Phenotypic switching in Candida lusitaniae on copper sulfate indicator agar: association with amphotericin B resistance and filamentation

Phenotypical Differences at the Physiological and Clinical Level between Two Genetically Closely Related Clavispora lusitaniae Strains Isolated from Patients

The occurrence of non-albicans species within the genus Candida poses a major challenge in the clinical setting. Clavispora lusitaniae, formerly known as Candida lusitaniae, has gained attention due to its potential multidrug resistance, particularly to amphotericin B (AmB). While intrinsic resistance to AmB is rare, secondary resistance may develop during treatment due to phenotypic rearrangement and the reorganization of the cell wall. Although there is evidence of genetic variability within C. lusitaniae, comprehensive genomic studies are lacking. This study examines the physiological differences within Candida species and focuses on the medical implications of this. Using two case reports, significant physiological and resistance differences between two strains of C. lusitaniae are demonstrated, highlighting the need for further research into genetic variability. While one strain showed higher resistance to antifungal drugs and slower growth compared to Strain 2, both strains showed minimal beta-D-glucan production, suggesting alternative pathogenic mechanisms. The study underlines the importance of understanding microbial adaptation and selection mechanisms, especially in the clinical setting, to effectively combat emerging drug resistance. Furthermore, research is needed to clarify the complex interplay between environmental causes, physiological traits, and the mechanisms of drug resistance in C. lusitaniae.

Candida lusitaniae: Biology, Pathogenicity, Virulence Factors, Diagnosis, and Treatment

The incidence of fungal infections is increasing at an alarming rate and has posed a great challenge for science in recent years. The rise in these infections has been related to the increase in immunocompromised patients and the resistance of different species to antifungal drugs. Infections caused by the different Candida species, especially Candida albicans, are one of the most common mycoses in humans, and the etiological agents are considered opportunistic pathogens associated with high mortality rates when disseminated infections occur. Candida lusitaniae is considered an emerging opportunistic pathogen that most frequently affects immunocompromised patients with some comorbidity. Although it is a low-frequency pathogen, and the mortality rate of C. lusitaniae-caused candidemia does not exceed 5%, some isolates are known to be resistant to antifungals such as amphotericin B, 5-fluorocytosine, and fluconazole. In this paper, a detailed review of the current literature on this organism and its different aspects, such as its biology, possible virulence factors, pathogen-host interaction, diagnosis, and treatment of infection, is provided. Of particular interest, through Blastp analysis we predicted possible virulence factors in this species.

Candida lusitaniae Breakthrough Fungemia in an Immuno-Compromised Adolescent: Case Report and Review of the Literature

Candida lusitaniae is a rare cause of candidemia that is known for its unique capability to rapidly acquire resistance to amphotericin B. We report the case of an adolescent with grade IV graft-vs.-host disease after hematopoietic cell transplantation who developed catheter-associated C. lusitaniae candidemia while on therapeutic doses of liposomal amphotericin B. We review the epidemiology of C. lusitaniae bloodstream infections in adult and pediatric patients, the development of resistance, and its role in breakthrough candidemia. Appropriate species identification, in vitro susceptibility testing, and source control are pivotal to optimal management of C. lusitaniae candidemia. Initial antifungal therapy may consist of an echinocandin and be guided by in vitro susceptibility and clinical response.

Chromatin Structure and Drug Resistance in Candida spp

Anti-microbial resistance (AMR) is currently one of the most serious threats to global human health and, appropriately, research to tackle AMR garnishes significant investment and extensive attention from the scientific community. However, most of this effort focuses on antibiotics, and research into anti-fungal resistance (AFR) is vastly under-represented in comparison. Given the growing number of vulnerable, immunocompromised individuals, as well as the positive impact global warming has on fungal growth, there is an immediate urgency to tackle fungal disease, and the disturbing rise in AFR. Chromatin structure and gene expression regulation play pivotal roles in the adaptation of fungal species to anti-fungal stress, suggesting a potential therapeutic avenue to tackle AFR. In this review we discuss both the genetic and epigenetic mechanisms by which chromatin structure can dictate AFR mechanisms and will present evidence of how pathogenic yeast, specifically from the Candida genus, modify chromatin structure to promote survival in the presence of anti-fungal drugs. We also discuss the mechanisms by which anti-chromatin therapy, specifically lysine deacetylase inhibitors, influence the acquisition and phenotypic expression of AFR in Candida spp. and their potential as effective adjuvants to mitigate against AFR.

Attack, Defend and Persist: How the Fungal Pathogen Candida auris was Able to Emerge Globally in Healthcare Environments

Within a decade after its first description, the multidrug-resistant yeast Candida auris has emerged globally as a nosocomial pathogen causing difficult to control outbreaks. This, together with the alarmingly high mortality rate of up to 66% associated with C. auris candidemia, calls for a better understanding of its virulence traits and routes of transmission. Unlike other clinically relevant Candida species, C. auris seems to have the unique ability to be easily transmitted between patients. Although initially thought to express fewer virulence traits than Candida albicans, recent genomic insights suggest C. auris to possess these traits to a much more similar extent. This review highlights the virulence traits C. auris expresses to attack the host, defend itself against antimicrobial agents and to persist within the healthcare environment.

Linking Cellular Morphogenesis with Antifungal Treatment and Susceptibility in Candida Pathogens

Fungal infections are a growing public health concern, and an increasingly important cause of human mortality, with Candida species being amongst the most frequently encountered of these opportunistic fungal pathogens. Several Candida species are polymorphic, and able to transition between distinct morphological states, including yeast, hyphal, and pseudohyphal forms. While not all Candida pathogens are polymorphic, the ability to undergo morphogenesis is linked with the virulence of many of these pathogens. There are also many connections between Candida morphogenesis and antifungal drug treatment and susceptibility. Here, we review how Candida morphogenesis-a key virulence trait-is linked with antifungal drugs and antifungal drug resistance. We highlight how antifungal therapeutics are able to modulate morphogenesis in both sensitive and drug-resistant Candida strains, the shared signaling pathways that mediate both morphogenesis and the cellular response to antifungal drugs and drug resistance, and the connection between Candida morphology, drug resistance, and biofilm growth. We further review the development of anti-virulence drugs, and targeting Candida morphogenesis as a novel therapeutic strategy to target fungal pathogens. Together, this review highlights important connections between fungal morphogenesis, virulence, and susceptibility to antifungals.

[Yeasts from the CTG clade (Candida clade): Biology, impact in human health, and biotechnological applications]

Among the subdivision of Saccharomycotina (ascomycetes budding yeasts), the CTG clade (formerly the Candida clade) includes species that display a particular genetic code. In these yeasts, the CTG codon is predominantly translated as a serine instead of a leucine residue. It is now well-known that some CTG clade species have a major impact on human and its activities. Some of them are recognized as opportunistic agents of fungal infections termed candidiasis. In addition, another series of species belonging to the CTG clade draws the attention of some research groups because they exhibit a strong potential in various areas of biotechnology such as biological control, bioremediation, but also in the production of valuable biocompounds (biofuel, vitamins, sweeteners, industrial enzymes). Here we provide an overview of recent advances concerning the biology, clinical relevance, and currently tested biotechnological applications of species of the CTG clade. Future directions for scientific research on these particular yeasts are also discussed.

The Role of Signaling via Aqueous Pore Formation in Resistance Responses to Amphotericin B

Drug resistance studies have played an important role in the validation of antibiotic targets. In the case of the polyene antibiotic amphotericin B (AmB), such studies have demonstrated the essential role that depletion of ergosterol plays in the development of AmB-resistant (AmB-R) organisms. However, AmB-R strains also occur in fungi and parasitic protozoa that maintain a normal level of ergosterol at the plasma membrane. Here, I review evidence that shows not only that there is increased protection against the deleterious consequences of AmB-induced ion leakage across the membrane in these resistant pathogens but also that a set of events are activated that block the cell signaling responses that trigger the oxidative damage produced by the antibiotic. Such signaling events appear to be the consequence of a membrane-thinning effect that is exerted upon lipid-anchored Ras proteins by the aqueous pores formed by AmB. A similar membrane disturbance effect may also explain the activity of AmB on mammalian cells containing Toll-like receptors. These resistance mechanisms expand our current understanding of the role that the formation of AmB aqueous pores plays in triggering signal transduction responses in both pathogens and host immune cells.

Growth Inhibition and Membrane Permeabilization of Candida lusitaniae Using Varied Pulse Shape Electroporation

Candida lusitaniae is an opportunistic yeast pathogen, which can readily develop resistance to antifungal compounds and result in a complex long-term treatment. The efficient treatment is difficult since structure and metabolic properties of the fungal cells are similar to those of eukaryotic host. One of the potential methods to improve the inhibition rate or the cell permeability to inhibitors is the application of electroporation. In this work we investigated the dynamics of the growth inhibition and membrane permeabilization of C. lusitaniae by utilizing the various pulse shape and duration electric field pulses. Our results indicated that single electroporation procedure using 8 kV/cm electric field may result in up to 51 ± 5% inhibition rate. Also it has been experimentally shown that the electroporation pulse shape may influence the inhibitory effect; however, the amplitude of the electric field and the pulse energy remain the most important parameters for definition of the treatment outcome. The dynamics of the cell membrane permeabilization in the 2–8 kV/cm electric field were overviewed.

Acquired Multidrug Antifungal Resistance in Candida lusitaniae during Therapy

Candida lusitaniae is usually susceptible to echinocandins. Beta-1,3-glucan synthase encoded by FKS genes is the target of echinocandins. A few missense mutations in the C. lusitaniae FKS1 hot spot 1 (HS1) have been reported. We report here the rapid emergence of antifungal resistance in C. lusitaniae isolated during therapy with amphotericin B (AMB), caspofungin (CAS), and azoles for treatment of persistent candidemia in an immunocompromised child with severe enterocolitis and visceral adenoviral disease. As documented from restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) analysis, the five C. lusitaniae isolates examined were related to each other. From antifungal susceptibility and molecular analyses, 5 different profiles (P) were obtained. These profiles included the following: profile 1 (P1) (CAS MIC [μg/ml], 0.5; fluconazole [FLC] MIC, 0.25), determined while the patient was being treated with liposomal AMB for 3 months; P2 (FLC MIC [μg/ml], 0.25; CAS MIC, 4), while the patient was being treated with CAS for 2 weeks; P3 (CAS MIC [μg/ml], 0.5; FLC MIC, 32), while the patient was being treated with azoles and CAS initially followed by azoles alone for a week; P4 (CAS MIC [μg/ml], 8; FLC MIC, 8), while the patient was being treated with both drugs for 3 weeks; and P5 (AMB MIC [μg/ml], 0.125; CAS MIC, 8), while the patient was being treated with AMB and FLC for 2 weeks. CAS resistance was associated with resistance not only to micafungin and anidulafungin but also to AMB. Analysis of CAS resistance revealed 3 novel FKS1 mutations in CAS-resistant isolates (S638Y in P2; S631Y in P4; S638P in P5). While S638Y and -P are within HS1, S631Y is in close proximity to this domain but was confirmed to confer candin resistance using a site-directed mutagenesis approach. FLC resistance could be linked with overexpression of major facilitator gene 7 (MFS7) in C. lusitaniae P2 and P4 and was associated with resistance to 5-flurocytosine. This clinical report describes resistance of C. lusitaniae to all common antifungals. While candins or azole resistance followed monotherapy, multidrug antifungal resistance emerged during combined therapy.

Phenotypic switching in Candida tropicalis: association with modification of putative virulence attributes and antifungal drug sensitivity

Although Candida tropicalis has become an increasingly important human pathogen, little is known regarding its potential to cause disease. In this study we evaluated the phenotypic switching ability of C. tropicalis and analyzed the effect of switching on biological properties related to virulence factors. We demonstrated that C. tropicalis switched spontaneously, reversibly and at high frequency (10(-1) to 10(-3)) when grown on yeast extract-peptone-D-glucose (YPD) agar medium. Phenotypic switching in five clinical isolates of C. tropicalis resulted in colonies exhibiting the following morphologies: crepe, rough, crater, irregular center, mycelial and diffuse. The majority of the variant colonies were associated with higher percentages of filamentous growth relative to their parental unswitched isolates. Significant differences (P < 0.05) in the production of hemolytic factor were found between most of the switched variants and their respective parental counterparts. Variant colonies exhibiting the crepe (derived from isolates 49.07 and 100.10) and rough phenotype (derived from isolate 49.07) had higher biofilm formation than their parental counterparts exhibiting a smooth dome surface (P < 0.05). Our data revealed that switching was correlated with changes in the in vitro minimum inhibitory concentrations (MICs) of a subset of the switched variants phenotypes to itraconazole. While the MIC to itraconazole was higher for crepe variant compared with its parental isolate 49.07, the rough variant of 100.10 had a lower MIC to this antifungal agent. The presented data support the role of phenotypic switching in promoting changes in phenotypic expression of putative virulence traits and itraconazole susceptibility of clinical isolates of C. tropicalis.

Formic acid and acetic acid induce a programmed cell death in pathogenic Candida species

Cutaneous fungal infections are common and widespread. Antifungal agents used for the treatment of these infections often have undesirable side effects. Furthermore, increased resistance of the microorganisms to the antifungal drugs becomes the growing problem. Accordingly, the search for natural antifungal compounds continues to receive attention. Apoptosis is highly regulated programmed cell death. During yeast cell apoptosis, amino acids and peptides are released and can stimulate regeneration of human epithelium cells. Thus, detection of chemical compounds inducing apoptosis in yeast and nontoxic for humans is of great medical relevance. The aim of this study was to detect chemical compound inducing apoptosis in pathogenic Candida species with the lowest toxicity to the mammalian cells. Five chemical compounds--acetic acid, sodium bicarbonate, potassium carbonate, lithium acetate, and formic acid--were tested for evaluation of antifungal activity on C. albicans, C. guilliermondii, and C. lusitaniae. The results showed that acetic acid and formic acid at the lowest concentrations induced yeast cells death. Apoptosis analysis revealed that cells death was accompanied by activation of caspase. Minimal inhibitory concentrations of potassium carbonate and sodium bicarbonate induced Candida cells necrosis. Toxicity test with mammalian cell cultures showed that formic acid has the lowest effect on the growth of Jurkat and NIH 3T3 cells. In conclusion, our results show that a low concentration of formic acid induces apoptosis-like programmed cell death in the Candida yeast and has a minimal effect on the survivability of mammalian cells, suggesting potential applications in the treatment of these infections.

The APSES transcription factor Efg1 is a global regulator that controls morphogenesis and biofilm formation in Candida parapsilosis

Efg1 (a member of the APSES family) is an important regulator of hyphal growth and of the white-to-opaque transition in Candida albicans and very closely related species. We show that in Candida parapsilosis Efg1 is a major regulator of a different morphological switch at the colony level, from a concentric to smooth morphology. The rate of switching is at least 20-fold increased in an efg1 knockout relative to wild type. Efg1 deletion strains also have reduced biofilm formation, attenuated virulence in an insect model, and increased sensitivity to SDS and caspofungin. Biofilm reduction is more dramatic in in vitro than in in vivo models. An Efg1 paralogue (Efh1) is restricted to Candida species, and does not regulate concentric-smooth phenotype switching, biofilm formation or stress response. We used ChIP-seq to identify the Efg1 regulon. A total of 931 promoter regions bound by Efg1 are highly enriched for transcription factors and regulatory proteins. Efg1 also binds to its own promoter, and negatively regulates its expression. Efg1 targets are enriched in binding sites for 93 additional transcription factors, including Ndt80. Our analysis suggests that Efg1 has an ancient role as regulator of development in fungi, and is central to several regulatory networks.

Calcineurin is required for pseudohyphal growth, virulence, and drug resistance in Candida lusitaniae

Candida lusitaniae is an emerging fungal pathogen that infects immunocompromised patients including HIV/AIDS, cancer, and neonatal pediatric patients. Though less prevalent than other Candida species, C. lusitaniae is unique in its ability to develop resistance to amphotericin B. We investigated the role of the calcium-activated protein phosphatase calcineurin in several virulence attributes of C. lusitaniae including pseudohyphal growth, serum survival, and growth at 37°C. We found that calcineurin and Crz1, a C. albicans Crz1 homolog acting as a downstream target of calcineurin, are required for C. lusitaniae pseudohyphal growth, a process for which the underlying mechanism remains largely unknown in C. lusitaniae but hyphal growth is fundamental to C. albicans virulence. We demonstrate that calcineurin is required for cell wall integrity, ER stress response, optimal growth in serum, virulence in a murine systemic infection model, and antifungal drug tolerance in C. lusitaniae. To further examine the potential of targeting the calcineurin signaling cascade for antifungal drug development, we examined the activity of a calcineurin inhibitor FK506 in combination with caspofungin against echinocandin resistant C. lusitaniae clinical isolates. Broth microdilution and drug disk diffusion assays demonstrate that FK506 has synergistic fungicidal activity with caspofungin against echinocandin resistant isolates. Our findings reveal that pseudohyphal growth is controlled by the calcineurin signaling cascade, and highlight the potential use of calcineurin inhibitors and caspofungin for emerging drug-resistant C. lusitaniae infections.

N-acetylglucosamine induces white-to-opaque switching and mating in Candida tropicalis, providing new insights into adaptation and fungal sexual evolution

Pathogenic fungi are capable of switching between different phenotypes, each of which has a different biological advantage. In the most prevalent human fungal pathogen, Candida albicans, phenotypic transitions not only improve its adaptation to a continuously changing host microenvironment but also regulate sexual mating. In this report, we show that Candida tropicalis, another important human opportunistic pathogen, undergoes reversible and heritable phenotypic switching, referred to as the "white-opaque" transition. Here we show that N-acetylglucosamine (GlcNAc), an inducer of white-to-opaque switching in C. albicans, promotes opaque-cell formation and mating and also inhibits filamentation in a number of natural C. tropicalis strains. Our results suggest that host chemical signals may facilitate this phenotypic switching and mating of C. tropicalis, which had been previously thought to reproduce asexually. Overexpression of the C. tropicalis WOR1 gene in C. albicans induces opaque-cell formation. Additionally, an intermediate phase between white and opaque was observed in C. tropicalis, indicating that the switching could be tristable.

Candida lusitaniae discitis after discogram in an immunocompetent patient

BACKGROUND CONTEXT

Discitis or epidural abscess after discogram is a rare but known complication. It is more commonly bacterial; however, fungal discitis has been previously reported in immunocompromised patients. The management of fungal discitis in immunocompetent patients is rarely presented or addressed in the literature.

PURPOSE

To present a rare atypical fungal discitis after routine discogram with a typical presentation in an immunocompetent host, review diagnostic and management guidelines for discitis, and provide recommendations for management of atypical discitis in immunocompetent patients.

STUDY DESIGN

Case report and review of the literature.

METHODS

A 40-year-old woman presented with a 3-week history of progressively worsening low back pain after a lumbar discogram. Magnetic resonance imaging revealed L3-L4 discitis without an epidural abscess. Left L3 and L4 hemilaminectomies with L3-L4 discectomy were performed. An inflammatory mass was seen in the L3-L4 disc space region extending to the left L3 foramen.

RESULTS

Culture specimens obtained during surgery from both the disc and epidural space speciated to Candida lusitaniae. The patient completed a 6-month course of fluconazole therapy. At 2-year follow-up, she continued to be asymptomatic, without any recurrence of infection or neurologic sequelae.

CONCLUSIONS

We report a case of C. lusitaniae spondylodiscitis after discography in an immunocompetent patient with long-term follow-up. Clinicians must maintain a high index of suspicion for discitis in patients who undergo this procedure. If discitis is suspected, culture specimens must be evaluated for fungal and mycobacterial organisms, even in the immunocompetent host. With proper surveillance, surgical intervention, and appropriate postoperative follow-up, this complication can be effectively managed with excellent long-term outcome.

Ultrastructural architecture of colonies of different morphologies produced by phenotypic switching of a clinical strain of Candida tropicalis and biofilm formation by variant phenotypes

Candida tropicalis has been identified as one of the most prevalent pathogenic yeast species of the Candida-non-albicans (CNA) group. Study of switching in C. tropicalis has not been the subject of extensive research. Therefore, we investigated switching event and characterized the ultrastructural architecture of different phenotypes and biofilm produced in a C. tropicalis clinical strain. Cells switched heritably, reversibly, and at a high frequency between four phenotypes readily distinguishable by the shape of colonies formed on agar at 25°C. SEM analysis was used to verify the architecture of whole Candida colonies at ultrastructural level. The smooth phenotype (parental phenotype) colony showed a hemispherical shape character, while the semi-smooth was characterized by the presence of shallow marginal depressions. The ring and rough phenotypes exhibited more complex architecture and were characterized by the presence of deep central and peripheral depressions areas. The biofilm-forming ability varied among the switch phenotypes. After 12h incubation, the smooth phenotype formed less biofilm compared to the other phenotypes (P<0.05). The electron microscopy analysis revealed that filamentation (pseudohyphae) was associated with ring and rough colonies. The ultrastructural analysis allowed the observation of the arrangement of individual cells within the colonies. At the deep central and peripheral depressions areas of the ring and rough colonies extracellular material was seen in different arrangements. The data presented here open new avenues to study a possible role for extracellular material in the formation and maintenance of the architecture of switch phenotypes in C. tropicalis. It is therefore essential that more strains be investigated to determine the biological significance of extracellular material in C. tropicalis phenotypic switching phenomenon.

Variability of phenotypic traits in Cryptococcus varieties and species and the resulting implications for pathogenesis

Variability of phenotypic characteristics in Cryptococcus neoformans var. grubii and var. neoformans as well as Cryptococcus gattii can have diverse effects on the virulence of these fungi and are thus important for pathogenesis. This article summarizes the diverse phenotypic changes that these fungi can manifest. We divide changes into those that affect the entire fungal population and are predominantly induced by environmental signals, and those that involve subpopulations of the fungal population and have to be selected. Last, the article summarizes the experimental evidence that epitopes on the polysaccharide capsule also vary, which may have implications for the pathogenesis as these findings would further diversify the fungal population.

Epidemiology of invasive mycoses in North America

The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.

In vitro activity of seven systemically active antifungal agents against a large global collection of rare Candida species as determined by CLSI broth microdilution methods

Five Candida species (C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, and C. krusei) account for over 95% of invasive candidiasis cases. Some less common Candida species have emerged as causes of nosocomial candidiasis, but there is little information about their in vitro susceptibilities to antifungals. We determined the in vitro activities of fluconazole, voriconazole, posaconazole, amphotericin B, anidulafungin, caspofungin, and micafungin against invasive, unique patient isolates of Candida collected from 100 centers worldwide between January 2001 and December 2007. Antifungal susceptibility testing was performed by the CLSI M27-A3 method. CLSI breakpoints for susceptibility were used for fluconazole, voriconazole, anidulafungin, caspofungin, and micafungin, while a provisional susceptibility breakpoint of < or = 1 microg/ml was used for amphotericin and posaconazole. Of 14,007 Candida isolates tested, 658 (4.7%) were among the less common species. Against all 658 isolates combined, the activity of each agent, expressed as the MIC50/MIC90 ratio (and the percentage of susceptible isolates) was as follows: fluconazole, 1/4 (94.8%); voriconazole, 0.03/0.12 (98.6%); posaconazole, 0.12/0.5 (95.9%); amphotericin, 0.5/2 (88.3%); anidulafungin, 0.5/2 (97.4%); caspofungin, 0.12/0.5 (98.0%); and micafungin, 0.25/1 (99.2%). Among the isolates not susceptible to one or more of the echinocandins, most (68%) were C. guilliermondii. All isolates of the less common species within the C. parapsilosis complex (C. orthopsilosis and C. metapsilosis) were susceptible to voriconazole, posaconazole, anidulafungin, caspofungin, and micafungin. Over 95% of clinical isolates of the rare Candida species were susceptible to the available antifungals. However, activity did vary by drug-species combination, with some species (e.g., C. rugosa and C. guilliermondii) demonstrating reduced susceptibilities to commonly used agents such as fluconazole and echinocandins.

In vitro susceptibilities of invasive isolates of Candida species: rapid increase in rates of fluconazole susceptible-dose dependent Candida glabrata isolates

Voriconazole, posaconazole, caspofungin, micafungin, and anidulafungin demonstrated potent in vitro activities against 286 invasive Candida isolates. Analysis of the fluconazole susceptibilities of 204 bloodstream Candida glabrata isolates revealed a rapid shift from susceptible (64% in 1999 to 2001 to 19% in 2007) to susceptible-dose dependent (27% in 1999 to 2001 and 75% in 2007).

El papel del voriconazol en el tratamiento de las micosis emergentes

Voriconazole is a broad-spectrum antifungal drug belonging to triazoles class. Recently, it has been recommended for the treatment of invasive candidiasis in non neutropenic patients. In addition, this drug has showed clinical efficacy in the treatment of fungal infections caused by Candida species other than Candida albicans, and also in several other infections caused by less common fungi, such as Aspergillus terreus, Fusarium and Scedosporium.

Antifungal susceptibility of 1000 Candida bloodstream isolates to 5 antifungal drugs: results of a multicenter study conducted in São Paulo, Brazil, 1995–2003

We evaluated all Candida sp. bloodstream isolates obtained from patients admitted to 4 tertiary care hospitals between 1995 and 2003 in the city of São Paulo, Brazil. Susceptibility to amphotericin B, 5-fluorocytosine, fluconazole (FCZ), itraconazole (ITZ), and voriconazole (VCZ) was determined using the Clinical Laboratory Standards Institute broth microdilution method. We tested a total of 1000 strains, including 400 strains of Candida albicans (40%), 243 of Candida tropicalis (24.3%), 238 of Candida parapsilosis (23.8%), 44 of C. glabrata (4.4%), 30 of Candida guilliermondii (3%), and 25 of Candida rugosa (2.5%). Only 1.9% of the strains tested were susceptible in a dose-dependent manner, and 0.2% of them were resistant to FCZ. Almost 100% of the strains were susceptible to VCZ. Despite that azole resistance was a rare finding, a trend toward increased resistance among C. rugosa strains to FCZ and ITZ was noted.

Epidemiology of invasive candidiasis: a persistent public health problem

Invasive candidiasis (IC) is a leading cause of mycosis-associated mortality in the United States. We examined data from the National Center for Health Statistics and reviewed recent literature in order to update the epidemiology of IC. IC-associated mortality has remained stable, at approximately 0.4 deaths per 100,000 population, since 1997, while mortality associated with invasive aspergillosis has continued to decline. Candida albicans remains the predominant cause of IC, accounting for over half of all cases, but Candida glabrata has emerged as the second most common cause of IC in the United States, and several less common Candida species may be emerging, some of which can exhibit resistance to triazoles and/or amphotericin B. Crude and attributable rates of mortality due to IC remain unacceptably high and unchanged for the past 2 decades. Nonpharmacologic preventive strategies should be emphasized, including hand hygiene; appropriate use, placement, and care of central venous catheters; and prudent use of antimicrobial therapy. Given that delays in appropriate antifungal therapy are associated with increased mortality, improved use of early empirical, preemptive, and prophylactic therapies should also help reduce IC-associated mortality. Several studies have now identified important variables that can be used to predict risk of IC and to help guide preventive strategies such as antifungal prophylaxis and early empirical therapy. However, improved non-culture-based diagnostics are needed to expand the potential for preemptive (or early directed) therapy. Further research to improve diagnostic, preventive, and therapeutic strategies is necessary to reduce the considerable morbidity and mortality associated with IC.