Candidosis in the intensive care unit: a 20-year survey

Atypical changes in Candida albicans cells treated with the Venetin-1 complex from earthworm coelomic fluid

In the present research, the effect of a protein-polysaccharide complex Venetin-1 obtained from the coelomic fluid of Dendrobaena veneta earthworm on Candida albicans cells was characterized. The compound destroyed fungal cells without showing cytotoxicity to human skin fibroblasts, which was demonstrated in earlier studies. Since it had an effect on the fungal cell wall and membrane, this complex was compared with the known antifungal antibiotic fluconazole. Both preparations disturbed the division of yeast cells and resulted in the formation of aggregates and chains of unseparated cells, which was illustrated by staining with fluorochromes. Fluorescent staining of the cell wall with Calcofluor white facilitated comparison of the types of aggregates formed after the action of both substances. The analysis performed with the use of Congo red showed that Venetin-1 exposed deeper layers of the cell wall, whereas no such effect was visible after the use of fluconazole. The FTIR analysis confirmed changes in the mannoprotein layer of the cell wall after the application of the Venetin-1 complex. Staining with Rhodamine 123 and the use of flow cytometry allowed comparison of changes in the mitochondria. Significantly elongated mitochondria were observed after the Venetin-1 application, but not after the application of the classic antibiotic. Phase contrast microscopy revealed vacuole enlargement after the Venetin-1 application. The flow cytometry analysis of C. albicans cells treated with Venetin-1 and fluconazole showed that both substances caused a significant decrease in cell viability.

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

Introduction

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

Aim of the study

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

Methods

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

Results

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

Conclusion

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

A new assay based on terminal restriction fragment length polymorphism of homocitrate synthase gene fragments for Candida species identification

Candida sp. have been responsible for an increasing number of infections, especially in patients with immunodeficiency. Species-specific differentiation of Candida sp. is difficult in routine diagnosis. This identification can have a highly significant association in therapy and prophylaxis. This work has shown a new application of the terminal restriction fragment length polymorphism (t-RFLP) method in the molecular identification of six species of Candida, which are the most common causes of fungal infections. Specific for fungi homocitrate synthase gene was chosen as a molecular target for amplification. The use of three restriction enzymes, DraI, RsaI, and BglII, for amplicon digestion can generate species-specific fluorescence labeled DNA fragment profiles, which can be used to determine the diagnostic algorithm. The designed method can be a cost-efficient high-throughput molecular technique for the identification of six clinically important Candida species.

Study of strains of Candida spp. Isolated from catheters in UHC of Oran (Algeria): Identification and antifungal susceptibility

OBJECTIVES

The increasing incidence of Candida spp., and the vital prognosis often compromise for patients with Candida species make urgent the exact knowledge of their distribution worldwide and exhaust action antifungals currently used in clinical. That why we carry out an epidemiological study of Candida species and testing their susceptibility against two antifungals: amphotericin B and caspofungin.

MATERIALS AND METHODS

Samplings of peripheral venous catheters (PVC) were carried out from during 8months on the services of Internal medicine, Surgery A and Neonatology of Oran's University Hospital Center (UHC). The study of the susceptibility of Candida species to antifungal agents was performed according to the Clinical Laboratory Standards Institute (CLSI 2008).

RESULTS

From 300 samples, 25 yeasts were isolated. The rate of colonization PVC was 8.33% by Candida spp. The most isolated strains were Candida parapsilosis with 64% of cases, followed by Candida albicans (12%) then 8% for Candida glabrata and Candida krusei. However, only 4% of isolates were Candida famata or Candida lusitaniae. Furthermore all isolated strains were susceptible to amphotericin B with Minimum Inhibitory Concentrations (MIC) ranging from 0.25 to 1μg/mL. MIC obtained with caspofungin vary from 0.0625 to 2μg/mL for all strains. Moreover, one strain of C. krusei is resistant to caspofungin with a MIC superior to 8μg/mL.

CONCLUSION

All though caspofungin is at least as effective as amphotericin B, it is better tolerated for the treatment of invasive fungal infections.

Per-species risk factors and predictors of invasive Candida infections in patients admitted to pediatric intensive care units: development of ERICAP scoring systems

BACKGROUND

Prediction rules for invasive Candida infection (ICI) are available for adult but not for infants and children managed in pediatric intensive care units (PICU).

METHODS

Observational study in 24 PICU with prospective phase (all children admitted during 1 year) and retrospective review of ICI records. Four logistic regression models were performed using ICI by Candida spp., Candida albicans, Candida parapsilosis or Candida tropicalis as dependent variables. Scores were constructed.

RESULTS

One hundred and twenty five ICI (47 C. albicans, 37 C. parapsilosis, 19 C. tropicalis and 22 others) and 1022 controls were included. Incidence (cases/100 PICU admissions): 4.22 (all Candida), 2.44 (C. albicans), 1.41 (C. parapsilosis), 0.19 (C. tropicalis). ICI was associated [Area under the receiver operating characteristics curve (AUC) = 0.764, 95% confidence interval (CI) = 0.719-0.809, P < 0.001] with pre-PICU hospitalization ≥ 15 days [odds ratio (OR) = 3.3; score: +3], fever (OR = 2.6; +2), thrombopenia (OR = 2.0; +1) and parenteral nutrition (OR=2.4; +2). Additionally, the following associations were noted: C. albicans ICI (AUC = 0.716, 95% CI = 0.640-0.792, P < 0.001) with chronic metabolic disease (OR = 10.7; score:+4), surgical digestive process (OR = 2.8; +1), fever (OR = 2.8; +1) and parenteral nutrition (OR = 2.3; +1); C. parapsilosis ICI (AUC = 0.808, 95% CI = 0.739-0.877, P < 0.001) with previous colonization (OR = 7.1; score:+3), tracheostomy (OR = 5.1; +2), parenteral nutrition (OR = 4.3; +2), thrombopenia (OR = 3.6; +1) and previous bacterial infection (OR = 3.0; +1) and ICI by C. tropicalis (AUC = 0.941, 95% CI=0.886-0.995, P < 0.001) with thrombopenia (OR = 53.8; score: +10), neutropenia (OR = 7.2; +1), pre-PICU hospitalization ≥ 15 days (OR = 17.2; +3) and hematologic (OR = 22.4; +4) and cardiovascular infectious processes (OR = 5.5; +1). Specificity was >90% for cut offs of 5 (all Candida), 3 (C. albicans), 3 (C. parapsilosis) and 11 (C. tropicalis).

CONCLUSIONS

Once validated, these scores may help for identification of ICI by specific species allowing adequate empiric/prophylactic treatment.

Epidemiology and risk factors for invasive candidiasis

The number of immunosuppressive patients has increased significantly in recent years. These patients are at risk for opportunistic infections, especially fungal infections. Candidiasis is one of the most frequent fungal infections determined in these immunosuppressive patients and its epidemiology has changed over the last two decades. Recently, new antifungal agents and new therapy strategies such as antifungal prophylaxis, secondary prophylaxis, and preemptive therapy have come into use. These changes resulted in the alteration of Candida species causing invasive infections. The incidence of Candida albicans was decreased in many countries, especially among patients with immunosuppressive disorders, while the incidence of species other than C. albicans was increased. In this review, incidence, risk factors, and species distribution of invasive candidiasis are discussed.

Intermolecular interaction of voriconazole analogues with model membrane by DSC and NMR, and their antifungal activity using NMR based metabolic profiling

The development of novel antifungal agents with high susceptibility and increased potency can be achieved by increasing their overall lipophilicity. To enhance the lipophilicity of voriconazole, a second generation azole antifungal agent, we have synthesized its carboxylic acid ester analogues, namely p-methoxybenzoate (Vpmb), toluate (Vtol), benzoate (Vbz) and p-nitrobenzoate (Vpnb). The intermolecular interactions of these analogues with model membrane have been investigated using nuclear magnetic resonance (NMR) and differential scanning calorimetric (DSC) techniques. The results indicate varying degree of changes in the membrane bilayer's structural architecture and physico-chemical characteristics which possibly can be correlated with the antifungal effects via fungal membrane. Rapid metabolite profiling of chemical entities using cell preparations is one of the most important steps in drug discovery. We have evaluated the effect of synthesized analogues on Candida albicans. The method involves real time (1)H NMR measurement of intact cells monitoring NMR signals from fungal metabolites which gives Metabolic End Point (MEP). This is then compared with Minimum Inhibitory Concentration (MIC) determined using conventional methods. Results indicate that one of the synthesized analogues, Vpmb shows reasonably good activity.

Intensive care unit-related fluconazole use in Spain and Germany: patient characteristics and outcomes of a prospective multicenter longitudinal observational study

BACKGROUND

Candida spp. are a frequent cause of nosocomial bloodstream infections worldwide.

OBJECTIVE

To evaluate the use patterns and outcomes associated with intravenous (IV) fluconazole therapy in intensive care units in Spain and Germany.

PATIENTS AND METHODS

The research reported here was a prospective multicenter longitudinal observational study in adult intensive care unit patients receiving IV fluconazole. Demographic, microbiologic, therapy success, length of hospital stay, adverse event, and all-cause mortality data were collected at 14 sites in Spain and five in Germany, from February 2004 to November 2005.

RESULTS

Patients (n = 303) received prophylaxis (n = 29), empiric therapy (n = 140), preemptive therapy (n = 85), or definitive therapy (n = 49). A total of 298 patients (98.4%) were treated with IV fluconazole as first-line therapy. The treating physicians judged therapy successful in 66% of prophylactic, 55% of empiric, 45% of preemptive, and 43% of definitive group patients. In the subgroup of 152 patients with proven and specified Candida infection only, 32% suffered from Candida specified as potentially resistant to IV fluconazole. The overall mortality rate was 42%.

CONCLUSION

Our study informs treatment decision makers that approximately 32% of the patients with microbiological results available suffered from Candida specified as potentially resistant to IV fluconazole, highlighting the importance of appropriate therapy.

Assessment of the types of catheter infectivity caused by Candida species and their biofilm formation. First study in an intensive care unit in Algeria

Nosocomial candidiasis remains a potential risk in intensive care units (ICUs), wherein Candida albicans is most responsible for its occurrence. Equally, non-C. albicans species, especially C. glabrata, are also involved. These infections are frequently associated with biofilms that contaminate medical devices, such as catheters. These biofilms constitute a significant clinical problem, and cause therapeutic failures, because they can escape the immune response and considerably decrease sensitivity to antifungal therapy. The diagnosis of catheter-related candidiasis is difficult; however, the differentiation between an infection of the catheter (or other medical implant) and a simple contamination is essential to start an antifungal treatment. Among the methods used for this type of study is the Brun-Buisson method, but this method only examines the infectivity of catheters caused by bacteria. For this reason, we wanted to adapt this method to the yeast cells of Candida spp. To assess the various types of infectivity of catheters (contamination, colonization, or infection) and their corresponding rates, as well as the responsible yeast species, we conducted our study, between February 2011 and January 2012, in the ICU at the University Hospital Center of Sidi Bel Abbes, Algeria; during this study, we took photographic images of the tongue of one patient and of that patient’s implanted orobronchial catheter. In addition, catheters contaminated by C. albicans biofilms were observed by scanning electron microscopy.

Oral nystatin prophylaxis in surgical/trauma ICU patients: a randomised clinical trial

Introduction

Candida prophylaxis in ICU is still a matter of debate. Oral chemoprophylaxis has been advocated to reduce the incidence of Candida colonisation and infection.

Methods

We performed a randomised trial studying a single drug (nystatin) versus control in surgical/trauma ICU patients. Multiple-site testing for fungi was performed in each patient on ICU admission (T0) and subsequently every 3 days (T3, T6, T9, and so forth). The primary evaluation criterion was the time course of the corrected colonisation index.

Results

Ninety-nine patients were enrolled. At admission, 69 patients exhibited Candida colonisation: the most frequently colonised body sites were the stomach and the pharynx. The most frequent isolated species was Candida albicans. The corrected colonisation index was similar in the two groups at T0 (P = 0.36), while a significant statistical difference was observed between the treatment and control groups at T6 (median 0.14 and 0.33, respectively; P = 0.0016), at T9 (median 0.00 and 0.28, respectively; P = 0.0001), at T12 (median 0.00 and 0.41, respectively; P = 0.0008), and at T15 (median 0.00 and 0.42, respectively; P <0.0003). The same results were obtained in the subgroup of patients already colonised at ICU admission.

Conclusion

This trial shows that nystatin prophylaxis significantly reduces fungal colonisation in surgical/trauma ICU patients, even if already colonised.

Trial registration

ClinicalTrials.gov: NCT01495039

Candida dubliniensis: an appraisal of its clinical significance as a bloodstream pathogen

A nine-year prospective study (2002–2010) on the prevalence of Candida dubliniensis among Candida bloodstream isolates is presented. The germ tube positive isolates were provisionally identified as C. dubliniensis by presence of fringed and rough colonies on sunflower seed agar. Subsequently, their identity was confirmed by Vitek2 Yeast identification system and/or by amplification and sequencing of the ITS region of rDNA. In all, 368 isolates were identified as C. dubliniensis; 67.1% came from respiratory specimens, 11.7% from oral swabs, 9.2% from urine, 3.8% from blood, 2.7% from vaginal swabs and 5.4% from other sources. All C. dubliniensis isolates tested by Etest were susceptible to voriconazole and amphotericin B. Resistance to fluconazole (≥8 µg/ml) was observed in 2.5% of C. dubliniensis isolates, 7 of which occurred between 2008–2010. Of note was the diagnosis of C. dubliniensis candidemia in 14 patients, 11 of them occurring between 2008–2010. None of the bloodstream isolate was resistant to fluconazole, while a solitary isolate showed increased MIC to 5-flucytosine (>32 µg/ml) and belonged to genotype 4. A review of literature since 1999 revealed 28 additional cases of C. dubliniensis candidemia, and 167 isolates identified from blood cultures since 1982. In conclusion, this study highlights a greater role of C. dubliniensis in bloodstream infections than hitherto recognized.

Nosocomial fungal infections: epidemiology, infection control, and prevention

Fungal infections are an increasing cause of morbidity and mortality in hospitalized patients. This article reviews the current epidemiology of nosocomial fungal infections in adult patients, with an emphasis on invasive candidiasis and aspergillosis. Recently published recommendations and guidelines for the control and prevention of these nosocomial fungal infections are summarized.

Candidemia after cardiac surgery in the intensive care unit: an observational study

Candidemia is a well-recognized complication of hospital stay, especially in critically ill patients. There is not a general consensus that predictors for candidemia in cardiosurgical intensive care unit (cICU) are different from a general ICU and it has been reported that cardiopulmonary bypass time is a specific risk factor in the cICU. We performed a prospective study to evaluate the main predictors for candidemia in patients admitted to the cICU. Included patients were adults admitted between July 2005 and December 2007 with an ICU-length of stay (ICU-LOS) ≥48 hours after cardiac surgery. Exclusion criteria were solid organ or bone marrow transplants, previous diagnosis of candidemia or other invasive infections and ICU stay before surgery. A multiple regression analysis was performed to identify the risk factors. Among 1955 patients admitted to the cICU, 345 were enrolled. Only 26 patients (1.3%) had candidemia after an ICU-LOS of 20 days (inter-quartile range, IQR 8-49 days). Total parenteral nutrition [odds ratio (OR)=9.56; confidence interval (CI)=1.741-52.534], severe sepsis (OR=4.20; CI=1.292-13.667), simplified acute physiology score II (OR=1.16; CI=1.052-1.278) and ICU-LOS >20 days (OR=6.38; CI=1.971-20.660) were independent predictors of candidemia. Patients undergoing cardiac surgery developed candidemia late after cICU admission and the independent predictors were similar to the general ICU.

Invasive candidiasis in pediatric intensive care units

Candidemia and disseminated candidiasis are major causes of morbidity and mortality in hospitalized patients especially in the intensive care units (ICU). The incidence of invasive candidasis is on a steady rise because of increasing use of multiple antibiotics and invasive procedures carried out in the ICUs. Worldwide there is a shifting trend from C. albicans towards non albicans species, with an associated increase in mortality and antifungal resistance. In the ICU a predisposed host in one who is on broad spectrum antibiotics, parenteral nutrition, and central venous catheters. There are no pathognomonic signs or symptoms. The clinical clues are: unexplained fever or signs of severe sepsis or septic shock while on antibiotics, multiple, non-tender, nodular erythematous cutaneous lesions. The spectrum of infection with candida species range from superficial candidiasis of the skin and mucosa to more serious life threatening infections. Treatment of candidiasis involves removal of the most likely source of infection and drug therapy to speed up the clearance of infection. Amphotericin B remains the initial drug of first choice in hemodynamically unstable critically ill children in the wake of increasing resistance to azoles. Evaluation of newer antifungal agents and precise role of prophylactic therapy in ICU patients is needed.

Purification and identification of bovine cheese whey fatty acids exhibiting in vitro antifungal activity

Milk lipids contain several bioactive factors exhibiting antimicrobial activity against bacteria, viruses, and fungi. In the present study, we demonstrate that free fatty acids (FFA) derived from the saponification of bovine whey cream lipids are active in vitro at inhibiting the germination of Candida albicans, a morphological transition associated with pathogenicity. This activity was found to be significantly increased when bovine FFA were enriched in non-straight-chain FFA. At low cell density, this non-straight-chain FFA-enriched fraction was also found to inhibit in a dose-dependant manner the growth of both developmental forms of C. albicans as well as the growth of Aspergillus fumigatus. Using an assay-guided fractionation, the main components responsible for these activities were isolated. On the basis of mass spectroscopic and gas chromatographic analysis, antifungal compounds were identified as capric acid (C10:0), lauroleic acid (C12:1), 11-methyldodecanoic acid (iso-C13:0), myristoleic acid (C14:1n-5), and gamma-linolenic acid (C18:3n-6). The most potent compound was gamma-linolenic acid, with minimal inhibitory concentration values of 5.4 mg/L for C. albicans and 1.3 mg/L for A. fumigatus, in standardized conditions. The results of this study indicate that bovine whey contains bioactive fatty acids exhibiting antifungal activity in vitro against 2 important human fungal pathogens.

Candidemia in nonneutropenic critically ill patients: risk factors for non-albicans Candida spp

OBJECTIVE

The objective of this study was to determine the clinical features associated with candidemia caused by non-albicans Candida spp. and with potentially fluconazole-resistant Candida spp. (C. glabrata and C. krusei) among candidemic intensive care unit patients.

DESIGN

The authors conducted a nationwide prospective cohort study.

SETTING

The study was conducted in Australian intensive care units.

PATIENTS

All patients with intensive care unit-acquired candidemia over a 3-yr period were included in the study.

MEASUREMENTS

Clinical risk factors occurring up to 30 days before candidemia, Candida spp. associated with candidemia, and outcomes were determined. Risk factors associated with either non-albicans Candida spp. or with potentially fluconazole-resistant Candida spp. (C. glabrata or C. krusei) were assessed using multivariate logistic regression.

MAIN RESULTS

Among 179 episodes of intensive care unit-acquired candidemia, C. albicans accounted for 62%, C. glabrata 18%, C. krusei 4%, and other Candida spp. 16%. Independently significant variables associated with non-albicans Candida bloodstream infection included recent prior gastrointestinal surgery (adjusted odds ratio, 2.87; 95% confidence interval, 1.68-4.91) and recent prior systemic antifungal exposure (4.6; 1.36-15.53). Those associated with potentially fluconazole-resistant candidemia included recent prior gastrointestinal surgery (3.31; 1.79-6.11) and recent prior fluconazole exposure (5.47; 1.23-24.32). No significant differences in outcomes were demonstrated for non-albicans or potentially fluconazole-resistant candidemia.

CONCLUSIONS

Among candidemic intensive care unit patients, prior gastrointestinal surgery and systemic antifungal exposure were significantly associated with both a non-albicans Candida spp. and a potentially fluconazole-resistant Candida spp.

Management of Candida infections in the adult intensive care unit

The epidemiology of Candida infection in intensive care units (ICUs) and the management strategies for such infections in non-neutropenic intensive care patients are discussed in this review. Candida species are one of the leading causes of nosocomial bloodstream infections and a significant cause of morbidity in patients admitted to the ICU. Prophylactic, pre-emptive and empiric treatment strategies for Candida infections have been explored in ICU patients. Routine prophylaxis should not be administered to the whole population of ICU patients, because the concerns about the selection of azole-resistant Candida strains or the induction of resistance are justified. Treatment of fungal infections is now possible with newer antifungal agents, including newer azoles (e.g., voriconazole, posaconazole) and echinocandins (e.g., micafungin, anidulafungin). However, there is a critical need for improvement in diagnosis of invasive Candida infection in order to provide clinicians the opportunity to intervene earlier in the diseases course.

Fungal Infections

The incidence of invasive fungal infections has increased dramatically over the past two decades, mostly due to an increase in the number of immunocompromised patients.1–4 Patients who undergo chemotherapy for a variety of diseases, patients with organ transplants, and patients with the acquired immune deficiency syndrome have contributed most to the increase in fungal infections.5 The actual incidence of invasive fungal infections in transplant patients ranges from 15% to 25% in bone marrow transplant recipients to 5% to 42% in solid organ transplant recipients.6,7 The most frequently encountered are Aspergillus species, followed by Cryptococcus and Candida species. Fungal infections are also associated with a higher mortality than either bacterial or viral infections in these patient populations. This is because of the limited number of available therapies, dose-limiting toxicities of the antifungal drugs, fewer symptoms due to lack of inflammatory response, and the lack of sensitive tests to aid in the diagnosis of invasive fungal infections.1 A study of patients with fungal infections admitted to a university-affiliated hospital indicated that community-acquired infections are becoming a serious problem; 67% of the 140 patients had community-acquired fungal pneumonia.8

Susceptibility patterns of Candida species recovered from Canadian intensive care units

OBJECTIVE

The objective of this study was to determine the speciation and susceptibility patterns of Candida species recovered from Canadian intensive care units (ICUs) during a 1-day point-prevalence study on fungal colonization/infection in Canadian ICUs.

METHODS AND SETTING

Blood, urine, respiratory tract, rectal, and wound fungal cultures were performed for 357 patients present at any time during a single-day 24-hour period in 35 Canadian ICUs. Comparative in vitro activities of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, micafungin, anidulafungin, and aminocandin were determined.

RESULTS

Four hundred fifteen yeasts (409 Candida species and 6 non-Candida yeasts) were recovered. Almost 50% of the patients were found to have positive respiratory tract or rectal cultures. Candida albicans accounted for 72% of the Candida species isolated, followed by Candida glabrata (16%), Candida tropicalis (5%), Candida parapsilosis (3%), Candida krusei (2%), and other Candida species or nonspeciated isolates (2%). Minimum inhibitory concentrations (milligrams per liter) at which 90% of the strains were inhibited were 0.06 for micafungin as well as anidulafungin, 0.12 for voriconazole, 0.25 for itraconazole, posaconazole, as well as aminocandin, 1 for amphotericin B, and 4 for fluconazole. Only 4% of the isolates were resistant to fluconazole and/or itraconazole.

CONCLUSIONS

Candida albicans is the predominant species colonizing Canadian ICU patients. Overall, the triazoles, both older and new compounds, and the echinocandins have excellent in vitro antifungal activities against Candida species recovered from Canadian ICUs patients.

Synthesis and antifungal activities of new fluconazole analogues with azaheterocycle moiety

A series of fluconazole analogues 5-20 incorporating azaindole and indole moieties were prepared using oxirane intermediates synthesized under microwave irradiation. All of the compounds were evaluated in vitro against two clinically important fungi, Candida albicans and Aspergillus fumigatus. Four derivatives 6, 13, 14 and 18 exerted high antifungal activity against C. albicans with MIC(80) values 3- to 28-fold lower than that of fluconazole.

Adequacy of empirical antifungal therapy and effect on outcome among patients with invasive Candida species infections

OBJECTIVES

Although inadequate antimicrobial therapy has been demonstrated in multiple studies to increase the risk for death in bacterial infections, few data investigating the effect of antifungal therapy on outcome of serious fungal disease are available. We sought to assess the adequacy of empirical therapy and its effect on mortality in invasive Candida species infections.

METHODS

Population-based surveillance of all patients with Candida spp. cultured from blood and/or cerebrospinal fluid was conducted. Adequacy of empirical therapy was assessed according to published guidelines.

RESULTS

During a 5 year period, 207 patients had an invasive Candida spp. infection identified; in 199 cases (96%) adequate data were available for assessment of treatment and outcome at hospital discharge. One hundred and three (52%) cases were due to Candida albicans, 44 (22%) were due to Candida glabrata and the remainder were due to other species. Between the time of culture draw and reporting of a positive culture, only 64 (32%) patients were treated with empirical therapy; this was deemed adequate in 51 (26%). Patients who received adequate empirical therapy had a significant decrease in crude mortality [14/51 (27%) versus 68/148 (46%); risk ratio 0.60 (95% confidence interval 0.37-0.96); P = 0.02]. After adjusting for age and the need for intensive care unit admission in logistic regression analysis, the use of adequate empirical therapy was independently associated with a reduced risk for death [odds ratio 0.46 (95% confidence interval 0.22-1.00); P = 0.05].

CONCLUSIONS

Adequate empirical therapy is used in a minority of patients with invasive Candida spp. infections but is associated with improved survival.

[Efficacy of micafungin sodium on fungal infection in critical care]

The clinical effects and tolerability of micafungin sodium in daily practice for the treatment of fungal infection in critically ill patients were evaluated in an open-labeled, non-comparative, observational study. All patients admitted to intensive care units (ICUs) of 3 hospitals in Chiba prefecture between June 2003 and March 2005, who were treated with micafungin because of known or suspected fungal infection, were included in the study. A total of 34 patients received micafungin and 29 cases of them were subjected to analysis. Fungal infections were classified as "proven" in 3 patients (10.3%) and "possible" in 26 (89.7%). Candida was detected in 16 patients, most of them were Candida albicans and 4 cases were non-albicans Candida. Clinical effects of micafungin were "cured" and "improved" in 20 patients (77%), "failure" in 6 (23%), and "undetermined" in 3 cases. Adverse events were reported in 10 patients, but there was no significant event. In conclusion, micafungin was effective in 77% of proven or suspected fungal infections in critically ill patients admitted to the ICU. The drug was well tolerated and discontinuation of its treatment due to adverse events was not experienced during the study period.

Antifungal resistance in Candida spp. isolated in Italy between 2002 and 2005 from children and adults

The activity of amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole was tested in vitro against 618 clinical Candida spp. isolates, using the broth microdilution or the disk diffusion method (voriconazole). Amphotericin B and voriconazole were the most potent antifungal agents assayed (100% of susceptible strains). Resistance to fluconazole and itraconazole was detected in three (0.7%) and 11 (2.7%) isolates of Candida albicans and in four (3.7%) isolates of Candida glabrata. Flucytosine intermediate, resistant strains, or both, were observed in C. albicans (0.3% and 0.7%), C. glabrata (2.8% intermediate) and C. tropicalis (15.2% and 15.2%). C. krusei was the least susceptible species to azoles. No statistically significant differences in the rates of resistant isolates depending on site of infection and age of the patient were observed, with the exception of C. albicans and itraconazole (higher percentage of resistance in children). At present, acquired antifungal resistance represents an uncommon finding in most Candida spp. circulating in Northern Italy.

Multilocus sequence typing reveals intrafamilial transmission and microevolutions of Candida albicans isolates from the human digestive tract

Candida albicans is a human commensal that is also responsible for superficial and systemic infections. Little is known about the carriage of C. albicans in the digestive tract and the genome dynamics that occur during commensalisms of this diploid species. The aim of this study was to evaluate the prevalence, diversity, and genetic relationships among C. albicans isolates recovered during natural colonization of the digestive tract of humans, with emphasis on Crohn's disease patients who produce anti-yeast antibodies and may have altered Candida sp. carriage. Candida sp. isolates were recovered from 234 subjects within 25 families with multiple cases of Crohn's disease and 10 control families, sampled at the oral and fecal sites. Prevalences of Candida sp. and C. albicans carriage were 53.4% and 46.5%, respectively, indicating frequent commensal carriage. No differences in prevalence of carriage could be observed between Crohn's disease patients and healthy subjects. Multilocus sequence typing (MLST) of C. albicans isolates revealed frequent colonization of a subject or several members of the same family by genetically indistinguishable or genetically close isolates. These latter isolates differed by loss-of-heterozygosity events at one or several of the MLST loci. These loss-of-heterozygosity events could be due to either chromosome loss followed by duplication or large mitotic recombination events between complementary chromosomes. This study was the first to jointly assess commensal carriage of C. albicans, intrafamilial transmission, and microevolution. The high frequency of each of these events suggests that the digestive tract provides an important and natural niche for microevolutions of diploid C. albicans through the loss of heterozygosity.

Invasive fungal infections: a review of epidemiology and management options

Fungi are increasingly recognised as major pathogens in critically ill patients. Candida spp. and Cryptococcus spp. are the yeasts most frequently isolated in clinical practice. The most frequent filamentous fungi (moulds) isolated are Aspergillus spp., but Fusarium spp., Scedosporium spp., Penicillium spp., and Zygomycetes are increasingly seen. Several reasons have been proposed for the increase in invasive fungal infections, including the use of antineoplastic and immunosuppressive agents, broad-spectrum antibiotics, and prosthetic devices and grafts, and more aggressive surgery. Patients with burns, neutropenia, HIV infection and pancreatitis are also predisposed to fungal infection. The epidemiology and clinical features of fungal infections are reviewed, together with antifungal agents currently or soon to be available.

Internal transcribed spacer sequencing versus biochemical profiling for identification of medically important yeasts

In this study, we established an in-house database of yeast internal transcribed spacer (ITS) sequences. This database includes medically important as well as colonizing yeasts that frequently occur in the diagnostic laboratory. In a prospective study, we compared molecular identification with phenotypic identification by using the ID32C system (bioMérieux) for yeast strains that could not be identified by a combination of CHROMagar Candida and morphology on rice agar. In total, 113 yeast strains were included in the study. By sequence analysis, 98% of all strains were identified correctly to the species level. With the ID32C, 87% of all strains were identified correctly to the species or genus level, 7% of the isolates could not be identified, and 6% of the isolates were misidentified, most of them as Candida rugosa or Candida utilis. For a diagnostic algorithm, we suggest a three-step procedure which integrates morphological criteria, biochemical investigation, and sequence analysis of the ITS region.

Fluconazole for the management of invasive candidiasis: where do we stand after 15 years?

Candida spp. are responsible for most of the fungal infections in humans. Available since 1990, fluconazole is well established as a leading drug in the setting of prevention and treatment of mucosal and invasive candidiasis. Fluconazole displays predictable pharmacokinetics and an excellent tolerance profile in all groups, including the elderly and children. Fluconazole is a fungistatic drug against yeasts and lacks activity against moulds. Candida krusei is intrinsically resistant to fluconazole, and other species, notably Candida glabrata, often manifest reduced susceptibility. Emergence of azole-resistant strains as well as discovery of new antifungal drugs (new triazoles and echinocandins) have raised important questions about its use as a first line drug. The aim of this review is to summarize the main available data on the position of fluconazole in the prophylaxis or curative treatment of invasive Candida spp. infections. Fluconazole is still a major drug for antifungal prophylaxis in the setting of transplantation (solid organ and bone marrow), intensive care unit, and in neutropenic patients. Prophylactic fluconazole still has a place in HIV-positive patients in viro-immunological failure with recurrent mucosal candidiasis. Fluconazole can be used in adult neutropenic patients with systemic candidiasis, as long as the species identified is a priori susceptible. Among non-neutropenic patients with candidaemia fluconazole is one of the first line drugs for susceptible species. Cases reports and uncontrolled studies have also reported its efficacy in the setting of osteoarthritis, endophthalmitis, meningitis, endocarditis and peritonitis caused by Candida spp. among immunocompetent adults. In paediatrics, fluconazole is a well tolerated and major prophylactic drug for high-risk neonates, as well as an alternative treatment for neonatal candidiasis. Importantly 15 years after its introduction in the antifungal armamentarium, fluconazole is still a first line treatment option in several cases of invasive candidiasis. Its prophylactic use should however be limited to selected high-risk patients to limit the risk of emergence of azole-resistant strains.

Clinical consequences of resistant Candida infections in intensive care

Many issues need to be addressed by the Intensive Care Unit physician in the decision-making process regarding antifungal therapy for Candida infection, most importantly pharmacokinetic concerns and/or organ failure limitations. In addition, the extensive use of antifungal agents can select for Candida spp. that exhibit decreased susceptibility to these agents. However, the risk appears low, even in the case of prophylactic or pre-emptive antifungal therapy, but this needs to be confirmed in large-scale studies.

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

Candida species are an important cause of health care-related bloodstream infections (BSI). Understanding the current Candida BSI incidence trends, the dominant species causing disease, and the mortality associated with this infection are important to help guide therapeutic and prophylaxis measures. In this review, trends in the incidence of Candida BSI are assessed using data extracted from reports published worldwide during 1995 to 2005. The incidence trend of Candida BSI was found to be stable for most of the reports reviewed, and Candida albicans remains the most common species causing Candida BSIs. Surveillance to monitor the burden of disease and emergence of resistance, among the general patient population and among high risk patient populations, should be continued.

The trend of susceptibilities to amphotericin B and fluconazole of Candida species from 1999 to 2002 in Taiwan

Background

Candida species have various degrees of susceptibility to common antifungal drugs. The extent of resistance to amphotericin B and fluconazole of Candida glabrata isolates causing candidemia has been reported. Active surveillance may help us to monitor the trend of susceptibility to antifungal drugs and to determine if there is an emerging co-resistance to both drugs of Candida species, specifically, of C. glabrata in Taiwan.

Methods

The susceptibilities to amphotericin B and fluconazole of Candida species collected in 1999 and 2002 of the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) were determined by the microdilution method.

Results

The antifungal susceptibilities of 342 and 456 isolates collected from 11 hospitals participating in both TSARY 1999 and TSARY 2002, respectively, have been determined. The resistance rate to amphotericin B has increased from 0.3% in the TSARY1999 to 2.2% in the TSARY 2002. In contrast, the resistance rate to fluconazole has decreased from 8.8% to 2.2%. Nevertheless, significantly more C. glabrata isolates were not susceptible to fluconazole in the TSARY 2002 (47.4%) than that in the TSARY 1999 (20.8%). There were 9.8% and 11% of C. glabrata isolates having susceptible-dose dependent and resistant phenotype to fluconazole in the TSARY 1999, verse 45.3% and 2.1% in the TSARY 2002.

Conclusion

There was an increase of resistance rate to amphotericin B in C. glabrata. On the other hand, although the resistance rate to fluconazole has decreased, almost half of C. glabrata isolates were not susceptible to this drug. Hence, continuous monitoring the emerging of co-resistance to both amphotericin B and fluconazole of Candida species, specifically, of C. glabrata, will be an important early-warning system.

Susceptibility to antifungal agents of Candida species isolated from paediatric and adult patients with haematological diseases

Summary The susceptibility to six antifungals: amphotericin B (AMF), 5-fluorocytosine (5-F), miconazole (MIK), ketoconazole (KET), fluconazole (FLU) and itraconazole (ITR) was tested among 206 Candida spp. isolated from paediatric and adult patients with haematological malignancies. To determinate the susceptibility the commercial microdilution method Fungitest (Bio-Rad, France) was used. The strains were classified as susceptible, intermediate susceptible, or resistant on the base of the growth in following breakpoint concentrations of particular drugs: 2 and 8 microg ml(-1) for AMF, 2 and 32 microg ml(-1) for 5-F, 0.5 and 8 microg ml(-1) for MIK, 0.5 and 4 microg ml(-1) for KET and ITR, and 8 and 64 microg ml(-1) for FLU. The highest activity to overall species showed AMF (only one resistant strain) and 5-F (85% susceptible strains). Most of C. albicans isolates were susceptible to tested azoles. The percentages of C. albicans resistant to FLU, ITR, KET and MIK were 4, 11, 8, and 0.8%, respectively. The less susceptible to azoles were C. glabrata and C. krusei (14% and 44% isolates resistant to FLU). A non-albicans Candida isolated from adult patients receiving KET prophylaxis was more frequently resistant to FLU than isolates from patients without previous exposure to azoles (P < 0.05). We did not observe differences in the susceptibility of Candida strains isolated from children compared with those from adults.

Risk factors for fatal candidemia caused by Candida albicans and non-albicans Candida species

Background

Invasive fungal infections, such as candidemia, caused by Candida species have been increasing. Candidemia is not only associated with a high mortality (30% to 40%) but also extends the length of hospital stay and increases the costs of medical care. Sepsis caused by Candida species is clinically indistinguishable from bacterial infections. Although, the clinical presentations of the patients with candidemia caused by Candida albicans and non-albicans Candida species (NAC) are indistinguishable, the susceptibilities to antifungal agents of these species are different. In this study, we attempted to identify the risk factors for candidemia caused by C. albicans and NAC in the hope that this may guide initial empiric therapy.

Methods

A retrospective chart review was conducted during 1996 to 1999 at the Veterans General Hospital-Taipei.

Results

There were 130 fatal cases of candidemia, including 68 patients with C. albicans and 62 with NAC. Candidemia was the most likely cause of death in 55 of the 130 patients (42.3 %). There was no significant difference in the distribution of Candida species between those died of candidemia and those died of underlying conditions. Patients who had one of the following conditions were more likely to have C. albicans, age ≧ 65 years, immunosuppression accounted to prior use of steroids, leukocytosis, in the intensive care unit (ICU), and intravascular and urinary catheters. Patients who had undergone cancer chemotherapy often appeared less critically ill and were more likely to have NAC.

Conclusion

Clinical and epidemiological differences in the risk factors between candidemia caused by C. albicans and NAC may provide helpful clues to initiate empiric therapy for patients infected with C. albicans versus NAC.