariate analysis revealed that mucositis (p = 0.019) and diarrhoea (p = 0.017) were significantly associated with an increased risk of candidaemia. The crude mortality rate of candidaemia was 91.7%.

Conclusion

This study highlights the significance of nosocomial candidaemia and the need for proactive laboratory investigation and clinical management of this life-threatening disease.

Development of multiplex loop-mediated isothermal amplification assays to detect medically important yeasts in dairy products

Rapid detection of yeast contamination is important in the food industry. We have developed loop-mediated isothermal amplification (LAMP) assays to detect the emerging opportunistic pathogenic yeasts: Candida albicans, Candida glabrata, Candida tropicalis, the Candida parapsilosis group, Trichosporon asahii, and Trichosporon mucoides. These yeasts may cause deep-seated candidiasis or trichosporonosis. Four LAMP primer sets specific for Candida were designed to target the internal transcribed spacer 2 (ITS2) region between the 5.8S and 26S rRNA genes, and two LAMP primer sets specific for Trichosporon were designed to target the intergenic spacer 1 (IGS1) region between the 26S and 5S rRNA genes. The LAMP assays could detect these yeasts in a range between 10(0) and 10(3)  cells mL(-1) in a contaminated dairy product within 1 h. We also developed multiplex LAMP assays to detect these Candida or Trichosporon species in a single reaction. Multiplex LAMP assays can detect contamination if at least one of the target species is present; they are more time- and cost-efficient than conventional methods and could detect target yeasts with sensitivity close to that of the LAMP assays. Multiplex LAMP assays established in this study can be used as a primary screening method for yeast contamination in food products.

In pursuit of the ideal antifungal agent for Candida infections: high-throughput screening of small molecules

Candida infections have created a great burden on the public healthcare sector. The situation is worsened by recent epidemiological changes. Furthermore, the current arsenal of antifungal agents is limited and associated with undesirable drawbacks. Therefore, new antifungal agents that surpass the existing ones are urgently needed. High-throughput screening of small molecule libraries enables rapid hit identification and, possibly, increases hit rate. Moreover, the identified hits could be associated with unrecognized or multiple drug targets, which would provide novel insights into the biological processes of the pathogen. Hence, it is proposed that high-throughput screening of small molecules is particularly important in the pursuit of the ideal antifungal agents for Candida infections.

Changing epidemiology of candidemia in a medical center in middle Taiwan

BACKGROUND

Candidemia remains a major cause of morbidity and mortality in the health care setting, and the epidemiology of Candida infection is changing.

METHODS

Clinical and laboratory data from patients with candidemia were collected retrospectively at a tertiary medical center in Taiwan from July 1, 2009 to June 30, 2012 (a 36-month period). Demographics, clinical characteristics, and drug susceptibility of the invading Candida species of patients at the onset of candidemia were analyzed and compared with previous study from January 1, 2001 to June 30, 2003 (a 30-month period).

RESULTS

A total of 209 episodes of candidemia in 205 patients were identified in this study period. When compared with the previous study period, more patients were admitted for medical conditions at percentages ranging from 49.5% to 69.8%; the incidence rate of health care-associated candidemia increased from 0.76 to 1.14 per 1000 discharges; the proportion of Candida albicans in patients with candidemia decreased from 64.8% to 43.6% whereas the proportion of Candida glabrata increased greatly from 1.1% to 21.6% and the proportions of Candida tropicalis and Candida parapsilosis were slightly elevated (19.8-22.0% and 2.2-7.3%, respectively). All of the C. albicans isolates remained susceptible to fluconazole, whereas 66.7% of C. glabrata isolates were dose-dependent susceptible, and 4.4% of C. glabrata isolates and 11.6% C. tropicalis isolates were resistant. There was one C. glabrata and one Candida guilliermondii resistant to echinocandin. The predictors for 30-day mortality included the high Acute Physiology and Chronic Health Evaluation II (APACHE II) score, use of parenteral nutrition, underlying malignancy, liver cirrhosis, and neutropenia whereas candidemia by C. parapsilosis or C. glabrata is a favorable predictor when compared with C. albicans.

CONCLUSION

The distribution of Candida species in candidemia was changed. Although C. albicans remained the major species, the isolation of non-C. albicans spp., especially C. glabrata, increased. Patients with candidemia still had high mortalities due to severity of illness and underlying conditions.

Emergence of nonalbicans Candida in neonatal septicemia and antifungal susceptibility: experience from a tertiary care center

Aims:

To know the distribution and antifungal susceptibility pattern of Candida species in neonatal septicemia cases.

Materials and Methods:

In a prospective analysis blood samples from 825 clinically suspected cases of neonatal septicemia, collected aseptically, were cultured to look for the role of Candida spp. in septicemia. Candida isolates were speciated by germ tube test, Hi-CHROME agar, sugar fermentation, and sugar assimilation tests using standard protocol. All the Candida isolates were tested for antifungal susceptibility to fluconazole by the Disk Diffusion (DD) method and broth micro dilution-minimum inhibitory concentration (BMD-MIC) method using NCCLS guidelines.

Results:

Isolation rate of Candida from neonatal septicemia cases was 8.1%. Most common isolate was C. tropicalis (61.19%), followed by C. albicans (19.40%), C. glabrata (11.94%), C. parapsilosis (5.97%) and C. guillermondii (1.49%). Low birth weight and previous antibiotic prophylaxis was found in 100% cases. Crude mortality rate was 50.1%. By DD method, 95.53% of the Candida isolates were sensitive to fluconazole. A discrepancy between DD method and BMD-MIC method was noted in 4.47% strains. One isolates each of C. tropicalis, C. albicans, and C. glabrata showed discrepancy.

Conclusion:

Nonalbicans Candida has emerged as an important cause of neonatal septicemia. Routine susceptibility testing of Candida isolates by DD method should be confirmed by BMD-MIC method. Fluconazole can be used as empirical therapy for neonatal candidemia at our center.

Small-molecule suppressors of Candida albicans biofilm formation synergistically enhance the antifungal activity of amphotericin B against clinical Candida isolates

A new class of fungal biofilm inhibitors represented by shearinines D (3) and E (4) were obtained from a Penicillium sp. isolate. The inhibitory activities of 3 and 4 were characterized using a new imaging flow-cytometer technique, which enabled the rapid phenotypic analysis of Candida albicans cell types (budding yeast cells, germ tube cells, pseudohyphae, and hyphae) in biofilm populations. The results were confirmed by experimental data obtained from three-dimensional confocal laser scanning microscopy and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assays. These data indicate that 3 and 4 inhibited C. albicans biofilm formation by blocking the outgrowth of hyphae at a relatively late stage of biofilm development (IC50 = 8.5 and 7.6 μM, respectively). However, 3 and 4 demonstrated comparatively weak activity at disrupting existing biofilms. Compounds 3 and 4 also exhibited synergistic activities with amphotericin B against C. albicans and other clinical Candida isolates by enhancing the potency of amphotericin B up to 8-fold against cells in both developing and established biofilms. These data suggest that the Candida biofilm disruption and amphotericin B potentiating effects of 3 and 4 could be mediated through multiple biological targets. The shearinines are good tools for testing the potential advantages of using adjunctive therapies in combination with antifungals.

Trends in the utilization of, spending on, and prices for outpatient antifungal agents in US Medicaid programs: 1991-2009

BACKGROUND

The incidence of invasive fungal infections (IFIs) has increased substantially in the recent past. Advances in medical technology, including broad-spectrum antibiotics, may increase the risk for fungal infections. Moreover, immunocompromised patients with cancer, HIV/AIDS, and/or transplants are susceptible to IFIs. Meanwhile, superficial fungal infections (SFIs) are common and can be difficult to cure.

OBJECTIVE

To provide a historical perspective on a dynamic market with expensive medications, this study describes trends in the utilization of, spending on, and average per-prescription spending on outpatient antifungal medications individually, in classes (for IFIs or SFIs), and overall, by the US Medicaid programs from 1991 to 2009.

METHODS

The publicly available Medicaid State Drug Utilization Data, maintained by the Centers for Medicare & Medicaid Services, were used. Annual prescription counts and reimbursement amounts were calculated for each of the antifungals reimbursed by Medicaid. Average per-prescription spending as a proxy for drug price was calculated by dividing reimbursement by the number of prescriptions.

RESULTS

Overall utilization for Medicaid beneficiaries remained steady, with 4.56 million prescriptions in 1991 and 4.51 million in 2009. Expenditures rose from $93.87 million to $143.76 million (in current-year US$) over the same time period. The drop in the utilization of first-generation azoles over the last 5 years of the study period can be explained in part by the movement of dual-eligibles from Medicaid to Medicare Part D and in part to a rise in fungal infections better treated with second-generation azoles or echinocandins. Whereas the average per-prescription price for generic (oral) fluconazole was $8 in 2009, the price per prescription of branded (intravenous) voriconazole was $2178.

CONCLUSIONS

Overall spending by Medicaid on outpatient antifungal medications increased more slowly than did the growth of the Medicaid programs from 1991 to 2009. However, the utilization of antifungal agents for IFIs increased almost 10-fold over this period, far outpacing the rise in the number of Medicaid beneficiaries.

Associated clinical characteristics of patients with candidemia among different Candida species

BACKGROUND

The rising incidence of non-albicans Candida (NAC) infection has been associated with a potentially adverse outcome for patients with candidemia. However, categorizing various species causing candidemia into a single NAC group might lead to inappropriate conclusions due to heterogeneity in species. Thus we examined the associated factors among patients with candidemia caused by different species.

METHODS

This retrospective study was conducted at a tertiary medical center in Taiwan from 2006 to 2009. Mortality rate, demographic and clinical characteristics, albumin levels, and severity scores of acute illness of patients at the onset of candidemia were analyzed.

RESULTS

A total of 447 episodes among 418 patients were included for analysis. The overall 30-day crude mortality was 48.2%, with no significant difference between C. albicans and NAC candidemia, but apparently C. parapsilosis candidemia was associated with a lower mortality rate. Time to positivity for yeast was significantly different between species. Compared with infection involving C. albicans, more frequent use of total parenteral nutrition, lower Sequential Organ Failure Assessment score and higher albumin levels were observed for C. parapsilosis candidemia.

CONCLUSION

Identifying associated factors for each species may be a more effective approach than single NAC grouping. Time to positivity may be a hint for treatment guidance in candidemia. More frequent use of total parenteral nutrition and less virulent nature were noted for C. parapsilosis candidemia.

Identification and functional characterization of Rca1, a transcription factor involved in both antifungal susceptibility and host response in Candida albicans

The identification of novel transcription factors associated with antifungal response may allow the discovery of fungus-specific targets for new therapeutic strategies. A collection of 241 Candida albicans transcriptional regulator mutants was screened for altered susceptibility to fluconazole, caspofungin, amphotericin B, and 5-fluorocytosine. Thirteen of these mutants not yet identified in terms of their role in antifungal response were further investigated, and the function of one of them, a mutant of orf19.6102 (RCA1), was characterized by transcriptome analysis. Strand-specific RNA sequencing and phenotypic tests assigned Rca1 as the regulator of hyphal formation through the cyclic AMP/protein kinase A (cAMP/PKA) signaling pathway and the transcription factor Efg1, but also probably through its interaction with a transcriptional repressor, most likely Tup1. The mechanisms responsible for the high level of resistance to caspofungin and fluconazole observed resulting from RCA1 deletion were investigated. From our observations, we propose that caspofungin resistance was the consequence of the deregulation of cell wall gene expression and that fluconazole resistance was linked to the modulation of the cAMP/PKA signaling pathway activity. In conclusion, our large-scale screening of a C. albicans transcription factor mutant collection allowed the identification of new effectors of the response to antifungals. The functional characterization of Rca1 assigned this transcription factor and its downstream targets as promising candidates for the development of new therapeutic strategies, as Rca1 influences host sensing, hyphal development, and antifungal response.

Antifungal effect of 4-arylthiosemicarbazides against Candida species. Search for molecular basis of antifungal activity of thiosemicarbazide derivatives

The in vitro antifungal potency of six series of 4-arylthiosemicarbazides was evaluated. Two isoquinoline derivatives with an ortho-methoxy or ortho-methyl group at the phenyl ring were the most potent antifungal agents. Molecular modeling studies and docking of all 4-arylthiosemicarbazides into the active sites of sterol 14α-demethylase (CYP51), topoisomerase II (topo II), l-glutamine: d-fructose-6-phosphate amidotransferase (GlcN-6-P), secreted aspartic proteinase (SAP), N-myristoyltransferase (NMT), and UDP-N-acetylmuramoyl-l-alanine:d-glutamate ligase (MurD) indicated the importance of both structural and electronic factors in ligand recognition and thus for the antifungal effectiveness of 4-arylthiosemicarbazides. A possible antifungal target was identified (NMT) and isoquinoline-thiosemicarbazides showed more favorable affinity than the native ligand.

Figure

Pharmacological, genotoxic and phytochemical properties of selected South African medicinal plants used in treating stomach-related ailments

ETHNOPHARMACOLOGICAL RELEVANCE

The evaluated medicinal plants are used in South African traditional medicine in treating stomach-related ailments.

AIMS OF THE STUDY

The study aimed at evaluating the pharmacological, genotoxic and phytochemical properties of the seven selected medicinal plants used for treating stomach-related ailments.

MATERIALS AND METHODS

Ethyl acetate (EtOAc), ethanol (EtOH) 70% and water extracts of the selected plant parts were evaluated for their antimicrobial and anthelmintic activities using microdilution assays. Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus), Gram-negative bacterium (Escherichia coli) and Candida albicans were used for antimicrobial assays. Caenorhabditis elegans was used for the anthelmintic assay. Plant extracts were also assayed for their cyclooxygenase-inhibitory activity against cyclooxygenase-1 and -2 enzymes. The Ames test was used to evaluate the genotoxicity of the plant extracts. A spectrophotometric method was used to determine the total phenolics, gallotannins, flavonoids and saponins.

RESULTS

Twelve extracts exhibited minimum inhibitory concentration (MIC) <1 mg/mL against the bacterial test strains, and five extracts exhibited MIC <1 mg/mL against Candida albicans. The EtOAc extract of Tetradenia riparia had the best minimum lethal concentration (MLC) value (0.004 mg/mL) against Caenorhabditis elegans. All the EtOAc extracts exhibited percentage inhibition in the range of 50.7-94.7% against COX-1 and -2 enzymes at 250 μg/mL. All the plant extracts were non-mutagenic towards Salmonella typhimurium tester strains TA98, TA100 and TA1537 without metabolic activation. Phytochemical analysis revealed relatively high amounts of total phenolics, gallotannins and flavonoids in the evaluated plant extracts.

CONCLUSIONS

The general pharmacological activities exhibited by some of the plant extracts in this study support the traditional uses of the selected plants in treating stomach-related ailments. The Ames test showed that all the plant extracts were non-mutagenic but cytotoxicity tests are needed to ascertain the safety for long-term consumption.

N-Cyclo-propyl-N-[2-(2,4-difluoro-phen-yl)-2-hy-droxy-1-(1H-1,2,4-triazol-1-yl)prop-yl]-2-(5-methyl-2,4-dioxo-1,2,3,4-tetra-hydro-pyrimidin-1-yl)acetamide dichloro-methane 0.62-solvate

In the title compound, C(21)H(22)F(2)N(6)O(4)·0.62CH(2)Cl(2), the difluoro-substituted benzene ring forms dihedral angles of 54.6 (3)° with the mean plane of the thymine ring and 50.9 (2)° with the triazole ring. The dihedral angle between the thymine and triazole rings is 7.4 (3)°. In the crystal, inter-molecular N-H⋯N and O-H⋯O hydrogen bonds link the main mol-ecules into chains along [10[Formula: see text]]. The CH(2)Cl(2) solvent mol-ecule was refined as partial occupancy over two sets of sites with refined occupancies of 0.308 (9) and 0.310 (8).

Expression of mouse beta defensin 2 in escherichia coli and its broad-spectrum antimicrobial activity

Mature mouse beta defensin 2 (mBD2) is a small cationic peptide with antimicrobial activity. Here we established a prokaryotic expression vector containing the cDNA of mature mBD2 fused with thioredoxin (TrxA), pET32a-mBD2. The vector was transformed into Escherichia Coli (E. coli) Rosseta-gami (2) for expression fusion protein. Under the optimization of fermentation parameters: induce with 0.6 mM isopropylthiogalactoside (IPTG) at 34°C in 2×YT medium and harvest at 6 h postinduction, fusion protein TrxA-mBD2 was high expressed in the soluble fraction (>95%). After cleaved fusion protein by enterokinase, soluble mature mBD2 was achieved 6 mg/L with a volumetric productivity. Purified recombinant mBD2 demonstrated clear broad-spectrum antimicrobial activity for fungi, bacteria and virus. The MIC of antibacterial activity of against Staphylococcus aureus was 50 μg/ml. The MIC of against Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans) was 12.5μg/ml and 25μg/ml, respectively. Also, the antimicrobial activity of mBD2 was effected by NaCl concentration. Additionally, mBD2 showed antiviral activity against influenza A virus (IAV), the protective rate for Madin-Darby canine kidney cells (MDCK) was 93.86% at the mBD2 concentration of 100 μg/ml. These works might provide a foundation for the following research on the mBD2 as therapeutic agent for medical microbes.

Changes in the incidence of candidaemia during 2000-2008 in a tertiary medical centre in northern Taiwan

Candidaemia is associated with high mortality and high healthcare costs. The incidence of candidaemia in Taiwan rose markedly during the period 1980-2000. We conducted this hospital-based surveillance study in order to explore the secular trend in incidence of candidaemia during the period 2000 to 2008. In our study, Candida spp. were the fourth most common cause of bloodstream infections, with a 30-day crude mortality rate of 36.7%. Candida albicans was the most common species identified, although mortality rate did not differ significantly among species. The incidence of candidaemia began to decrease in 2004. Risk factors related to higher mortality included longer hospital stay before onset of candidaemia, liver cirrhosis, malignancy, end-stage renal disease requiring renal dialysis, dependence on mechanical ventilation and urinary catheterisation.

Susceptibility of Candida spp. clinical isolates to antimycotics and disinfectants

The incidence of candidiasis among immunocompromised patients and emergence of antimycotics resistant strains has increased significantly. The aims of this study were: to examine the in vitro activity of antimycotics and biocides against Candida clinical isolates; to detect cross-resistance of fungi to these preparations and to estimate whether disinfectants applied in hospital areas are active against clinical Candida isolates. In vitro susceptibility of 102 Candida isolates to eight antimycotics was examined by Etest and ATB Fungus. Sensitivity of these strains to four disinfectants and an antiseptic agent was tested according to EN 1275:2005. Amphotericin B, caspofungin and 5-fluorocytosine were the most effective antimycotics against all Candida isolates. Resistance to itraconazole and fluconazole was observed among C. krusei and C. glabrata. The MICs (Minimal Inhibitory Concentrations) for ketoconazole, voriconazole and posaconazole against Candida albicans ranged: 0.003 - >32 μg/ml and one strain was resistant to three agents tested. All analysed Candida strains were sensitive to biocides containing either chlorine, aldehyde, alcohol mixtures, glucoprotamin or chlorhexidine gluconate with isopropanol. Sensitivity to these agents was observed at concentrations lower than those concentrations recommended by manufacturers to achieve proper biocidal activity to those preparations. Our data suggest that these disinfectants can be effectively applied in clinical wards to prevent nosocomial Candida infections.

Bloodstream yeast infections in a university hospital in Northeast Turkey: a 4-year survey

This study presents data on species distribution and antifungal susceptibility profiles of Candida bloodstream isolates obtained from a Turkish Tertiary Care Hospital during a 4-year period. All hospitalized patients who had ≥ 1 blood culture positive for yeast during their hospital stay from January 2005 through 2009 were included in this study. All isolates were identified to species level using CHROMagar and ID 32 C. Fluconazole and voriconazole antifungal susceptibility testing was performed using the disk diffusion method according to CLSI M44-A. In vitro activity of amphotericin B was determined by the Etest. Of all 166 yeast isolates, C. albicans was the dominant species (34.3%), followed by Candida parapsilosis (28.9%) and C. tropicalis (8.4%). All of the 48 C. parapsilosis strains were identified as C. parapsilosis sensu stricto. Resistance to fluconazole was more common among C. krusei isolates. Voriconazole resistance was absent. One C. lusitaniae strain showed a high amphotericin MIC (4 μg/ml). Our survey indicated an increase of some non-C. albicans Candida species in our hospital while antifungal resistance was uncommon.

Candida parapsilosis: a review of its epidemiology, pathogenesis, clinical aspects, typing and antimicrobial susceptibility

The Candida parapsilosis family has emerged as a major opportunistic and nosocomial pathogen. It causes multifaceted pathology in immuno-compromised and normal hosts, notably low birth weight neonates. Its emergence may relate to an ability to colonize the skin, proliferate in glucose-containing solutions, and adhere to plastic. When clusters appear, determination of genetic relatedness among strains and identification of a common source are important. Its virulence appears associated with a capacity to produce biofilm and production of phospholipase and aspartyl protease. Further investigations of the host-pathogen interactions are needed. This review summarizes basic science, clinical and experimental information about C. parapsilosis.

Performance of optimized McRAPD in identification of 9 yeast species frequently isolated from patient samples: potential for automation

Background

Rapid, easy, economical and accurate species identification of yeasts isolated from clinical samples remains an important challenge for routine microbiological laboratories, because susceptibility to antifungal agents, probability to develop resistance and ability to cause disease vary in different species. To overcome the drawbacks of the currently available techniques we have recently proposed an innovative approach to yeast species identification based on RAPD genotyping and termed McRAPD (Melting curve of RAPD). Here we have evaluated its performance on a broader spectrum of clinically relevant yeast species and also examined the potential of automated and semi-automated interpretation of McRAPD data for yeast species identification.

Results

A simple fully automated algorithm based on normalized melting data identified 80% of the isolates correctly. When this algorithm was supplemented by semi-automated matching of decisive peaks in first derivative plots, 87% of the isolates were identified correctly. However, a computer-aided visual matching of derivative plots showed the best performance with average 98.3% of the accurately identified isolates, almost matching the 99.4% performance of traditional RAPD fingerprinting.

Conclusion

Since McRAPD technique omits gel electrophoresis and can be performed in a rapid, economical and convenient way, we believe that it can find its place in routine identification of medically important yeasts in advanced diagnostic laboratories that are able to adopt this technique. It can also serve as a broad-range high-throughput technique for epidemiological surveillance.

Echinocandins: The Newest Class of Antifungals

Objective:

To review the mechanism of action, antifungal spectrum of activity, pharmacodynamics, pharmacokinetics, clinical efficacy, and safety of the echinocandins.

Data Sources:

A MEDLINE search (1982–May 2009) was conducted for articles published in the English language using the key words caspofungin, micafungin, anidulafungin, and echinocandins.

Study Selection and Data Extraction:

Medicinal chemistry, in vitro, and animal studies, as well as human trials were reviewed for information on the pharmacodynamics, pharmacokinetics, efficacy, and safety of each echinocandin. Clinical trials were reviewed and included to compare and contrast the available echinocandins.

Data Synthesis:

Three echinocandin antifungal agents are currently approved for use in the US: caspofungin, micafungin, and anidulafungin. The echinocandins have a unique mechanism of action, inhibiting β-(1,3)-d-glucan synthase, an enzyme that is necessary for the synthesis of an essential component of the cell wall of several fungi. The echinocandins display fungistatic activity against Aspergillus spp. and fungicidal activity against most Candida spp., including strains that are fluconazole-resistant. The echinocandins have been shown to be efficacious for the treatment of esophageal candidiasis, candidemia, and invasive candidiasis. In addition, caspofungin has demonstrated efficacy as empiric treatment of febrile neutropenia and salvage therapy for the treatment of invasive aspergillosis, and it is the only echinocandin approved for use in pediatric patients. Micafungin is the only echinocandin approved for use as prophylaxis against Candida infections in patients undergoing hematopoietic stem cell transplantation. Overall, resistance to echinocandins is still rare, and all agents are well tolerated, with similar adverse effect profiles and few drug–drug interactions.

Conclusions:

Echinocandins, the newest addition to the arsenal of antifungals, offer potential advantages over other classes of agents. Clinicians should assess their distinguishing characteristics, including route of metabolism, drug interaction profile, and approved indications for use, when determining which agent to include on a formulary.