Fluconazole in transplant recipients: options and limitations

Canadian clinical practice guidelines for invasive candidiasis in adults

Candidemia and invasive candidiasis (C/IC) are life-threatening opportunistic infections that add excess morbidity, mortality and cost to the management of patients with a range of potentially curable underlying conditions. The Association of Medical Microbiology and Infectious Disease Canada developed evidence-based guidelines for the approach to the diagnosis and management of these infections in the ever-increasing population of at-risk adult patients in the health care system. Over the past few years, a new and broader understanding of the epidemiology and pathogenesis of C/IC has emerged and has been coupled with the availability of new antifungal agents and defined strategies for targeting groups at risk including, but not limited to, acute leukemia patients, hematopoietic stem cell transplants and solid organ transplants, and critical care unit patients. Accordingly, these guidelines have focused on patients at risk for C/IC, and on approaches of prevention, early therapy for suspected but unproven infection, and targeted therapy for probable and proven infection.

Antifungal prophylaxis with azoles in high-risk, surgical intensive care unit patients: A meta-analysis of randomized, placebo-controlled trials*

OBJECTIVE

The use of antifungal prophylaxis remains controversial in most populations including surgical intensive care unit patients. A meta-analysis of randomized controlled trials was performed to evaluate the safety and effectiveness of azoles as antifungal prophylaxis in high-risk patients receiving treatment in the surgical intensive care unit.

DATA SOURCE

Data were obtained from PubMed, Current Contents, Cochrane central register of controlled trials, and references from relevant articles.

STUDY SELECTION

Randomized controlled trials using azoles as antifungal prophylaxis vs. placebo were included in the study.

DATA EXTRACTION

Two independent reviewers extracted data concerning the development of fungal infections (superficial or invasive), adverse effects, and mortality.

SYNTHESIS

Six randomized controlled trials were included in the main analysis. Publication bias and statistically significant heterogeneity were not observed among the analyzed studies. Patients receiving antifungal prophylaxis developed fewer episodes of candidemia (odds ratio [OR] = 0.28, 95% confidence interval [CI] 0.09-0.86), nonbloodstream invasive fungal infections (OR = 0.26, 95% CI 0.12-0.53), and noninvasive (superficial) fungal infections (OR = 0.22, 95% CI 0.11-0.43), respectively. No reduction in mortality was observed among patients who received azole prophylaxis (OR = 0.74, 95% CI 0.52-1.05). There was no significant difference in reported adverse effects (OR = 1.28, 95% CI 0.82-1.98).

CONCLUSIONS

Despite its limitations, our meta-analysis suggests that the prophylactic use of azoles in high-risk surgical intensive care unit patients is associated with a reduction of fungal infections but not in all-cause mortality. However, although not noted in the analyzed randomized controlled trials, there is concern about the use of azoles due to possible shift toward non-albicans species and development of resistance to azoles.

Choices aplenty: antifungal prophylaxis in hematopoietic stem cell transplant recipients

The incidence of invasive fungal infection (IFIs) in hematopoietic stem cell transplantation (HSCT) recipients ranges from 10 to 25% with an overall case fatality rate of up to 70-90%. Candida and Aspergillus genera remain the two most common pathogens. Although fluconazole prophylaxis in this population has been moderately effective in reducing mortality due to invasive candidiasis, this agent does not have activity against invasive aspergillosis (IA) and other mould. Several new agents such as voriconazole and caspofungin have enhanced potency and broad-spectrum antifungal activity and show promising results against yeasts and filamentous fungi when given as therapy and as chemoprophylaxis. Further, new diagnostic tools to detect circulating fungal antigens in biological fluids and PCR-based methods to detect species or genus-specific DNA or RNA have been developed. Incorporating these techniques along with clinical criteria appear to improve the accuracy of preclinical diagnosis of IFIs. Such approaches may alter the current treatment strategy from prophylaxis to pre-emptive therapy, thereby potentially decreasing cost and toxicity in high-risk patients.

Fungal Infections in Solid Organ Transplant Patients

BACKGROUND

Solid organ transplantation is becoming increasingly more common in the treatment of end-stage organ failure. Opportunistic fungal infections are a frequent life-threatening complication of transplantation.

MATERIALS AND METHODS

In this article, a review of the infections in the different organ transplant recipients is presented.

RESULTS

The incidence of fungal infections in organ transplant patients ranges from 2% to 50% depending on the type of organ transplanted, kidney recipients being the least frequent and liver recipients having the highest rate of infection. New antifungal medications and immunosuppressants have changed the spectrum of fungal treatment and prevention.

CONCLUSION

Prompt recognition and treatment of infection is imperative for successful therapy. Further advancements in early detection and the development of less toxic medications will lead to refinements in the treatment of fungal infections.

Multicenter comparative evaluation of six commercial systems and the national committee for clinical laboratory standards m27-a broth microdilution method for fluconazole susceptibility testing of Candida species

Fluconazole susceptibility among 800 clinical Candida isolates (60% C. albicans) and two control strains (C. krusei ATCC 6258 and C. parapsilosis ATCC 22019) was tested with the NCCLS M27-A method (gold standard) and six commercial products (Candifast, disk, Etest, Fungitest, Integral System Yeasts, and Sensititre YeastOne). Results were classified as susceptible, susceptible-dose dependent, or resistant using M27-A breakpoints or, for Fungitest, Integral System Yeasts, and Candifast, as susceptible, intermediate, or resistant, according to the manufacturers' instructions. Concordance with NCCLS M27-A results was analyzed with the chi(2) test. Intra- and interlaboratory reproducibility was also evaluated. NCCLS M27-A (90.1%), Etest (93.1%), Sensititre YeastOne (93.1%), disk (96.7%), Fungitest (92.6%), Integral System Yeasts (40.6%), and Candifast (6.0%) classified the indicated percentages of C. albicans isolates as susceptible. Among non-C. albicans strains, the percentages of susceptible isolates were as follows: NCCLS M27-A, 74.0%; Etest, 83.8%; Sensititre YeastOne, 64.1%; disk, 60.6%; Fungitest, 76.6%; Integral System Yeasts, 28.3%; and Candifast, 27.4%. All methods except Candifast and Integral System Yeasts showed good agreement with NCCLS M27-A results for both C albicans and non-C. albicans isolates. Intralaboratory reproducibility was excellent for NCCLS M27-A, Etest, Sensititre YeastOne, disk, and Fungitest (88 to 91%). Similar results emerged from the interlaboratory reproducibility evaluation. Our findings indicate that some commercial methods can be useful for fluconazole susceptibility testing of clinical Candida isolates. Those characterized by a lack of medium standardization and/or objective interpretative criteria should be avoided. Particular caution is necessary when testing is being done for clinical and epidemiological purposes.