Guidelines for Treatment of Candidiasis

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.

Anidulafungin versus fluconazole for invasive candidiasis

BACKGROUND

Anidulafungin, a new echinocandin, has potent activity against candida species. We compared anidulafungin with fluconazole in a randomized, double-blind, noninferiority trial of treatment for invasive candidiasis.

METHODS

Adults with invasive candidiasis were randomly assigned to receive either intravenous anidulafungin or intravenous fluconazole. All patients could receive oral fluconazole after 10 days of intravenous therapy. The primary efficacy analysis assessed the global response (clinical and microbiologic) at the end of intravenous therapy in patients who had a positive baseline culture. Efficacy was also assessed at other time points.

RESULTS

Eighty-nine percent of the 245 patients in the primary analysis had candidemia only. Candida albicans was isolated in 62% of the 245 patients. In vitro fluconazole resistance was infrequent. Most of the patients (97%) did not have neutropenia. At the end of intravenous therapy, treatment was successful in 75.6% of patients treated with anidulafungin, as compared with 60.2% of those treated with fluconazole (difference, 15.4 percentage points; 95% confidence interval [CI], 3.9 to 27.0). The results were similar for other efficacy end points. The statistical analyses failed to show a "center effect"; when data from the site enrolling the largest number of patients were removed, success rates at the end of intravenous therapy were 73.2% in the anidulafungin group and 61.1% in the fluconazole group (difference, 12.1 percentage points; 95% CI, -1.1 to 25.3). The frequency and types of adverse events were similar in the two groups. The rate of death from all causes was 31% in the fluconazole group and 23% in the anidulafungin group (P=0.13).

CONCLUSIONS

Anidulafungin was shown to be noninferior to fluconazole in the treatment of invasive candidiasis. (ClinicalTrials.gov number, NCT00056368 [ClinicalTrials.gov]).

A multicenter, randomized trial of prophylactic fluconazole in preterm neonates

BACKGROUND

Invasive candida infections are a major cause of morbidity and mortality in preterm infants. We performed a multicenter, randomized, double-blind, placebo-controlled trial of fluconazole for the prevention of fungal colonization and infection in very-low-birth-weight neonates.

METHODS

During a 15-month period, all neonates weighing less than 1500 g at birth from eight tertiary Italian neonatal intensive care units (322 infants) were randomly assigned to receive either fluconazole (at a dose of either 6 mg or 3 mg per kilogram of body weight) or placebo from birth until day 30 of life (day 45 for neonates weighing <1000 g at birth). We performed weekly surveillance cultures and systematic fungal susceptibility testing.

RESULTS

Among infants receiving fluconazole, fungal colonization occurred in 9.8% in the 6-mg group and 7.7% in the 3-mg group, as compared with 29.2% in the placebo group (P<0.001 for both fluconazole groups vs. the placebo group). The incidence of invasive fungal infection was 2.7% in the 6-mg group and 3.8% in the 3-mg group, as compared with 13.2% in the placebo group (P=0.005 for the 6-mg group and P=0.02 for the 3-mg group vs. the placebo group). The use of fluconazole did not modify the relationship between colonization and the subsequent development of invasive fungal infection. Overall mortality was similar among groups, as was the incidence of cholestasis. No evidence for the emergence of resistant candida species was observed, but the study did not have substantial power to detect such an effect.

CONCLUSIONS

Prophylactic fluconazole reduces the incidence of colonization and invasive candida infection in neonates weighing less than 1500 g at birth. The benefit of treating candida colonization is unclear. (Current Controlled Trials number, ISRCTN85753869 [controlled-trials.com]).

[Guidelines for the diagnosis and treatment of patients with bacteriemia. Guidelines of the Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica]

Bacteremia is a complex clinical syndrome in constant transformation that is an important, growing cause of morbidity and mortality. Even though there is a great deal of specific information about bacteremia, few comprehensive reviews integrate this information with a practical AIM. The main objective of these Guidelines, which target hospital physicians, is to improve the clinical care provided to patients with bacteremia by integrating blood culture results with clinical data, and optimizing the use of diagnostic procedures and antimicrobial testing. The document is structured into sections that cover the epidemiology and etiology of bacteremia, stratified according to the various patient populations, and the diagnostic work-up, therapy, and follow-up of patients with bacteremia. Diagnostic and therapeutic decisions are presented as recommendations based on the grade of available scientific evidence.

[Management of fungal urinary tract infections]

Fungal urinary tract infections (funguria) are rare in community medicine, but common in hospitals where 10 to 30% of urine cultures isolate Candida species. Clinical features vary from asymptomatic urinary tract colonization (the most common situation) to cystitis, pyelonephritis, or even severe sepsis with fungemia. The pathologic nature of funguria is closely related to host factors, and management depends mainly on the patient's underlying health status. Microbiological diagnosis of funguria is usually based on a fungal concentration of more than 10(3)/mm(3) in urine. No cutoff point has been defined for leukocyte concentration in urine. Candida albicans is the most commonly isolated species, but previous antifungal treatment and previous hospitalization affect both species and susceptibility to antifungal agents. Treatment is recommended only when funguria is symptomatic or in cases of fungal colonization when host factors increase the risk of fungemia. The antifungal agents used for funguria are mainly fluconazole and amphotericin B deoxycholate, because other drugs have extremely low concentrations in urine. Primary and secondary preventions are essential. The reduction of risk factors requires removing urinary catheters, limiting antibiotic treatment, and optimizing diabetes mellitus treatment.

Preemptive therapy in nonneutropenic patients with Candida infection using the Japanese guidelines

BACKGROUND

The Japanese Guidelines for the Diagnosis and Treatment of Deep-Seated Mycosis were established in 2003. Proven Candida infection (CI) is defined as at least one positive blood culture yielding a Candida species. Clinically documented CI requires documentation of more than 2 sites of colonization and a positive plasma beta-D-glucan test. Possible CI is diagnosed by one of the above criteria in febrile, nonneutropenic critically ill patients.

OBJECTIVE

To assess the use of definitions of clinically documented and possible CI for guiding preemptive antifungal therapy in critically ill patients.

METHODS

The patients treated in our intensive care unit (ICU) for at least 48 hours between 2000 and 2004 were investigated. The administration of antifungal agents and ICU mortality were compared among proven, clinically documented, and possible CI groups for age, sex, APACHE II score, diagnosis, length of ICU stay, treatment, number of colonization sites, and plasma beta-D-glucan level.

RESULTS

Six patients were diagnosed with proven CI, 25 were diagnosed with clinically documented CI, and 104 with possible CI. The patients with clinically documented CI were compared with those with possible CI, and statistically significant differences were found in the following variables: APACHE II score (p = 0.018), length of ICU stay (p < 0.01), use of ventilator (p = 0.027), tracheotomy (p = 0.027), number of colonization sites (p < 0.001), plasma beta-D-glucan level (p < 0.001), and administration of antifungal agents (p < 0.001); incidence of mortality was not statistically significant (p = 0.33). The shorter length of ICU stay, use of ventilator, and continuous hemodiafiltration were risk factors for death after adjusting for APACHE II score, admission before/after 2003, antifungal therapy, and other factors. Although the frequency of the administration of preemptive antifungal therapy was higher after 2003 than before, the mortality rate did not differ significantly.

CONCLUSIONS

The use of the definitions of clinically documented and possible CI may be beneficial for determining when it is appropriate to initiate preemptive antifungal therapy. However, use of the guidelines did not lead to prevention of possible CI proceeding to clinically documented CI or to improved mortality.

Caspofungin for the treatment of less common forms of invasive candidiasis

OBJECTIVES

Caspofungin has demonstrated efficacy in invasive candidiasis. However, in a comparative study, most patients (>83%) had candidaemia. Therefore, we performed a study in patients with non-fungaemic invasive candidiasis.

PATIENTS AND METHODS

Adults with proven non-fungaemic invasive candidiasis or probable chronic disseminated candidiasis (CDC) received caspofungin primary or salvage monotherapy. Most patients received 50 mg daily following a 70 mg loading dose. Patients with endocarditis, osteomyelitis or septic arthritis received caspofungin at 100 mg daily and were allowed dose escalation up to 150 mg. Primary efficacy endpoint was the overall response at end of caspofungin therapy. A favourable overall response required complete resolution of symptoms and either eradication of Candida or radiographic resolution.

RESULTS

All 48 patients enrolled had confirmed infection and received>or=1 dose of caspofungin. At study entry, 8% were neutropenic. The mean APACHE II score was 14.3. Most infections were due to Candida albicans (60%) or Candida glabrata (14%). The overall success at end of caspofungin therapy was 81%. Success by site of infection was as follows: peritonitis 77% (10/13), abdominal abscess 89% (8/9), CDC 88% (7/8), osteomyelitis/septic arthritis 100% (4/4), endocarditis 33% (1/3) and multiple sites 75% (6/8). Outcomes were similar across Candida spp. None of the patients had a serious drug-related adverse event or discontinued caspofungin due to toxicity. Overall mortality until 12 week follow-up was 23%.

CONCLUSIONS

In deep-seated invasive candidiasis, including peritonitis, abdominal abscesses, CDC and arthritis, caspofungin was effective and safe at regular doses and up to 100 mg daily.

Do clinical features allow for accurate prediction of fungal pathogenesis in bloodstream infections? Potential implications of the increasing prevalence of non-albicans candidemia

OBJECTIVE

To describe the evolving epidemiology of fungal bloodstream infections in critically ill and noncritically ill patients and to identify predictors of infection with non-albicans yeast species.

DESIGN

Retrospective case series.

SETTING

Two academic, tertiary care centers.

PARTICIPANTS

All persons during a 4-yr period who developed fungemia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We initially compared subjects with Candida albicans vs. alternative yeast. In a sensitivity analysis, we compared persons with potentially fluconazole-resistant organisms (Candida glabrata and Candida krusei) to those with other fungi. We also repeated these analyses in the subgroup of persons in the intensive care unit when they developed fungemia. The study cohort included 245 patients (60% in the intensive care unit), and C. albicans accounted for 52% of infections, whereas C. glabrata represented 20% of cases. The distribution of isolates was similar in both intensive care unit patients and those on the wards. In the entire population, no variable, including both previous fluconazole exposure and severity of illness, correlated with the fungemia due to a non-albicans species. In our sensitivity analysis, no factor was independently associated with a potentially fluconazole-resistant yeast. For the subgroup of subjects whose fungemia was diagnosed while they were in the intensive care unit, no variable differentiated C. albicans from non-albicans isolates.

CONCLUSIONS

Non-albicans yeast are common both in the intensive care unit and on the wards. Simple clinical factors do not allow the clinician to effectively identify patients likely infected with non-albicans pathogens or with possible fluconazole-resistant fungi.

Invasive candidiasis in pediatric intensive care patients: epidemiology, risk factors, management, and outcome

BACKGROUND

The incidence of candidemia in pediatric patients follows the same pattern of increase as in adults, but the rate of increase is greater. Pediatric patients in critical condition, particularly young infants, are especially vulnerable to invasive Candida infections (ICI), partly because of their age and severe underlying disease and partly because of the invasive procedures used.

DISCUSSION

Central venous catheters and arterial lines, parenteral nutrition, mechanical ventilation and extended use of antimicrobials enhance the risk of ICI. C. albicans continues to be the most prevalent isolate. However, an increasing role of non-C. albicans (NAC) spp., some of which are intrinsically or potentially resistant to antifungal agents, has been observed. NAC spp., particularly C. parapsilosis and C. tropicalis, account for almost half of ICI. The increased use of antifungals in immunocompromised patients, mainly prophylactically, is considered the strongest contributory factor to the changes in species distribution, which have subsequently affected the mortality and choice of empirical treatment.

CONCLUSIONS

Prompt removal of lines and initiation of antifungal treatment are the milestones of management. Conventional amphotericin B remains a commonly used antifungal agent, but its lipid formulations and fluconazole are also used frequently. Novel antifungal agents such as second-generation triazoles and echinocandins exhibit potential as alternative agents in critically ill children with ICI. Although response rates are still far from satisfactory, improved understanding of risk factors, preventive strategies and new treatment options promise a better future outcome.

Combined herpes viral and candidal esophagitis in a CAPD patient: case report and review of literature

Concomitant herpetic and candidal esophagitis is a very rare disease that had not been reported in uremic patients. A 57-year-old woman receiving continuous ambulatory peritoneal dialysis (CAPD) therapy for 3 years was admitted due to CAPD-related peritonitis. Endoscopic examination was performed due to severe epigastralgia and upper gastrointestinal bleeding, and combined herpetic and candidal esophagitis was diagnosed. Intravenous acyclovir and fluconazole were prescribed and symptoms improved. The patient subsequently died due to progressive sepsis and respiratory failure. This is the first report of a dual infectious esophagitis in a uremic patient. Since infectious esophagitis may cause severe complications, early diagnosis and aggressive treatment are important.

[Nosocomial urinary tract infection in adults]

Urinary tract infection (UTI) is the most common infection in hospitalized adults. Nosocomial UTIs are mainly associated with the use of urinary catheters. Thus, the decision for catheterization should be made carefully and catheters removed in time. In order to prevent unnecessary antibiotic use in patients with urinary catheters correct diagnosis is crucial. Chinolones, broad-spectrum penicillins and third-generation cephalosporins are the mainstay of therapy. Comorbidities should be considered and potential obstructions of urinary flow removed. Economically important are the normally higher prices of i.v. antibiotics compared to oral use.

Micafungin versus liposomal amphotericin B for candidaemia and invasive candidosis: a phase III randomised double-blind trial

BACKGROUND

Invasive candidosis is increasingly prevalent in seriously ill patients. Our aim was to compare micafungin with liposomal amphotericin B for the treatment of adult patients with candidaemia or invasive candidosis.

METHODS

We did a double-blind, randomised, multinational non-inferiority study to compare micafungin (100 mg/day) with liposomal amphotericin B (3 mg/kg per day) as first-line treatment of candidaemia and invasive candidosis. The primary endpoint was treatment success, defined as both a clinical and a mycological response at the end of treatment. Primary analyses were done on a per-protocol basis. This trial is registered with ClinicalTrials.gov, number NCT00106288.

FINDINGS

264 individuals were randomly assigned to treatment with micafungin; 267 were randomly assigned to receive liposomal amphotericin B. 202 individuals in the micafungin group and 190 in the liposomal amphotericin B group were included in the per-protocol analyses. Treatment success was observed for 181 (89.6%) patients treated with micafungin and 170 (89.5%) patients treated with liposomal amphotericin B. The difference in proportions, after stratification by neutropenic status at baseline, was 0.7% (95% CI -5.3 to 6.7). Efficacy was independent of the Candida spp and primary site of infection, as well as neutropenic status, APACHE II score, and whether a catheter was removed or replaced during the study. There were fewer treatment-related adverse events--including those that were serious or led to treatment discontinuation--with micafungin than there were with liposomal amphotericin B.

INTERPRETATION

Micafungin was as effective as--and caused fewer adverse events than--liposomal amphotericin B as first-line treatment of candidaemia and invasive candidosis.

Voriconazole : a review of its use in the management of invasive fungal infections

Voriconazole (VFEND), a synthetic second-generation, broad-spectrum triazole derivative of fluconazole, inhibits the cytochrome P450 (CYP)-dependent enzyme 14-alpha-sterol demethylase, thereby disrupting the cell membrane and halting fungal growth. In the US, intravenous and/or oral voriconazole is recommended in adults for the treatment of invasive aspergillosis, candidaemia in non-neutropenic patients, disseminated infections caused by Candida spp., oesophageal candidiasis, and in patients with scedosporiosis and fusariosis who are refractory to or intolerant of other antifungal therapy. In Europe, intravenous and/or oral voriconazole is recommended in adults and paediatric patients of at least 2 years of age for the treatment of invasive aspergillosis, candidaemia in non-neutropenic patients, fluconazole-resistant serious invasive Candida spp. infections, scedosporiosis and fusariosis. In large randomised trials, voriconazole was an effective and generally well tolerated primary treatment for candidiasis and invasive aspergillosis in adults and adolescents. More limited data also support the use of voriconazole for the treatment of invasive fungal infections in children, in those with rare fungal infections, such as Fusarium spp. or Scedosporium spp., and in those refractory to or intolerant of other standard antifungal therapies. The availability of both parenteral and oral formulations and the almost complete absorption of the drug after oral administration provide for ease of use and potential cost savings, and ensure that therapeutic plasma concentrations are maintained when switching from intravenous to oral therapy. On the other hand, the numerous drug interactions associated with voriconazole may limit its usefulness in some patients. Further clinical experience will help to more fully determine the position of voriconazole in relation to other licensed antifungal agents. In the meantime, voriconazole is a valuable emerging option for the treatment of invasive aspergillosis and rare fungal infections, including Fusarium spp. and Scedosporium spp. infections, and provides an alternative option for the treatment of candidiasis, particularly where the causative organism is inherently resistant to other licensed antifungal agents.

Micafungin activity against Candida bloodstream isolates: effect of growth medium and susceptibility testing method

An excellent correlation between micafungin MICs were demonstrated against Candida bloodstream isolates (n = 200) by the Sensititre YeastOne and National Committee for Clinical Laboratory Standards M27-A2 methods. Use of antibiotic medium 3 (2%) dextrose improved micafungin activity and was not associated with paradoxical growth as noted with 3 Candida isolates tested using RPMI (2%) dextrose.

High- versus low-dose fluconazole therapy for empiric treatment of suspected invasive candidiasis among high-risk patients in the intensive care unit: a cost-effectiveness analysis

BACKGROUND

High-dose fluconazole is an alternative for patients with candidemia caused by Candida glabrata or other Candida species with decreased fluconazole susceptibility. However, empiric high-dose fluconazole is not currently recommended and may result in higher drug costs and toxicity.

OBJECTIVE

To determine the cost-effectiveness of using empiric high-dose fluconazole in intensive care unit (ICU) with suspected invasive candidiasis.

DESIGN

Decision analytic model.

TARGET POPULATION

ICU patients with suspected invasive candidiasis.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTIONS

Low-dose fluconazole (loading dose of 800 mg followed by 400 mg daily) vs. high-dose fluconazole (loading dose of 1600 mg followed by 800 mg daily). Generic fluconazole costs were used for the analysis.

OUTCOME MEASURES

Incremental life expectancy and incremental cost per discounted life year (DLY) saved. RESULT OF BASE-CASE ANALYSIS: Based on current national levels of fluconazole resistance and ability to correctly identify patients with candidemia, high-dose fluconazole was the more effective but more expensive treatment strategy. Empiric high-dose fluconazole therapy decreased the mortality rate by 0.15% compared to low-dose strategy with a cost-effectiveness rate of $55,526 per DLY saved.

RESULTS OF SENSITIVITY ANALYSIS

Empirical high-dose fluconazole was an acceptable treatment strategy (using $100,000 per DLY saved as threshold) unless the physical age of an ICU survivor was 66 years or older. Empirical high-dose fluconazole was an acceptable treatment strategy using $50,000 per DLY saved with minor changes in parameters estimates.

LIMITATIONS

The estimates of our model may not be applicable to all ICU patients. Other hospitals with differences in fluconazole resistance, prevalence of invasive candidiasis, or duration of fluconazole therapy may produce different results.

CONCLUSION

These results suggest that empiric high-dose fluconazole therapy should reduce the mortality associated with invasive candidiasis at an acceptable cost.

[Systemic antifungals. Pharmacodynamics and pharmacokinetics]

Invasive fungal infections are important causes of morbidity and mortality in critically ill non neutropenic patients. For many years, amphotericin B and flucytosine have been the only available antifungal agents for invasive fungal infections. Fortunately, the antifungal armamentarium has increased during the past two decades with the addition of several new agents. In addition to itraconazole and fluconazole, lipid formulations of amphotericin B, voriconazole, and caspofungin have been recently licensed. These various antifungal agents differ in their pharmacokinetic and pharmacodynamic profile.

Economic analysis of inadequate fluconazole therapy in non-neutropenic patients with candidaemia: a multi-institutional study

Mortality significantly increases in patients with candidaemia who receive inappropriate fluconazole therapy. The goals of this study were to compare hospital length of stay and costs for non-neutropenic patients with candidaemia treated with fluconazole based on the empirical dose and time until initiation of therapy. A retrospective cohort study was conducted of patients with candidaemia who were prescribed fluconazole at the onset of candidaemia or later. Hospital-related costs were compared based on time to initiation of fluconazole therapy and empirical fluconazole dose. A total of 192 non-neutropenic patients (55% male; mean age+/-standard deviation, 56+/-17 years) were identified. Isolated Candida species included C. albicans (59%), C. glabrata (15%), C. parapsilosis (11%), C. tropicalis (6%), C. krusei (3%) or other Candida spp. (6%). Time to initiation of fluconazole was Day 0 (35.4%), Day 1 (14.1%), Day 2 (26.6%) or Day >or=3 (23.9%). Thirty-two patients (17%) received a dose of fluconazole >or=6 mg/kg on Day 0. Total costs were lowest for patients started on fluconazole on the culture day with adequate doses ($35,459+/-25,988) compared with all other patients ($52,158+/-53,492) (P=0.0088). After controlling for covariates, each 1-day delay in fluconazole therapy was associated with increased total hospital costs of $6392+/-3000 (P=0.0344), and an adequate fluconazole dose was associated with decreased total hospital costs of $18,744+/-7173 (P=0.0097). A delay or an inadequate dose or fluconazole in patients with candidaemia was associated with increased hospital costs. Improved methods to diagnose patients with candidaemia quickly are needed.

Results from the ARTEMIS DISK Global Antifungal Surveillance study, 1997 to 2005: an 8.5-year analysis of susceptibilities of Candida species and other yeast species to fluconazole and voriconazole determined by CLSI standardized disk diffusion testing

Fluconazole in vitro susceptibility test results for 205,329 yeasts were collected from 134 study sites in 40 countries from June 1997 through December 2005. Data were collected for 147,776 yeast isolates tested with voriconazole from 2001 through 2005. All investigators tested clinical yeast isolates by the CLSI M44-A disk diffusion method. Test plates were automatically read and results recorded with a BIOMIC image analysis system. Species, drug, zone diameter, susceptibility category, and quality control results were collected quarterly. Duplicate (same patient, same species, and same susceptible-resistant biotype profile during any 7-day period) and uncontrolled test results were not analyzed. Overall, 90.1% of all Candida isolates tested were susceptible (S) to fluconazole; however, 10 of the 22 species identified exhibited decreased susceptibility (<75% S) on the order of that seen with the resistant (R) species C. glabrata and C. krusei. Among 137,487 isolates of Candida spp. tested against voriconazole, 94.8% were S and 3.1% were R. Less than 30% of fluconazole-resistant isolates of C. albicans, C. glabrata, C. tropicalis, and C. rugosa remained S to voriconazole. The non-Candida yeasts (8,821 isolates) were generally less susceptible to fluconazole than Candida spp. but, aside from Rhodotorula spp., remained susceptible to voriconazole. This survey demonstrates the broad spectrum of these azoles against the most common opportunistic yeast pathogens but identifies several less common yeast species with decreased susceptibility to antifungal agents. These organisms may pose a future threat to optimal antifungal therapy and emphasize the importance of prompt and accurate species identification.

Invasive candidiasis treated in the intensive care unit: observations from a randomized clinical trial

OBJECTIVES

The objectives of this study were to contrast risk factors, microbiology, and outcomes in patients with invasive candidiasis treated in an intensive care unit (ICU) with those in patients with invasive candidiasis treated outside an ICU and to describe therapeutic results with caspofungin in ICU patients.

MATERIALS AND METHODS

We retrospectively identified patients with documented invasive candidiasis who received their first dose of the study drug in the ICU as part of a double-blind randomized trial. Participants were not stratified at entry by their ICU status. Patients received caspofungin (50 mg/d after a 70-mg loading dose) or conventional amphotericin B (0.6-1.0 mg/kg per day) for 10 to 14 days. A favorable response required resolution of signs and symptoms as well as eradication of Candida pathogens.

RESULTS

Of the 224 patients, 97 (43%) received their first dose of the study drug in the ICU. Most patients had well-recognized risk factors for invasive candidiasis, including broad-spectrum antibiotics, central venous catheters, and hyperalimentation. Recent surgery was more common whereas malignancy, neutropenia, and immunosuppression were less common among ICU patients than among non-ICU patients. Candidemia was demonstrated in 81% of ICU patients and in 84% of non-ICU patients. Favorable response rates in the ICU patients vs the non-ICU patients were 68% (95% confidence interval [CI] = 53%, 82%) vs 77% (95% CI = 67%, 87%) for caspofungin and 56% (95% CI = 43%, 69%) vs 67% (95% CI = 55%, 79%) for amphotericin B. After accounting for differences in APACHE (Acute Physiology and Chronic Health Evaluation) II score, neutropenia status, and geographic region, we found that patients initiating the study therapy in an ICU were still more likely to die than patients initiating study therapy outside an ICU. For ICU patients, all-cause mortality rates were 45% (95% CI = 30%, 60%) for caspofungin recipients and 40% (95% CI = 28%, 53%) for amphotericin B recipients, whereas candidiasis-attributable mortality rates were 5% (95% CI = 0%, 12%) for caspofungin recipients and 11% (95% CI = 3%, 19%) for amphotericin B recipients. Overall, drug-related adverse events were reported less often among the ICU patients than among the non-ICU patients.

CONCLUSIONS

In ICU patients treated with antifungal therapy, invasive candidiasis is associated with substantial mortality, but most deaths cannot be directly attributed to this infection.

To test or not to test: a cost minimization analysis of susceptibility testing for patients with documented Candida glabrata fungemias

This cost minimization analysis investigated the financial impact of the treatment of fungemias due to Candida glabrata from a hospital perspective using three competing alternatives: (i) performing in-house susceptibility testing on all C. glabrata isolates and changing patients to less expensive fluconazole therapy for isolates that test susceptible; (ii) susceptibility testing at outside laboratories with delayed deescalation to fluconazole if isolates test susceptible; and (iii) no routine susceptibility testing with full echinocandin treatment course. Sensitivity analyses and Monte Carlo simulation enhanced the robustness of the model through variation of all assumptions and costs. In the base case, the use of in-house testing displayed a cost advantage over the options of send-out testing and no susceptibility testing ($2,226 versus $2,410 versus $3,136, respectively). Sensitivity analyses determined that the cost of echinocandin therapy and the turnaround time for send-out testing had the potential to impact the base case model. The decision model indicated that in-house susceptibility testing of C. glabrata isolates should result in lower overall treatment costs in patients with documented C. glabrata fungemias.

Antifungal therapy in children with invasive fungal infections: a systematic review

Invasive fungal infections are associated with significant morbidity and mortality. Differences between children and adults are reported, yet few trials of antifungal agents have been performed in pediatric populations. We performed a systematic review of the literature to guide appropriate pediatric treatment recommendations. From available trials that compared antifungal agents in either prolonged febrile neutropenia or invasive candidal or Aspergillus infection, no clear difference in treatment efficacy was demonstrated, although few trials were adequately powered. Differing antifungal pharmacokinetics between children and adults were demonstrated, requiring dose modification. Significant differences in toxicity, particularly nephrotoxicity, were identified between classes of antifungal agents. Therapy needs to be guided by the pathogen or suspected pathogens, the degree of immunosuppression, comorbidities (particularly renal dysfunction), concurrent nephrotoxins, and the expected length of therapy.

Prospective evaluation of the new chromogenic medium CandiSelect 4 for differentiation and presumptive identification of the major pathogenic Candida species

The rapid identification of pathogenic yeasts is a crucial step in ensuring that effective antifungal treatment is started as early as possible. CandiSelect 4 (CS4; Bio-Rad) is a new chromogenic medium for the isolation of fungi, the direct identification of Candida albicans and the presumptive identification of the major pathogenic Candida species. The performance of CS4 was compared with that of another chromogenic medium, CHROMagar Candida (CA; Becton Dickinson). For primary cultures, 502 of the 1549 (32 %) samples were culture-positive. A total of 542 yeasts were isolated including 465 monomicrobial and 37 mixed cultures: 392 C. albicans, 60 Candida glabrata, 25 Candida tropicalis, 12 Candida krusei and 53 other Candida species. The percentage of C. albicans isolates that could be identified directly after 24, 48 and 72 h culture was 31.6, 82.9 and 92.1 %, respectively, for CS4, and 32.9, 82.9 and 91.1 % for CA. The presumptive identification of C. glabrata, C. tropicalis and C. krusei was evaluated after 48 h incubation. The percentage of strains with morphologically typical colonies was 80, 68 and 84.6 %, respectively, for CS4 compared with 75, 76 and 76.9 % for CA. For pure subcultures, from 24 h, all isolates of C. albicans (n=21) were directly identifiable on the two chromogenic media CA and CS4. At 48 h, the proportion of typical strains observed on the two chromogenic media was identical for C. glabrata (85 %) and C. krusei (100 %). A slight difference in favour of CS4 was observed for C. tropicalis (100 vs 95 %). CS4 also allowed the growth of several other fungi. CS4 can be recommended as a primary isolation medium for the identification of C. albicans, and for the rapid and effective differentiation of the major pathogenic Candida species.

Candida peritonitis

PURPOSE OF REVIEW

The review highlights current insights in the epidemiology, diagnosis and therapy of Candida peritonitis, focusing on complicated secondary and tertiary peritonitis.

RECENT FINDINGS

Candida peritonitis is still associated with poor prognosis. Antifungal prophylaxis is therefore recommended in patients with an overt risk profile for invasive candidiasis (immunodeficiency and prior antibiotic exposure). The clinical and microbiological diagnosis of Candida peritonitis remains problematic. It is still unclear which peritonitis patients may benefit from antifungal treatment. Antifungal therapy can be suggested in critically ill patients with nosocomial peritonitis where Candida is diagnosed based on perioperatively sampled peritoneal fluid. Patients with prior exposure to fluconazole are at risk for Candida nonalbicans spp. involvement with possible reduced susceptibility.

SUMMARY

The main challenge in Candida peritonitis remains the interpretation of Candida cultured from the peritoneal cavity. Future research should focus on more conclusive diagnosis and on factors potentially confounding outcome, such as site of the perforation and failure of surgical source control. While awaiting progress to discriminate Candida colonization from invasive infection, antifungal therapy is recommended in high-risk critically ill surgical patients. Rapid detection of Candida might be beneficial in this regard. Besides antifungal therapy, adequate source control is of key importance.

Anidulafungin: a new echinocandin for candidal infections

Anidulafungin, a new echinocandin, has recently been approved for the treatment of esophageal candidiasis, candidemia and other forms of invasive candidiasis, such as peritonitis and intra-abdominal abscesses in non-neutropenic patients. It is fungicidal against Candida spp. including those that are azole- and polyene-resistant and fungistatic against Aspergillus spp. Owing to its poor oral bioavailability it can only be administered intravenously. Its pharmacokinetics allow for once-daily dosing and a steady state concentration is easily achieved on day 2 following a loading dose of double the maintenance dose on day 1. It does not need adjustment for hepatic or renal insufficiency; there are no known drug interactions and it has a favorable tolerability profile. Its mechanism of action, which differs from other classes of antifungals, should prevent cross-resistance with azoles and polyenes.

Serum and intraperitoneal levels of amphotericin B and flucytosine during intravenous treatment of critically ill patients with Candida peritonitis

OBJECTIVES

To study the relation between serum and peritoneal levels of amphotericin B and flucytosine during intravenous treatment in patients with abdominal sepsis due to a perforated gut.

PATIENTS AND METHODS

Included were consecutive patients with abdominal sepsis due to a perforated gut, who were treated intravenously with amphotericin B and/or flucytosine after surgery if an abdominal drain was present. Amphotericin B and flucytosine were measured from simultaneously collected serum and abdominal fluid samples.

RESULTS

Twenty-one consecutive patients were included. Five repeated samples were taken from three patients. The time interval between the start of the medication and the first sampling was median 4.0 days (range 2-7 days). The correlation coefficient (r(2)) between serum and peritoneal levels of amphotericin B was 0.79. In nine patients (43%) with a maximum serum level of 0.28 mg/L, amphotericin B in the peritoneal fluid was undetectable. The lowest serum level that was present with a detectable peritoneal level was 0.16 mg/L. A short duration of treatment (2 days) was associated with low serum and undetectable peritoneal levels. In seven patients, flucytosine levels were measured. Peritoneal flucytosine levels did not differ significantly from serum levels. Serum and peritoneal flucytosine levels correlated well with r(2)=0.88. Peritoneal amphotericin B level was inversely correlated with C-reactive protein level on the same day (r(2)=0.30).

CONCLUSIONS

It is shown, during continuous infusion, that peritoneal levels of amphotericin B are lower than serum levels. The amphotericin B serum levels should exceed 0.5 mg/L to obtain peritoneal levels above MIC values. Flucytosine levels in the abdominal fluid are comparable to serum levels and within MIC ranges.

Epidemiology of invasive candidiasis: a persistent public health problem

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

Flucytosine therapeutic monitoring: 15 years experience from the UK

BACKGROUND

There is uniform consensus that flucytosine blood concentrations should be measured to avoid toxicity and ensure adequate efficacy.

OBJECTIVES AND METHODS

The purpose of this study was to evaluate all flucytosine levels performed in a regional centre in the UK from October 1991 to May 2006. Concentrations were measured by bioassay.

RESULTS

We reviewed 1071 flucytosine levels in 233 patients, including 33 neonates. Overall, only 20.5% of levels were in the expected therapeutic range. Low levels were observed in 40.5%, of which 5.1% were undetectable levels (<12.5 mg/L). High levels occurred in 38.9%, of which 9.9% were considered potentially toxic (>100 mg/L). High flucytosine levels occurred more frequently amongst neonates, which could be related to an immature renal system resulting in drug accumulation.

CONCLUSIONS

Our findings reveal that the vast majority of patients were out of range for flucytosine levels. These data emphasize the importance of monitoring flucytosine levels.

Caspofungin in the Treatment of Symptomatic Candiduria

BACKGROUND

Because the urine concentrations achieved by echinocandin antifungal agents are low, drugs from this class are excluded from consideration when candiduria treatment is selected.

METHODS

We performed a retrospective view (sponsored by Merck Research Laboratories) of case records of patients participating in phase II-III clinical studies of caspofungin to identify patients with candiduria.

RESULTS

Of 12 case records collected by Merck Research Laboratories, 6 met the criteria for significant candiduria, allowing the evaluation of caspofungin therapy as judged by J.D.S. Three reported cases of candiduria secondary to hematogenous renal candidiasis were promptly eradicated. Of greater significance are 3 cases of complicated, ascending Candida glabrata infection (i.e., C. glabrata infection plus renal insufficiency), which were successfully treated with caspofungin.

CONCLUSIONS

Caspofungin may have a role in treating complicated Candida urinary tract infections, especially when the infection is caused by non-albicans species of Candida.

Active surveillance for candidemia, Australia

This infection has a high death rate and is predominantly associated with healthcare.

Population-based surveillance for candidemia in Australia from 2001 to 2004 identified 1,095 cases. Annual overall and hospital-specific incidences were 1.81/100,000 and 0.21/1,000 separations (completed admissions), respectively. Predisposing factors included malignancy (32.1%), indwelling vascular catheters (72.6%), use of antimicrobial agents (77%), and surgery (37.1%). Of 919 episodes, 81.5% were inpatient healthcare associated (IHCA), 11.6% were outpatient healthcare associated (OHCA), and 6.9% were community acquired (CA). Concomitant illnesses and risk factors were similar in IHCA and OHCA candidemia. IHCA candidemia was associated with sepsis at diagnosis (p<0.001), death <30 days after infection (p<0.001), and prolonged hospital admission (p<0.001). Non–Candida albicans species (52.7%) caused 60.5% of cases acquired outside hospitals and 49.9% of IHCA candidemia (p = 0.02). The 30-day death rate was 27.7% in those >65 years of age. Adult critical care stay, sepsis syndrome, and corticosteroid therapy were associated with the greatest risk for death. Systematic epidemiologic studies that use standardized definitions for IHCA, OHCA, and CA candidemia are indicated.

Posaconazole for the Treatment of Azole-Refractory Oropharyngeal and Esophageal Candidiasis in Subjects with HIV Infection

BACKGROUND

We evaluated the efficacy and safety of oral posaconazole for human immunodeficiency virus (HIV)-infected subjects with oropharyngeal candidiasis (OPC) and/or esophageal candidiasis (EC) who were clinically refractory to treatment with oral fluconazole or itraconazole.

METHODS

Subjects with confirmed OPC or EC who did not improve after receiving standard courses of fluconazole or itraconazole treatment were eligible for study enrollment. Subjects received either oral posaconazole (400 mg twice daily) for 3 days followed by oral posaconazole (400 mg once daily) for 25 days (regimen A; 103 patients) or oral posaconazole (400 mg twice daily) for 28 days (regimen B; 96 patients). The primary end point was cure or improvement after 28 days. Primary efficacy analyses were performed on the subset of treated subjects with refractory disease (e.g., baseline culture positive for fluconazole- or itraconazole-resistant Candida species or persistent or progressive clinical signs or symptoms consistent with treatment failure).

RESULTS

Of the modified intent-to-treat population, 132 (75%) of 176 subjects achieved a clinical response to posaconazole treatment. Clinical response rates were similar between regimen A recipients (75.3%) and regimen B recipients (74.7%). Clinical responses occurred in 67 (73%) of 92 subjects with baseline isolates resistant to fluconazole, 49 (74%) of 66 subjects with baseline isolates resistant to itraconazole, and 42 (74%) of 57 subjects with isolates resistant to both. Clinical response was achieved in 32 (74.4%) of 43 subjects with endoscopically documented EC. The most common treatment-related adverse events were diarrhea (11%), neutropenia (7%), flatulence (6%), and nausea (6%). Eight subjects (4%) discontinued therapy as a result of a treatment-related adverse event.

CONCLUSIONS

Posaconazole offers a safe and effective treatment option for HIV-infected subjects with azole-refractory OPC and/or EC.

Pharmacokinetics and pharmacodynamics of antifungals

Application of pharmacodynamic principles to antifungal drug therapy of Candida and Aspergillus infections has provided and understanding of the relationship between drug dosing and treatment efficacy. Observations of the pharmacodynamics of triazoles and AmB have correlated with the results of clinical trials and have proven useful for validation of in vitro susceptibility breakpoints. Although there remain many unanswered questions regarding antifungal pharmacodynamics, available data suggest usefulness in the application of pharmacodynamics to antifungal clinical development. Future application of these principles should aid in the design of optimal combination antifungal therapies.

Putative role of beta-1,3 glucans in Candida albicans biofilm resistance

Biofilms are microbial communities, embedded in a polymeric matrix, growing attached to a surface. Nearly all device-associated infections involve growth in the biofilm life style. Biofilm communities have characteristic architecture and distinct phenotypic properties. The most clinically important phenotype involves extraordinary resistance to antimicrobial therapy, making biofilm infections very difficulty to cure without device removal. The current studies examine drug resistance in Candida albicans biofilms. Similar to previous reports, we observed marked fluconazole and amphotericin B resistance in a C. albicans biofilm both in vitro and in vivo. We identified biofilm-associated cell wall architectural changes and increased beta-1,3 glucan content in C. albicans cell walls from a biofilm compared to planktonic organisms. Elevated beta-1,3 glucan levels were also found in the surrounding biofilm milieu and as part of the matrix both from in vitro and in vivo biofilm models. We thus investigated the possible contribution of beta-glucans to antimicrobial resistance in Candida albicans biofilms. Initial studies examined the ability of cell wall and cell supernatant from biofilm and planktonic C. albicans to bind fluconazole. The cell walls from both environmental conditions bound fluconazole; however, four- to fivefold more compound was bound to the biofilm cell walls. Culture supernatant from the biofilm, but not planktonic cells, bound a measurable amount of this antifungal agent. We next investigated the effect of enzymatic modification of beta-1,3 glucans on biofilm cell viability and the susceptibility of biofilm cells to fluconazole and amphotericin B. We observed a dose-dependent killing of in vitro biofilm cells in the presence of three different beta-glucanase preparations. These same concentrations had no impact on planktonic cell viability. beta-1,3 Glucanase markedly enhanced the activity of both fluconazole and amphotericin B. These observations were corroborated with an in vivo biofilm model. Exogenous biofilm matrix and commercial beta-1,3 glucan reduced the activity of fluconazole against planktonic C. albicans in vitro. In sum, the current investigation identified glucan changes associated with C. albicans biofilm cells, demonstrated preferential binding of these biofilm cell components to antifungals, and showed a positive impact of the modification of biofilm beta-1,3 glucans on drug susceptibility. These results provide indirect evidence suggesting a role for glucans in biofilm resistance and present a strong rationale for further molecular dissection of this resistance mechanism to identify new drug targets to treat biofilm infections.

Candida infections in the intensive care unit: epidemiology, risk factors and therapeutic strategies

This article reviews the epidemiology, predisposing risk factors and outcome of systemic Candida spp. infections in the intensive care unit setting. Incidence of systemic Candida infections in patients requiring intensive care has increased substantially in recent years; while diagnosis of serious Candida infection may be difficult, the clinical conditions which predispose patients to these infections are now better understood and effective antifungal therapies are becoming increasingly available. Severe fungal infections are generally associated with poor outcomes in these patients. Patients at highest risk for Candida infection may be potential candidates for early, presumptive therapy. In this article we review antifungal treatment, including the use of polyenes, azoles and echinocandines, and the role of prophylaxis.

Rapid differentiation of Candida albicans from non-albicans species by germ tube test directly from BacTAlert blood culture bottles

Bloodstream infections (BSIs) caused by Candida species are increasing in incidence, and are associated with high mortality rates, which are due in part to a delay in the administration of appropriate antifungal therapy. Earlier identification of yeast isolates from blood cultures may improve clinical outcomes. Identification of a Candida as albicans or non-albicans species depends on the presence or absence of germ tubes. Conventionally, germ tube test (GTT) is performed on colonies grown on agar plate after 24-48 h of incubation. In the present study, the GTT was performed earlier on an aliquot taken from blood culture bottle, after yeast cells were seen in Gram stain and the results were compared with the GTT using the conventional method. Thirty-one consecutive bloodstream isolates of yeast were included in this prospective study over 10 months. There was 100% concordance between the two GTT methods. Final identification was confirmed by standard laboratory procedures. The performance of GTT directly from blood culture bottles has important implications for early, appropriate therapy in patients with candidaemia.

Micafungin: A New Echinocandin Antifungal

The echinocandins represent the newest class of antifungals to combat infections caused by Candida sp. Micafungin is an echinocandin recently approved by the United States Food and Drug Administration. It is indicated in adults for esophageal candidiasis and prophylaxis against candidal infections in hematopoietic stem cell transplant recipients. Micafungin exhibits in vitro fungicidal activity against Candida sp, including fluconazole-resistant isolates. Its in vivo efficacy is comparable to that of fluconazole in the treatment of esophageal candidiasis and superior to that of fluconazole for prophylaxis of invasive candidal infections. Because it is not significantly metabolized by the cytochrome P450 3A system, micafungin is associated with few drug interactions. Micafungin does not require adjustment in patients with renal and/or hepatic impairment, and it has been shown to be well tolerated in both adult and pediatric patients. Its efficacy against Candida sp, coupled with its overall safety and drug interaction profiles, makes it an attractive option in the treatment against esophageal candidiasis and prophylaxis against invasive candidal infections.

Nosocomial fungal infections: epidemiology, diagnosis, and treatment

Invasive fungal infections are increasingly common in the nosocomial setting. Furthermore, because risk factors for these infections continue to increase in frequency, it is likely that nosocomial fungal infections will continue to increase in frequency in the coming decades. The predominant nosocomial fungal pathogens include Candida spp., Aspergillus spp., Mucorales, Fusarium spp., and other molds, including Scedosporium spp. These infections are difficult to diagnose and cause high morbidity and mortality despite antifungal therapy. Early initiation of effective antifungal therapy and reversal of underlying host defects remain the cornerstones of treatment for nosocomial fungal infections. In recent years, new antifungal agents have become available, resulting in a change in standard of care for many of these infections. Nevertheless, the mortality of nosocomial fungal infections remains high, and new therapeutic and preventative strategies are needed.