Changing pattern of candidaemia 2001–2006 and use of antifungal therapy at the University Hospital of Vienna, Austria

The changing epidemiology of fungal infections

Invasive fungal diseases are common complications in critically ill patients and in those with significant underlying imbalanced immune systems. Fungal co-, and/or super-infections are emerging and have become a rising concern within the last few years. In Europe, cases of candidiasis and aspergillosis dominate, followed by mucormycosis in India. Epidemiological studies show an increasing trend in the incidence of all three entities. Parallel to this, a shift within the underlying fungal pathogens is observed. More non-albicans Candida infections and aspergillosis with cryptic species are on the rise; cryptic species may cover intrinsic resistance to azoles and other antifungal drugs. The recent COVID-19 pandemic led to a significantly increasing incidence of invasive fungal diseases among hospitalized patients.

Adherence and Cytotoxicity of Candida spp. to HaCaT and A549 cells

Candida species are opportunistic fungal pathogens that cause superficial or invasive infections. Recently, the incidence of infection by non-Candida albicans species, especially Candida glabrata, has increased. In this study, we analyzed the adhesion and cytotoxicity of various Candida spp. that are part of the normal human microbiota. C. albicans adheres well to cell culture plates and to cultured cells. C. glabrata selectively adheres to epithelial cells rather than to cell culture plates. Candida parapsilosis insufficiently adheres to confluent monolayers of human lung epithelial A549 and keratinocyte HaCaT cells. We then analyzed the cytotoxicity of C. albicans and C. glabrata, which adhered well to epithelial cells. C. glabrata has been found to cause more damage to A549 cells than to HaCaT cells, suggesting that resident Candida spp. have distinct cytotoxic effects in different tissues. It is important to clarify the properties of Candida spp. as there is evidence that normal microbiota can cause infections. Our data suggest that it is necessary to use appropriate cell lines for characterizing the adherence and cytotoxicity of Candida spp.

Increasing candidaemia incidence from 2004 to 2015 with a shift in epidemiology in patients preexposed to antifungals

Candidaemia is an important health problem in immunocompromised patients with an epidemiology varying with region, period and patient population involved. The occurrence of candidaemia and the associated species distribution over a 12-year period at a large tertiary care centre in Belgium were analysed. The trend in incidence in the intensive care units (ICUs) and non-ICUs was investigated as well as the influence of antifungal exposure on the species distribution. From 2004 until 2015, 865 candidaemia episodes occurred in 826 patients at the University Hospitals Leuven. Candida albicans (59%) remained the most important cause of candidaemia, followed by C. glabrata (22.4%) and C. parapsilosis (8%). The mean incidence in the whole hospital was 1.48 per 10 000 patient days (PD). The incidence in ICUs increased reaching up to 10.7 per 10 000 PD whereas in the non-ICUs, the incidence decreased. Prior exposure to fluconazole and echinocandins was associated with candidaemia caused by less susceptible species. Candidaemia incidence increased in the whole hospital, driven by ICUs. Surveillance of candidaemia epidemiology on a local scale is of high value to guide empirical treatment strategies.

Candidemia in the Neonatal Intensive Care Unit: A Retrospective, Observational Survey and Analysis of Literature Data

We evaluated the epidemiology of Candida bloodstream infections in the neonatal intensive care unit (NICU) of an Italian university hospital during a 9-year period as a means of quantifying the burden of infection and identifying emerging trends. Clinical data were searched for in the microbiological laboratory database. For comparative purposes, we performed a review of NICU candidemia. Forty-one candidemia cases were reviewed (overall incidence, 3.0 per 100 admissions). Candida parapsilosis sensu stricto (58.5%) and C. albicans (34.1%) were the most common species recovered. A variable drift through years was observed; in 2015, 75% of the cases were caused by non-albicans species. The duration of NICU hospitalization of patients with non-albicans was significantly longer than in those with C. albicans (median days, 10 versus 12). Patients with non-albicans species were more likely to have parenteral nutrition than those with C. albicans (96.3% versus 71.4%). Candida albicans was the dominant species in Europe and America (median, 55% and 60%; resp.); non-albicans species predominate in Asia (75%). Significant geographic variation is evident among cases of candidemia in different parts of the world, recognizing the importance of epidemiological data to facilitate the treatment.

Antifungal drug resistance among Candida species: mechanisms and clinical impact

The epidemiology of Candida infections has changed in recent years. Although Candida albicans is still the main cause of invasive candidiasis in most clinical settings, a substantial proportion of patients is now infected with non-albicans Candida species. The various Candida species vary in their susceptibility to the most commonly used antifungal agents, and the intrinsic resistance to antifungal therapy seen in some species, along with the development of acquired resistance during treatment in others, is becoming a major problem in the management of Candida infection. A better understanding of the mechanisms and clinical impact of antifungal drug resistance is essential for the efficient treatment of patients with Candida infection and for improving treatment outcomes. Herein, we report resistance to the azoles and echinocandins among Candida species.

Characteristics of hospital-acquired and community-onset blood stream infections, South-East Austria

Purpose

The objective of this study was to compare epidemiology, causative pathogens, outcome, and levels of laboratory markers of inflammation of community-onset (i.e. community-acquired and healthcare-associated) and hospital-acquired bloodstream infection (BSI) in South-East Austria.

Methods

In this prospective cohort study, 672 patients fulfilling criteria of systemic inflammatory response syndrome with positive peripheral blood cultures (277 community-onset [192 community-acquired, 85 healthcare-associated BSI], 395 hospital-acquired) were enrolled at the Medical University of Graz, Austria from 2011 throughout 2012. Clinical, microbiological, demographic as well as outcome and laboratory data was collected.

Results

Escherichia coli followed by Staphylococcus aureus were the most frequently isolated pathogens. While Streptococcus spp. and Escherichia coli were isolated more frequently in patients with community-onset BSI, Enterococcus spp., Candida spp., Pseudomonas spp., Enterobacter spp., and coagulase-negative staphylococci were isolated more frequently among those with hospital-acquired BSI. With regard to the outcome, 30-day (82/395 vs. 31/277; p = 0.001) and 90-day mortality (106/395 vs. 35/277; p<0.001) was significantly higher among patients with hospital-acquired BSI even though these patients were significantly younger. Also, hospital-acquired BSI remained a significant predictor of mortality in multivariable analysis. At the time the blood cultures were drawn, patients with community-onset BSI had significantly higher leukocyte counts, neutrophil-leucocyte ratios as well as C-reactive protein, procalcitonin, interleukin-6 and serum creatinine levels when compared to those with hospital-acquired BSI. Patients with healthcare-associated BSI presented with significantly higher PCT and creatinine levels than those with community-acquired BSI.

Conclusions

Hospital-acquired BSI was associated with significantly higher 30- and 90-day mortality rates. Hospital-acquired BSI therefore poses an important target for the most aggressive strategies for prevention and infection control.

In vitro susceptibility of Candida isolates from organ transplant recipients to newer antifungals

Organ transplant recipients (OTR) are at higher risk of developing life-threatening infections. In this study, we tested 527 Candida isolates obtained from the oral and genital mucosa from OTR and healthy controls in order to monitor antifungal susceptibility patterns in this particular risk group. Testing was carried out in parallel for already marketed azoles and anidulafungin. Minimal inhibitory concentrations (MICs) were determined using the E-test(®) for azoles and CLSI broth microdilution for anidulafungin. Overall, there was no difference in the distribution of Candida spp. for both groups, C. albicans being the most frequently isolated Candida sp. followed by C. glabrata. Also, there were only minor differences in the susceptibility patterns to all antifungal agents. All C. albicans isolates were fully susceptible to fluconazole and voriconazole. In C. glabrata, 2.2% (n = 1) were resistant to fluconazole, and 82.6% (n = 38) to itraconazole, and in C. krusei, 66.7% (n = 2) were resistant in itraconazole. All strains were susceptible to voriconazole. Only fluconazole showed a higher rate of resistant C. glabrata isolates for OTR (3.7%), whereas the control group showed only intermediate susceptible and no resistant isolates. As there are no breakpoints established for posaconazole by CLSI, breakpoints determined by EUCAST were used. A total of 87.9% of C. albicans, 81.3% of C. parapsilosis and 66.7% of C. tropicalis were considered susceptible. C. glabrata and C. krusei showed higher MIC values and thus lesser susceptibility than the other Candida species. There were no differences observed between OTR and control groups. For anidulafungin, 99.8% of C. albicans isolates were susceptible, 0.2% were intermediate, whereas for C. glabrata, only 95.3% were susceptible, 0.2% were resistant and 4.5% were interpreted as intermediate. Interestingly, the two resistant isolates were found in the control group. Also, the controls showed a marginally higher percentage of intermediate strains compared to the transplant patients. All in all, resistant isolates were only observed for C. glabrata of the control group.

Clinical and economic burden of invasive fungal diseases in Europe: focus on pre-emptive and empirical treatment of Aspergillus and Candida species

Invasive fungal diseases (IFDs) have been widely studied in recent years, largely because of the increasing population at risk. Aspergillus and Candida species remain the most common causes of IFDs, but other fungi are emerging. The early and accurate diagnosis of IFD is critical to outcome and the optimisation of treatment. Rapid diagnostic methods and new antifungal therapies have advanced disease management in recent years. Strategies for the prevention and treatment of IFDs include prophylaxis, and empirical and pre-emptive therapy. Here, we review the available primary literature on the clinical and economic burden of IFDs in Europe from 2000 to early 2011, with a focus on the value and outcomes of different approaches.

Epidemiology of candidaemia and invasive candidiasis. A changing face

Invasive candidiasis is a leading cause of mortality. Candidaemia is the most common clinical presentation of invasive candidiasis but more that 30% of these infections do not yield positive blood cultures. Candida albicans remains the predominant aetiology, accounting for 50% of all cases. However, there has been an epidemiological shift in the last decades. Some species of Candida different to C. albicans have emerged as an important cause of severe candidaemia as they can exhibit resistance to fluconazole and other antifungal agents. Moreover, there is a different distribution of non C. albicans Candida species in relationship to patients' and hospital characteristics. Thus, Candida parapsilosis has been associated to candidaemia in neonates and young adults. This species usually has an exogenously origin and contaminates medical devices, causing central venous catheter-associated candidaemias. Candida glabrata, Candida tropicalis and Candida krusei are isolated in blood cultures from older patients (>65 years) with important risk factors, such as major abdominal surgery, solid tumours and haematologic malignancies, transplants, and/or prolonged treatment with corticoids. Moreover, important geographical differences in the distribution of the Candida species different to C. albicans causing invasive candidiasis have been reported: C. parapsilosis predominates in Australia, Latin America and Mediterranean countries of Africa, Asia and Europe. In contrast, C. glabrata has an important aetiological role in USA and Central and Northern Europe. Finally, an important and worrying issue is that mortality due to invasive candidiasis remains unacceptably high. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).

Role of glutathione in the oxidative stress response in the fungal pathogen Candida glabrata

Candida glabrata, an opportunistic fungal pathogen, accounts for 18-26 % of all Candida systemic infections in the US. C. glabrata has a robust oxidative stress response (OSR) and in this work we characterized the role of glutathione (GSH), an essential tripeptide-like thiol-containing molecule required to keep the redox homeostasis and in the detoxification of metal ions. GSH is synthesized from glutamate, cysteine, and glycine by the sequential action of Gsh1 (γ-glutamyl-cysteine synthetase) and Gsh2 (glutathione synthetase) enzymes. We first screened for suppressor mutations that would allow growth in the absence of GSH1 (gsh1∆ background) and found a single point mutation in PRO2 (pro2-4), a gene that encodes a γ-glutamyl phosphate reductase and catalyzes the second step in the biosynthesis of proline. We demonstrate that GSH is important in the OSR since the gsh1∆ pro2-4 and gsh2∆ mutant strains are more sensitive to oxidative stress generated by H2O2 and menadione. GSH is also required for Cadmium tolerance. In the absence of Gsh1 and Gsh2, cells show decreased viability in stationary phase. Furthermore, C. glabrata does not contain Saccharomyces cerevisiae high affinity GSH transporter ortholog, ScOpt1/Hgt1, however, our genetic and biochemical experiments show that the gsh1∆ pro2-4 and gsh2∆ mutant strains are able to incorporate GSH from the medium. Finally, GSH and thioredoxin, which is a second redox system in the cell, are not essential for the catalase-independent adaptation response to H2O2.

Microsatellite genotyping clarified conspicuous accumulation of Candida parapsilosis at a cardiothoracic surgery intensive care unit

Candida parapsilosis has become a significant cause of invasive fungal infections in seriously ill patients. Nosocomial outbreaks through direct and indirect contact have been described. The aim of this study was the molecular characterization of what appeared to be an ongoing C. parapsilosis outbreak at the cardiothoracic intensive care unit of the University Hospital of Vienna between January 2007 and December 2008. Using two different molecular typing methods-automated repetitive sequence-based PCR (DiversiLab; bioMérieux) and microsatellite genotyping-we investigated the genetic relationship of 99 C. parapsilosis isolates. Eighty-three isolates originated from the cardiothoracic intensive care unit, while 16 isolates were random control isolates from other intensive care units and a different Austrian hospital. The 99 C. parapsilosis isolates analyzed by repetitive-element PCR all showed identical genotypes, suggesting an ongoing outbreak. In contrast, microsatellite genotyping showed a total of 56 different genotypes. Two major genotypes were observed in 10 and 15 isolates, respectively, whereas another 13 genotypes were observed in 2 to 4 isolates each. Forty-one genotypes were observed only once. Closely related genotypes that differed in only a single microsatellite marker were grouped into clonal complexes. When it comes to C. parapsilosis, microsatellite genotyping is a more discriminative method than repetitive-element PCR genotyping to investigate outbreaks.

Antifungal therapy in European hospitals: data from the ESAC point-prevalence surveys 2008 and 2009

The study aimed to identify targets for quality improvement in antifungal use in European hospitals and determine the variability of such prescribing. Hospitals that participated in the European Surveillance of Antimicrobial Consumption Point Prevalence Surveys (ESAC-PPS) were included. The WHO Anatomical Therapeutic Chemical (ATC) classification for 'antimycotics for systemic use' (J02) 2009 version was used. Demographic data and information about indications and diagnoses were collected in 2008 and 2009. From 99,053 patients, 29,324 (29.6%) received antimicrobials. Antifungals represented 1529 of 40,878 (3.7%) antimicrobials. Antifungals were mainly (54.2%) administered orally. Hospital-acquired infections represented 44.5% of indications for antifungals followed by medical prophylaxis at 31.2%. The site of infection was not defined in 36.0% of cases but the most commonly targeted sites were respiratory (19.2%) and gastrointestinal (18.8%). The most used antifungal was fluconazole (60.5%) followed by caspofungin (10.5%). Antifungal-antibacterial combinations were frequently used (77.5%). The predominance of fluconazole use in participating hospitals could result in an increase in prevalence of inherently resistant fungi, increasing the need for newer antifungals. Although acknowledging that antifungal prophylaxis in the immunocompromised host needs further exploration, repetitive surveys using ESAC-PPS methodology may help to monitor the effects of interventions set to regulate antifungal use.

[Epidemiological profile and sensitivity pattern of isolates causing invasive fungal infection vs. colonizing isolates in non-neutropenic critically ill patients]

BACKGROUND

Patients admitted to critical care units can be infected with a large number of fungal isolates that are occasionally responsible for invasive fungal infections (IFI).

AIMS

To describe the epidemiological profile and antifungal susceptibility patterns of fungal isolates in our unit, and to identify key risk factors associated with the development of IFI.

METHODS

A descriptive cohort and retrospective study with patients admitted to a polyvalent Critical Care Unit of a university hospital was carried out. The isolation of at least one fungal species in a culture of biological samples, over a period of 48 months was considered.

RESULTS

Twenty patients out of 232 developed IFI. Patients in the IFI group had a higher mortality and higher Candida score value 48 h prior to clinical diagnosis. Risk factors associated with the development of IFI were chronic obstructive pulmonary disease, gastrointestinal surgery, total parenteral nutrition, and prolonged systemic corticosteroid therapy. The predominant fungal species in both groups was Candida albicans, with global resistance to fluconazole and itraconazole of 1.94%.

CONCLUSIONS

We found a low incidence of species of Candida non-C. albicans in our unit. The rate of resistance to azoles in C. albicans was similar to that of larger series. Gastrointestinal surgery, COPD, prolonged treatment with corticosteroids, and parenteral nutrition administration are risk factors associated with the development of IFI.

[Trends in systemic antifungal use in critically ill patients. Multicenter observational study, 2006-2010]

INTRODUCTION

There are limited data about the use of antifungal agents (AF) in critically ill patients and treatment trends since the inclusion of the new generation AF. The use of these agents may have a significant influence on the development of new resistances.

METHODS

Observational prospective study of the systemic use of AF in patients admitted to Spanish intensive care units (ICU) participating in the ENVIN-HELICS register, from 2006 to 2010. The annual use, the indications that led to that use and, the intra-ICU infections, the AF employment related to the hospital size, and per 1000 patients/day, were compared.

RESULTS

Of the 8240 prescriptions for AF, fluconazole and caspofungin were the most often employed (55% and 19.5%, respectively). An increase in use was observed to the year 2008, with subsequent stabilisation. A decrease in the use of fluconazole and an increase in echinocandins consumption was observed over time. As regards the intra-ICU infections, the AF were ordered empirically in 47.9% of the indications. Fluconazole was more frequently used in medium size hospitals than in the large ones (60.4% versus 53.3%; P=.036) and the opposite occurred in the case of caspofungin (15.8% versus 21.8%; P<.001). Fluconazole was more prematurely employed (median 12 days since ICU admission) and the duration of the therapy was similar to the other AF (median 8 days). The total therapy days were 39.51 per 1000 patient/day, with predominance in fluconazole use (21.48 per 1000 patients/day).

CONCLUSIONS

Fluconazole is the most used antifungal agent in critically ill patients in any of the indications, although a progressive decrease in its use is observed, with a proportional increase in the use of echinocandins.

Efficacy of micafungin in empirical therapy of deep mycosis in surgically ill patients

Micafungin (MCFG), an echinocandin antifungal agent, exhibits antifungal activity against Candida albicans and non-albicans Candida. The fungicidal activity of MCFG against clinical isolates of Candida species was investigated, and the clinical efficacy of MCFG in therapy of deep mycosis in surgery was studied using the AKOTT algorithm. The minimum inhibitory concentration and minimum fungicidal concentration values of fluconazole were ≤0.06-4 and >64 μg/ml, respectively, for each strain, whereas these values of MCFG were 0.008-0.5 and 0.016-1 μg/ml, suggesting that MCFG provided superior fungicidal ability against Candida albicans and non-albicans Candida. The subjects were separated into two groups: group A consisted of 20 subjects with both persisting fever refractory to broad-spectrum antibiotics and positive reaction to β-D-glucan test, and group B consisted of 20 subjects with either of those conditions. The overall response was evaluated as "effective" in 17 patients (85%) and 20 patients (100%) in groups A and B, respectively. In total, response was evaluated as "effective" in 37 patients (92.5%) and "ineffective" in 3 patients (7.5%). These findings suggest that MCFG administration should be used as empirical therapy for deep mycosis in surgically ill patients as it was shown to be an effective antifungal drug lacking serious adverse effects.

Hosting infection: experimental models to assay Candida virulence

Although normally commensals in humans, Candida albicans, Candida tropicalis, Candida parapsilosis, Candida glabrata, and Candida krusei are capable of causing opportunistic infections in individuals with altered physiological and/or immunological responses. These fungal species are linked with a variety of infections, including oral, vaginal, gastrointestinal, and systemic infections, with C. albicans the major cause of infection. To assess the ability of different Candida species and strains to cause infection and disease requires the use of experimental infection models. This paper discusses the mucosal and systemic models of infection available to assay Candida virulence and gives examples of some of the knowledge that has been gained to date from these models.

E1210, a new broad-spectrum antifungal, suppresses Candida albicans hyphal growth through inhibition of glycosylphosphatidylinositol biosynthesis

Continued research toward the development of new antifungals that act via inhibition of glycosylphosphatidylinositol (GPI) biosynthesis led to the design of E1210. In this study, we assessed the selectivity of the inhibitory activity of E1210 against Candida albicans GWT1 (Orf19.6884) protein, Aspergillus fumigatus GWT1 (AFUA_1G14870) protein, and human PIG-W protein, which can catalyze the inositol acylation of GPI early in the GPI biosynthesis pathway, and then we assessed the effects of E1210 on key C. albicans virulence factors. E1210 inhibited the inositol acylation activity of C. albicans Gwt1p and A. fumigatus Gwt1p with 50% inhibitory concentrations (IC(50)s) of 0.3 to 0.6 μM but had no inhibitory activity against human Pig-Wp even at concentrations as high as 100 μM. To confirm the inhibition of fungal GPI biosynthesis, expression of ALS1 protein, a GPI-anchored protein, on the surfaces of C. albicans cells treated with E1210 was studied and shown to be significantly lower than that on untreated cells. However, the ALS1 protein levels in the crude extract and the RHO1 protein levels on the cell surface were found to be almost the same. Furthermore, E1210 inhibited germ tube formation, adherence to polystyrene surfaces, and biofilm formation of C. albicans at concentrations above its MIC. These results suggested that E1210 selectively inhibited inositol acylation of fungus-specific GPI which would be catalyzed by Gwt1p, leading to the inhibition of GPI-anchored protein maturation, and also that E1210 suppressed the expression of some important virulence factors of C. albicans, through its GPI biosynthesis inhibition.

Efficacy of oral E1210, a new broad-spectrum antifungal with a novel mechanism of action, in murine models of candidiasis, aspergillosis, and fusariosis

E1210 is a first-in-class, broad-spectrum antifungal with a novel mechanism of action-inhibition of fungal glycosylphosphatidylinositol biosynthesis. In this study, the efficacies of E1210 and reference antifungals were evaluated in murine models of oropharyngeal and disseminated candidiasis, pulmonary aspergillosis, and disseminated fusariosis. Oral E1210 demonstrated dose-dependent efficacy in infections caused by Candida species, Aspergillus spp., and Fusarium solani. In the treatment of oropharyngeal candidiasis, E1210 and fluconazole each caused a significantly greater reduction in the number of oral CFU than the control treatment (P < 0.05). In the disseminated candidiasis model, mice treated with E1210, fluconazole, caspofungin, or liposomal amphotericin B showed significantly higher survival rates than the control mice (P < 0.05). E1210 was also highly effective in treating disseminated candidiasis caused by azole-resistant Candida albicans or Candida tropicalis. A 24-h delay in treatment onset minimally affected the efficacy outcome of E1210 in the treatment of disseminated candidiasis. In the Aspergillus flavus pulmonary aspergillosis model, mice treated with E1210, voriconazole, or caspofungin showed significantly higher survival rates than the control mice (P < 0.05). E1210 was also effective in the treatment of Aspergillus fumigatus pulmonary aspergillosis. In contrast to many antifungals, E1210 was also effective against disseminated fusariosis caused by F. solani. In conclusion, E1210 demonstrated consistent efficacy in murine models of oropharyngeal and disseminated candidiasis, pulmonary aspergillosis, and disseminated fusariosis. These data suggest that further studies to determine E1210's potential for the treatment of disseminated fungal infections are indicated.

The role of fluconazole in the treatment of Candida endocarditis: a meta-analysis

The treatment of Candida infective endocarditis generally involves infected valve removal accompanied by antifungal therapy with amphotericin B or a lipid-based derivative, with or without flucytosine. While often used as chronic suppressive therapy in these patients, the precise role for fluconazole has not been established. We conducted a meta-analysis of 64 literature cases of Candida endocarditis whose management did not include valve replacement but who received fluconazole, alone or concurrently or in sequence with 1 or more other antifungal drugs.Forty-nine (77%) patients were cured (n = 44) or improved (n = 5), 4 relapsed (6%), and 11 failed (10 of whom died) (17%). Among 19 patients for whom fluconazole was administered as the sole antifungal therapy, 11 (58%) were cured or improved. In contrast, among 45 patients who received 1 or more other antifungal agents in addition to fluconazole, 38 (84%) were cured or improved (p = 0.02). Eighteen of 21 (86%) patients with native valve infection were cured or improved compared with 13 of 19 (68%) patients with prosthetic valve endocarditis (p = 0.13). The mean duration of successful fluconazole regimens was 134 days. Twenty of 21 (95%) patients who received fluconazole as chronic suppressive therapy for ≥6 months were cured. Prognosis was independent of Candida species or patient age. Among 23 historical controls managed with fluconazole-containing antifungal therapy plus valvular surgery, survival was 91%.In conclusion, fluconazole-containing, combination antifungal therapy, with or without concomitant valve replacement, and followed by prolonged, perhaps indefinite fluconazole suppression, is effective in patients with Candida endocarditis.

Eleven-year retrospective survey of candidaemia in a university hospital in southwestern Greece

The aim of this study was to investigate the isolation and distribution rate of Candida spp. in blood cultures and evaluate antifungal susceptibility during an 11-year period (1998–2008) at a tertiary-care hospital. The causative species were as follows: Candida albicans, 163 strains (64%); Candida parapsilosis, 35 strains (13.7%); Candida glabrata, 25 strains (9.8%); Candida tropicalis, 19 strains (7.4%); and other Candida spp., 13 strains (5.1%). Candidaemia is predominantly caused by C. albicans. C. parapsilosis is the most common non-albicans Candida isolated in neonatal intensive-care units. All Candida isolates remain susceptible to amphotericin B, whereas the highest degree of resistance was observed for azoles.

Cdr2p contributes to fluconazole resistance in Candida dubliniensis clinical isolates

The development of resistance to azole antifungals used in the treatment of fungal infections can be a serious medical problem. Here, we investigate the molecular mechanisms associated with reduced susceptibility to fluconazole in clinical isolates of Candida dubliniensis , showing evidence of the trailing growth phenomenon. The changes in membrane sterol composition were studied in the presence of subinhibitory fluconazole concentrations. Despite lanosterol and eburicol accumulating as the most prevalent sterols after fluconazole treatment, these ergosterol precursors still support growth of Candida isolates. The overexpression of ABC transporters was demonstrated by immunoblotting employing specific antibodies against Cdr1p and Cdr2p. The presence of a full-length 170 kDa protein Cdr1p was detected in two isolates, while a truncated form of Cdr1p with the molecular mass of 85 kDa was observed in isolate 966/3(2). Notably, Cdr2p was detected in this isolate, and the expression of this transporter was modulated by subinhibitory concentrations of fluconazole. These results suggest that C. dubliniensis can display the trailing growth phenomenon, and such isolates express similar molecular mechanisms like that of fluconazole-resistant isolates and can therefore be associated with recurrent infections.

Epidemiology of invasive candidiasis

PURPOSE OF REVIEW

This review covers candidaemia in numbers, susceptibility issues, host groups, risk factors and outcome.

RECENT FINDINGS

The incidence of candidaemia has increased over the last decades. Candida glabrata is particularly common in the northern hemisphere and with increasing age whilst the opposite is true for C. parapsilosis, C. glabrata, C. krusei and a number of emerging species are not fully susceptible to azoles. C. parapsilosis and C. guilliermondii are not fully susceptible to echinocandins. Increasing rates of C. parapsilosis have been observed at centres with a high use of echinocandins, and outcome for this species is not superior comparing echinocandins with fluconazole. Acquired azole resistance has recently been described in as many as a third of 19% resistant isolates and echinocandin resistance has emerged and been detected as early as day 12 of echinocandin therapy. ICU stay and abdominal surgery are among the most important risk factors. Outcome is dependent on species involved, timing, dosing and choice of therapy and management of the primary focus of infection. However, host factors are dominating predictors of mortality in recent studies of ICU candidiasis.

SUMMARY

The changing epidemiology highlights the need for close monitoring of local incidence, species distribution and susceptibility in order to optimize therapy and outcome.

National surveillance of fungemia in Denmark (2004 to 2009)

A 6-year nationwide study of fungemia in Denmark was performed using data from an active fungemia surveillance program and from laboratory information systems in nonparticipating regions. A total of 2,820 episodes of fungemia were recorded. The incidence increased from 2004 to 2007 (7.7 to 9.6/100,000) and decreased slightly from 2008 to 2009 (8.7 to 8.6/100,000). The highest incidences were seen at the extremes of age (i.e., 11.3 and 37.1/100,000 for those <1 and 70 to 79 years old, respectively). The rate was higher for males than for females (10.1 versus 7.6/100,000, P = 0.003), with the largest difference observed for patients >50 years of age. The species distribution varied significantly by both age and gender. Candida species accounted for 98% of the pathogens, and C. albicans was predominant, although the proportion decreased (64.4% to 53.2%, P < 0.0001). C. glabrata ranked second, and the proportion increased (16.5% to 25.9%, P = 0.003). C. glabrata was more common in adults and females than in children and males, whereas C. tropicalis was more common in males (P = 0.020). C. krusei was a rare isolate (4.1%) except at one university hospital. Acquired resistance to amphotericin and echinocandins was rare. However, resistance to fluconazole (MIC of >4 μg/ml) occurred in C. albicans (7/1,183 [0.6%]), C. dubliniensis (2/65 [3.1%]), C. parapsilosis (5/83 [6.0%]), and C. tropicalis (7/104 [6.7%]). Overall, 70.8% of fungemia isolates were fully fluconazole susceptible, but the proportion decreased (79.7% to 68.9%, P = 0.02). The study confirmed an incidence rate of fungemia in Denmark three times higher than those in other Nordic countries and identified marked differences related to age and gender. Decreased susceptibility to fluconazole was frequent and increasing.

Candida tropicalis in human disease

Candida tropicalis is one of the more common Candida causing human disease in tropical countries; the frequency of invasive disease varies by geography causing 3--66% of candidaemia. C. tropicalis is taxonomically close to C. albicans and shares many pathogenic traits. C. tropicalis is particularly virulent in neutropenic hosts commonly with hematogenous seeding to peripheral organs. For candidaemia and invasive candidiasis amphotericin B or an echinocandin are recommended as first-line treatment, with extended-spectrum triazoles acceptable alternatives. Primary fluconazole resistance is uncommon but may be induced on exposure. Physicians in regions where C. tropicalis is common need to be mindful of this lesser-described pathogen.

Regulation of Candida glabrata oxidative stress resistance is adapted to host environment

The human fungal pathogen Candida glabrata is related to Saccharomyces cerevisiae but has developed high resistance against reactive oxygen species. We find that induction of conserved genes encoding antioxidant functions is dependent on the transcription factors CgYap1 and CgSkn7 which cooperate for promoter recognition. Superoxide stress resistance of C. glabrata is provided by superoxide dismutase CgSod1, which is not dependent on CgYap1/Skn7. Only double mutants lacking both CgSod1 and CgYap1 were efficiently killed by primary mouse macrophages. Our results suggest that in C. glabrata the regulation of key genes providing stress protection is adopted to meet a host-pathogen situation.

Multilocus microsatellite markers for molecular typing of Candida glabrata: application to analysis of genetic relationships between bloodstream and digestive system isolates

Candida glabrata has emerged as the second most common etiologic agent, after Candida albicans, of superficial and invasive candidiasis in adults. Strain typing is essential for epidemiological investigation, but easy-to-use and reliable typing methods are still lacking. We report the use of a multilocus microsatellite typing method with a set of eight markers on a panel of 180 strains, including 136 blood isolates from hospitalized patients and 34 digestive tract isolates from nonhospitalized patients. A total of 44 different alleles were observed, generating 87 distinct genotypes. In addition to perfect reproducibility, typing ability, and stability, the method had a discriminatory power calculated at 0.97 when all 8 markers were associated, making it suitable for tracing strains. In addition, it is shown that digestive tract isolates differed from blood culture isolates by exhibiting a higher genotypic diversity associated with different allelic frequencies and preferentially did not group in clonal complexes (CCs). The demonstration of the occurrence of microevolution in digestive strains supports the idea that C. glabrata can be a persistent commensal of the human gut.

Candida isolation in patients hospitalized on a surgical ward: significance and mortality-related factors

BACKGROUND

Infections caused by Candida are an emerging pathology on surgical wards. The aim of the present study was to evaluate the incidence, characteristics, and predictive factors of mortality in patients colonized and/or infected by Candida spp. in this setting.

METHODS

A consecutive series of 105 patients hospitalized on a general surgery ward between 2000 and 2004 were included, and 118 positive cultures for Candida were identified. The variables age, sex, previous medical history, current disease, anemia, ICU stay, type and localization of the microorganism, need for parenteral nutrition, and transfusions were recorded. The primary outcome was in-hospital mortality. A univariate analysis was performed to determine which of these variables were associated with mortality. With a logistic regression model, independent prognostic factors of mortality were determined.

RESULTS

The prevalence of patients colonized and/or infected by Candida on our surgical ward was 0.98% (CI 95%: 0.79-1.17), and the incidence was 49 cases per 1,000 patient-years. Of the 105 patients in this series, 56 were men (53%) and 49 women (47%); the mean age was 63.8 years (SD +/- 15.7). Twelve patients (11.4%) had candidemia. Crude mortality was 23% (24 patients), whereas the mortality attributable to candidemia was 25% (3/12 cases). Anemia (p = 0.001); transfusions (p = 0.003), and an ICU stay (p = 0.002) were associated with mortality. Candidemia was associated with neoplasms (p = 0.02) and the infection caused by Candida parapsilosis (p = 0.04). The only independent factor related to mortality was the anemia (p = 0.028; Odds Ratio: 6.43; 95% CI: 1.23-33.73).

CONCLUSIONS

Colonization and/or infection by Candida spp. in non-ICU hospitalized surgical patients implies a relative high mortality. Anemia is an independent factor for mortality.

Autophagy supports Candida glabrata survival during phagocytosis

The opportunistic human fungal pathogen Candida glabrata is confronted with phagocytic cells of the host defence system. Survival of internalized cells is thought to contribute to successful dissemination. We investigated the reaction of engulfed C. glabrata cells using fluorescent protein fusions of the transcription factors CgYap1 and CgMig1 and catalase CgCta1. The expression level and peroxisomal localization of catalase was used to monitor the metabolic and stress status of internalized C. glabrata cells. These reporters revealed that the phagocytosed C. glabrata cells were exposed to transient oxidative stress and starved for carbon source. Cells trapped within macrophages increased their peroxisome numbers indicating a metabolic switch. Prolonged phagocytosis caused a pexophagy-mediated decline in peroxisome numbers. Autophagy, and in particular pexophagy, contributed to survival of C. glabrata during engulfment. Mutants lacking CgATG11 or CgATG17, genes required for pexophagy and non-selective autophagy, respectively, displayed reduced survival rates. Furthermore, both CgAtg11 and CgAtg17 contribute to survival, since the double mutant was highly sensitive to engulfment. Inhibition of peroxisome formation by deletion of CgPEX3 partially restored viability of CgATG11 deletion mutants during engulfment. This suggests that peroxisome formation and maintenance might sequester resources required for optimal survival. Mobilization of intracellular resources via autophagy is an important virulence factor that supports the viability of C. glabrata in the phagosomal compartment of infected innate immune cells.

The changing face of epidemiology of invasive fungal disease in Europe

Invasive fungal diseases (IFDs) are an increasingly common complication in critically ill patients in Europe and are frequently fatal. Because of changes in treatment strategies and the increased use of antifungal prophylaxis, the epidemiology of IFDs has changed substantially in recent years and infections due to Candida species are no longer the majority in many institutions. In contrast, the emergence of non-Candida IFDs such as aspergillosis, zygomycosis and fusariosis has increased. European surveys indicate that Candida albicans is responsible for more than half the cases of invasive candidaemia; however, the occurrence of non-albicans-related IFDs appears to be increasing. Rates of IFD-related mortality in Europe depend on the pathogen, geographical location and underlying patient characteristics, with rates ranging from 28 to 59% for Candida infections and from 38 to 80% for invasive aspergillosis. Early initiation of antifungal therapy is critical for improving outcomes; however, this is complicated by the difficulty in diagnosing IFDs rapidly and accurately. The introduction of new extended-spectrum azole antifungal agents (e.g. voriconazole, posaconazole) and echinocandins (e.g. micafungin, caspofungin, anidulafungin) has increased the number of therapeutic options for early therapy. Choice between agents should be based on a variety of factors, including spectrum of activity, adverse events, drug interactions, route of administration, clinical efficacy of individual agents and local epidemiology.

Infections caused by Candida krusei in five transplant and two surgical patients

BACKGROUND

Candida krusei (Ck) may cause severe infections in immunocompromised hosts and is innately resistant to fluconazole.

PATIENTS AND METHODS

During an 18-month period, seven patients with Ck infection were identified at our center. All were treated in the transplant intensive care unit. Candida isolates were grown on Sabouraud agar, and chromosomal DNA was extracted; clonality was investigated using random amplified polymorphic DNA-polymerase chain reaction with primers M13, OPA-18, and OPE-18.

RESULTS

Among the patients with Ck infection, there were three pancreas recipients with intra-abdominal infection, one liver recipient with cholangitis, one lung recipient with pleural empyema, one patient with pleural empyema after esophageal perforation, and one case of pneumonia in a patient with a ventricular assist device. Treatment consisted of caspofungin (n = 3), voriconazole (n = 1), or a combination of the two (n = 2) together with surgery (n = 3) or pigtail catheter drainage (n = 3). One patient underwent drainage without antifungal treatment, and one patient did not have drainage. The infection was controlled in all cases. The patient with the assist device died from multiple organ dysfunction, the lung recipient died after four months from graft failure, and one pancreas graft was lost. Four patients (57%) harbored the same Ck strain.

CONCLUSION

Solid organ recipients seem to be at particular risk for Ck infections; clonal outbreaks may occur in intensive care units.

Genetic variability of Candida albicans isolates in a university hospital in Hungary

The occurrence and genetic variability of Candida albicans isolates in a Hungarian hospital were examined. Among the 103 Candida isolates, 44 (42.7%) proved to be C. albicans species. Comparing with a previous study carried out in 2002, the percentage of infections caused by C. albicans decreased in Hungary in this period with an increasing incidence of non-albicans species, in accordance with the world-wide trend. The genetic variability of the isolates was examined using mitochondrial DNA (mtDNA), restriction fragment length polymorphism (RFLP), random amplified polymorphic DNA (RAPD) analysis and electrophoretic karyotyping. The examined C. albicans isolates could be clustered into four groups based on their mtDNA profiles. The electrophoretic karyotypes of the isolates were mostly identical to that of the reference strain 1006, with the exception of mtDNA type II isolates. RAPD analysis could be used to cluster the isolates into different groups, but this clustering was not in complete agreement with their assignment to mtDNA types. Population genetic analyses of the data indicated low amounts of recombination among these C. albicans strains. None of the isolates exhibited decreased susceptibilities to 5-fluorocytosine.