Mannan and D-arabinitol concentrations in serum from a patient with Candida albicans endocarditis

A meta-analysis of medical versus surgical therapy for Candida endocarditis

OBJECTIVES

The optimal management of Candida infective endocarditis (IE) is unknown.

METHODS

We reviewed all 879 cases of Candida IE reported from 1966-2002 in the peer-reviewed literature to better understand the role of medical and surgical therapies. This review included 163 patients from 105 reports that met our inclusion criteria: 31 cases treated with antifungal monotherapy, 25 cases treated with medical antifungal combination therapy, and 107 cases treated with adjunctive surgical plus medical antifungal therapy. We also used meta-analytic techniques to evaluate 22 observational case-series (72 patients) of the 105 reports with two or more patients with definite Candida IE.

RESULTS

We found that in patients who underwent adjunctive surgery there was a lower reported proportion of deaths [prevalence odds ratio (POR)=0.56; 95% confidence interval (CI)=0.16, 1.99)]. Higher mortality was noted in patients treated prior to 1980 (POR=2.03; 95% CI=0.55, 7.61), treated with antifungal monotherapy (POR=1.49; 95% CI=0.39, 5.81), infected with Candida parapsilosis (POR=1.51; 95% CI=0.41, 5.52), or with left-sided endocarditis (POR=2.36; 95% CI=0.55, 10.07).

CONCLUSIONS

Medical antifungal therapy of Candida IE is poorly characterized, and recent antifungal developments lend promise for those patients who cannot undergo surgery.

D-arabinitol versus mannan antigen and candidal protein antigen as a serum marker for Candida pyelonephritis

To evaluate serum markers for the diagnosis of Candida pyelonephritis, levels of D-arabinitol, candidal mannan antigen and candidal protein antigen were measured using an enzymatic fluorometric assay, an enzyme immunoassay and a latex agglutination assay, respectively. The study group comprised 36 patients with candiduria (11 disseminated candidiasis, 9 Candida pyelonephritis and 16 colonization) and 27 without candiduria. The D-arabinitol/creatinine ratio was the only marker that differentiated between Candida pyelonephritis and colonization (p < 0.01). Using the cut-off values (1.4 mumol/mg of D-arabinitol/creatinine ratio, 0.28 of mannan/creatinine ratio (x 10(4)) and 1:4 of protein antigen titer) D-arabinitol/creatinine ratio showed the highest sensitivity in Candida pyelonephritis (77.8%) as compared to mannan/creatinine ratio (55.6%) and protein antigen titer (11.1%) although there were no differences in specificity, positive predictive value or negative predictive value. These results suggest that D-arabinitol/creatinine ratio is the most useful marker of Candida pyelonephritis.

Nonculture methods for diagnosis of disseminated candidiasis

Two of the nonculture approaches to the diagnosis of DC, enzymatic-fluorometric determination of serum D-arabinitol and detection of marker antigens in antigenemia (enolase and CWMP), have been commercialized and have shown promise in limited clinical trials. These approaches are not new but are the culmination of efforts made over 10 or more years. Clearly, further fine-tuning of both metabolite and antigen detection is needed to simplify the methods and to improve their sensitivity and specificity so that they will be valuable in guiding clinical treatment decisions. An alternative approach, detection of DC by DNA amplification methods such as PCR, is a special case of a compelling technology and one that is capable of standardization across microbial genera. The availability of simplified PCR diagnostic methods for DC remains a tantalizing prospect. Nevertheless, the development of methods to release DNA from very small numbers of Candida organisms in the blood in a form that is sufficiently free of inhibitors of PCR will require further intensive effort. The maturation of these converging laboratory approaches to nonculture diagnosis of DC leads to more optimism about the eventual use of these methods in clinical laboratories.

Diagnostic value of determination of serum mannan concentrations in patients with candiduria

The diagnostic value of determination of serum mannan levels was studied in 41 patients with candiduria and 20 control patients without candiduria. The patients with candiduria comprised 18 asymptomatic afebrile patients (group 1) and 23 febrile patients with suspected Candida pyelonephritis (group 2). Mannan antigenemia (> or equal to 0.5 ng/ml) was detected in 14 patients in group 2, this rate being significantly higher than the rate of four patients in group 1 (p < 0.05) and none in the control group (p < 0.01). Serum mannan levels decreased gradually and became undetectable in six patients in whom therapy with an anticandidal agent was effective. Determination of serum mannan levels may be a useful parameter in diagnosing Candida pyelonephritis and deciding on effective treatment.

Detection of serum Candida antigens by enzyme-linked immunosorbent assay and a latex agglutination test with anti-Candida albicans and anti-Candida krusei antibodies

Serum samples from 197 patients with and without candidiasis were assayed for Candida albicans mannan and Candida krusei mannan by an enzyme-linked immunosorbent assay (ELISA) and a latex agglutination test (LA) and for D-arabinitol by the enzymatic fluorometric method. Of the 43 patients positive for C. albicans mannan (> or = 0.2 ng/ml), 34 were infected with C. albicans and 9 were infected with Candida tropicalis. C. krusei mannan (> or = 0.3 ng/ml) was detected in 10 patients infected with Candida parapsilosis, 2 patients infected with Candida guilliermondii, and 1 patient infected with C. krusei. With both anti-C. albicans antibodies and anti-C. krusei antibodies, the sensitivities of ELISA and LA for detection of invasive candidiasis (58 patients) were 74 and 38%, respectively. No false-positive reactions were observed by the ELISA or the LA. The sensitivity and specificity of the D-arabinitol/creatinine ratio (> or = 1.5 mumol/mg) to invasive candidiasis were 50 and 91%, respectively. The ELISA with antibodies against both C. albicans and C. krusei may be useful in diagnosing invasive candidiasis caused by medically important Candida strains excluding Candida glabrata.