Global trends in candidemia: Review of reports from 1995–2005

Niclosamide-loaded nanoparticles disrupt Candida biofilms and protect mice from mucosal candidiasis

Candida albicans biofilms are a complex multilayer community of cells that are resistant to almost all classes of antifungal drugs. The bottommost layers of biofilms experience nutrient limitation where C. albicans cells are required to respire. We previously reported that a protein Ndu1 is essential for Candida mitochondrial respiration; loss of NDU1 causes inability of C. albicans to grow on alternative carbon sources and triggers early biofilm detachment. Here, we screened a repurposed library of FDA-approved small molecule inhibitors to identify those that prevent NDU1-associated functions. We identified an antihelminthic drug, Niclosamide (NCL), which not only prevented growth on acetate, C. albicans hyphenation and early biofilm growth, but also completely disengaged fully grown biofilms of drug-resistant C. albicans and Candida auris from their growth surface. To overcome the suboptimal solubility and permeability of NCL that is well known to affect its in vivo efficacy, we developed NCL-encapsulated Eudragit EPO (an FDA-approved polymer) nanoparticles (NCL-EPO-NPs) with high niclosamide loading, which also provided long-term stability. The developed NCL-EPO-NPs completely penetrated mature biofilms and attained anti-biofilm activity at low microgram concentrations. NCL-EPO-NPs induced ROS activity in C. albicans and drastically reduced oxygen consumption rate in the fungus, similar to that seen in an NDU1 mutant. NCL-EPO-NPs also significantly abrogated mucocutaneous candidiasis by fluconazole-resistant strains of C. albicans, in mice models of oropharyngeal and vulvovaginal candidiasis. To our knowledge, this is the first study that targets biofilm detachment as a target to get rid of drug-resistant Candida biofilms and uses NPs of an FDA-approved nontoxic drug to improve biofilm penetrability and microbial killing.

Adhesins in the virulence of opportunistic fungal pathogens of human

Aspergillosis, candidiasis, and cryptococcosis are the most common cause of mycoses-related disease and death among immune-compromised patients. Adhesins are cell-surface exposed proteins or glycoproteins of pathogens that bind to the extracellular matrix (ECM) constituents or mucosal epithelial surfaces of the host cells. The forces of interaction between fungal adhesins and host tissues are accompanied by ligand binding, hydrophobic interactions and protein-protein aggregation. Adherence is the primary and critical step involved in the pathogenesis; however, there is limited information on fungal adhesins compared to that on the bacterial adhesins. Except a few studies based on screening of proteome for adhesin identification, majority are based on characterization of individual adhesins. Recently, based on their characteristic signatures, many putative novel fungal adhesins have been predicted using bioinformatics algorithms. Some of these novel adhesin candidates have been validated by in-vitro studies; though, most of them are yet to be characterised experimentally. Morphotype specific adhesin expression as well as tissue tropism are the crucial determinants for a successful adhesion process. This review presents a comprehensive overview of various studies on fungal adhesins and discusses the targetability of the adhesins and adherence phenomenon, for combating the fungal infection in a preventive or therapeutic mode.

Intestinal mycobiota in health and diseases: from a disrupted equilibrium to clinical opportunities

Bacteria, viruses, protozoa, and fungi establish a complex ecosystem in the gut. Like other microbiota, gut mycobiota plays an indispensable role in modulating intestinal physiology. Notably, the most striking characteristics of intestinal fungi are their extraintestinal functions. Here, we provide a comprehensive review of the importance of gut fungi in the regulation of intestinal, pulmonary, hepatic, renal, pancreatic, and brain functions, and we present possible opportunities for the application of gut mycobiota to alleviate/treat human diseases. Video Abstract.

Does leukotriene F4 play a major role in the infection mechanism of Candida sp.?

Candidiasis is the most common fungal infection affecting hospitalized patients, especially immunocompromised and critical patients. Limitations regarding the assertive diagnosis of both Candidemia and Candidiasis not only impairs the introduction of effective treatments but also lays a heavy financial burden over the health system. Furthermore, it is still challenging to ascertain whether diagnostic methods are accurate and whether treatment is effective for patients with Candidemia. These constraints come from the uncertainty of the pathophysiological mechanism by which the pathogen establishes the opportunistic infection. Additionally, it is the reason why some patients present positive blood culture results, and others do not, and why it is very difficult during clinical routines to prove Candidemia or invasive candidiasis. Taking into account the current situation, this contribution proposes two markers that may help to understand the mechanisms of infection by the pathogen: Leukotriene F4 and 5,6-dihydroxy-eicosatetraenoic. These two lipids putatively modulate the host's immune response, and the initial data presented in this contribution suggest that these lipids allow the opportunistic infection to be installed. The study was carried out using an omics-based platform using direct-infusion high-resolution mass spectrometry and allied with bioinformatics tools to provide accurate and reliable results for biomarker candidates screening.

Thoughts on the evolution of Core Environmental Responses in yeasts

The model yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, display Core Environmental Responses (CERs) that include the induction of a core set of stress genes in response to diverse environmental stresses. CERs underlie the phenomenon of stress cross-protection, whereby exposure to one type of stress can provide protection against subsequent exposure to a second type of stress. CERs have probably arisen through the accumulation, over evolutionary time, of protective anticipatory responses (“adaptive prediction”). CERs have been observed in other evolutionarily divergent fungi but, interestingly, not in the pathogenic yeast, Candida albicans. We argue that this is because we have not looked in the right place. In response to specific host inputs, C. albicans does activate anticipatory responses that protect it against impending attack from the immune system. Therefore, we suggest that C. albicans has evolved a CER that reflects the environmental challenges it faces in host niches.

•

We review Core Environmental Responses (CERs) in domesticated and pathogenic yeasts.

•

CERs probably evolved through the accumulation of protective anticipatory responses.

•

Evolutionarily diverse yeasts display CERs, but the pathogen, Candida albicans, does not.

•

C. albicans has evolved an alternative CER that protects against immune clearance.

•

This has implications for the investigation of CERs in other fungi.

Candida Bloodstream Infection: Changing Pattern of Occurrence and Antifungal Susceptibility over 10 Years in a Tertiary Care Saudi Hospital

Background

Candida has emerged as one of the most important pathogens that cause bloodstream infection (BSI).Understanding the current Candida BSI trends, the dominant species causing disease and the mortality associated with this infection are crucial to optimize therapeutic and prophylaxis measures.

Objectives

To study the epidemiology and to evaluate the risk factors, prognostic factors, and mortality associated with candidemia and to compare these findings with previously published studies from Saudi Arabia.

Design

A retrospective medical record review.

Setting

Tertiary hospital in Riyadh.

Patients and Methods

The analysis included all cases of Candida blood stream infection who are >18 years old over the period from 2013 to 2018. Continuous variables were compared using the parametric T-test while categorical variables were compared using the Chi-squared test.

Main Outcome Measure

Incidence, resistance, and hospital outcomes in Candida blood stream infection.

Sample Size

324 patients.

Results

Three hundred and twenty-four episodes of Candida blood stream infections were identified. Median age of patients was 49.7 SD ± 28.1 years, and 53% of patients were males. More than half of the patients had an underlying disease involving the abdomen or laparotomy, 78% had an indwelling intravenous catheter, and 62% had suffered a bacterial infection within 2 weeks prior to candidemia. Candida albicans represents 33% of all isolates with decreasing trend overtime. There was an increase in the number of nonalbicans Candida overtime with Candida tropicalis in the lead (20%). Use of broad spectrum antibiotics (82%), prior ICU admission (60%) and use of central venous catheters (58%) were the most prevalent predisposing factors of candidemia. Azole resistance was variable overtime. Resistance to caspofungin remained very low (1.9%). Fourteen days crude mortality was 37% for ICU patients and 26.7% in non-ICU patients, while hospital crude mortality was 64.4% and 46.7%, respectively.

Conclusion

There is an increasing trend of nonalbicans Candida blood stream infection. Fluconazole resistance remained low to C. albicans. Most isolates remain susceptible to caspofungin, voriconazole, and amphotericin B. Candida bloodstream infection is associated with high 14-day hospital mortality.

Deletion of the fungus specific protein phosphatase Z1 exaggerates the oxidative stress response in Candida albicans

BACKGROUND

Candida albicans is an opportunistic pathogen which is responsible for widespread nosocomial infections. It encompasses a fungus specific serine/threonine protein phosphatase gene, CaPPZ1 that is involved in cation transport, cell wall integrity, oxidative stress response, morphological transition, and virulence according to the phenotypes of the cappz1 deletion mutant.

RESULTS

We demonstrated that a short-term treatment with a sublethal concentration of tert-butyl hydroperoxide suppressed the growth of the fungal cells without affecting their viability, both in the cappz1 mutant and in the genetically matching QMY23 control strains. To reveal the gene expression changes behind the above observations we carried out a global transcriptome analysis. We used a pilot DNA microarray hybridization together with extensive RNA sequencing, and confirmed our results by quantitative RT-PCR. Novel functions of the CaPpz1 enzyme and oxidative stress mechanisms have been unraveled. The numbers of genes affected as well as the amplitudes of the transcript level changes indicated that the deletion of the phosphatase sensitized the response of C. albicans to oxidative stress conditions in important physiological functions like membrane transport, cell surface interactions, oxidation-reduction processes, translation and RNA metabolism.

CONCLUSIONS

We conclude that in the wild type C. albicans CaPPZ1 has a protective role against oxidative damage. We suggest that the specific inhibition of this phosphatase combined with mild oxidative treatment could be a feasible approach to topical antifungal therapy.

Synergistic fungicidal activity with low doses of eugenol and amphotericin B against Candida albicans

Candida albicans frequently causes variety of superficial and invasive disseminated infections in HIV infected patients. Further, the emergence of non albicans species causing candidiasis predominantly in patients with advanced immune-suppression and drug resistance brings great apprehension. Hence, in this study we evaluate the capability of eugenol (EUG), a natural compound in combination with less toxic concentrations of amphotericin B (AmpB) for enhanced antifungal effects and reduced toxicity. Antifungal activity and time-kill assay were employed according to Clinical Laboratory Standard Institute (CLSI) guidelines with minor modifications on clinical isolates of Candida albicans. To confirm the synergistic interaction of EUG and AmpB, checkerboard experiments were employed. Interestingly, EUG-Amp B combination shows many fold higher anti-candida activity compared to single component treatment. Furthermore, our results depicts reactive oxygen species (ROS) driven killing and mitochondrial hyperpolarisation on treatment. Our data also suggests inhibition of calcium channel by EUG and predicts longer retainment of AmpB. Pronounced cellular damage was observed with combination treatment than to EUG and AmpB alone. Our finding is helpful for the removal of toxic concentrations of antifungal agents.

Effectiveness of Phytoactive Molecules on Transcriptional Expression, Biofilm Matrix, and Cell Wall Components of Candida glabrata and Its Clinical Isolates

Toxicity challenges by antifungal arsenals and emergence of multidrug resistance scenario has posed a serious threat to global community. To cope up with this alarming situation, phytoactive molecules are richest, safest, and most effective source of broad spectrum antimicrobial compounds. In the present investigation, six phytoactive molecules [cinnamaldehyde (CIN), epigallocatechin, vanillin, eugenol (EUG), furanone, and epigallocatechin gallate] were studied against Candida glabrata and its clinical isolates. Among these, CIN and EUG which are active components of cinnamon and clove essential oils, respectively, exhibited maximum inhibition against planktonic growth of C. glabrata at a concentration of 64 and 128 μg mL-1, respectively. These two molecules effectively inhibited and eradicated approximately 80% biofilm of C. glabrata and its clinical isolates from biomaterials. CIN and EUG increased reactive oxygen species generation, cell lysis, and ergosterol content in plasma membrane and reduced virulence attributes (phospholipase and proteinase) as well as catalase activity of C. glabrata cells. Reduction of mitochondrial membrane potential with increased release of cytochrome c from mitochondria to cytosol indicated initiation of early apoptosis in CIN- and EUG-treated C. glabrata cells. Transcriptional analysis showed that multidrug transporter (CDR1) and ergosterol biosynthesis genes were downregulated in the presence of CIN, while getting upregulated in EUG-treated cells. Interestingly, genes such as 1,3-β-glucan synthase (FKS1), GPI-anchored protein (KRE1), and sterol importer (AUS1) were downregulated upon treatment of CIN/EUG. These results provided molecular-level insights about the antifungal mechanism of CIN and EUG against C. glabrata including its resistant clinical isolate. The current data established that CIN and EUG can be potentially formulated in new antifungal strategies.

Candida albicans Dispersed Cells Are Developmentally Distinct from Biofilm and Planktonic Cells

Candida albicans surface-attached biofilms such as those formed on intravenous catheters with direct access to the bloodstream often serve as a nidus for continuous release of cells capable of initiating new infectious foci. We previously reported that cells dispersed from a biofilm are yeast cells that originate from the top-most hyphal layers of the biofilm. Compared to their planktonic counterparts, these biofilm dispersal yeast cells displayed enhanced virulence-associated characteristics and drug resistance. However, little is known about their molecular properties. To address that issue, in this study we aimed to define the molecular characteristics of these biofilm dispersal cells. We found that the inducer of dispersal, PES1, genetically interacts with the repressor of filamentation, NRG1, in a manner consistent with the definition of dispersed cells as yeast cells. Further, using a flow biofilm model, we performed comprehensive comparative RNA sequencing on freshly dispersed cells in order to identify unique transcriptomic characteristics. Gene expression analysis demonstrated that dispersed cells largely inherit a biofilm-like mRNA profile. Strikingly, however, dispersed cells seemed transcriptionally reprogrammed to acquire nutrients such as zinc and amino acids and to metabolize alternative carbon sources, while their biofilm-associated parent cells did not induce the same high-affinity transporters or express gluconeogenetic genes, despite exposure to the same nutritional signals. Collectively, the findings from this study characterize cell dispersal as an intrinsic step of biofilm development which generates propagules more adept at colonizing distant host sites. This developmental step anticipates the need for virulence-associated gene expression before the cells experience the associated external signals.

Candida albicans surface-attached biofilms serve as a reservoir of cells to perpetuate and expand an infection; cells released from biofilms on catheters have direct access to the bloodstream. Biofilm dispersal yeast cells exhibit enhanced adhesion, invasion, and biofilm formation compared to their planktonic counterparts. Here, we show using transcriptome sequencing (RNA-seq) that dispersed yeast cells are developmentally distinct from the cells in their parent biofilms as well as from planktonic yeast cells. Dispersal cells possess an anticipatory expression pattern that primes them to infect new sites in the host, to survive in nutrient-starved niches, and to invade new sites. These studies identified dispersal cells as a unique proliferative cell type of the biofilm and showed that they could serve as targets for antibiofilm drug development in the future.

Enhanced Killing and Antibiofilm Activity of Encapsulated Cinnamaldehyde against Candida albicans

Candida sp. impelled opportunistic infection in immune-compromised patients ensuing from asymptomatic colonization to pathogenic forms. Moreover, slow spread of Candida species inducing refractory mucosal and invasive infections brings acute resistance to antifungal drugs. Hence, here we probed the effect of encapsulated preparation of cinnamaldehyde (CNMA) in multilamellar liposomes (ML) against Candida albicans. The efficacy of ML-CNMA against Candida biofilm was assessed by scanning electron microscopy, transmission electron microscopy, as well as light microscopy and its percent inhibition, was determined by XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] and crystal violet assay. ML-CNMA showed more fungicidal activity than free CNMA as well as multilamellar liposomal amphotericin B (ML-Amp B), which was further confirmed by spot test assay and Log-logistic dose–response analysis. Antifungal activity was driven by reactive oxygen species and cellular damage by sustained release of CNMA. Effect on hyphal formation during 48 h in presence/absence of ML-CNMA was observed under a microscope and further substantiated by RT-PCR by amplifying HWP1, the gene responsible for hyphal wall protein formation. Apoptotic programmed cell death was analyzed by FACS analysis which was further confirmed by cytochrome C release assay. This study elucidates the mechanistic insight of the enhanced antifungal activity of ML preparation of CNMA against Candida infections.

Antifungal Drug Susceptibility of Candida Species Isolated from HIV-Positive Patients Recruited at a Public Hospital in São Luís, Maranhão, Brazil

Oropharyngeal candidiasis is the most common fungal infection in hospitalized patients with acquired immune deficiency syndrome (AIDS). Its progression results in invasive infections, which are a significant cause of morbidity and mortality. This study aimed to quickly and accurately identify Candida spp. from oral mucosa of AIDS patients recruited at Presidente Vargas Hospital, in São Luís city, Brazil and to evaluate the sensitivity profile of these fungi to antifungals by using an automated system. Isolates were collected from oropharyngeal mucosa of 52 hospitalized AIDS patients, under anti-viral and antifungal therapies. Patients were included in research if they were HIV-positive, above 18 years of age and after obtaining their written consent. CHROMagar^®Candida and the automated ViteK-2^®system were used to isolate and identify Candida spp., respectively. Antifungal susceptibility testing was performed using the ViteK-2^®system, complemented with the Etest^®, using the drugs amphotericin B, fluconazole, flucytosine, and voriconazole. Oropharyngeal candidiasis had a high prevalence in these hospitalized AIDS patients (83%), and the most prevalent species was Candida albicans (56%). Antifungal susceptibility test showed that 64.7% of the Candida spp. were susceptible, 11.8% were dose-dependent sensitive, and 23.5% were resistant. All the Candida krusei and Candida famata isolates and two of Candida glabrata were resistant to fluconazole. Most of AIDS patients presented oropharyngeal candidiasis and C. albicans was the most frequently isolated species. The results showed high variability in resistance among isolated species and indicates the need to identify the Candida spp. involved in the infection and the need to test antifungal susceptibility as a guide in drug therapy in patients hospitalized with AIDS. This is the first relate about AIDS patients monitoring in a public hospital in São Luís concerning the precise identification and establishing of antifungal profile of Candida spp..

Metal Chelation as a Powerful Strategy to Probe Cellular Circuitry Governing Fungal Drug Resistance and Morphogenesis

Fungal pathogens have evolved diverse strategies to sense host-relevant cues and coordinate cellular responses, which enable virulence and drug resistance. Defining circuitry controlling these traits opens new opportunities for chemical diversity in therapeutics, as the cognate inhibitors are rarely explored by conventional screening approaches. This has great potential to address the pressing need for new therapeutic strategies for invasive fungal infections, which have a staggering impact on human health. To explore this approach, we focused on a leading human fungal pathogen, Candida albicans, and screened 1,280 pharmacologically active compounds to identify those that potentiate the activity of echinocandins, which are front-line therapeutics that target fungal cell wall synthesis. We identified 19 compounds that enhance activity of the echinocandin caspofungin against an echinocandin-resistant clinical isolate, with the broad-spectrum chelator DTPA demonstrating the greatest synergistic activity. We found that DTPA increases susceptibility to echinocandins via chelation of magnesium. Whole genome sequencing of mutants resistant to the combination of DTPA and caspofungin identified mutations in the histidine kinase gene NIK1 that confer resistance to the combination. Functional analyses demonstrated that DTPA activates the mitogen-activated protein kinase Hog1, and that NIK1 mutations block Hog1 activation in response to both caspofungin and DTPA. The combination has therapeutic relevance as DTPA enhanced the efficacy of caspofungin in a mouse model of echinocandin-resistant candidiasis. We found that DTPA not only reduces drug resistance but also modulates morphogenesis, a key virulence trait that is normally regulated by environmental cues. DTPA induced filamentation via depletion of zinc, in a manner that is contingent upon Ras1-PKA signaling, as well as the transcription factors Brg1 and Rob1. Thus, we establish a new mechanism by which metal chelation modulates morphogenetic circuitry and echinocandin resistance, and illuminate a novel facet to metal homeostasis at the host-pathogen interface, with broad therapeutic potential.

Invasive fungal infections pose a serious threat to human health worldwide, with Candida albicans being a leading fungal pathogen. Mortality is in part due to the limited arsenal of effective antifungals, with drug resistance on the rise. The echinocandins, which target the fungal cell wall, are the newest class of antifungal, and echinocandin resistance has already emerged. Here, we screened a library of 1,280 pharmacologically active compounds to identify those that potentiate echinocandin activity against an echinocandin-resistant isolate. The lead compound was a chelator, DTPA, which affects resistance by depleting magnesium. Genome sequencing of mutants resistant to the combination of DTPA and echinocandin revealed mutations in the gene encoding Nik1, which signals upstream of the Hog1 stress response pathway. We established that DTPA acts through Nik1 to modulate Hog1 signaling and enhance echinocandin activity, and that this combination has therapeutic benefits in a murine model of candidiasis. We also discovered that DTPA modulates C. albicans morphogenesis, a key virulence trait. DTPA induced filamentation by chelating zinc, in a manner that is contingent upon core filamentation pathways and specialized circuitry. Thus, we establish novel roles for metal homeostasis in C. albicans pathogenesis, thereby illuminating new therapeutic strategies for life-threatening infectious disease.

Burden of serious fungal infections in Ukraine

Ukraine has high rates of TB, AIDS and cancer. We estimated the burden of fungal disease from epidemiology papers and specific populations at risk and fungal infection frequencies. HIV/AIDS cases and deaths (2012) and tuberculosis statistics were obtained from the State Service of Ukraine, while chronic obstructive pulmonary disease (COPD) cases were from M. Miravitlles et al., Thorax 64, 863-868 (2009). Annual estimates are 893,579 Ukrainian women get recurrent vaginal thrush (≥4× per year), 50,847 cases of oral candidiasis and 13,727 cases of oesophageal candidiasis in HIV, and 101 (1%) of 10,085 new AIDS cases develop cryptococcal meningitis, 6152 cases of Pneumocystis pneumonia (13.5 cases per 100,000). Of the 29,265 cases of active respiratory TB in 2012, it is estimated that 2881 new cases of chronic pulmonary aspergillosis (CPA) occurred and that the 5-year period prevalence is 7724 cases with a total CPA burden of 10,054 cases. Assuming adult asthma prevalence is ~2.9%, 28,447 patients with allergic bronchopulmonary aspergillosis (ABPA) are likely and 37,491 with severe asthma with fungal sensitisation. We estimate 2278 cases and 376 postsurgical intra-abdominal Candida infections. Invasive aspergillosis in immunocompromised patients is estimated at 303 patients annually; 930 cases in COPD patients. Ninety cases of mucormycosis (2 per 1,000,000) are estimated. In total, ~1,000,000 (2.2%) people in Ukraine develop serious fungal infections annually.

Pho4 mediates phosphate acquisition in Candida albicans and is vital for stress resistance and metal homeostasis

This study provides the first evidence that the phosphate-responsive transcription factor Pho4 is vital for survival of Candida albicans to diverse and physiologically relevant stresses. Pho4 is important for C. albicans pathogenesis, and thus these findings illustrate how metabolic adaptation promotes C. albicans survival in the host.

During interactions with its mammalian host, the pathogenic yeast Candida albicans is exposed to a range of stresses such as superoxide radicals and cationic fluxes. Unexpectedly, a nonbiased screen of transcription factor deletion mutants revealed that the phosphate-responsive transcription factor Pho4 is vital for the resistance of C. albicans to these diverse stresses. RNA-Seq analysis indicated that Pho4 does not induce stress-protective genes directly. Instead, we show that loss of Pho4 affects metal cation toxicity, accumulation, and bioavailability. We demonstrate that pho4Δ cells are sensitive to metal and nonmetal cations and that Pho4-mediated polyphosphate synthesis mediates manganese resistance. Significantly, we show that Pho4 is important for mediating copper bioavailability to support the activity of the copper/zinc superoxide dismutase Sod1 and that loss of Sod1 activity contributes to the superoxide sensitivity of pho4Δ cells. Consistent with the key role of fungal stress responses in countering host phagocytic defenses, we also report that C. albicans pho4Δ cells are acutely sensitive to macrophage-mediated killing and display attenuated virulence in animal infection models. The novel connections between phosphate metabolism, metal homeostasis, and superoxide stress resistance presented in this study highlight the importance of metabolic adaptation in promoting C. albicans survival in the host.

CaTip41 regulates protein phosphatase 2A activity, CaRad53 deactivation and the recovery of DNA damage-induced filamentation to yeast form in Candida albicans

Phosphorylation and dephosphorylation of the checkpoint kinase CaRad53 is crucial for fungal cells in response to genotoxic stresses. The protein phosphatase 2A (PP2A) CaPph3/CaPsy2 phosphatase complex is involved in CaRad53 dephosphorylation in Candida albicans. In view of the role of ScTip41/ScTap42 in regulating PP2A phosphatases in Saccharomyces cerevisiae, we have explored the function of CaTip41 in C. albicans. Here, we show that CaTIP41 is a functional ortholog of ScTIP41 in the sensitivity of S. cerevisiae cells to rapamycin. Deletion of CaTIP41 causes C. albicans cells to be sensitive to DNA damaging agents, methylmethane sulfonate (MMS) and cisplatin, and resistant to both rapamycin and caffeine. Accordingly, expression of CaTip41 increases in response to MMS and cisplatin. In addition, C. albicans cells lacking CaTIP41 show a delay in the recovery from MMS-induced filamentation to yeast form, decreased PP2A activity and a defect in deactivation of CaRad53 during recovery from DNA damage. Through yeast two-hybrid assay we show that CaTip41 interacts with either CaPph3, CaPsy2 or CaTap42. Therefore, CaTip41 plays regulatory roles in both the CaRad53 deactivation during recovery from DNA damage and the target of rapamycin signaling pathway.

Potential Use of Phenolic Acids as Anti-Candida Agents: A Review

There has been a sharp rise in the occurrence of Candida infections and associated mortality over the last few years, due to the growing body of immunocompromised population. Limited number of currently available antifungal agents, undesirable side effects and toxicity, as well as emergence of resistant strains pose a considerable clinical challenge for the treatment of candidiasis. Therefore, molecules that derived from natural sources exhibiting considerable antifungal properties are a promising source for the development of novel anti-candidal therapy. Phenolic compounds isolated from natural sources possess antifungal properties of interest. Particularly, phenolic acids have shown promising in vitro and in vivo activity against Candida species. However, studies on their mechanism of action alone or in synergism with known antifungals are still scarce. This review attempts to discuss the potential use, proposed mechanisms of action and limitations of the phenolic acids in anti-candidal therapy.

Emergence of azole-resistant Candida species in AIDS patients with oropharyngeal candidiasis in Iran

Background and Purpose:

Oropharyngeal candidiasis (OPC) and antifungal drug resistance are major health concerns in patients with human immunodeficiency virus (HIV). The increased reports of antifungal resistance and expanding drug therapy options prompted the determination of antifungal susceptibility profile. The present study was performed to determine the antifungal susceptibility of Candida species isolated from AIDS patients with OPC in Iran.

Materials and Methods:

In total, 100 Candida isolates from the oral cavity of patients with OPC (TCD4 < 200 cells/μL) were obtained and cultured on CHROMagar and Sabouraud’s dextrose agar. All isolates were identified according to the assimilation profile, colony color and other conventional methods. Broth microdilution of antifungal drugs was carried out, according to the methods described in M27-S4 and M44-A guidelines by the Clinical and Laboratory Standards Institute (CLSI).

Results:

Among 60 Candida albicans (C. albicans) strains, 56.7% were resistant to fluconazole, while 38.3% were resistant to ketoconazole and clotrimazole. The resistance of C. albicans isolates against polyene antifungals including amphotericin B was scarce (1.7%). Based on the results, 52.2% of C.glabrata strains were resistant to fluconazole, while 47.8% and 30.4% of these isolates were resistant to ketoconazole and clotrimazole, respectively. All Candida isolates were susceptible to nystatin and caspofungin.

Conclusion:

Based on the findings, it can be concluded that screening of resistant Candida isolates by disk diffusion or broth dilution method is essential for the surveillance and prevention of antifungal resistance in patient management. Although nystatin is widely used in clinical practice for HIV patients in Iran, no evidence of enhanced resistance against this agent was found; on the other hand, resistance to azole antifungals, particularly fluconazole, increased. Considering the lack of resistance to caspofungin, administration of this agent is suggested for the treatment of OPC in AIDS patients.

Candida species bloodstream infections in hospitalised children: A 10-year experience

In a 10-year retrospective study we assessed the epidemiology of candidemia and the association between the presence and removal of indwelling central venous catheters, antifungal use and clinical outcomes among hospitalised children. Demographic and clinical information were retrieved from the electronic medical records. One hundred six episodes of candidemia were identified in 83 unique patients. Candida parapsilosis was the most prevalent (52%) species, followed by C. albicans (25%). Non-oncologic children receiving fluconazole within 30 days of developing candidemia were most likely to develop C. parapsilosis infection (40%, P = 0.006), independent of total parenteral nutrition (odds ratio (OR) 2.5, 95% confidence interval (CI): 0.6-11, P = 0.3). Crude mortality rate was 12% and significantly higher for children less than 2 years (OR: 6.7, 95% CI: 1.9-23, P = 0.003), and those infected with C. lusitaniae (OR: 9, 95% CI: 1.6-51, P = 0.02). The aggregate use of antifungal agents decreased overtime (χ(2) : 16.7, P < 0.0001). Fluconazole remained the most common antifungal agent used during the study.

Oxidative stress responses in the human fungal pathogen, Candida albicans

Candida albicans is a major fungal pathogen of humans, causing approximately 400,000 life-threatening systemic infections world-wide each year in severely immunocompromised patients. An important fungicidal mechanism employed by innate immune cells involves the generation of toxic reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. Consequently, there is much interest in the strategies employed by C. albicans to evade the oxidative killing by macrophages and neutrophils. Our understanding of how C. albicans senses and responds to ROS has significantly increased in recent years. Key findings include the observations that hydrogen peroxide triggers the filamentation of this polymorphic fungus and that a superoxide dismutase enzyme with a novel mode of action is expressed at the cell surface of C. albicans. Furthermore, recent studies have indicated that combinations of the chemical stresses generated by phagocytes can actively prevent C. albicans oxidative stress responses through a mechanism termed the stress pathway interference. In this review, we present an up-date of our current understanding of the role and regulation of oxidative stress responses in this important human fungal pathogen.

No specific time window distinguishes between community-, healthcare-, and hospital-acquired bacteremia, but they are prognostically robust

OBJECTIVE

We examined whether specific time windows after hospital admission reflected a sharp transition between community and hospital acquisition of bacteremia. We further examined whether different time windows to distinguish between community acquisition, healthcare association (HCA), and hospital acquisition influenced the results of prognostic models.

DESIGN

Population-based cohort study.

SETTING

Hospitals in 3 areas of Denmark (2.3 million inhabitants) during 2000-2011.

METHODS

We computed graphs depicting proportions of males, absence of comorbidity, microorganisms, and 30-day mortality pertaining to bacteremia 0, 1, 2, …, 30, and 31 days and later after admission. Next, we assessed whether different admission (0-1, 0-2, 0-3, 0-7 days) and HCA (30, 90 days) time windows were associated with changes in odds ratio (OR) and area under the receiver operating characteristic (ROC) curve for 30-day mortality, adjusting for sex, age, comorbidity, and microorganisms.

RESULTS

For 56,606 bacteremic episodes, no sharp transitions were detected on a specific day after admission. Among the 8 combined time windows, ORs for 30-day mortality varied from 1.30 (95% confidence interval [CI], 1.23-1.37) to 1.99 (95% CI, 1.48-2.67) for HCA and from 1.36 (95% CI, 1.24-1.50) to 2.53 (95% CI, 2.01-3.20) for hospital acquisition compared with community acquisition. Area under the ROC curve changed marginally from 0.684 (95% CI, 0.679-0.689) to 0.700 (95% CI, 0.695-0.705).

CONCLUSIONS

No time transitions unanimously distinguished between community and hospital acquisition with regard to sex, comorbidity, or microorganisms, and no difference in 30-day mortality was seen for HCA patients in relation to a 30- or 90-day time window. ORs decreased consistently in the order of hospital acquisition, HCA, and community acquisition, regardless of time window combination, and differences in area under the ROC curve were immaterial.

Invasive fungal infections in transplant recipients

Invasive fungal infections are an important cause of morbidity and mortality in hematopoietic stem cell transplant and solid organ transplant recipients. Evolving transplant modalities and techniques, complex and extensive immunosuppressant strategies, and the increased use of broad spectrum antifungal prophylaxis has greatly impacted the epidemiology and temporal pattern of invasive fungal infections in the transplant population. The goal of this article is to provide an up-to-date review of the most commonly encountered invasive fungal infections seen in transplant recipients, including epidemiology, risk factors, clinical features, diagnostic dilemmas, management and their overall influence on outcomes.

Nosocomial candidemia; risk factors and prognosis revisited; 11 years experience from a Norwegian secondary hospital

The aim of the study was to review the epidemiology and prognosis of candidemia in a secondary hospital, and to examine the intra-hospital distribution of candidemia patients. Study design is a retrospective cohort study. Trough 2002–2012, 110 cases of candidemia were diagnosed, giving an incidence of 2, 6/100000 citizens/year. Overall prognosis of candidemia was dismal, with a 30 days case fatality rate of 49% and one year case fatality rate of 64%. Candidemia was a terminal event in 55% of 30 days non-survivors, defined as Candida blood cultures reported positive on the day of death or thereafter (39%), or treatment refrained due to hopeless short-term prognosis (16%). In terminal event candidemias, advanced or incurable cancer was present in 29%. Non-survivors at 30 days were 9 years (median) older than survivors. In 30 days survivors, candidemia was not recognised before discharge in 13% of cases. No treatment were given and no deaths or complications were observed in this group. Candidemia patients were grouped into 8 patient categories: Abdominal surgery (35%), urology (13%), other surgery (11%), pneumonia (13%), haematological malignancy (7%), intravenous drug abuse (4%), other medical (15%), and new-borns (3%). Candidemia was diagnosed while admitted in the ICU in 46% of patients. Urology related cases were all diagnosed in the general ward. Multiple surgical procedures were done in 60% of abdominal surgery patients. Antibiotics were administered prior to candidemia in 87% of patients, with median duration 17 (1–108) days. Neutropenia was less common than expected in patients with candidemia (8/105) and closely associated to haematological malignancy (6/8). Compared with previous national figures the epidemiology of invasive candidiasis seems not to have changed over the last decade.

Epidemiology and outcomes of invasive candidiasis due to non-albicans species of Candida in 2,496 patients: data from the Prospective Antifungal Therapy (PATH) registry 2004-2008

This analysis describes the epidemiology and outcomes of invasive candidiasis caused by non-albicans species of Candida in patients enrolled in the Prospective Antifungal Therapy Alliance (PATH Alliance) registry from 2004 to 2008. A total of 2,496 patients with non-albicans species of Candida isolates were identified. The identified species were C. glabrata (46.4%), C. parapsilosis (24.7%), C. tropicalis (13.9%), C. krusei (5.5%), C. lusitaniae (1.6%), C. dubliniensis (1.5%) and C. guilliermondii (0.4%); 111 infections involved two or more species of Candida (4.4%). Non-albicans species accounted for more than 50% of all cases of invasive candidiasis in 15 of the 24 sites (62.5%) that contributed more than one case to the survey. Among solid organ transplant recipients, patients with non-transplant surgery, and patients with solid tumors, the most prevalent non-albicans species was C. glabrata at 63.7%, 48.0%, and 53.8%, respectively. In 1,883 patients receiving antifungal therapy on day 3, fluconazole (30.5%) and echinocandins (47.5%) were the most frequently administered monotherapies. Among the 15 reported species, 90-day survival was highest for patients infected with either C. parapsilosis (70.7%) or C. lusitaniae (74.5%) and lowest for patients infected with an unknown species (46.7%) or two or more species (53.2%). In conclusion, this study expands the current knowledge of the epidemiology and outcomes of invasive candidiasis caused by non-albicans species of Candida in North America. The variability in species distribution in these centers underscores the importance of local epidemiology in guiding the selection of antifungal therapy.

Isolation of a new broad spectrum antifungal polyene from Streptomyces sp. MTCC 5680

A new polyene macrolide antibiotic PN00053 was isolated from the fermentation broth of Streptomyces sp. wild-type strain MTCC-5680. The producer strain was isolated from fertile mountain soil of Naldehra region, Himachal Pradesh, India. The compound PN00053 was purified through various steps of chromatographic techniques and bio-activity guided fractionation followed by its characterization using physiochemical properties, spectral data ((1) H-NMR, (13) C-NMR, HMBC, HSQC, and COSY) and MS analysis. PN00053 exhibited broad spectrum in vitro antifungal activity against strains of Aspergillus fumigatus (HMR), A. fumigatus ATCC 16424, Candida albicans (I.V.), C. albicans ATCC 14503, C. krusei GO6, C. glabrata HO4, Cryptococcus neoformans, Trichophyton sp. as well as fluconazole resistant strains C. krusei GO3 and C. glabrata HO5. It did not inhibit growth of gram positive and gram-negative bacteria, displaying its specificity against fungi.

SIGNIFICANCE AND IMPACT OF THE STUDY

PN00053 is a novel polyene macrolide isolated from a wild strain of Streptomyces sp. PM0727240 (MTCC5680), an isolate from the mountainous rocky regions of Himachal Pradesh, India. The compound is a new derivative of the antibiotic Roflamycoin [32, 33-didehydroroflamycoin (DDHR)]. It displayed broad spectrum antifungal activity against yeast and filamentous fungi. However, it did not show any antibacterial activity. The in vitro study revealed that PN00053 has better potency as compared to clinical gold standard fluconazole. The development of pathogenic resistance against the polyenes has been seldom reported. Hence, we envisage PN00053 could be a potential antifungal lead.

Predictors and outcomes of Candida bloodstream infection: eight-year surveillance, western Saudi Arabia

OBJECTIVES

To assess the epidemiological pattern of Candida bloodstream infection (BSI) over an 8-year period (2002-2009) in King Abdulaziz Medical City, western Saudi Arabia.

METHOD

A retrospective chart review was performed.

RESULTS

A total of 258 BSI were identified in 134 males (53.2%) and 118 females (46.8%). There were 86 (34.1%) cases of Candida albicans and 166 (65.9%) non-albicans Candida species. Malignancy was independently associated with the development of candidemia by non-albicans Candida species (odds ratio 3.24, 95% confidence interval 1.25-8.41). Fluconazole in vitro susceptibility was 38.5% for C. albicans and 52.5% for other Candida species. The overall, crude 12-month mortality rate was 50% for C. albicans and 57.8% for non-albicans Candida species.

CONCLUSIONS

The antifungal resistance coinciding with a change in the epidemiologic pattern of candidemia identified in this study is alarming and urges the need for a review of empiric antifungal therapy and potential contributing environmental factors.

Epidemiology of candidemia in Qatar, the Middle East: performance of MALDI-TOF MS for the identification of Candida species, species distribution, outcome, and susceptibility pattern

INTRODUCTION

Bloodstream infections (BSIs) due to Candida spp. constitute the predominant group of hospital-based fungal infections worldwide. A retrospective study evaluated the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of BSI Candida isolates. The epidemiology, risk factors, demographic features, species distribution, and clinical outcome associated with candidemia in patients admitted to a single tertiary-care hospital in Qatar, were analyzed.

METHODS

A single-center, retrospective analysis covering the period from January 1, 2004 to December 31, 2010 was performed. Molecular identification used sequence analysis of the D1/D2 domains of the large subunit ribosomal DNA (LSU rDNA) and the ITS1/2 regions of the rDNA. MALDI-TOF MS-based identification of all yeast isolates was performed with the ethanol/formic acid extraction protocol according to Bruker Daltonics (Bremen, Germany). The susceptibility profiles of 201 isolates to amphotericin B, itraconazole, fluconazole, voriconazole, anidulafungin, caspofungin, posaconazole, and isavuconazole were tested using CLSI standard broth microdilution method (M27-A3 and M27 S4) guidelines. Statistical analyses were performed with the statistical package SPSS 19.0.

RESULTS

A total of 187 patients with 201 episodes of candidemia were identified. Candida albicans was the most common species isolated (33.8 %; n = 68), whereas non-albicans Candida species represented 66.2 % (n = 133) of the episodes. The species distribution and outcome of candidemia showed a difference in the crude mortality between patients infected with C. albicans (n = 30; 45.5 %) and non-albicans Candida species. For example, C. parapsilosis candidemia was associated with the lowest mortality rate (40.6 %), and patients with other non-albicans species had the highest mortality rate (68-71.4 %). High mortality rates were observed among pediatric (<1 year of age) and elderly patients (>60 years of age). All strains showed low minimum inhibitory concentrations (MICs) (MIC90 of 0.063 μg/ml) to isavuconazole. The overall resistance to voriconazole in vitro antifungal activity was 2.5 %. C. glabrata (n = 38) had an MIC90 of 8 μg/ml for fluconazole. Most yeast isolates were susceptible to anidulafungin (>99.5 %) and 81.1 % to caspofungin. Resistance to anidulafungin was detected in 1/8 (12.5 %) isolates of C. orthopsilosis. According to new Clinical and Laboratory Standards Institute (CLSI) breakpoints, C. glabrata (n = 38) showed 100 % resistance, and 37/68 (54.4 %) C. albicans isolates were susceptible dose dependent (SDD) to caspofungin. Identification by MALDI-TOF MS was in 100 % concordance with molecular identification.

CONCLUSION

The Middle East epidemiology of candidemia has a unique species distribution pattern distinct from other parts of the globe. High mortality rates were observed among pediatric (<1 year of age) and elderly patients (>60 years of age). All strains were susceptible to isavuconazole. All isolates of C.glabrata were resistant to caspofungin based on M27 S4. MALDI-TOF MS is a highly useful method for the routine identification of yeast isolates in clinical setting to achieve successful therapeutic treatment.

Myriocin significantly increases the mortality of a non-mammalian model host during Candida pathogenesis

Candida albicans is a major human pathogen whose treatment is challenging due to antifungal drug toxicity, drug resistance and paucity of antifungal agents available. Myrocin (MYR) inhibits sphingosine synthesis, a precursor of sphingolipids, an important cell membrane and signaling molecule component. MYR also has dual immune suppressive and antifungal properties, potentially modulating mammalian immunity and simultaneously reducing fungal infection risk. Wax moth (Galleria mellonella) larvae, alternatives to mice, were used to establish if MYR suppressed insect immunity and increased survival of C. albicans-infected insects. MYR effects were studied in vivo and in vitro, and compared alone and combined with those of approved antifungal drugs, fluconazole (FLC) and amphotericin B (AMPH). Insect immune defenses failed to inhibit C. albicans with high mortalities. In insects pretreated with the drug followed by C. albicans inoculation, MYR+C. albicans significantly increased mortality to 93% from 67% with C. albicans alone 48 h post-infection whilst AMPH+C. albicans and FLC+C. albicans only showed 26% and 0% mortalities, respectively. MYR combinations with other antifungal drugs in vivo also enhanced larval mortalities, contrasting the synergistic antifungal effect of the MYR+AMPH combination in vitro. MYR treatment influenced immunity and stress management gene expression during C. albicans pathogenesis, modulating transcripts putatively associated with signal transduction/regulation of cytokines, I-kappaB kinase/NF-kappaB cascade, G-protein coupled receptor and inflammation. In contrast, all stress management gene expression was down-regulated in FLC and AMPH pretreated C. albicans -infected insects. Results are discussed with their implications for clinical use of MYR to treat sphingolipid-associated disorders.

Ureteric obstruction due to fungus-ball in a chronically immunosuppressed patient

Candida albicans is a fungus that can cause opportunistic urinary tract infections in immunocompromised patients. Disseminated fungaemia secondary to Candida albicans is associated with considerable mortality and therefore merits aggressive treatment. Diagnostic investigations for urosepsis and disseminated fungaemaia secondary to Candida albicans include positive urine and blood cultures. Herein, we describe an extremely unusual case of disseminated fungaemia associated with an obstructive fungus-ball in the distal ureter of an immunosuppressed patient. We also describe a novel application of an established endourological technique for managing this clinical scenario and discuss appropriate perioperative management strategies.

Hidden killers: human fungal infections

Although fungal infections contribute substantially to human morbidity and mortality, the impact of these diseases on human health is not widely appreciated. Moreover, despite the urgent need for efficient diagnostic tests and safe and effective new drugs and vaccines, research into the pathophysiology of human fungal infections lags behind that of diseases caused by other pathogens. In this Review, we highlight the importance of fungi as human pathogens and discuss the challenges we face in combating the devastating invasive infections caused by these microorganisms, in particular in immunocompromised individuals.

Candida albicans escapes from mouse neutrophils

Candida albicans, the most commonly isolated human fungal pathogen, is able to grow as budding yeasts or filamentous forms, such as hyphae. The ability to switch morphology has been attributed a crucial role for the pathogenesis of C. albicans. To mimic disseminated candidiasis in humans, the mouse is the most widely used model organism. Neutrophils are essential immune cells to prevent opportunistic mycoses. To explore potential differences between the rodent infection model and the human host, we compared the interactions of C. albicans with neutrophil granulocytes from mice and humans. We revealed that murine neutrophils exhibited a significantly lower ability to kill C. albicans than their human counterparts. Strikingly, C. albicans yeast cells formed germ tubes upon internalization by murine neutrophils, eventually rupturing the neutrophil membrane and thereby, killing the phagocyte. On the contrary, growth and subsequent escape of C. albicans are blocked inside human neutrophils. According to our findings, this blockage in human neutrophils might be a result of higher levels of MPO activity and the presence of α-defensins. We therefore outline differences in antifungal immune defense between humans and mouse strains, which facilitates a more accurate interpretation of in vivo results.

Candida mesorugosa sp. nov., a novel yeast species similar to Candida rugosa, isolated from a tertiary hospital in Brazil

Candida rugosa is a yeast species that is emerging as a causative agent of invasive infection, particularly in Latin America. Recently, C. pseudorugosa was proposed as a new species closely related to C. rugosa. We evaluated in this investigation the genetic heterogeneity within the C. rugosa species complex. All clinical isolates used in this study were identified phenotypically as C. rugosa but were genotypically different from the C. rugosa type, ATCC 10571. RAPD marker analysis revealed less than 83% similarity between our clinical isolates and the C. rugosa type strain. The D1/D2 region sequences of our clinical isolates showed 98% identity with C. rugosa but only 94-95% identity with C. pseudorugosa. The ITS rDNA sequences of the Brazilian isolates showed 91% identity with the C. rugosa ATCC 10571 ITS sequence. Network and Bayesian analyses of ITS and housekeeping gene sequences separated our clinical isolates into different branches from C. rugosa type strain. These differences are sufficient to reassign our isolates to a distinct species, named C. mesorugosa.

A potent plant-derived antifungal acetylenic acid mediates its activity by interfering with fatty acid homeostasis

6-Nonadecynoic acid (6-NDA), a plant-derived acetylenic acid, exhibits strong inhibitory activity against the human fungal pathogens Candida albicans, Aspergillus fumigatus, and Trichophyton mentagrophytes. In the present study, transcriptional profiling coupled with mutant and biochemical analyses were conducted using the model yeast Saccharomyces cerevisiae to investigate its mechanism of action. 6-NDA elicited a transcriptome response indicative of fatty acid stress, altering the expression of genes that are required for yeast growth in the presence of oleate. Mutants of S. cerevisiae lacking transcription factors that regulate fatty acid β-oxidation showed increased sensitivity to 6-NDA. Fatty acid profile analysis indicated that 6-NDA inhibited the formation of fatty acids longer than 14 carbons in length. In addition, the growth inhibitory effect of 6-NDA was rescued in the presence of exogenously supplied oleate. To investigate the response of a pathogenic fungal species to 6-NDA, transcriptional profiling and biochemical analyses were also conducted in C. albicans. The transcriptional response and fatty acid profile of C. albicans were comparable to those obtained in S. cerevisiae, and the rescue of growth inhibition with exogenous oleate was also observed in C. albicans. In a fluconazole-resistant clinical isolate of C. albicans, a fungicidal effect was produced when fluconazole was combined with 6-NDA. In hyphal growth assays, 6-NDA inhibited the formation of long hyphal filaments in C. albicans. Collectively, our results indicate that the antifungal activity of 6-NDA is mediated by a disruption in fatty acid homeostasis and that 6-NDA has potential utility in the treatment of superficial Candida infections.

Tissue distribution of anidulafungin in neonatal rats

Anidulafungin, an echinocandin, is currently approved for treatment of fungal infections in adults. There is a high unmet medical need for treatment of fungal infections in neonatal patients, who may be at higher risk of infections involving bone, brain, and heart tissues. This in vivo preclinical study investigated anidulafungin distribution in plasma, bone, brain, and heart tissues in neonatal rats. Postnatal day (PND) 4 and PND 8 Fischer (F344/DuCrl) rats were dosed subcutaneously once with anidulafungin (10 mg/kg) or once daily for 5 days (PND 4-8). Plasma and tissue samples were collected and anidulafungin levels were measured by liquid chromatography-tandem mass spectrometry. The mean plasma Cmax and AUC0-24 values were consistent with single-dose plasma pharmacokinetics (dose normalized) reported previously for adult rats. Observed bone concentrations were similar to plasma concentrations regardless of dosing duration, with bone-to-plasma concentration ratios of approximately 1.0. Heart concentrations were higher than plasma, with heart to plasma concentration ratios of 1.3- to 1.8-fold. Brain concentrations were low after single dose, with brain-to-plasma concentration ratio of approximately 0.23, but increased to approximately 0.71 after 5 days of dosing. Tissue concentrations were nearly identical after single-dose administration in both PND 4 and PND 8 animals, indicating that anidulafungin does not appear to differentially distribute in this period in neonatal rats. In conclusion, anidulafungin distributes to bone, brain, and heart tissues of neonatal rats; such results are supportive of further investigation of efficacy against infections involving bone, brain, and heart tissues.

Protein phosphatase Pph3 and its regulatory subunit Psy2 regulate Rad53 dephosphorylation and cell morphogenesis during recovery from DNA damage in Candida albicans

The ability of the pathogenic fungus Candida albicans to switch cellular morphologies is important for infection and virulence. Recent studies have revealed that C. albicans yeast cells can switch to filamentous growth under genotoxic stress in a manner dependent on the DNA replication/damage checkpoint. Here, we have investigated the functions of Pph3 (orf19.4378) and Psy2 (orf19.3685), whose orthologues in Saccharomyces cerevisiae mediate the dephosphorylation of the DNA damage checkpoint kinase Rad53 and the histone variant H2AX during recovery from DNA damage. Deleting PPH3 or PSY2 causes hypersensitivity to DNA-damaging agents, including cisplatin, methylmethane sulfonate (MMS), and UV light. In addition, pph3Δ and psy2Δ cells exhibit strong filamentous growth under genotoxic stress. Flow cytometry analysis shows that the mutant cells have lost the ability to adapt to genotoxic stress and remain arrested even after the stress is withdrawn. Furthermore, we show that Pph3 and Psy2 are required for the dephosphorylation of Rad53, but not H2AX, during DNA damage recovery. Taken together, these results show that C. albicans Pph3 and Psy2 have important roles in mediating genotoxin-induced filamentous growth and regulating Rad53 dephosphorylation.

Increased mortality in young candidemia patients associated with presence of a Candida albicans general-purpose genotype

The yeast Candida albicans causes life-threatening candidemia. A general-purpose genotype (GPG; corresponds to clade 1) causes more infections than other C. albicans genotypes. To investigate if GPG strains also cause higher mortality, we developed a duplex PCR assay which was 98% accurate in identifying GPG strains in an international collection of strains typed with probe Ca3. We applied the assay to 635 European C. albicans candidemia isolates. Of these, 18% conformed to the GPG genotype, 4% were of a borderline genotype, and 78% were of a non-GPG genotype, broadly consistent with genotype distributions in earlier studies. The prevalence of GPG strains was increased in females and in younger patients, exceeding 40% in infants aged ≤1 year. Logistic regression confirmed sex and age as significant determinants of GPG prevalence. Across the entire patient cohort, there was no difference in mortality for patients infected with GPG strains or other strains (36% versus 37%). However, mortality in patients aged ≤48 years was 33% for infection with GPG strains but only 15% for infection with other strains (z test; P < 0.01). Mortality rates associated with GPG and non-GPG strains were comparable in older patients (39% versus 46%). A logistic regression analysis confirmed the age-dependent impact of genotype on mortality. Thus, GPG strains may be more virulent than other strains in younger patients. Because candidemia is usually caused by endogenous strains, our PCR assay could potentially be used as a risk assessment tool for identifying younger patients most at risk of death from candidemia.