To determine the incidence of Candida bloodstream infections (BSI) and antifungal drug resistance, population-based active laboratory surveillance was conducted from October 1998 through September 2000 in two areas of the United States (Baltimore, Md., and the state of Connecticut; combined population, 4.7 million). A total of 1,143 cases were detected, for an average adjusted annual incidence of 10 per 100,000 population or 1.5 per 10,000 hospital days. In 28% of patients, Candida BSI developed prior to or on the day of admission; only 36% of patients were in an intensive care unit at the time of diagnosis. No fewer than 78% of patients had a central catheter in place at the time of diagnosis, and 50% had undergone surgery within the previous 3 months. Candida albicans comprised 45% of the isolates, followed by C. glabrata (24%), C. parapsilosis (13%), and C. tropicalis (12%). Only 1.2% of C. albicans isolates were resistant to fluconazole (MIC, >64 g/ml), compared to 7% of C. glabrata isolates and 6% of C. tropicalis isolates. Only 0.9% of C. albicans isolates were resistant to itraconazole (MIC, >1 g/ml), compared to 19.5% of C. glabrata isolates and 6% of C. tropicalis isolates. Only 4.3% of C. albicans isolates were resistant to flucytosine (MIC, >32 g/ml), compared to <1% of C. parapsilosis and C. tropicalis isolates and no C. glabrata isolates. As determined by E-test, the MICs of amphotericin B were >0.38 g/ml for 10% of Candida isolates, >1 g/ml for 1.7% of isolates, and >2 g/ml for 0.4% of isolates. Our findings highlight changes in the epidemiology of Candida BSI in the 1990s and provide a basis upon which to conduct further studies of selected high-risk subpopulations.

The incidence of invasive fungal infections has increased dramatically in recent decades, especially among immunocompromised patients. However, the diagnosis of these infections in a timely fashion is often very difficult. Conventional microbiologic and histopathologic approaches generally are neither sensitive nor specific, and they often do not detect invasive fungal infection until late in the course of disease. Since early diagnosis may guide appropriate treatment and prevent mortality, there has been considerable interest in developing nonculture approaches to diagnosing fungal infections. These approaches include detection of specific host immune responses to fungal antigens, detection of specific macromolecular antigens using immunologic reagents, amplification and detection of specific fungal nucleic acid sequences, and detection and quantitation of specific fungal metabolite products. This work reviews the current status and recent developments as well as problems in the design of nonculture diagnostic methods for invasive fungal infections

D-Arabinitol (DA) is a useful diagnostic marker for candidiasis in patients with neutropenia and other high-risk groups, but its use in unselected patients with a broad range of underlying diseases and conditions has not been studied. We used an automated enzymatic fluorometric assay to measure serum DA/creatinine ratios (DA/cr's) in 30 healthy adults, 100 hospitalized controls without Candida fungemia, and 83 patients from a study of all Candida fungemias in Connecticut between October 1998 and September 1999. Sixty-three of 83 (76%) fungemic patients and 11 of 100 (11%) nonfungemic controls had serum DA/cr's >3.9 M/mg/dl (mean ؉ 3 standard deviations for 30 healthy adults). High serum DA/cr's were less frequent in patients with cancer or fungemia caused by the DA nonproducer Candida glabrata than in patients with cancer or fungemia caused by a DA producer, C. albicans, C. tropicalis, or C. parapsilosis. The serum DA/cr was first >3.9 M/mg/dl before, on the same day as, or after the first positive blood culture was drawn for 30 (36%), 22 (27%), and 11 (13%) fungemia patients, respectively. Mortality did not differ significantly among the patients with high or normal initial or peak serum DA/cr's, but mortality was higher if any serum DA/cr value was >3.9 M/mg/dl 3 or more days after the onset of fungemia (18/27 versus 4/24 patients, respectively; P < 0.001). We conclude that serum DA/cr's are useful both for the initial diagnosis of Candida fungemia and for prognostic purposes for unselected patients with a broad range of underlying diseases and conditions.The incidence of invasive candidiasis has increased dramatically in recent years, but the timely and accurate detection of this infection is difficult. Conventional culture-based clinical methods may take several days to become positive and are not very sensitive for the detection of invasive disease (1,13,14). Alternative approaches, such as immunologic detection of macromolecular fungal antigens or PCR assays for fungal nucleic acid sequences, have been described; but these methods are not yet sufficiently sensitive and specific to be widely adopted into clinical practice (14,20). It has been known for many years that several medically important Candida species produce large amounts of the five-carbon polyol D-arabinitol (DA) in culture (2, 8), and several groups have shown that serum DA concentrations and serum D-arabinitol/creatinine ratios (DA/cr's) are higher in animals and humans with invasive Candida infections than in uninfected or colonized controls (4,6,8,11,12,(17)(18)(19). However, DA measurements are not widely used for the diagnosis of invasive candidiasis. One reason for this is that the methods used to measure DA levels in serum in early studies were cumbersome and required the use of instruments and reagents that are seldom available in clinical laboratories. Switchenko et al. (12) developed an automated enzymatic method for quantifying DA in human serum, and Walsh et al. (16) used this method in a large prospective study of high-risk, neut...

A rapid enzymatic fluorometric assay for measuringd-arabinitol in serum was developed using recombinantd-arabinitol dehydrogenase from Candida albicans (rArDH). rArDH was produced in Escherichia coli and purified by dye-ligand affinity chromatography. rArDH was highly specific for d-arabinitol, cross-reacting only with xylitol (4.9%) among all polyols tested. A Cobas Fara II centrifugal autoanalyzer (Roche) was used to measure NADH fluorometrically when rArDH and NAD were added to serum extracts, andd-arabinitol concentrations were calculated from standard curves derived from pooled human serum containing known amounts ofd-arabinitol. The method was precise (mean intra-assay coefficients of variation [CVs], 0.8%, and mean interassay CVs, 1.6%) and rapid (3.5 min per assay) and showed excellent recovery of added d-arabinitol in serum (mean recovery rate, 101%). The mean and median d-arabinitol/creatinine ratios were 2.74 and 2.23 μM/mg/dl, respectively, for the 11 patients with candidemia compared to 1.14 and 1.23 μM/mg/dl, respectively, for 10 healthy controls (P < 0.01). These results confirm earlier studies showing that serum d-arabinitol measurement may help to promptly diagnose invasive candidiasis. The technique shows a significant improvement in terms of accuracy, cost, simplicity, specificity, and speed compared with gas chromatography, mass spectrometry, and earlier enzymatic assays.