Epidemiology of candidemia: 3-year results from the emerging infections and the epidemiology of Iowa organisms study

Posaconazole (Noxafil): a new triazole antifungal agent

Posaconazole is the newest triazole antifungal agent. It is structurally related to itraconazole and has activity against Candida species, Aspergillus species, Cryptococcus neoformans, the zygomycetes, and other filamentous fungi. Randomized, double-blind trials have shown posaconazole to be at least as efficacious as fluconazole for the prevention of invasive fungal infections in immunocompromised patients. It has also shown promising results in the treatment of various fungal infections refractory to other antifungal therapy. The dose of posaconazole is 200 mg orally three times daily for the prevention of invasive fungal infections and 800 mg daily in two to four divided doses for the treatment of invasive fungal infections refractory to other antifungal treatment. All posaconazole doses should be given with food or a nutritional supplement to enhance absorption. The most common adverse effects reported with posaconazole therapy were fever, diarrhea, nausea, vomiting, and headache. Instances of elevated liver enzyme levels, hyperbilirubinemia, and hepatocellular damage were also noted in clinical trials, and these laboratory values should be monitored during treatment with posaconazole.

Anidulafungin compared with fluconazole for treatment of candidemia and other forms of invasive candidiasis caused by Candida albicans: a multivariate analysis of factors associated with improved outcome

BACKGROUND

Candida albicans is the most common cause of candidemia and other forms of invasive candidiasis. Systemic infections due to C. albicans exhibit good susceptibility to fluconazole and echinocandins. However, the echinocandin anidulafungin was recently demonstrated to be more effective than fluconazole for systemic Candida infections in a randomized, double-blind trial among 245 patients. In that trial, most infections were caused by C. albicans, and all respective isolates were susceptible to randomized study drug. We sought to better understand the factors associated with the enhanced efficacy of anidulafungin and hypothesized that intrinsic properties of the antifungal agents contributed to the treatment differences.

METHODS

Global responses at end of intravenous study treatment in patients with C. albicans infection were compared post-hoc. Multivariate logistic regression analyses were performed to predict response and to adjust for differences in independent baseline characteristics. Analyses focused on time to negative blood cultures, persistent infection at end of intravenous study treatment, and 6-week survival.

RESULTS

In total, 135 patients with C. albicans infections were identified. Among these, baseline APACHE II scores were similar between treatment arms. In these patients, global response was significantly better for anidulafungin than fluconazole (81.1% vs 62.3%; 95% confidence interval [CI] for difference, 3.7-33.9). After adjusting for baseline characteristics, the odds ratio for global response was 2.36 (95% CI, 1.06-5.25). Study treatment and APACHE II score were significant predictors of outcome. The most predictive logistic regression model found that the odds ratio for study treatment was 2.60 (95% CI, 1.14-5.91) in favor of anidulafungin, and the odds ratio for APACHE II score was 0.935 (95% CI, 0.885-0.987), with poorer responses associated with higher baseline APACHE II scores. Anidulafungin was associated with significantly faster clearance of blood cultures (log-rank p < 0.05) and significantly fewer persistent infections (2.7% vs 13.1%; p < 0.05). Survival through 6 weeks did not differ between treatment groups.

CONCLUSIONS

In patients with C. albicans infection, anidulafungin was more effective than fluconazole, with more rapid clearance of positive blood cultures. This suggests that the fungicidal activity of echinocandins may have important clinical implications.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00058682.

Diagnosis and therapy of Candida infections: joint recommendations of the German Speaking Mycological Society and the Paul-Ehrlich-Society for Chemotherapy

Invasive Candida infections are important causes of morbidity and mortality in immunocompromised and hospitalised patients. This article provides the joint recommendations of the German-speaking Mycological Society (Deutschsprachige Mykologische Gesellschaft, DMyKG) and the Paul-Ehrlich-Society for Chemotherapy (PEG) for diagnosis and treatment of invasive and superficial Candida infections. The recommendations are based on published results of clinical trials, case-series and expert opinion using the evidence criteria set forth by the Infectious Diseases Society of America (IDSA). Key recommendations are summarised here: The cornerstone of diagnosis remains the detection of the organism by culture with identification of the isolate at the species level; in vitro susceptibility testing is mandatory for invasive isolates. Options for initial therapy of candidaemia and other invasive Candida infections in non-granulocytopenic patients include fluconazole or one of the three approved echinocandin compounds; liposomal amphotericin B and voriconazole are secondary alternatives because of their less favourable pharmacological properties. In granulocytopenic patients, an echinocandin or liposomal amphotericin B is recommended as initial therapy based on the fungicidal mode of action. Indwelling central venous catheters serve as a main source of infection independent of the pathogenesis of candidaemia in the individual patients and should be removed whenever feasible. Pre-existing immunosuppressive treatment, particularly by glucocorticosteroids, ought to be discontinued, if feasible, or reduced. The duration of treatment for uncomplicated candidaemia is 14 days following the first negative blood culture and resolution of all associated symptoms and findings. Ophthalmoscopy is recommended prior to the discontinuation of antifungal chemotherapy to rule out endophthalmitis or chorioretinitis. Beyond these key recommendations, this article provides detailed recommendations for specific disease entities, for antifungal treatment in paediatric patients as well as a comprehensive discussion of epidemiology, clinical presentation and emerging diagnostic options of invasive and superficial Candida infections.

Epidemiology, species distribution, antifungal susceptibility and outcome of nosocomial candidemia in a tertiary care hospital in Italy

Candida is an important cause of bloodstream infections (BSI), causing significant mortality and morbidity in health care settings. From January 2008 to December 2010 all consecutive patients who developed candidemia at San Martino University Hospital, Italy were enrolled in the study. A total of 348 episodes of candidaemia were identified during the study period (January 2008–December 2010), with an incidence of 1,73 episodes/1000 admissions. Globally, albicans and non-albicans species caused around 50% of the cases each. Non-albicans included Candida parapsilosis (28.4%), Candida glabrata (9.5%), Candida tropicalis (6.6%), and Candida krusei (2.6%). Out of 324 evaluable patients, 141 (43.5%) died within 30 days from the onset of candidemia. C. parapsilosis candidemia was associated with the lowest mortality rate (36.2%). In contrast, patients with C. krusei BSI had the highest mortality rate (55.5%) in this cohort. Regarding the crude mortality in the different units, patients in Internal Medicine wards had the highest mortality rate (54.1%), followed by patients in ICU and Hemato-Oncology wards (47.6%).

This report shows that candidemia is a significant source of morbidity in Italy, with a substantial burden of disease, mortality, and likely high associated costs. Although our high rates of candidemia may be related to high rates of BSI in general in Italian public hospitals, reasons for these high rates are not clear and warrant further study. Determining factors associated with these high rates may lead to identifying measures that can help to prevent disease.

Candida non-albicans versus Candida albicans fungemia in the non-neonatal pediatric population

BACKGROUND

Non-albicans Candida (NAC) species have been implicated as major pathogens in patients with hospital-acquired candidemia. Few studies have investigated the impact of NAC fungemia among pediatric patients outside of the neonatal age group.

MATERIALS/METHODS

Between 2000 and 2009, we performed a retrospective case-control study in children aged 6 months to ≤18 years with blood culture proven candidemia at Texas Children's Hospital, Houston, TX.

RESULTS

A total of 276 episodes of candidemia occurred in 226 patients. The overall incidence ranged between 0.06 and 0.3 per 1000 inpatient days. The median patient age was 50 months (range, 6 months to ≤18 years) with 55.4% males; 40.2% Hispanics; and 31.8% whites. Candida albicans (CA) was the most common (44.2%) species although, collectively, NAC was more frequently (55.8%) isolated. Among the NAC group, Candida parapsilosis was most common (23.9%) followed by Candida tropicalis (14.8%), Candida glabrata (6.5%), and Candida lusitaniae (5.4%). No difference was found between CA and NAC candidemia in terms of demographics, underlying diagnosis, risk factors, clinical features, dissemination, or 30-day mortality. Disseminated candidiasis was independently associated with the use of vasopressors (adjusted odds ratio [OR], 4.58; confidence interval [CI]: 1.03-20.5; P = 0.05), prolonged fungemia (≥3 days of persistently positive cultures) after catheter removal (OR, 3.2; CI: 1.08-9.3; P = 0.04), and neutropenia (OR, 4.06; CI: 1.2-13.2; P = 0.02), but not with NAC fungemia.

CONCLUSIONS

Though CA was the single most common species, NAC species collectively have emerged as the predominant pathogens responsible for candidemia in non-neonatal patients at our institution. Risk factors, clinical features, and outcomes were not different between the 2 groups.

A single-centre 10-year experience with Candida bloodstream infections

OBJECTIVE

To describe the clinical and microbiological features associated with Candida bloodstream infections observed at Hôpital Maisonneuve-Rosemont (Montreal, Quebec) between August 1996 and July 2006.

METHODS

Episodes were retrieved from the microbiology laboratory. Different patient episodes and different isolate episodes in the same patient were selected. Antifungal susceptibility was determined by the Clinical and Laboratory Standards Institute's (USA) M27A2 method.

RESULTS

A total of 190 different episodes of candidemia in 185 patients were identified. Eleven (6%) episodes occurred in outpatients. Candida albicans was identified in the majority of episodes (57%). Its frequency remained stable over the years. The proportion of Candida krusei candidemia episodes increased between 2003 and 2006, but this was not statistically significant. A central venous indwelling catheter or a peripherally inserted central catheter line was present in the majority of patients (167 [88%]). Of the indwelling catheters removed at the time of diagnosis, 39% were positive for Candida species on culture. Overall, voriconazole was the most active agent (the minimum inhibitory concentration required to inhibit the growth of 90% of organisms was 0.5 mg/L). Resistance to fluconazole was observed in 26 (14%) isolates (C albicans, 4%; versus non-albicans Candida species, 27%; P<0.001). Being on the hematology-oncology unit at the time of diagnosis (adjusted OR 7.8; 95% CI 2.3 to 27.1; P=0.001) and having received fluconazole or itraconazole within the past three months (adjusted OR 8.3; 95% CI 2.8 to 24.4; P<0.001) were significantly associated with resistance to fluconazole in multivariate analysis.

CONCLUSIONS

At Hôpital Maisonneuve-Rosemont, the frequency and species distribution of blood isolates of Candida remained stable over the past decade. In vitro resistance of C albicans to fluconazole and itraconazole remained minimal; resistance of non-albicans Candida species to fluconazole did not increase significantly. The new antifungal agents all had high in vitro activity against the bloodstream Candida isolates.

Epidemiology and antifungal susceptibility of bloodstream Candida isolates in Quebec: Report on 453 cases between 2003 and 2005

BACKGROUND

Between May 2003 and April 2005, a population-based surveillance of Candida bloodstream infections was conducted in Quebec. A total of 453 episodes of candidemia (464 yeast isolates) from 54 participating hospitals were studied.

RESULTS

The annual incidence rate was three per 100,000 population. Global hospital mortality was 38%. The most common predisposing factors were the presence of an intravascular catheter (80%), use of antibacterial therapy (67%), stay in an intensive care unit (49%), use of parenteral nutrition (32%) and intra-abdominal surgery (31%). Fluconazole alone or in association with other antifungals was used for treatment in over 80% of cases. Candida albicans comprised 62% of isolates, followed by Candida glabrata (17%), Candida parapsilosis (9%), Candida tropicalis (5%), Candida lusitaniae (3%) and Candida krusei (3%). Of the 288 C albicans isolates, seven (2%) were resistant to flucytosine, one to fluconazole and none to itraconazole or voriconazole. Of the 75 non-C albicans species isolates with reduced susceptibility to fluconazole (minimum inhibitory concentration [MIC] 16 mug/mL or greater), none were susceptible to itraconazole (MIC 0.12 mg/L or lower), whereas 71 (95%) were susceptible to voriconazole (MIC 1 mug/mL or lower). However, only five of 12 (42%) fluconazole-resistant isolates were susceptible to voriconazole. Posaconazole, ravuconazole and caspofungin displayed a broad spectrum of activity against these isolates, with MICs of 1 mg/L or lower in 56%, 92% and 100% of isolates, respectively. Overall, a correlation (r(2)>0.87) was observed among increasing fluconazole MICs and the geometric mean MICs of itraconazole, voriconazole, posaconazole and ravuconazole.

CONCLUSIONS

These surveillance results when compared with those of the 1993 to 1995 survey confirm little variation in the distribution of species causing invasive Candida infection over a 10-year period in Quebec, as well as the continuous excellent overall in vitro activity of fluconazole.

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.

Antifungal susceptibility of invasive yeast isolates in Italy: the GISIA3 study in critically ill patients

Background

Yeasts are a common cause of invasive fungal infections in critically ill patients. Antifungal susceptibility testing results of clinically significant fungal strains are of interest to physicians, enabling them to adopt appropriate strategies for empiric and prophylactic therapies. We investigated the antifungal susceptibility of yeasts isolated over a 2-year period from hospitalised patients with invasive yeast infections.

Methods

638 yeasts were isolated from the blood, central venous catheters and sterile fluids of 578 patients on general and surgical intensive care units and surgical wards. Etest strips and Sensititre panels were used to test the susceptibility of the isolates to amphotericin B, anidulafungin, caspofungin, fluconazole, itraconazole, posaconazole and voriconazole in 13 laboratories centres (LC) and two co-ordinating centres (CC). The Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution method was used at the CCs for comparison.

Results

Etest and Sensititre (LC/CC) MIC₉₀ values were, respectively: amphotericin B 0.5/0.38, 1/1 mg/L; anidulafungin 2/1.5 and 1/1 mg/L; caspofungin 1/0.75 and 0.5/0.5 mg/L; fluconazole 12/8 and 16/16 mg/L; itraconazole 1/1.5, 0.5/0.5 mg/L; posaconazole 0.5 mg/L and voriconazole 0.25 mg/L for all. The overall MIC₉₀ values were influenced by the reduced susceptibility of Candida parapsilosis isolates to echinocandins and a reduced or lack of susceptibility of Candida glabrata and Candida krusei to azoles, in particular fluconazole and itraconazole. Comparison of the LC and CC results showed good Essential Agreement (90.3% for Etest and 92.9% for Sensititre), and even higher Categorical Agreement (93.9% for Etest and 96% for Sensititre); differences were observed according to the species, method, and antifungal drug. No cross-resistance between echinocandins and triazoles was detected.

Conclusions

Our data confirm the different antifungal susceptibility patterns among species, and highlight the need to perform antifungal susceptibility testing of clinically relevant yeasts. With the exception of a few species (e.g. C. glabrata for azoles and C. parapsilosis for echinocandins), the findings of our study suggest that two of the most widely used commercial methods (Etest and Sensititre) provide valid and reproducible results.

Candidemic complications in patients with intravascular catheters colonized with Candida species: an indication for preemptive antifungal therapy?

BACKGROUND

The impact of Candida-colonized catheter tips in patients without candidemia is unclear.

METHODS

A retrospective study of patients with tip cultures positive for Candida was conducted over an 8-year period, to determine the outcomes in patients with Candida cultured from an intravascular catheter tip in the absence of preceding Candida-positive blood cultures. The primary outcome measure was definite candidemia. Secondary outcomes included possible candidemia and in-hospital mortality. A possible candidemia was defined as clinical signs and symptoms of invasive candidiasis without explanation other than a candidemia, but with negative blood cultures.

RESULTS

Sixty-eight cultures from 64 patients were included in the study. Definite candidemia developed in three cases (4%) and possible candidemia developed in five cases (7%). In-hospital mortality was significantly increased in patients with definite or possible candidemia (63% vs. 22%, p=0.028). Risk factors for the development of definite or possible candidemia were catheter time in situ >8 days (odds ratio (OR) 6.0, 95% confidence interval (CI) 1.1-32.9) and abdominal surgery (OR 6.0, 95% CI 1.1-32.4).

CONCLUSIONS

Intravascular catheter tip colonization in patients without preceding blood cultures with Candida is associated with candidemia in from 4% of patients (definite candidemia) up to 12% of patients (definite and possible candidemia combined). Considering the adverse prognosis associated with delayed treatment of candidemia, preemptive treatment based on catheter tip cultures might outweigh the disadvantages of costs and side effects of antifungal therapy.

A prospective survey of Aspergillus spp. in respiratory tract samples: prevalence, clinical impact and antifungal susceptibility

A three-month laboratory-based prospective survey was conducted at four major university hospitals covering one-third of the Danish population in order to determine the prevalence, significance, and susceptibility pattern of aspergilli in airway samples. Samples received in January-March 2007 for routine microbiologic investigation were examined for Aspergillus following routine procedures and with extended incubation (5 days). Identification was done by morphologic criteria and susceptibility testing using EUCAST method for azoles and amphotericin B E-test. Invasive aspergillosis (IA) was evaluated using modified EORTC/MSG criteria. A total of 11,368 airway samples were received. Growth of Aspergillus spp. was found in 129 and 151 patients using routine and extended incubation, respectively. Three patients had proven IA (2%), 11 probable (7%), four had allergic bronchopulmonary aspergillosis (ABPA) (3%), but the majority was colonised (88%). Underlying conditions were cystic fibrosis in 82 patients (55%), chronic obstructive pulmonary disease in 19 (13%) and haematological disorder in 11 (7%). Twenty-six patients (18%) were at intensive care unit and 69 (47%) received steroid treatment. Azole MICs were elevated for five isolates as follows (itraconazole, posaconazole, voriconazole MICs [mg/L]): two A. fumigatus isolates (>4; >4; 2 and >4; 0.125; 1), one A. lentulus isolate (2; 2; 0.5) and two A. terreus isolates (2; 2; 2 and 2; 0.125; 1). For four isolates the amphotericin B MIC was >1 μg/ml (3/112 A. fumigatus, 1/2 A. terreus). In conclusion, Aspergillus appears to be an important pathogen in Denmark. Elevated itraconazole MICs were detected in 4% of the isolates including a multi-azole resistant isolate.

Design and use of Candida scores at the intensive care unit

Invasive Candida infections are recognised as a cause of increased morbidity and mortality in intensive care patients, particularly those with recent extensive gastroabdominal surgery. Due to the difficulties of diagnosis, several authors have analysed risk factors suggestive of invasive candidiasis to identify patients at highest risk. Such patients may be potential candidates for preemptive antifungal therapy before becoming seriously ill. The extent of body site colonisation due to Candida species was recognised to be related with consequent invasive disease. The quantification of the colonisation was expressed as the Candida colonisation index. Based on the evaluation of independent risk factors predictive of invasive Candida infections, clinically relevant scores were evaluated in the last decade. Particularly, the Candida score that combines the clinical risk factors preceding surgery, total parenteral nutrition and severe sepsis with Candida multi-site colonisation can be considered a useful bedside scoring system to discern patients with mere Candida colonisation from patients with the risk of invasive candidiasis in non-neutropaenic critically ill patient population.

Epidemiology of invasive fungal infections in the mediterranean area

Although Candida species remain the relevant cause of IFI, other fungi (especially moulds) have become increasingly prevalent. In particular, Aspergillus species are the leading cause of mould infections but also Glomeromycota (formerly Zygomycetes) and Fusarium species are increasing in frequency, and are associated with high mortality rates. Many of these emerging infections occur as breakthrough infections in patients treated with new antifungal drugs. The causative pathogens, incidence rate and severity are dependent on the underlying condition, as well as on the geographic location of the patient population. France and Italy show the highest incident rates of Fusarium infections in Europe, following the US, where numbers are still increasing. Scedosporium prolificans, which primarily is found in soil in Spain and Australia, is most frequently isolated from blood cultures in a Spanish hospital. Geotrichum capitatum represents another species predominantly found in Europe with especially high rates in Mediterranean countries. The increasing resistance to antifungal drugs especially of these new emerging pathogens is a severe problem for managing these IFIs.

Predictors of candidaemia caused by non-albicans Candida species: results of a population-based surveillance in Barcelona, Spain

Although Candida albicans (CA) is the most common cause of Candida bloodstream infections (BSIs), recent studies have observed an increasing percentage of candidaemias caused by non-albicans Candida species (NAC). In the present study, we attempted to identify the predictors of candidaemia due to NAC compared to CA. We analyzed data from an active population-based surveillance in Barcelona (Spain) from January 2002 to December 2003. Factors associated with NAC fungaemia were determined by multivariate analysis. A total of 339 episodes of Candida BSI, in 336 patients (median age 63 years, interquartile range: 41-72 years), were included. CA was the most commonly isolated (52%), followed by Candida parapsilosis (23%), Candida tropicalis (10%), Candida glabrata (8.6%), Candida krusei (3.4%) and other NAC spp. (3%).Overall, 48% of cases were due to NAC spp. Multivariate logistic regression analysis identified factors associated with a risk of BSI due to NAC spp.: having received a haematologic transplant (OR 10.8; 95% CI 1.31-90.01; p 0.027), previous fluconazole exposure (OR 4.47; 95% CI 2.12-9.43; p <0.001) and neonatal age (OR 4.42; 95% CI 1.63-12.04; p 0.004). Conversely, previous CA colonization (OR 0.33; 95% CI 0.19-0.57; p 0.001) and previous antibiotic use (OR 0.42; 95% CI 0.21-0.85; p 0.017) were associated with CA fungaemia compared to NAC. In conclusion, NAC candidaemia comprised 48% of cases in our series. Predictors of NAC include having received a haematologic transplant, neonatal age and previous fluconazole use.

Misidentification of Candida parapsilosis as C famata in a clinical case of vertebral osteomyelitis

A case of vertebral osteomyelitis involving misidentification of Candida parapsilosis as C famata by the VITEK 2 compact is described. Species-specific primers were used in the polymerase chain reaction to correctly identify the clinical isolate. When uncommon species of Candida are reported using automated systems, heightened clinical suspicion is warranted.

Comparison of BD Bactec Plus Aerobic/F medium to VersaTREK Redox 1 blood culture medium for detection of Candida spp. in seeded blood culture specimens containing therapeutic levels of antifungal agents

Recovery of Candida spp. using the BD Bactec FX blood culture (BC) system (Bactec Plus Aerobic/F medium) and the VersaTREK system (aerobic Redox medium) was evaluated using seeded BC bottles with and without the addition of commonly used antifungal agents. BC bottles (n = 1,442) were each inoculated with 10 ml human whole blood and 0.1 ml of suspensions of Candida spp., with or without antifungal agents. BC bottles were incubated in the corresponding system for a maximum of 5 days. In the absence of antifungal agents, Bactec FX recovered 97.4% of Candida spp., and VersaTREK recovered 99.1% (P = 0.154). With regard to length of time to detection (LTD) and overall recovery, both systems had various levels of effectiveness in recovering C. glabrata. In bottles containing antifungal agents, Bactec FX recovered 83.1% of isolates, whereas VersaTREK recovered 50.7% of Candida spp. (P < 0.001). For BC bottles without the addition of antifungal agents, the median LTD for VersaTREK was 2.2 h faster than that of Bactec FX (P < 0.001). In the presence of antifungal agents, the Bactec FX recovery time was significantly faster than that of VersaTREK (median difference of 10.8 h, P < 0.001). We conclude that both systems have comparable abilities to recover Candida spp. from seeded blood cultures in the absence of antifungal agents. In the presence of therapeutic levels of commonly used antifungal agents, the Bactec FX system demonstrated a significantly greater recovery of various Candida spp., as well as a shorter LTD.

Invasive candidiasis in non-hematological patients

Candida is one of the most frequent pathogens isolated in bloodstream infections, and is associated with significant morbidity and mortality. In addition to haematological patients, there are several other populations with a substantial risk of developing invasive candidiasis (IC). These include patients undergoing prolonged hospitalisation with the use of broad-spectrum antibiotics, those fitted with intravascular catheters, admitted to both adult and neonate intensive care units (ICU) or gastrointestinal surgery wards and subjects with solid tumours undergoing cytotoxic chemotherapy. As a general rule, every immunocompromised patient might be at risk of Candida infection, including, for example, diabetic patients.

The epidemiology of species responsible for IC has been changing, both at local and worldwide level, shifting from C. albicans to non-albicans species, that can be intrinsically resistant to fluconazole (C. krusei and, to some extent, C. glabrata), difficult to eradicate because of biofilm production (C. parapsilosis) or than might acquire resistance to azole during therapy.

Delaying the specific therapy has been shown to increase morbidity and mortality, but traditional microbiological diagnosis is poorly sensitive and slow. Thus, culture-based treatment may result in therapy started too late. In order to reduce the mortality in IC, several management strategies have been developed: prophylaxis, empirical and pre-emptive therapy. Compared to prophylaxis, the latter approaches allow to reduce the use of antifungals by targeting only patients at very high risk of IC. Non-invasive serological markers and scores based on clinical prediction rules such as the presence of risk factors or Candida colonisation, have been developed with the aim of allowing prompt initiation of treatment. Although the use of these diagnostic tools in pre-emptive strategies is promising, the performance and cost-effectiveness should be tested in large trials.

Agents recommended for initial treatment of candidemia in severely ill patients include echinocandins and lipid formulations of amphotericin B, while stable patients without risk factors for azole-resistance might be treated with fluconazole.

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.

Bench-to-bedside review: therapeutic management of invasive candidiasis in the intensive care unit

Candida is one of the most frequent pathogens in bloodstream infections, and is associated with significant morbidity and mortality. The epidemiology of species responsible for invasive candidiasis, both at local and worldwide levels, has been changing - shifting from Candida albicans to non-albicans species, which can be resistant to fluconazole (Candida krusei and Candida glabrata) or difficult to eradicate because of biofilm production (Candida parapsilosis). Numerous intensive care unit patients have multiple risk factors for developing this infection, which include prolonged hospitalisation, use of broad-spectrum antibiotics, presence of intravascular catheters, parenteral nutrition, high Acute Physiology and Chronic Health Evaluation score, and so forth. Moreover, delaying the specific therapy was shown to further increase morbidity and mortality. To minimise the impact of this infection, several management strategies have been developed - prophylaxis, empirical therapy, pre-emptive therapy and culture-based treatment. Compared with prophylaxis, empirical and pre-emptive approaches allow one to reduce the exposure to antifungals by targeting only the patients at high risk of candidemia, without delaying therapy until the moment blood Candida is identified in blood cultures. The agents recommended for initial treatment of candidemia in critically ill patients include echinocandins and lipid formulation of amphotericin B.

Candida bloodstream infections: comparison of species distributions and antifungal resistance patterns in community-onset and nosocomial isolates in the SENTRY Antimicrobial Surveillance Program, 2008-2009

Community-onset (CO) candidemia, defined as a positive blood culture taken at or within 2 days of hospital admission, represents a distinct clinical entity associated with substantial morbidity and mortality. Reference MIC results from the SENTRY Antimicrobial Surveillance Program (2008-2009) were analyzed to compare the antifungal resistance patterns and species distributions from patients with CO and nosocomial bloodstream infections (BSI) in 79 medical centers. Among 1,354 episodes of BSI, 494 (36.5%) were classified as CO and 860 (63.5%) as nosocomial in origin. More than 95% of the isolates from both BSI types were contributed by Candida albicans (48.4%), C. glabrata (18.2%), C. parapsilosis (17.1%), C. tropicalis (10.6%), and C. krusei (2.0%). C. albicans was more common in CO BSI (51.0%) than nosocomial BSI (46.9%), whereas C. parapsilosis and C. krusei were more common in nosocomial BSIs (18.1 and 2.7%, respectively) than in CO BSIs (15.4 and 0.8%, respectively). C. glabrata and C. tropicalis were comparable in both CO (18.4 and 10.5%, respectively) and nosocomial (18.1 and 10.6%, respectively) episodes. Resistance to azoles (fluconazole, posaconazole, and voriconazole) and echinocandins (anidulafungin, caspofungin, and micafungin) was uncommon (<5%) in CO BSI using recently established Clinical and Laboratory Standards Institute breakpoint criteria. Resistance to echinocandins (anidulafungin [3.8%], caspofungin [5.1%], and micafungin [3.2%]) and azoles (fluconazole [7.7%], posaconazole [5.1%], and voriconazole [6.4%]) was most prevalent among nosocomial BSI isolates of C. glabrata. CO candidemia is not uncommon and appears to be increasing worldwide due to changing health care practices. Although resistance to the azoles and echinocandins remains uncommon among CO isolates, we demonstrate the emergence of nosocomial occurrences of C. glabrata expressing resistance to both monitored classes of antifungal agents.

Secular trend in candidemia and the use of fluconazole in Finland, 2004-2007

Background

In a previous study we observed an increasing trend in candidemia in Finland in the 1990s. Our aim was now to investigate further population-based secular trends, as well as outcome, and evaluate the association of fluconazole consumption and prophylaxis policy with the observed findings.

Methods

We analyzed laboratory-based surveillance data on candidemia from the National Infectious Diseases Register during 2004-2007 in Finland. Data on fluconazole consumption, expressed as defined daily doses, DDDs, was obtained from the National Agency for Medicines, and regional prophylaxis policies were assessed by a telephone survey.

Results

A total of 603 candidemia cases were identified. The average annual incidence rate was 2.86 cases per 100,000 population (range by year, 2.59-3.09; range by region, 2.37-3.85). The highest incidence was detected in males aged >65 years (12.23 per 100,000 population). Candida albicans accounted for 67% of cases, and C. glabrata ranked the second (19%), both without any significant change in proportions. C. parapsilosis accounted for 5% of cases and C. krusei 3% of cases. The one-month case-fatality varied between 28-32% during the study period. Fluconazole consumption increased from 19.57 DDDs per 100,000 population in 2000 to 25.09 in 2007. Systematic fluconazole prophylaxis was implemented for premature neonates, patients with acute leukemias and liver transplant patients.

Conclusion

The dominant proportion of C. albicans remained stable, but C. glabrata was the most frequent non-albicans species. The proportion of C. glabrata had increased from our previous study period in the presence of increasing use of fluconazole. The rate of candidemia in Finland is still low but mortality high like in other countries.

[Management of candidemia and invasive candidiasis]

Candida species is the fourth most common cause of bloodstream infection and is the leading cause of invasive fungal infection among hospitalized patients. Acute disseminated candidiasis remains a life-threatening disease that now occurs mainly in intensive care units hospitalized patients. Delay in treatment of Candida bloodstream infections could be minimized by the development of more rapid and sensitive diagnostic techniques for the identification of Candida bloodstream infections. Current guidelines for the management of invasive candidiasis recommend fluconazole or an echinocandin as the primary therapeutic option. The optimal choice of the antifungal agent should depend on local epidemiology, prior antifungal therapy and patient's characteristics.

The distribution of species and susceptibility of amphotericin B and fluconazole of yeast pathogens isolated from sterile sites in Taiwan

To study the demographic changes of yeasts causing invasive infections in Taiwan, especially with respect to species distribution and antifungal susceptibility, we analyzed isolates obtained from four sterile sites of patients in 19 hospitals in 2002 (155 strains) and again from the same hospitals in 2006 (208 strains). Blood was the most common source of the yeasts, accounting for 73.8% of the total isolates, followed by ascites (21.5%), cerebrospinal fluid (3%), and synovia (1.7%). Candida albicans was the most frequently recovered species (50.1% of the total), followed by Candida tropicalis (20.7%), Candida glabrata (11.6%), Candida parapsilosis (8.5%), Cryptococcus neoformans (3.9%), Candida krusei (0.8%), and nine other species (4.3%). There were one (0.3%) and seven (1.9%) isolates with minimum inhibitory concentrations (MICs) of amphotericin B > or =2 mg/l after 24 h and 48 h incubation, respectively. In addition, there were 15 (4.3%) and 31 (8.6%) isolates with MICs of fluconazole > or =64 mg/l under the same conditions. The MIC(90) value of amphotericin B was 1 mg/l. The MIC(90) values of fluconazole were 4 mg/l after 24 h incubation and 32 mg/l after 48 h incubation. Interestingly, MICs for fluconazole > or =64 mg/l after 24 h were significantly higher for isolates obtained in 2006 than those in 2002 after 24 h (7.1% vs. 0.7%, p =0.009) and 48 h (13.5% vs. 2%, p =0.0003) incubations. The demographic difference between these two surveys is mainly due to one species, C. tropicalis.

Nationwide sentinel surveillance of bloodstream Candida infections in 40 tertiary care hospitals in Spain

Candidemia studies have documented geographic differences in rates and epidemiology, underscoring the need for surveillance to monitor trends. We conducted prospective candidemia surveillance in Spain to assess the incidence, species distribution, frequency of antifungal resistance, and risk factors for acquiring a Candida infection. Prospective laboratory-based surveillance was conducted from June 2008 to June 2009 in 40 medical centers located around the country. A case of candidemia was defined as the isolation of a Candida species from a blood culture. Incidence rates were calculated per 1,000 admissions. Antifungal susceptibility tests were performed by using broth microdilution assay according to the guidelines of the Clinical and Laboratory Standards Institute. We detected 984 cases, for an overall incidence of 1.09 cases per 1,000 admissions. The crude mortality was 20.20%. Candida albicans was the most common species (49.08%), followed by C. parapsilosis (20.73%), C. glabrata (13.61%), and C. tropicalis (10.77%). Overall, decreased susceptibility to fluconazole occurred in 69 (7.01%) incident isolates. Antifungal resistance was rare, and a moderate linear correlation between fluconazole and voriconazole MICs was observed. This is the largest multicenter candidemia study conducted to date and shows the substantial morbidity and mortality of candidemia in Spain.

Secular trends of candidemia in a tertiary care hospital

BACKGROUND

Candidemias account for 8% to 15% of hospital-acquired bloodstream infections. They have been associated with previous exposure to antimicrobials and are considered high-morbidity infections with high treatment costs. This study characterizes candidemias in a tertiary care hospital and assesses their incidence rates, clinical and microbiological features, and use of antifungals.

METHODS

We assessed hospital-acquired candidemias in the period from January 1997 to July 2007 in a high-complexity private hospital.

RESULTS

There were 151 cases of candidemia in 147 patients. The incidence rate was 0.74 episodes/1000 admissions. The mean age of the patients was 60 years (standard deviation +/- 24.9), and the mean length of hospital stay before the blood culture identified candidemia was 40.9 days (standard deviation +/- 86.3). The in-hospital mortality rate was 44.2%. C albicans was isolated in 44% (n = 67) of the cases, and no difference in mortality rates was found between species (Candida albicans vs C non-albicans, P = .6). The average use of antifungals in the period was 104.0 defined daily dose/1000 patient-days.

CONCLUSION

We found a high mortality rate associated to candidemia events and an increasingly important role of Candida non-albicans. New approaches to health care-related infection control and to defining prophylactic and preemptive therapies should change this scenario in the future.

Recognition and prevention of nosocomial invasive fungal infections in the intensive care unit

Despite recent advances in antifungal treatments, the morbidity and mortality of fungal infections, especially invasive candidiasis, in patients in the intensive care unit setting remain high. Because of this, there has been a great interest in improving the evaluation, risk assessment, and prevention of fungal infections in the intensive care unit. Some important advances in the diagnosis of invasive candidiasis include rapid species identification and improvements in antigen testing. The introduction of several prediction rules has helped to guide clinicians in the use of prophylaxis or preemptive antifungal therapy in high-risk patients. However, the most immediate benefit has been realized with the introduction of new antifungal agents that have proved to be safer than those available in the past.

Invasive candidiasis in the intensive care unit

Invasive fungal disease by Candida spp. is on the rise in the modem era of prolonged patient survival by virtue of improved critical care measures, novel chemotherapy regimens, and increasing immunosuppression following organ transplants. Invasive candidiasis (IC) in the setting of an intensive care unit results in prolonged hospital stay and increased morbidity. Clinical suspicion plays a major role in the diagnosis of IC, as current laboratory methods are not very sensitive. Various serum markers and molecular techniques are under development to improve diagnostic strategies. Treatment options involve an expanding spectrum of antifungals. Knowledge of local epidemiology and the risk factors that predispose patients to this disease are essential for effective patient care in an intensive care setting.

Trends in nosocomial bloodstream infections in a burn intensive care unit: an eight-year survey

This study was designed to evaluate the frequency and profile of bloodstream infection (BSI) in a burn intensive care unit (BICU) in Tripoli, Libya, from 1st January 2000 to 31st December 2007 and to determine the prevalence of different bacteria involved in such infections and their antimicrobial susceptibilities. During the eight-year study period, 995 patients were admitted to the BICU. Blood cultures were collected from each septicaemic case and reviewed for age, sex, total body surface area burned, isolated micro-organisms, and antibiotic sensitivity. There were 430 episodes of BSI among 830 cases; the annual true positive rate varied between 40.0 and 59.4%, the majority (87.9%) being caused by one species only. However, 22% had two or more episodes with different pathogens during hospitalization. The leading isolate was Staphylococcusaureus (40.4%) (methicillinresistant, 55.7%). Pseudomonas spp ranked second (23.9%). Klebsiella spp were third, responsible for 7.4%; the rate of extended spectrum beta lactamase among Klebsiella isolates was 47%. Candida spp were the fourth most common pathogen (6.7%), the majority (55%) being C. albicans. Staphylococci were generally resistant to trimethoprim (91%) and fusidic acid (80%). Pseudomonas spp proved moderately resistant (38-43%) to tobramicin, ciprofloxacin, amikacin, and impenem but remained relatively susceptible to cefepime (72%). Klebsiella isolates demonstrated moderate resistance (46-58%) to most agents tested, and relatively low resistance (19-27%) to meropenem, impenem, and cefepime. We suggest that extra infection control measures should be implemented and antibiotic policy and guidelines introduced to reduce the high resistance rate among isolates such as Pseudomonas, Acinetobacter, and MRSA.

Calcineurin regulates innate antifungal immunity in neutrophils

Patients taking immunosuppressive drugs, like cyclosporine A (CsA), that inhibit calcineurin are highly susceptible to disseminated fungal infections, although it is unclear how these drugs suppress resistance to these opportunistic pathogens. We show that in a mouse model of disseminated Candida albicans infection, CsA-induced susceptibility to fungal infection maps to the innate immune system. To further define the cell types targeted by CsA, we generated mice with a conditional deletion of calcineurin B (CnB) in neutrophils. These mice displayed markedly decreased resistance to infection with C. albicans, and both CnB-deficient and CsA-treated neutrophils showed a defect in the ex vivo killing of C. albicans. In response to the fungal-derived pathogen-associated molecular pattern zymosan, neutrophils lacking CnB displayed impaired up-regulation of genes (IL-10, Cox2, Egr1, and Egr2) regulated by nuclear factor of activated T cells, the best characterized CnB substrate. This activity was Myd88 independent and was reproduced by stimulation with the beta(1,3) glucan curdlan, indicating that dectin-1, rather than toll-like receptors, is the upstream activator of calcineurin. Our results suggest that disseminated fungal infections seen in CsA-treated patients are not just a general consequence of systemic suppression of adaptive immunity but are, rather, a result of the specific blockade of evolutionarily conserved innate pathways for fungal resistance.

Molecular analysis of Candida glabrata clinical isolates

Candida glabrata is an important human pathogen, and an understanding of the genetic relatedness of its clinical isolates is essential for the prevention and control of fungal infections. In this study, we determined the relatedness of 38 Candida glabrata clinical isolates originating from two teaching hospitals in Slovakia. The 14 different genotypes were found by using microsatellite marker analysis (RPM2, MTI and Cg6) and DNA sequencing for analysis of the entire ERG11 gene. Subsequent sequencing of amplified DNA fragments of the PDR1, NMT1, TRP1 and URA3 loci in ten selected clinical isolates revealed identical DNA sequence profiles in five of them. They displayed the same microsatellite marker sizes and contained the same H576Y amino acid substitution recently described in the Pdr1p multidrug resistance transcription factor responsible for azole resistance. These results demonstrate the genetic diversity of C. glabrata clinical isolates in our hospitals and indicate a common clonal origin of some drug resistant ones.

Epidemiology of invasive mycoses in North America

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

Surveillance programs for detection and characterization of emergent pathogens and antimicrobial resistance: results from the Division of Infectious Diseases, UNIFESP

Several epidemiological changes have occurred in the pattern of nosocomial and community acquired infectious diseases during the past 25 years. Social and demographic changes possibly related to this phenomenon include a rapid population growth, the increase in urban migration and movement across international borders by tourists and immigrants, alterations in the habitats of animals and arthropods that transmit disease, as well as the raise of patients with impaired host defense abilities. Continuous surveillance programs of emergent pathogens and antimicrobial resistance are warranted for detecting in real time new pathogens, as well as to characterize molecular mechanisms of resistance. In order to become more effective, surveillance programs of emergent pathogens should be organized as a multicenter laboratory network connected to the main public and private infection control centers. Microbiological data should be integrated to guide therapy, adapting therapy to local ecology and resistance patterns. This paper presents an overview of data generated by the Division of Infectious Diseases, Federal University of São Paulo, along with its participation in different surveillance programs of nosocomial and community acquired infectious diseases.

Candida bloodstream infections in hemodialysis recipients

Candidemia is a major cause of morbidity and mortality in patients undergoing hemodialysis but it has not been well defined in this patient population. We performed a retrospective case-control study to characterize the epidemiology, microbiology, and outcomes of hemodialysis-associated candidemia. All cases of candidemia at our institution were evaluated from 1 January 2000 until 1 September 2004. For each case, two non-candidemic dialysis patients served as controls. Among 350 cases of candidemia, 78 (22%) occurred in adult hemodialysis patients. Cases and controls were similar with respect to age, corticosteroid, antibiotics use, prevalence of diabetes mellitus, liver cirrhosis, surgical procedures, and cancer. Multivariate analysis found total parenteral nutrition (TPN) (19.5% vs. 1.3%; P<0.0001) and dialysis through a vascular catheter (74% vs. 46.8%; P=0.0001) to be independently associated with candidemia. Non-C.albicans Candida spp. particularly C. glabrata and C. krusei were more common in hemodialysis recipients than in candidemic patients not receiving hemodialysis (31% vs. 17% p = 0.009). In-hospital mortality was significantly elevated for candidemic vs. non-candidemic hemodialysis recipients (51.9% vs. 7.8%; P<0.0001). Candidemia in hemodialysis recipients is frequently caused by non-C. albicansCandida species, is associated with TPN and dialysis via a vascular catheter (vs. shunt or fistula) and carries a high mortality rate.

Candidemia distribution, associated risk factors, and attributed mortality at a university-based medical center

Candida is the fourth most common cause of nosocomial bloodstream infections (BSI), being Candida albicans the most common species. This study evaluated the distribution of Candida spp isolates at a tertiary care medical center. The associated factors and outcome of patients with candidemia at the Puerto Rico Medical Center (PRMC) were evaluated. Laboratory data from May 2005 to April 2006 was reviewed. Blood cultures reported as positive for Candida spp were identified and records were reviewed. Two hundred and four blood cultures were reported with Candida spp, corresponding to 85 different episodes of candidemia in 82 patients: 3 patients presented more than one candidemia episode with two different Candida spp. In seventy-two percent (61/85) of candidemia episodes, the organism isolated was a non-albicans Candida, being C. parapsilosis the most common species isolated with 49% (42/85). Sixty five records were evaluated; of which 45 cases were reviewed (20 cases were excluded from the study due to incomplete information). The predominant factors identified were being on broad spectrum antibiotics 95.6% (43/45), central catheter placement 97.8% (44/45), mechanical ventilation 64.4% (29/45), and urinary catheter placement 73.3% (33/45). The mortality among the reviewed cases was 48.9% (22/45).

Nosocomial candidaemia in a Finnish tertiary care centre during 1987-2004

We studied the epidemiology of nosocomial candidaemia by assessing the incidence and outcome of illness and causative species in a large Finnish tertiary care centre during 1987-2004. A total of 364 episodes were observed; annual incidence varied between 0.26 per 10,000 patient-d in 2000 and 0.59 in 1989. The most common species were C. albicans (65%), C. parapsilosis (13%), and C. glabrata (9%). The proportion of C. albicans decreased from 71% during 1987-1992 to 58% during 1999-2004, and C. glabrata increased from 3% to 14%, respectively. The proportion of intensive care patients increased from 27% during 1987-1992 to 44% by 1999-2004, associated with neonates and surgical patients. The 1-month case fatality ranged from 30% to 33%. Nosocomial candidaemias did not increase, but the distribution of Candida spp. changed. Mortality remained high. The observed changes may reflect differences in prevention strategies that need to be explored for further improvements in prevention.

Antifungal susceptibility testing of Candida isolates from the Candida surveillance study

Candida species are a common cause of nosocomial bloodstream infections. Recent surveillance has shown an increase in the relative proportion of infections caused by Candida glabrata, which has reduced susceptibility to fluconazole. We undertook sentinel surveillance with antifungal susceptibility testing to monitor the trends in the proportions of various Candida species causing invasive disease. Forty-one institutions participated in the Candida Surveillance Study. All isolates were submitted to a central laboratory for identification and susceptibility testing. Susceptibility testing was performed in compliance with CLSI guidelines using a custom, broth dilution, microtiter system. There were 5,900 isolates submitted for identification and antifungal susceptibility testing. The distribution of species was as follows: C. albicans, 2,567 (43.5%) isolates; C. glabrata, 1,464 (24.8%) isolates; C. parapsilosis, 1,048 (17.8%) isolates; C. tropicalis, 527 (8.9%) isolates; C. krusei, 109 (1.9%) isolates; C. lusitaniae, 76 (1.3%) isolates; and other Candida species, 109 (1.9%) isolates. Resistance to fluconazole occurred in 1.2% of C. albicans isolates, 5.9% of C. glabrata isolates, 0.3% of C. parapsilosis isolates, and 0.4% of C. tropicalis isolates. Resistance to fluconazole was highly predictive of resistance to voriconazole. Resistance to echinocandins was rarely found, occurring in only 0.2% of all isolates. The rate of fluconazole susceptibility increased significantly from 87.5% in 2005 to 97.4% in 2007. The proportion of cases of disease caused by various Candida species did not change appreciably between 2004 and 2007, and the rate of antifungal susceptibility was high.

Epidemiology, incidence and risk factors for invasive candidiasis in high-risk patients

Candida spp. are an increasing cause of bloodstream infections, and are associated with high morbidity and mortality in both neutropenic and non-neutropenic critically ill patients. Risk factors associated with candidaemia are diverse and include exposure to broad spectrum antimicrobial agents, mucosal colonization by Candida spp., indwelling vascular catheters, prior surgery and cancer chemotherapy. During the last 20 years, there has been an increasing incidence worldwide in invasive candidiasis, but differences in geographical epidemiology are emerging, in particular regarding a shift towards non-albicans species. This shift has been correlated with routine fluconazole prophylaxis adopted in some patients, and the intrinsic/acquired azole resistance of Candida spp., which represents a very real problem, in terms of both selecting the appropriate empirical therapeutic approach and making prophylactic choices.

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

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

Candida albicans hyphal formation and virulence assessed using a Caenorhabditis elegans infection model

Candida albicans colonizes the human gastrointestinal tract and can cause life-threatening systemic infection in susceptible hosts. We study here C. albicans virulence determinants using the nematode Caenorhabditis elegans in a pathogenesis system that models candidiasis. The yeast form of C. albicans is ingested into the C. elegans digestive tract. In liquid media, the yeast cells then undergo morphological change to form hyphae, which results in aggressive tissue destruction and death of the nematode. Several lines of evidence demonstrate that hyphal formation is critical for C. albicans pathogenesis in C. elegans. First, two yeast species unable to form hyphae (Debaryomyces hansenii and Candida lusitaniae) were less virulent than C. albicans in the C. elegans assay. Second, three C. albicans mutant strains compromised in their ability to form hyphae (efg1Delta/efg1Delta, flo8Delta/flo8Delta, and cph1Delta/cph1Delta efg1Delta/efg1Delta) were dramatically attenuated for virulence. Third, the conditional tet-NRG1 strain, which enables the external manipulation of morphogenesis in vivo, was more virulent toward C. elegans when the assay was conducted under conditions that permit hyphal growth. Finally, we demonstrate the utility of the C. elegans assay in a screen for C. albicans virulence determinants, which identified several genes important for both hyphal formation in vivo and the killing of C. elegans, including the recently described CAS5 and ADA2 genes. These studies in a C. elegans-C. albicans infection model provide insights into the virulence mechanisms of an important human pathogen.