Echinocandin resistance is increasing, including among FLC-resistant isolates. The new Clinical and Laboratory Standards Institute clinical breakpoints differentiate wild-type from C. glabrata strains bearing clinically significant FKS1/FKS2 mutations. These observations underscore the importance of knowing the local epidemiology and resistance patterns for Candida within institutions and susceptibility testing of echinocandins for C. glabrata to guide therapeutic decision making.

SUMMARY Mucocutaneous fungal infections are typically found in patients who have no known immune defects. We describe a family in which four women who were affected by either recurrent vulvovaginal candidiasis or onychomycosis had the early-stop-codon mutation Tyr238X in the β-glucan receptor dectin-1. The mutated form of dectin-1 was poorly expressed, did not mediate β-glucan binding, and led to defective production of cytokines (interleukin-17, tumor necrosis factor, and interleukin-6) after stimulation with β-glucan or Candida albicans. In contrast, fungal phagocytosis and fungal killing were normal in the patients, explaining why dectin-1 deficiency was not associated with invasive fungal infections and highlighting the specific role of dectin-1 in human mucosal antifungal defense.

5 RATIONALEThe availability of new antifungal agents with novel mechanisms of action has stimulated renewed interest in combination antifungal therapies. In particular, and despite the limited clinical data, the high mortality of mold infections and the relatively limited efficacy of current agents have produced significant interest in polyene-, extended-spectrum azole-, and echinocandin-based combinations for these difficult-to-treat infections. With the recent publication of the first large randomized trial of antifungal combination therapy to be conducted in two decades (166) and the rapid proliferation of new in vitro and in vivo data on antifungal combinations, we have sought to review the recent work and future challenges in this area.The focus of this review is on the efficacy of antifungal drugs in combination with respect to the extent or rate of killing of the fungal pathogen, although other potential interactions (such as pharmacokinetic drug interactions) can impact efficacy when these agents are used together. The value of giving two drugs because each is separately effective against a group of organisms exhibiting a variety of types of resistance is not specifically discussed, but this also is an obvious and straightforward reason to use a combination of agents.It cannot be simply assumed that the use of two or more effective drugs with different mechanisms of action will produce an improved outcome compared to the results seen with a single agent. Combination antifungal therapy could reduce antifungal killing and clinical efficacy, increase potential for drug interactions and drug toxicities, and carry a much higher cost for antifungal drug expenditures without proven clinical benefit (106). Thus, it is important to critically evaluate the role of combination therapy as new data become available.Conceptual models and terminology. Methods for studying antifungal combinations in vitro and in vivo have differed considerably over time and among investigators. These tools do not differ with respect to their application to combination antibacterial or antiviral therapies and have been discussed extensively and elegantly in the landmark 1995 review by Greco (79). In brief, all approaches to evaluating combinations can be reduced to two elements: (i) a conceptual model for predicting the expected result for a combination and (ii) a set of phrases used to categorize results that are better than expected, worse than expected, or as expected. Although many subtle variations are possible, the underlying mathematical model is based on either the assumption of additive interactions or the assumption of probabilistic (multiplicative) interactions. On the basis of the terminology employed by the author who first carefully described each of these models, the two models can be usefully referred to as the Loewe additivity model and the Bliss independence model (79).The terminology used to place results into interpretive categories is often the subject of debate and confusion. Greco et al. (79) have proposed a set ...

Systemic Candida albicans infection causes high morbidity and mortality and is associated with neutropenia; however, the roles of other innate immune cells in pathogenesis are poorly defined. Here, using a mouse model of systemic candidiasis, we found that resident macrophages accumulated in the kidney, the main target organ of infection, and formed direct contacts with the fungus in vivo mainly within the first few hours after infection. Macrophage accumulation and contact with Candida were both markedly reduced in mice lacking chemokine receptor CX 3 CR1, which was found almost exclusively on resident macrophages in uninfected kidneys. Infected Cx3cr1 -/-mice uniformly succumbed to Candida-induced renal failure, but exhibited clearance of the fungus in all other organs tested. Renal macrophage deficiency in infected Cx3cr1 -/-mice was due to reduced macrophage survival, not impaired proliferation, trafficking, or differentiation. In humans, the dysfunctional CX 3 CR1 allele CX 3 CR1-M280 was associated with increased risk of systemic candidiasis. Together, these data indicate that CX 3 CR1-mediated renal resident macrophage survival is a critical innate mechanism of early fungal control that influences host survival in systemic candidiasis.

Candida albicans is the most common human fungal pathogen causing mucosal and systemic infections. However, human antifungal immunity remains poorly defined. Here, by integrating transcriptional analysis and functional genomics, we identified Candida-specific host defense mechanisms in humans. Candida induced significant expression of genes from the type I interferon (IFN) pathway in human peripheral blood mononuclear cells. This unexpectedly prominent role of type I IFN pathway in anti-Candida host defense was supported by additional evidence. Polymorphisms in type I IFN genes modulated Candida-induced cytokine production and were correlated with susceptibility to systemic candidiasis. In in-vitro experiments, type I IFNs skewed Candida-induced inflammation from a Th17-response toward a Th1-response. Patients with chronic mucocutaneaous candidiasis displayed defective expression of genes in the type I IFN pathway. These findings indicate that the type I IFN pathway is a main signature of Candida-induced inflammation and plays a crucial role in anti-Candida host defense in humans.