The epidemiology of candidemia in two United States cities: results of a population-based active surveillance

Economic evaluations of treatments for systemic fungal infections: a systematic review of the literature

We systematically reviewed published economic evaluations of systemic antifungal therapies and assessed their strengths and weaknesses. The study identified all economic evaluations published before May 2002 and critically appraised their methods using a published checklist. Over 1000 papers on antifungal treatments and costs were retrieved, 40 of which were economic evaluations. Fifteen of these were evaluations of systemic antifungal therapy. The majority of studies examined prophylaxis (11 out of 15), two examined empiric treatment and two examined the treatment of confirmed infections. Methods varied quite dramatically and the quality of the studies was, in general, very poor. Consequently, we were unable to find a coherent body of economic evidence for any particular patient group and/or indication. Three methodological issues were identified as requiring improvement in future economic evaluations of the prevention and treatment of systemic mucoses: cost estimates, outcome measures and evidence of effectiveness. Costs of both antifungal infection and treatment are important, and despite this, seven of the studies only collected cost information on drug acquisition costs. This is such a fundamental flaw that these studies should not be used to inform decision making on the use of antifungal medication. The estimation of costs in the other studies appeared appropriate, although limited reporting obscured other important issues, such as the appropriate use of per diem costs. Outcome measures were necessarily produced in all evaluations, yet only two studies produced cost-effectiveness ratios. This makes comparisons across studies very difficult. Also, small samples sizes meant that 'hard' outcome measures such as life-years saved could not be used, as deaths were rare within the studies. Both studies that produced incremental cost-effectiveness ratios were model-based studies. These allow simulations to be run on large cohorts of hypothetical patients, thus allowing differences in mortality between treatments to be evaluated. Evidence of effectiveness was limited, with many of the studies based on non-randomised clinical studies and consequently open to bias. Future clinical trials of the effectiveness of antifungal prophylaxis and treatment need to incorporate the collection of costs and economic outcome measures. Even quite simple analyses can be quite powerful, particularly when combined with modelling work to allow other data sources to be added.

Twelve years of fluconazole in clinical practice: global trends in species distribution and fluconazole susceptibility of bloodstream isolates of Candida

We determined the species distribution and in-vitro susceptibility of 6082 bloodstream infection (BSI) isolates of Candida spp. collected from 250 medical centres in 32 nations over a 10-year period from 1992 through 2001. The species included 3401 C. albicans, 984 C. glabrata, 796 C. parapsilosis, 585 C. tropicalis, 153 C. krusei, 67 C. lusitaniae, 48 C. guilliermondii, 10 C. famata, 10 C. kefyr, six C. pelliculosa, five C. rugosa, four C. lipolytica, three C. dubliniensis, three C. inconspicua, two C. sake and one isolate each of C. lambica, C. norvegensis and C. zeylanoides. Minimum inhibitory concentration determinations were made using the National Committee for Clinical Laboratory Standards reference broth microdilution method. Variation in the rank order and frequency of the different species of Candida was observed over time and by geographic area. The proportion of BSI due to C. albicans and C. glabrata increased and C. parapsilosis decreased over time in Canada, the USA and Europe. C. glabrata was an infrequent cause of BSI in Latin America and the Asia-Pacific region. Very little variation in fluconazole susceptibility was observed among isolates of C. albicans, C. tropicalis and C. parapsilosis. These species accounted for 78% of all BSI and remained highly susceptible (91-100% susceptible) to fluconazole from 1992 to 2001 irrespective of geographic origin. The prevalence of fluconazole resistance among C. glabrata isolates was variable both over time and among the various countries and regions. Resistance to fluconazole among C. glabrata isolates was greatest in the USA and varied by US census region (range 0-23%). These observations are generally encouraging relative to the sustained usefulness of fluconazole as a systemically active antifungal agent for the treatment of candida BSI.

Epidemiology of Candida species infections in critically ill non-immunosuppressed patients

A substantial proportion of patients become colonised with Candida spp during hospital stay, but only few subsequently develop severe infection. Clinical signs of severe infection manifest early but lack specificity until late in the course of the disease, thus representing a particular challenge for diagnosis. Mostly nosocomial, invasive candidiasis occurs in only 1-8% of patients admitted to hospitals, but in around 10% of patients housed in intensive care units where it can represent up to 15% of all nosocomial infections. We review the epidemiology of invasive candidiasis in non-immunocompromised, critically ill patients with special emphasis on disease trends over time, pathophysiology, diagnostic approach, risk factors, and impact. Recent epidemiological data suggesting that the emergence of non-albicans candida strains with reduced susceptibility to azoles, previously linked to the use of new antifungals for empiric and prophylactic therapy in immunocompromised patients, may not have occurred in the critically ill. Management of invasive candidiasis in these patients will be addressed in the December issue of The Lancet Infectious Diseases.

The global epidemiology of invasive Candida infections—is the tide turning?

Invasive candidiasis is a condition of major medical importance. Its incidence has increased dramatically over the last 50 years, reflecting increasingly interventional standards of medical care. Candida spp. are regularly reported to be the fourth commonest cause of bloodstream infection, and it is perceived that the incidence of invasive Candida spp. infections continues to increase. The global disease burden of invasive Candida spp. infections is difficult to quantify because of wide geographic variation. Data originating from the United States indicate that mortality from candidiasis has been falling since 1989. Data from several locations have shown that the dramatic increases in Candida spp. bloodstream infections seen during the 1980s were not sustained through the 1990s. Some authors have reported a decreasing incidence. The contribution of non-albicans Candida spp. to invasive infection is rising. Invasive infections with Candida spp. continue to represent a major economic burden, increasing both mortality and morbidity in an already expensive group of hospital patients. There remains much scope for ongoing and future research into the epidemiology and basic disease processes underlying these infections.

Candidaemia in a London teaching hospital: analysis of 128 cases over a 7-year period. Candidamie in einer Londoner Universitatsklinik: Analyse von 128 Fallen uber einen Zeitraum von sieben Jahren

In a retrospective analysis of 128 cases of Candida bloodstream infections in a London teaching hospital between 1995 and 2001, the incidence of candidaemia increased from 0.2/1000 admissions in 1995 to 0.5 and 0.4/1000 admissions in 2000 and 2001, respectively. Risk factors for candidaemia included the presence of intravascular (IV) lines (88%), admission to intensive care (51%), parenteral nutrition (35%), multiple antibiotics (74%), corticosteroid therapy (12%), cancer chemotherapy (11%), renal transplantation (5%) and neutropenia (3%). The sources of infection were IV lines (77%), the urinary tract (7%) and the gastrointestinal tract (7%). Serious infective complications (endocarditis, endophthalmitis or brain abscess) were noted in 6% of cases. The most frequently isolated species were Candida albicans (64%), C. glabrata (20%), C. tropicalis (9%) and C. parapsilosis (5%). The overall fluconazole-resistance rate of Candida spp. was 7% (MIC > or = 64 mg l-1). All the C. albicans isolates were sensitive to fluconazole (MIC < or = 8 mg l-1) whereas 20% of non-C. albicans isolates (27% of C. glabrata and 14%C. tropicalis) were resistant. The mortality rate (35%) was lower than in other reports and may be due to the early recognition of candidaemia and the prompt removal of IV lines together with the initiation of appropriate antifungal therapy. Regular surveillance of local Candida species, resistance profiles and risk factors is important in order to identify patients at risk and to develop empirical treatment protocols to reduce the incidence and mortality of candidaemia.

Candida bloodstream infection in neonates

Neonatal candidemia is poorly understood and is a leading cause of nosocomial infectious mortality in the nursery. Prevention of candidemia has been difficult, although a combined approach of antifungal prophylaxis and targeted empirical therapy may eventually reduce morbidity and mortality. Multicenter prospective testing of an integrated approach to early diagnosis of neonatal candidemia using newer molecular techniques is also needed. Candidemia in the infant is cause for prompt removal (or replacement) of central vascular catheters and institution of antifungal therapy. End-organ evaluation is also probably warranted to guide treatment and facilitate prognostication. Given the continuing progress in clinical research infrastructure and development of new diagnostic tests and antifungal agents, substantial improvement in the prevention, diagnosis, and management of neonatal candidemia is plausible over the next decade.

Epidemiologia das infecções hematogênicas por Candida spp

O gênero Candida spp é responsável por cerca de 80% das infecções fúngicas no ambiente hospitalar e constitui causa relevante de infecções de corrente sanguínea. Nos Estados Unidos da América, Candida spp é a quarta causa mais comum de infecções de corrente sanguínea, respondendo por cerca de 8% dos casos das infecções documentadas neste sítio. Espécies não-albicans respondem hoje por ao menos 50% das infecções invasivas por Candida spp, apresentando peculiaridades de história natural e sensibilidade a antifúngicos. A mortalidade geral de fungemias por Candida spp é da ordem de 40 a 60%, tornado esta complicação infecciosa um grande desafio para os clínicos que trabalham em hospitais terciários em diferentes países.

Competitive binding inhibition enzyme-linked immunosorbent assay that uses the secreted aspartyl proteinase of Candida albicans as an antigenic marker for diagnosis of disseminated candidiasis

The secreted aspartyl proteinases (Saps) of Candida albicans have been implicated as virulence factors associated with adherence and tissue invasion. The potential use of proteinases as markers of invasive candidiasis led us to develop a competitive binding inhibition enzyme-linked immunosorbent assay (ELISA) to detect Sap in clinical specimens. Daily serum and urine specimens were collected from rabbits that had been immunosuppressed with cyclophosphamide and cortisone acetate and infected intravenously with 10(7) C. albicans blastoconidia. Disseminated infection was confirmed by organ culture and histopathology. Although ELISA inhibition was observed when serum specimens from these rabbits were used, more significant inhibition, which correlated with disease progression, occurred when urine specimens were used. Urine collected as early as 1 day after infection resulted in significant ELISA inhibition (mean inhibition +/- standard error [SE] compared with preinfection control urine, 15.7% +/- 2.7% [P < 0.01]), and inhibition increased on days 2 through 5 (29.4% +/- 4.8% to 44.5% +/- 3.5% [P < 0.001]). Urine specimens from immunosuppressed rabbits infected intravenously with Candida tropicalis, Candida parapsilosis, Candida krusei, Cryptococcus neoformans, Aspergillus fumigatus, or Staphylococcus aureus were negative in the assay despite culture-proven dissemination. Nonimmunosuppressed rabbits receiving oral tetracycline and gentamicin treatment were given 2 x 10(8) C. albicans blastoconidia orally or intraurethrally to establish colonization of the gastrointestinal tract or bladder, respectively, without systemic dissemination; urine specimens from these rabbits also gave negative ELISA results. Dissemination to the kidney and spleen occurred in one rabbit challenged by intragastric inoculation, and urine from this rabbit demonstrated significant inhibition in the ELISA (mean inhibition +/- SE by day 3 after infection, 32.9% +/- 2.7% [P < 0.001]). The overall test sensitivity was 83%, the specificity was 92%, the positive predictive value was 84%, the negative predictive value was 91%, and the efficiency was 89% (166 urine samples from 33 rabbits tested). The specificity, positive predictive value, and efficiency could be increased to 97, 95, and 92%, respectively, if at least two positive test results were required for a true positive designation. The ELISA was sensitive and specific for the detection of Sap in urine specimens from rabbits with disseminated C. albicans infection, discriminated between colonization and invasive disease, reflected disease progression and severity, and has the potential to be a noninvasive means to diagnose disseminated candidiasis.

A prospective observational study of candidemia: epidemiology, therapy, and influences on mortality in hospitalized adult and pediatric patients

We conducted a prospective, multicenter observational study of adults (n=1447) and children (n=144) with candidemia at tertiary care centers in the United States in parallel with a candidemia treatment trial that included nonneutropenic adults. Candida albicans was the most common bloodstream isolate recovered from adults and children (45% vs. 49%) and was associated with high mortality (47% among adults vs. 29% among children). Three-month survival was better among children than among adults (76% vs. 54%; P<.001). Most children received amphotericin B as initial therapy, whereas most adults received fluconazole. In adults, Candida parapsilosis fungemia was associated with lower mortality than was non-parapsilosis candidemia (24% vs. 46%; P<.001). Mortality was similar among subjects with Candida glabrata or non-glabrata candidemia; mortality was also similar among subjects with C. glabrata candidemia who received fluconazole rather than other antifungal therapy. Subjects in the observational cohort had higher Acute Physiology and Chronic Health Evaluation II scores than did participants in the clinical trial (18.6 vs. 16.1), which suggests that the former subjects are more often excluded from therapeutic trials.

Candidemia in Finland, 1995-1999

We analyzed laboratory-based surveillance candidemia data from the National Infectious Disease Register in Finland and reviewed cases of candidemia from one tertiary-care hospital from 1995 to 1999. A total of 479 candidemia cases were reported to the Register. The annual incidence rose from 1.7 per 100,000 population in 1995 to 2.2 in 1999. Species other than Candida albicans accounted for 30% of cases without change in the proportion. A total of 79 cases of candidemia were identified at the hospital; the rate varied from 0.03 to 0.05 per 1,000 patient-days by year. Predisposing factors included indwelling catheters (81%), gastrointestinal surgery (27%), hematologic malignancy (25%), other types of surgery (21%), and solid malignancies (20%). Crude 7-day and 30-day case-fatality ratios were 15% and 35%, respectively. The rate of candidemia increased in Finland but is still substantially lower than in the United States. No shift to non-C. albicans species could be detected.

Trends in frequency and in vitro susceptibilities to antifungal agents, including voriconazole and anidulafungin, of Candida bloodstream isolates. Results from a six-year study (1996-2001)

The frequency of isolation and antifungal susceptibility patterns to established and two new antifungal agents were determined for 218 Candida spp isolates causing bloodstream infection from 1996 to 2001. Overall, 41.7% of the candidemias were due to C. albicans, followed by C. parapsilosis (22%), C. tropicalis (16.1%), C. glabrata (11.9%), C. krusei (6%) and miscellaneous Candida spp (2.3%). Isolates of C. albicans C. parapsilosis and C. tropicalis (80% of isolates) were highly susceptible to fluconazole (94 to 100% at </= 8 microg/ml) and voriconazole (97 to 100% at </= 1 microg/ml). By comparison with the newer agents itraconazole was less active (77 to 97% at </=0.12 microg/ml). Only 77% and 15% of C. glabrata isolates were inhibited by fluconazole at </= 8 microg/ml and itraconazole at </=0.12 microg/ml, respectively. Voriconazole showed a remarkable in vitro potency against C. glabrata as well as C. krusei isolates (100% at </= 1 microg/ml). Anidulafungin was very active against Candida spp isolates (MIC90: </= 0.5 microg/ml), except C. parapsilosis (MIC90: 4 microg/ml) and two C. guilliermondii isolates (MIC: >/= 32 microg/ml).

Non-albicans Candida is the most common cause of candidemia in pediatric cancer patients

GOALS

Candidemia is a serious infection that can severely complicate the care of children with cancer. We sought to determine the spectrum of Candida species in children with cancer, since effective therapy may depend on the species involved.

PATIENTS AND METHODS

A retrospective review of candidemia episodes in our pediatric oncology patients over a 9-year period was conducted. During this period azole prophylaxis was not routine in this group.

RESULTS

38 episodes of candidemia were identified: C. albicans 29%, C. tropicalis 26%, C. parapsilosis 24%, C. krusei 8%, C. glabrata 8%, and C. lusitaniae 5%. Non-albicans Candida was common in patients not receiving azole prophylaxis. Species typically susceptible to azoles were common among patients not using azoles. Death attributed to the fungal infection occurred in 21% of episodes, with nearly all the deaths occurring in patients with C. albicans and C. tropicalis.

CONCLUSIONS

C. albicans is not the predominant species in pediatric oncology patients experiencing candidemia, even in azole-naive patients.

Management and outcome of bloodstream infections due to Candida species in England and Wales

This two-year prospective hospital population-based study of candidaemia is the first to be conducted in the UK. It was carried out on behalf on the British Society for Medical Mycology (BSMM) as part of the European Confederation of Medical Mycology (ECMM) epidemiological survey of candidaemia. Six hospitals in England and Wales acted as sentinel hospitals. Main outcome measures were hospital population-based incidence and 30-day mortality. There were 18.7 episodes of candidaemia per 100,000 finished consultant episodes or 3.0/100,000 bed days and 45.4% cases occurred in intensive care unit (ICU) patients. Candida albicans was isolated in 64.7% of confirmed cases. The majority of isolates were sensitive to standard antifungal agents, including fluconazole. The overall 30-day mortality was 26.4% and removal of the central venous catheter was associated with a significant reduction in mortality. In conclusion, the incidence of candidaemia in England and Wales is similar to that of the USA, the majority of isolates remain sensitive to commonly used antifungal agents and mortality associated with this infection appears to be falling.

Shifting patterns in the epidemiology of nosocomial Candida infections

The incidence of candidemia--a common and potentially fatal nosocomial infection--has risen dramatically, and this increase has been accompanied by a shift in the infecting pathogen away from Candida albicans to treatment-resistant non-albicans species. Prophylactic azole antifungals, such as fluconazole, may play an important role not only in the management of candidemia but also in the proliferation of hard-to-treat Candida species. In a variety of acute nosocomial settings, IV fluconazole, 400 mg/d, has reduced Candida colonization and infection. A growing body of evidence supports the still controversial contention that the increasing use of azole antifungals is at least partially responsible for the proliferation of treatment-resistant, non-albicans isolates, especially Candida glabrata. Thus, selecting the most appropriate candidates for prophylactic antifungal intervention--ie, those with the highest risk for candidemia--may be indispensable, not only in preventing candidemia, but also in reducing antifungal overuse, which may contribute to the emergence of treatment-resistant Candida isolates.

Systemic mycoses in the immunocompromised host: an update in antifungal therapy

Despite significant advances in the management of immunosuppressed patients, invasive fungal infections remain an important life-threatening complication. In the last decade several new antifungal agents, including compounds in pre-existing classes (new generation of triazoles, polyenes in lipid formulations) and novel classes of antifungals with a unique mechanism of action (echinocandins), have been introduced in clinical practice. Ongoing and future studies will determine their exact role in the management of different mycoses. The acceleration of antifungal drug discovery offers promise for the management of these difficult to treat opportunistic infections.

Use of amplified fragment length polymorphism analysis to identify medically important Candida spp., including C. dubliniensis

Non-Candida albicans Candida species are increasingly being isolated. These species show differences in levels of resistance to antimycotic agents and mortality. Therefore, it is important to be able to correctly identify the causative organism to the species level. Identification of C. dubliniensis in particular remains problematic due to the high degree of phenotypic similarity between this species and C. albicans. The use of amplified fragment length polymorphism (AFLP) analysis as an identification method for medically important Candida species was investigated. Our results show very clear differences among medically important Candida species. Furthermore, when screening a large collection of clinical isolates previously identified on CHROMagar as C. albicans, we found a misidentification rate of 6%. AFLP analysis is universally applicable, and the patterns can easily be stored in a general, accessible database. Therefore, AFLP might prove to be a reliable method for the identification of medically important Candida species.

Stability of allelic frequencies and distributions of Candida albicans microsatellite loci from U.S. population-based surveillance isolates

Allelic distributions and frequencies of five Candida albicans microsatellite loci have been determined for strains isolated from the bloodstream and obtained through active population-based surveillance in two U.S. metropolitan areas between 1998 and 2000. These data were compared to data for isolates obtained from two other U.S. regions in 1992 to 1993. In a majority of pairwise combinations between sites, no evidence was seen for shifts in microsatellite allelic frequencies. One to three alleles were highly predominant and correlated with major genotypes. These data both support the concepts of allelic stability and genetic equilibria and suggest that, in the United States, strains of C. albicans isolated from the bloodstream may form a defined, genetically homogeneous population across geographical distance and time.

Candida tropicalis in a neonatal intensive care unit: epidemiologic and molecular analysis of an outbreak of infection with an uncommon neonatal pathogen

From June to July 1998, two episodes of Candida tropicalis fungemia occurred in the Aristotle University neonatal intensive care unit (ICU). To investigate this uncommon event, a prospective study of fungal colonization and infection was conducted. From December 1998 to December 1999, surveillance cultures of the oral cavities and perinea of the 593 of the 781 neonates admitted to the neonatal ICU who were expected to stay for >7 days were performed. Potential environmental reservoirs and possible risk factors for acquisition of C. tropicalis were searched for. Molecular epidemiologic studies by two methods of restriction fragment length polymorphism analysis and two methods of random amplified polymorphic DNA analysis were performed. Seventy-two neonates were colonized by yeasts (12.1%), of which 30 were colonized by Candida albicans, 17 were colonized by C. tropicalis, and 5 were colonized by Candida parapsilosis. From December 1998 to December 1999, 10 cases of fungemia occurred; 6 were due to C. parapsilosis, 2 were due to C. tropicalis, 1 was due to Candida glabrata, and 1 was due to Trichosporon asahii (12.8/1,000 admissions). Fungemia occurred more frequently in colonized than in noncolonized neonates (P < 0.0001). Genetic analysis of 11 colonization isolates and the two late blood isolates of C. tropicalis demonstrated two genotypes. One blood isolate and nine colonization isolates belonged to a single type. The fungemia/colonization ratio of C. parapsilosis (3/5) was greater than that of C. tropicalis (2/17, P = 0.05), other non-C. albicans Candida spp. (1/11, P = 0.02), or C. albicans (0/27, P = 0.05). Extensive environmental cultures revealed no common source of C. tropicalis or C. parapsilosis. There was neither prophylactic use of azoles nor other risk factors found for acquisition of C. tropicalis except for total parenteral nutrition. A substantial risk of colonization by non-C. albicans Candida spp. in the neonatal ICU may lead to a preponderance of C. tropicalis as a significant cause of neonatal fungemia.

Candida infections in the neonate

Candida infections have become an increasingly frequent problem in neonatal intensive care units, particularly among extremely low birth weight infants. Transmission occurs both vertically and horizontally, with Candida albicans and C. parapsilosis as the predominant species. Multiple risk factors have been identified with prior antibiotic exposure, presence of a central line, endotracheal intubation, and prior fungal colonization reported most frequently. The primary site of infection can involve the bloodstream, meninges, or urinary tract, but disease is frequently disseminated to multiple organ systems. Amphotericin is the most commonly used antifungal agent, although fluconazole is being used more frequently. The potential role of antifungal prophylaxis is not yet clearly defined, but has been the topic of recent investigative efforts. The crude mortality rate among neonates with systemic candidiasis remains approximately 30%.

In vitro activities of voriconazole, posaconazole, and four licensed systemic antifungal agents against Candida species infrequently isolated from blood

We determined the in vitro susceptibilities of 314 strains of Candida spp., representing 13 species rarely isolated from blood, to posaconazole and voriconazole as well as four licensed systemic antifungal agents (amphotericin B, flucytosine, fluconazole, and itraconazole). The organisms included 153 isolates of C. krusei, 67 isolates of C. lusitaniae, 48 isolates of C. guilliermondii, 10 isolates of C. famata, 10 isolates of C. kefyr, 6 isolates of C. pelliculosa, 5 isolates of C. rugosa, 4 isolates of C. lipolytica, 3 isolates of C. dubliniensis, 3 isolates of C. inconspicua, 2 isolates of C. sake, and 1 isolate each of C. lambica, C. norvegensis, and C. zeylanoides. MIC determinations were made by the National Committee for Clinical Laboratory Standards reference broth microdilution method and Etest (amphotericin B). Resistance to both amphotericin B and fluconazole was observed in strains of C. krusei, C. lusitaniae, C. guilliermondii, C. inconspicua, and C. sake. Resistance to amphotericin B, but not to fluconazole, was also observed among isolates of C. kefyr and C. rugosa. Posaconazole and voriconazole were active (MIC, < or = 1 micro g/ml) against 94 to 100% of these isolates. In contrast to the more common species of Candida causing bloodstream infection, these rare species appear to be less susceptible to the currently licensed systemic antifungal agents, with the exception of voriconazole. Continued surveillance will be necessary to detect the emergence of these species as more prevalent, resistant pathogens. The new triazoles appear to offer acceptable coverage of uncommon Candida sp. bloodstream infections.

Caspofungin acetate for treatment of invasive fungal infections

OBJECTIVE

To briefly discuss the changing epidemiology of fungal infections and review currently available agents; provide a review of caspofungin; and discuss its pharmacology, pharmacokinetics, dosing guidelines, safety and efficacy, and role in the treatment of invasive fungal infections as it relates to current antifungal therapy.

DATA SOURCES

A MEDLINE (1966 to August 2002) database search using key words caspofungin, echino candins, fungal infections, and invasive aspergillosis, was completed to identify relevant articles including reviews, recent studies, treatment guidelines, and data from Merck and Company.

STUDY SELECTION

In vitro studies and all clinical trials were evaluated to summarize the clinical efficacy and safety of caspofungin.

DATA SYNTHESIS

The incidence of fungal infections is increasing as the population at risk expands. Cost, resistance, and morbidity and mortality are key issues. Adding to the antifungal armamentarium is necessary to address these therapeutic dilemmas. Caspofungin is the first member of a new class of antifungal agents, the echinocandins, to be approved for clinical use. Caspofungin is classified as a glucan synthase inhibitor and represents a class of agents with a novel mechanism of action. Unlike currently available agents (polyenes, pyrimidines, azoles) that exert their effect on the fungal cell membrane, the echinocandins are the first agents to inhibit fungal cell wall synthesis. Caspofungin exhibits activity against Aspergillus spp. and Candida spp., including non-albicans species. Data from clinical trials demonstrate that caspofungin is effective in patients with invasive aspergillosis as well as candida esophagitis. Its Food and Drug Administration-approved indication is limited to invasive aspergillosis refractory to or intolerant of current therapy.

CONCLUSIONS

Caspofungin has activity against Aspergillus spp. as well as a variety of Candida spp. Clinical data support its usefulness in the treatment of invasive aspergillosis and select candida infections. As additional clinical data become available, it seems likely that the therapeutic role of caspofungin will expand.

Prevalence of Candida species, including Candida dubliniensis, in Singapore

We present data on the prevalence of Candida species isolated from inpatients in three Singapore hospitals and from vaginal samples collected at community clinics. Strikingly, approximately 20% of the isolates from blood and vaginal samples were fluconazole-resistant species. By analyzing species-specific gene sequence signatures, we identified Candida dubliniensis from both groups of patients.

Functional genomics approaches for the identification and validation of antifungal drug targets

So far, antifungal drug discovery seems to have benefited little from the enormous advances in the field of genomics in the last decade. Although it has become clear that traditional drug screening is not delivering the long-awaited novel potent antifungals, little has been reported on efforts to use novel genome-based methodologies in the quest for new drugs acting on human pathogenic fungi. Although the market for a novel systemic and even topical broad-spectrum antifungal appears considerable, many large pharmaceutical companies have decided to scale back their activities in antifungal drug discovery. Here we report on some of the recent advances in genomics-based technologies that will allow us not only to identify and validate novel drug targets but hopefully also to discover active therapeutic agents. Novel drug targets have already been found by 'en masse' gene inactivation strategies (e.g. using antisense RNA inhibition). In addition, genome expression profiling using DNA microarrays helps to assign gene function but also to understand better the mechanism of action of known drugs (e.g. itraconazole) and to elucidate how new drug candidates work. No doubt, we have a long way to go just to catch up with the advances made in other therapeutic areas, but all tools are at hand to derive practical benefits from the genomics revolution. The next few years should prove a very exciting time in the history of antifungal drug discovery.

Comparison of caspofungin and amphotericin B for invasive candidiasis

BACKGROUND

Caspofungin is an echinocandin agent with fungicidal activity against candida species. We performed a double-blind trial to compare caspofungin with amphotericin B deoxycholate for the primary treatment of invasive candidiasis.

METHODS

We enrolled patients who had clinical evidence of infection and a positive culture for candida species from blood or another site. Patients were stratified according to the severity of disease, as indicated by the Acute Physiology and Chronic Health Evaluation (APACHE II) score, and the presence or absence of neutropenia and were randomly assigned to receive either caspofungin or amphotericin B. The study was designed to compare the efficacy of caspofungin with that of amphotericin B in patients with invasive candidiasis and in a subgroup with candidemia.

RESULTS

Of the 239 patients enrolled, 224 were included in the modified intention-to-treat analysis. Base-line characteristics, including the percentage of patients with neutropenia and the mean APACHE II score, were similar in the two treatment groups. A modified intention-to-treat analysis showed that the efficacy of caspofungin was similar to that of amphotericin B, with successful outcomes in 73.4 percent of the patients treated with caspofungin and in 61.7 percent of those treated with amphotericin B (difference after adjustment for APACHE II score and neutropenic status, 12.7 percentage points; 95.6 percent confidence interval, -0.7 to 26.0). An analysis of patients who met prespecified criteria for evaluation showed that caspofungin was superior, with a favorable response in 80.7 percent of patients, as compared with 64.9 percent of those who received amphotericin B (difference, 15.4 percentage points; 95.6 percent confidence interval, 1.1 to 29.7). Caspofungin was as effective as amphotericin B in patients who had candidemia, with a favorable response in 71.7 percent and 62.8 percent of patients, respectively (difference, 10.0 percentage points; 95.0 percent confidence interval, -4.5 to 24.5). There were significantly fewer drug-related adverse events in the caspofungin group than in the amphotericin B group.

CONCLUSIONS

Caspofungin is at least as effective as amphotericin B for the treatment of invasive candidiasis and, more specifically, candidemia.

Yeasts isolated from blood and catheter in children from a public hospital of São Paulo, Brazil

The great majority of nosocomial fungal infections, especially fungemias, are caused by yeasts, mostly of the genus Candida. In addition, such infections may be associated with intravascular catheters. In this study, 80 yeast strains were isolated from hospitalized children, being 59 from blood cultures and 21 from vascular catheter cultures. The prevalent species in both blood and catheter was C. parapsilosis (32.2% and 48.9%, respectively), followed by C. albicans (16.9% and 28.6%, respectively). Concerning enzyme production, 78.8% of the 80 isolates presented strong proteolytic activity but 78.8% showed no phospholipase activity. We also detected two prevalent "killer" biotypes: 511 and 888. Additionally, in five patients, it was possible to observe that the yeast species, "killer" biotype and proteolytic and phospholipase activity of blood and catheter were similar. In view of this, we suggest a transmission of nosocomial yeast infection from catheter to blood.

Recent trends in the epidemiology of invasive mycoses

PURPOSE OF REVIEW

Invasive mycoses are emerging as an important public health problem. This development has occurred in large measure due to the increasing numbers of persons at risk. In addition, advances in therapeutic technologies and in particular the development of novel immunosuppressive therapies have prolonged the period of risk for many individuals.

RECENT FINDINGS

Although rates of candida bloodstream infections have been increasing over the past several decades, recent evidence suggests this trend may be reversing. The emergence of non-albicans Candida species, and in particular C. glabrata, has been documented. Invasive aspergillosis and other mold infections have become a significant and increasing problem in hematopoietic stem cell transplant recipients and certain high-risk groups of solid organ transplant recipients. These infections are associated with high mortality rates. Despite marked reductions in the rates of AIDS-associated fungal infections in the USA and other developed countries, the burden of these mycoses in developing countries is large and increasing.

SUMMARY

While gains have been made in the treatment and prevention of invasive mycoses, changes in the epidemiology of these infections and in healthcare practices have resulted in the emergence of new at-risk populations. A better understanding of specific risk factors will be needed if prevention strategies, such as chemoprophylaxis and environmental control measures, are to become more widely applicable and cost-effective.

Deeply invasive candidiasis

The incidence of invasive candidiasis is on the rise because of increasing numbers of immunocompromised hosts and more invasive medical technology. Recovery of Candida spp from several body sites in a critically ill or immunocompromised patient should raise the question of disseminated disease. Although identification to the species level and antifungal susceptibility testing should guide therapy, at this time amphotericin B preparations are the usual initial therapy for severe life-threatening disease. Azole therapy has an expanding body of evidence that proves it is as effective as and safer than amphotericin B therapy. Some forms of candidiasis (e.g., those with ocular, bone, or heart involvement) require a combined medical and surgical approach.

In vitro activities of 5-fluorocytosine against 8,803 clinical isolates of Candida spp.: global assessment of primary resistance using National Committee for Clinical Laboratory Standards susceptibility testing methods

We determined the in vitro activity of flucytosine (5-fluorocytosine [5FC]) against 8,803 clinical isolates of Candida spp. (18 species) obtained from more than 200 medical centers worldwide between 1992 and 2001. The MICs were determined by broth microdilution tests performed according to NCCLS guidelines by using RPMI 1640 as the test medium and the following interpretive breakpoints: susceptible (S), < or =4 micro g/ml; intermediate (I), 8 to 16 micro g/ml; resistant (R), > or =32 micro g/ml. 5FC was very active against the 8,803 Candida isolates (MIC(90), 1 micro g/ml), 95% S. A total of 99 to 100% of C. glabrata (MIC(90), 0.12 micro g/ml), C. parapsilosis (MIC(90), 0.25 micro g/ml), C. dubliniensis (MIC(90), 0.12 micro g/ml), C. guilliermondii (MIC(90), 0.5 micro g/ml), and C. kefyr (MIC(90), 1 micro g/ml) were susceptible to 5FC at the NCCLS breakpoint. C. albicans (MIC(90), 1 micro g/ml; 97% S) and C. tropicalis (MIC(90), 1 micro g/ml; 92% S) were only slightly less susceptible. In contrast, C. krusei was the least susceptible species: 5% S; MIC(90), 32 micro g/ml. Primary resistance to 5FC is very uncommon among Candida spp. (95% S, 2% I, and 3% R), with the exception of C. krusei (5% S, 67% I, and 28% R). The in vitro activity of 5FC, combined with previous data demonstrating a prolonged post-antifungal effect (2.5 to 4 h) and concentration-independent activity (optimized at 4x MIC), suggest that 5FC could be used in lower doses to reduce host toxicity while maintaining antifungal efficacy.

Secular trends of candidemia over 12 years in adult patients at a tertiary care hospital

The incidence of fungal infections has been increasing for the last 3 decades, especially among neutropenic, cancer, and critically ill patients. These infections are associated with high mortality rates. We retrospectively reviewed medical charts of adult patients with fungemia from 1989 to 2000 at our institution. The characteristics of the population groups served by the hospital were described. Of 328 patients with fungemia, we reviewed 315 (96%) medical records, and focused on those with candidemia (n = 294). The species distribution in patients with candidemia showed that the most commonly identified species were Candida albicans (66%), followed by C. glabrata (17%), and C. parapsilosis (6%). The incidence of candidemia ranged from 0.2 to 0.46 per 10,000 patient-days with the highest incidence in 1993 and the lowest in 1997. Although most studies show an increased incidence of candidemia, we observed a reduction over the study period. Furthermore, we observed no shift from C. albicans to non-albicans Candida species despite a significant increase in the use of fluconazole. The overall mortality among patients with candidemia was 44%, with the highest rate in patients over 65 years (52%). Factors independently associated with higher mortality were patient age greater than 65 years, intensive care unit admission, and underlying cancer.

Frequency and clinical significance of bloodstream infections caused by C albicans strains with reduced susceptibility to fluconazole

Reduced susceptibility to fluconazole (RSF) is relatively common in non-albicans Candida isolates and in Candida albicans recovered from HIV-infected patients with relapsing Candida stomatitis or esophagitis. However, little clinical data on bloodstream infections caused by C. albicans with RSF is available. We analyzed 116 episodes of C. albicans fungemia detected over an 11-year period. Four patients (3.4%) had a blood isolate of C. albicans with RSF. Fluconazole MICs were 16 (3 SDD strains) and 128 microg/ml (1 resistant strain), respectively. Three of the patients were HIV (+) and the fourth was a liver transplant recipient. All of them had been previously treated with an azole compound. The liver recipient had breakthrough fungemia while being treated with 400 mg of preemptive fluconazole despite having an MIC of 16 microg/ml. Fluconazole clinical failure was documented in two of the remaining three cases. Only five other patients with C. albicans fungemia caused by fluconazole-resistant strains (>or=64 microg/ml) are described in the literature. Candida albicans fungemia produced by strains with RSF is still uncommon. It should be suspected in patients previously treated with azole agents or with breakthrough fungemia. In our experience, fluconazole remains a safe option for the treatment of most C. albicans fungemias, although surveillance seems advisable.

Secular trend of hospital-acquired candidemia among intensive care unit patients in the United States during 1989-1999

We describe the annual incidence of primary bloodstream infection (BSI) associated with Candida albicans and common non-albicans species of Candida among patients in intensive care units that participated in the National Nosocomial Infections Surveillance system from 1 January 1989 through 31 December 1999. During the study period, there was a significant decrease in the incidence of C. albicans BSI (P<.001) and a significant increase in the incidence of Candida glabrata BSI (P=.05).

Hematogenous infections due to Candida parapsilosis: changing trends in fungemic patients at a comprehensive cancer center during the last four decades

This study was performed to evaluate trends in species distribution in patients' with hematogenous candidiasis at a comprehensive cancer center. The results of a retrospective analysis from January 1, 1993 to December 31, 1998 were compared with prior reports from Memorial Sloan-Kettering Cancer Center in the last forty years. In 570 total episodes since 1974, 43.9% were due to Candida albicans. During 1990's, C. parapsilosis emerged as the most frequent yeast species in the non-C. albicans group (36.1% during 1993-1998 from 20.9% 1974-1982; p < 0.01). An increase in C. krusei from 5.9% (1974-1982) to 10.5% during the recent six years (1993-1998) was also noticed. The proportion of C. tropicalis among non-albicans fungemia during 1974-1982 was 42.8%, whereas in 1993 to 1998 a marked decline in C. tropicalis hematogenous infection was observed (27.8%; p < 0.01). During 1998, the incidence of candidemia declined from 7.1% (1972-1973) and 6.5% (1982) to 3.4% (p < 0.01), and improved survival among fungemic patients (33% mortality in 1998; 77.3% during 1974-1982; p < 0.001) was encouraging. The increase in C. parapsilosis bloodstream invasion during 1990's was associated with a significant reduction in the endogenous non-albicans Candida tropicalis infection that probably resulted in part due to the common prophylaxis, and/or preemptive fluconazole given routinely in high-risk patients undergoing treatment for cancer. The widespread use of extraneous implantable and/or semi-implantable indwelling intra-vascular devices may also have played an important role in promoting (exogenous) C. parapsilosis infection. This study emphasizes the importance of periodic evaluation of candidemia, especially at centers caring for patients at risk.

European Confederation of Medical Mycology (ECMM) prospective survey of candidaemia: report from one Italian region

An ECMM epidemiological prospective survey of candidaemia was performed in one Italian region (Lombardy; population: 8 924 870) by the National Society of Medical Mycology (FIMUA) from September 1997 to December 1999. In total, 569 episodes were reported with an overall rate of 0.38/1000 admissions, 4.4/100000 patient days. Predisposing factors included presence of an intravascular catheter (89%), antibiotic treatment (88%), surgery (56%), intensive care (45%), solid tumour (28%), steroid treatment (15%), haematological malignancy (7%), HIV infection (6%), fetal immaturity (4%). Mucous membrane colonization preceded candidaemia in 83% of patients. Candida albicans was identified in 58% of cases, followed by Candida parapsilosis (15%), Candida glabrata (13%), Candida tropicalis (6%). Septic shock occurred in 95 patients. Crude mortality was 35%, the highest in C. tropicalis fungaemia (44%), the elderly (64%) and solid tumour cancer patients (43%). Intravascular catheter removal was associated with higher survival rate (71 vs. 47%). This survey underscores the importance of candidaemia in hospital settings.

Horizontal transmission of Candida parapsilosis candidemia in a neonatal intensive care unit

This report describes the nosocomial acquisition of Candida parapsilosis candidemia by one of the six premature newborns housed in the same room of a neonatal intensive care unit at the Ospedale Santa Chiara, Pisa, Italy. The infant had progeria, a disorder characterized by retarded physical development and progressive senile degeneration. The infant, who was not found to harbor C. parapsilosis at the time of his admission to the intensive care unit, had exhibited symptomatic conjunctivitis before the onset of a severe bloodstream infection. In order to evaluate the source of infection and the route of transmission, two independent molecular typing methods were used to determine the genetic relatedness among the isolates recovered from the newborn, the inanimate hospital environment, hospital personnel, topically and intravenously administered medicaments, and indwelling catheters. Among the isolates collected, only those recovered from the hands of two nurses attending the newborns and from both the conjunctiva and the blood of the infected infant were genetically indistinguishable. Since C. parapsilosis was never recovered from indwelling catheters or from any of the drugs administered to the newborn, we concluded that (i) horizontal transmission of C. parapsilosis occurred through direct interaction between nurses and the newborn and (ii) the conjunctiva was the site through which C. parapsilosis entered the bloodstream. This finding highlights the possibility that a previous C. parapsilosis colonization and/or infection of other body sites may be a predisposing condition for subsequent C. parapsilosis hematogenous dissemination in severely ill newborns.

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

Bloodstream infections due to Candida species cause significant morbidity and mortality. Surveillance for candidemia is necessary to detect trends in species distribution and antifungal resistance. We performed prospective surveillance for candidemia at 16 hospitals in the State of Iowa from 1 July 1998 through 30 June 2001. Using U.S. Census Bureau and Iowa Hospital Association data to estimate a population denominator, we calculated the annual incidence of candidemia in Iowa to be 6.0 per 100,000 of population. Candida albicans was the most common species detected, but 43% of candidemias were due to species other than C. albicans. Overall, only 3% of Candida species were resistant to fluconazole. However, Candida glabrata was the most commonly isolated species other than C. albicans and demonstrated some resistance to azoles (fluconazole MIC at which 90% of the isolates tested are inhibited, 32 microg/ml; 10% resistant, 10% susceptible dose dependent). C. glabrata was more commonly isolated from older patients (P = 0.02) and caused over 25% of candidemias among persons 65 years of age or older. The investigational triazoles posaconazole, ravuconazole, and voriconazole had excellent in vitro activity overall against Candida species. C. albicans is the most important cause of candidemia and remains highly susceptible to available antifungal agents. However, C. glabrata has emerged as an important and potentially antifungal resistant cause of candidemia, particularly among the elderly.

Antifungal activities of posaconazole, ravuconazole, and voriconazole compared to those of itraconazole and amphotericin B against 239 clinical isolates of Aspergillus spp. and other filamentous fungi: report from SENTRY Antimicrobial Surveillance Program, 2000

Posaconazole, ravuconazole, and voriconazole are new triazole derivatives that possess potent, broad-spectrum antifungal activity. We evaluated the in vitro activity of these investigational triazoles compared with that of itraconazole and amphotericin B against 239 clinical isolates of filamentous fungi from the SENTRY Program, including Aspergillus spp. (198 isolates), Fusarium spp. (7 isolates), Penicillium spp. (19 isolates), Rhizopus spp. (4 isolates), Mucor spp. (2 isolates), and miscellaneous species (9 isolates). The isolates were obtained from 16 different medical centers in the United States and Canada between January and December 2000. In vitro susceptibility testing was performed using the microdilution broth method outlined in the National Committee for Clinical Laboratory Standards M38-P document. Overall, posaconazole was the most active compound, inhibiting 94% of isolates at a MIC of < or = 1 microg/ml, followed by voriconazole (91%), amphotericin B (89%), ravuconazole (88%), and itraconazole (70%). All three new triazoles demonstrated excellent activity (MIC, < or = 1 microg/ml) against Aspergillus spp. (114 Aspergillus fumigatus, 22 Aspergillus niger, 13 Aspergillus flavus, 9 Aspergillus versicolor, 8 Aspergillus terreus, and 32 Aspergillus spp.): posaconazole (98%), voriconazole (98%), ravuconazole (92%), amphotericin B (89%), and itraconazole (72%). None of the triazoles were active against Fusarium spp. (MIC at which 50% of the isolates tested were inhibited [MIC(50)], >8 microg/ml) or Mucor spp. (MIC(50), >8 microg/ml). Posaconazole and ravuconazole were more active than voriconazole against Rhizopus spp. (MIC(50), 1 to 2 microg/ml versus >8 microg/ml, respectively). Based on these results, all three new triazoles exhibited promising activity against Aspergillus spp. and other less commonly encountered isolates of filamentous fungi. The clinical value of these in vitro data remains to be seen, and in vitro-in vivo correlation is needed for both new and established antifungal agents. Surveillance efforts should be expanded in order to monitor the spectrum of filamentous fungal pathogens and their in vitro susceptibility as these new antifungal agents are introduced into clinical use.

Trends in antifungal susceptibility of Candida spp. isolated from pediatric and adult patients with bloodstream infections: SENTRY Antimicrobial Surveillance Program, 1997 to 2000

From 1 January 1997 through 31 December 2000, 2,047 bloodstream infections (BSIs) due to Candida spp. were reported from hospitals in the United States, Canada, Latin America, and Europe participating in the SENTRY Antifungal Surveillance Program. Among individuals in four age groups (< or =1, 2 to 15, 16 to 64, and > or =65 years) Candida albicans was the most common species, causing 60, 55, 55, and 50% of infections, respectively. C. glabrata caused 17 to 23% of BSIs in those ages 16 to 64 and > or = 65 years, whereas it caused only 3% of BSIs in the individuals in the two younger age groups (P < 0.001). C. parapsilosis (which caused 21 to 24% of BSIs) and C. tropicalis (which caused 7 to 10% of BSIs) were more common than C. glabrata in individuals ages < or =1 year and 2 to 15 years. Isolates of Candida spp. showed a trend of decreasing susceptibility to fluconazole, itraconazole, and amphotericin B with increasing patient age (P < or = 0.01). None of the C. glabrata isolates from individuals < or =1 year old were resistant to fluconazole, whereas they made up 5 to 9% of isolates from individuals ages 16 to 64 and > or =65 years. Isolates of C. tropicalis from patients < or =1 year old were more susceptible to flucytosine (MIC at which 90% of isolates are inhibited [MIC(90)], 0.5 microg/ml; 0% resistant isolates) than those from patients > or =65 years old (MIC(90), 32 microg/ml; 11% resistant isolates). The investigational triazoles posaconazole, ravuconazole, and voriconazole were all highly active against all species of Candida from individuals in all age groups. These data demonstrate differences in the species distributions of pathogens and differences in antifungal resistance among isolates from individuals in the pediatric and adult age groups. Ongoing surveillance will enhance efforts to limit the extent of antifungal resistance in individuals in various age groups.

Resistance of Candida species to antifungal agents: molecular mechanisms and clinical consequences

Candida albicans and related species pathogenic for man become resistant to antifungal agents, in particular triazole compounds, by expression of efflux pumps that reduce drug accumulation, alteration of the structure or concentration of antifungal target proteins, and alteration of membrane sterol composition. The clinical consequences of antifungal resistance can be seen in treatment failures in patients and in changes in the prevalences of Candida species causing disease. These effects were seen unequivocally in HIV-infected patients with oropharyngeal candida infections, but their incidence has decreased dramatically with the introduction of highly active antiretroviral therapy. The evidence for similar emergence of antifungal-resistant yeast strains and species in other types of candida infections is confounded by non-standardised susceptibility testing methods and definitions of a resistant fungal isolate. Recent large-scale surveys of yeasts isolated from blood cultures, based on standardised methodology and resistance definitions, do not support the view that antifungal resistance in pathogenic yeasts constitutes a significant or growing therapeutic problem.

Neonatal Candida glabrata sepsis: clinical and laboratory features compared with other Candida species

BACKGROUND

Recent studies have shown a rise in Candida glabrata infections among immunocompromised adults. In published case series of neonatal candidemia, however, the species glabrata is uncommon. We conducted a retrospective chart review to examine the epidemiology, clinical presentation and outcome of neonatal infection with C. glabrata compared with other species of Candida.

METHODS

Neonatal and microbiology databases of two affiliated hospitals were searched for all cases of candidemia in neonatal intensive care unit patients with suspected sepsis from 1991 through 1998.

RESULTS

Of 58 cases of Candida sepsis, 9 (15%) were caused by C. glabrata (CG), 41 (71%) by C. albicans (CA) and 8 (14%) by C. parapsilosis (CP). There was no change in the proportion of candidemia caused by glabrata species in the years studied. Although there was a significantly higher proportion of CG cases at 1 hospital (29% vs. 6%, P = 0.01), there was no case clustering to suggest direct nosocomial spread. Compared with other Candida species, CG occurred in infants of higher gestational age (CG 29.7 weeks, CA 26.6 weeks, CP 27.3 weeks) and birth weight (CG 1442 g, CA 931 g, CP 965 g). Patients with CG sepsis were more likely to be receiving broad spectrum antibiotics at the time of diagnosis (CG 67%, CA 38%, CP 38%), were less likely to present with apnea and had less severe thrombocytopenia. Of 9 patients with CG sepsis, 1 had meningitis, 1 had necrotizing enterocolitis and 3 had candiduria.

CONCLUSION

C. glabrata is a significant nosocomial pathogen in the neonate.

The Ess1 prolyl isomerase is required for growth and morphogenetic switching in Candida albicans

Prolyl-isomerases (PPIases) are found in all organisms and are important for the folding and activity of many proteins. Of the 13 PPIases in Saccharomyces cerevisiae only Ess1, a parvulin-class PPIase, is essential for growth. Ess1 is required to complete mitosis, and Ess1 and its mammalian homolog, Pin1, interact directly with RNA polymerase II. Here, we isolate the ESS1 gene from the pathogenic fungus Candida albicans and show that it is functionally homologous to the S. cerevisiae ESS1. We generate conditional-lethal (ts) alleles of C. albicans ESS1 and use these mutations to demonstrate that ESS1 is essential for growth in C. albicans. We also show that reducing the dosage or activity of ESS1 blocks morphogenetic switching from the yeast to the hyphal and pseudohyphal forms under certain conditions. Analysis of double mutants of ESS1 and TUP1 or CPH1, two genes known to be involved in morphogenetic switching, suggests that ESS1 functions in the same pathway as CPH1 and upstream of or in parallel to TUP1. Given that switching is important for virulence of C. albicans, inhibitors of Ess1 might be useful as antifungal agents.

Antifungal susceptibility testing. New technology and clinical applications

The state of the art for susceptibility testing of yeasts is comparable with that of bacteria. Standardized methods for performing antifungal susceptibility testing are reproducible, accurate, and available in clinical laboratories. The development of quality control limits and interpretive criteria for a limited number of antifungal agents provides a basis for the application of this testing in the clinical laboratory. A proficiency testing program is available as a quality assurance measure for laboratories and has documented steady improvement among laboratories using the NCCLS method. As with antibacterial agents, surveillance programs are now in place using reference quality testing methods to monitor antifungal resistance trends on a global scale. It is clear that antifungal susceptibility testing can predict outcome in several clinical situations. Susceptibility testing is most helpful in dealing with infection caused by non-albicans species of Candida, and susceptibility testing of azoles is increasingly important in the management of candidiasis in critically ill patients. Susceptibility testing also has been standardized for filamentous fungi that cause invasive infections. Studies are ongoing to further refine this approach and evaluate the in vivo correlation with the in vitro data for molds. Future efforts must be directed toward establishing and validating interpretive break-points for licensed antifungals such as amphotericin B, and for new antifungals that are not yet licensed. Finally, procedures must be optimized for testing non-Candida yeasts (e.g., C. neoformans) and molds.

Trends in species causing fungaemia in a tertiary care medical centre over 12 years

Trends in the species of yeast causing fungaemia over a 12-year period at a large tertiary care medical centre were reviewed. A total of 966 unique episodes of fungaemia occurred in 898 patients. There was an overall trend toward fewer fungaemic episodes due to Candida albicans and more due to Candida glabrata and Candida parapsilosis. However, C. albicans remained the predominant species causing fungaemia, and the proportion due to other species varied from year to year. Candida glabrata was disproportionately isolated from older adults, whereas C. parapsilosis was common among neonates and infants. The trends of increasing isolation of C. glabrata and decreasing isolation of C. albicans were associated with increasing usage of fluconazole, but changes in the proportion of fungaemias due to other species appeared to have no association with fluconazole usage.

Improving efficacy of antifungal therapy by polymerase chain reaction-based strategy among febrile patients with neutropenia and cancer

Early detection of fungal infections in and corresponding early treatment of febrile patients with neutropenia and cancer have been important issues and continue to be major challenges for clinicians. The use of nested PCR to make therapeutic decisions was studied. Sequential blood samples obtained from 42 patients with neutropenia and cancer were tested by nested PCR and culture. Instead of the empirical antifungal therapy strategy, amphotericin B treatment was initiated only for patients who had 2 consecutive positive results by nested PCR. A reduced mortality rate was observed for febrile patients with neutropenia and cancer who had fungal infections. Thus, this strategy, combined with the nested PCR for early detection of fungal infection in febrile patients with neutropenia, may be used as a guideline for antifungal therapy.

Risk Factors for Candida tropicalis fungemia in patients with cancer

The risk factors for and presentation of Candida tropicalis fungemia, in comparison with those of Candida albicans, have been incompletely characterized. We compared 43 cases of C. tropicalis fungemia with 148 cases of C. albicans fungemia. In univariate analysis, patients with C. tropicalis fungemia were more likely to have leukemia (P=.0006), prolonged neutropenia (P=.03), and a positive blood culture for more days (P=.02). The 2 groups did not differ with regard to baseline Acute Physiology and Chronic Health Evaluation (APACHE) II score, frequency of catheter-associated fungemia, or response to antifungals. In multivariate analysis, patients with C. tropicalis fungemia were more likely to have leukemia (P=.02), previous neutropenia (P=.002), and a longer stay in the intensive care unit during the infectious episode (P=.01). Also, the response of the breakthrough C. tropicalis fungemia was lower (P=.05). In conclusion, the host determinants associated with susceptibility to C. tropicalis are leukemia and prolonged neutropenia.

Treatment of systemic fungal infections in older patients: achieving optimal outcomes

Systemic fungal infections are an increasing problem in older adults. For several of the endemic mycoses, this increase is the result of increased travel and leisure activities in areas endemic for these fungi. Immunosuppressive agents, care in an intensive care unit, and invasive devices all contribute to infection with opportunistic fungi. Treatment of systemic fungal infections is usually with an azole or amphotericin B. The preferred regimen depends on the specific fungal infection, the site and the severity of the infection, the state of immunosuppression of the patient and the possible toxicities of each drug for a specific patient. In older adults, drug-drug interactions between the azoles and drugs commonly prescribed for older persons may lead to serious toxicity, and absorption of itraconazole can be problematic. Amphotericin B is associated with significant nephrotoxicity, especially in older adults with pre-existing renal disease, and infusion-related adverse effects. Newer lipid formulations of amphotericin B can obviate some of these toxicities, but their role in the treatment of systemic fungal infections in older adults has not yet been clarified.

Survival of some medically important fungi on hospital fabrics and plastics

Tests of the survival of Candida spp., Aspergillus spp., a Fusarium sp., a Mucor sp., and a Paecilomyces sp. on hospital fabrics and plastics indicated that viability was variable, with most fungi surviving at least 1 day but many living for weeks. These findings reinforce the need for appropriate disinfection and conscientious contact control precautions.

Trends in mortality due to invasive mycotic diseases in the United States, 1980-1997

To determine national trends in mortality due to invasive mycoses, we analyzed National Center for Health Statistics multiple-cause-of-death record tapes for the years 1980 through 1997, with use of their specific codes in the International Classification of Diseases, Ninth Revision (ICD-9 codes 112.4-118 and 136.3). In the United States, of deaths in which an infectious disease was the underlying cause, those due to mycoses increased from the tenth most common in 1980 to the seventh most common in 1997. From 1980 through 1997, the annual number of deaths in which an invasive mycosis was listed on the death certificate (multiple-cause [MC] mortality) increased from 1557 to 6534. In addition, rates of MC mortality for the different mycoses varied markedly according to human immunodeficiency virus (HIV) status but were consistently higher among males, blacks, and persons > or =65 years of age. These data highlight the public health importance of mycotic diseases and emphasize the need for continuing surveillance.