The echinocandin caspofungin impairs the innate immune mechanism against Candida parapsilosis

Antifungal Drugs Influence Neutrophil Effector Functions

There is a growing body of evidence for immunomodulatory side effects of antifungal agents on different immune cells, e.g., T cells. Therefore, the aim of our study was to clarify these interactions with regard to the effector functions of polymorphonuclear neutrophils (PMN). Human PMN were preincubated with fluconazole (FLC), voriconazole (VRC), posaconazole (POS), isavuconazole (ISA), caspofungin (CAS), micafungin (MFG), conventional amphotericin B (AMB), and liposomal amphotericin B (LAMB). PMN then were analyzed by flow cytometry for activation, degranulation, and phagocytosis and by dichlorofluorescein assay to detect reactive oxygen species (ROS). Additionally, interleukin-8 (IL-8) release was measured by enzyme-linked immunosorbent assay. POS led to enhanced activation, degranulation, and generation of ROS, whereas IL-8 release was reduced. In contrast, ISA-pretreated PMN showed decreased activation signaling, impaired degranulation, and lower generation of ROS. MFG caused enhanced expression of activation markers but impaired degranulation, phagocytosis, generation of ROS, and IL-8 release. CAS showed increased phagocytosis, whereas degranulation and generation of ROS were reduced. AMB led to activation of almost all effector functions besides impaired phagocytosis, whereas LAMB did not alter any effector functions. Independent from class, antifungal agents show variable influence on neutrophil effector functions in vitro Whether this is clinically relevant needs to be clarified.

Caspofungin: Pharmacodynamics, pharmacokinetics, clinical uses and treatment outcomes

Over the past decade, echinocandins have emerged as first-line antifungal agents for many Candida infections. The echinocandins have a unique mechanism of action, inhibiting the synthesis of β-1,3-d-glucan polymers, key components of the cell wall in pathogenic fungi. Caspofungin was the first echinocandin antifungal agent to become licensed for use. The objectives of this review are to summarize the existing published data on caspofungin, under the subject headings of chemistry and mechanism of action, spectrum of activity, pharmacodynamics, pharmacokinetics, clinical studies, safety, drug interactions, dosing, and an overview of the drug's current place in therapy.

Anidulafungin versus caspofungin in a mouse model of candidiasis caused by anidulafungin-susceptible Candida parapsilosis isolates with different degrees of caspofungin susceptibility

Candida parapsilosis isolates occasionally display resistance in vitro to echinocandins and cause breakthrough infections to echinocandins. The degree of the in vivo cross-resistance among echinocandins and the fitness loss associated with caspofungin (CAS) resistance of C. parapsilosis are not well studied. We compared the activities of CAS and anidulafungin (ANF), each given at 2 dosing schedules (high dose or low dose) in a nonneutropenic mouse model of invasive candidiasis (IC) caused by ANF-susceptible isolates of C. parapsilosis with different degrees of susceptibility to CAS (CAS resistant [CAS-R], MIC, >16 mg/liter; CAS intermediate [CAS-I], MIC, 4 mg/liter; and CAS susceptible [CAS-S], MIC, 2 mg/liter). We analyzed tissue fungal burden, histopathology, and weight loss patterns. Increasing CAS resistance was associated with reduced virulence of C. parapsilosis isolates (mortality rates for CAS-S versus CAS-I versus CAS-R, 100% versus 11.1% versus 0%, respectively; P < 0.001). High doses of either echinocandin were active against infection with the CAS-I isolate when assessed by fungal burden reduction and weight gain. In contrast to CAS-S and CAS-I isolates, there was no reduction in fungal burden in mice infected with the CAS-R isolate following treatment with either echinocandin, each given at a high or low dose. Nevertheless, mice infected with the CAS-R isolate had reduced disease severity following echinocandin treatment, suggesting that echinocandins have activity in vivo, even against echinocandin-resistant strains. A complex interplay of residual echinocandin activity, decreased virulence, and/or fitness of isolates with altered cell wall and possible immunomodulatory effects can be encountered in vivo during infection with CAS-resistant C. parapsilosis isolates.

Additive antifungal activity of anidulafungin and human neutrophils against Candida parapsilosis biofilms

OBJECTIVES

To investigate the activities of two newer triazoles and two echinocandins combined with human phagocytes against Candida parapsilosis biofilms.

METHODS

An in vitro model of C. parapsilosis biofilms was used. Biofilms were grown on silicone elastomer discs in 96-well plates at 37°C for 72 h. Biofilms or planktonic cells were incubated with voriconazole, posaconazole, caspofungin or anidulafungin, at clinically relevant concentrations, and human phagocytes (neutrophils or monocytes) alone or in combination with each of the antifungal agents for a further 22 h. Fungal damage induced by antifungal agents and/or phagocytes was determined by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)2H-tetrazolium-5-carboxanilide] metabolic assay.

RESULTS

Each of the antifungal agents alone and in combination with human phagocytes induced less damage against C. parapsilosis biofilms compared with planktonic cells. No antagonistic interactions between antifungal agents and phagocytes were found. Furthermore, anidulafungin, but not caspofungin, and neutrophils exerted additive activity against C. parapsilosis biofilms.

CONCLUSIONS

Besides a lack of antagonistic interactions between newer antifungal agents and phagocytes, anidulafungin exerts additive immunopharmacological activity against C. parapsilosis biofilms.

Epidemiology of oral yeast colonization and infection in patients with hematological malignancies, head neck and solid tumors

BACKGROUND

The aim of this study was to investigate the epidemiology of oral yeast colonization and infection amongst cancer patients.

METHODS

Patients with solid tumor, head-neck cancer or hematological malignancy were recruited into the study. Demographic data on age, gender, type of cancer, preceding treatment with antibiotics, anti-fungal agents, chemotherapy, radiation or surgery and presence of dentures were recorded on admission. Oral examination and microbial swabs were obtained and yeast culture, identification and antifungal susceptibility performed.

RESULTS

Oral yeast colonization was prevalent in 56.8% (227/400) of all cancer patients and 18.9% (43/227) of those had clinical and microbiological evidence of infection. The incidence of oral candidiasis in yeast colonized patients was highest in head neck cancer (29.2%) followed by hematological malignancies (20.5%) and solid tumor (17%) patients. Age and dentures were identified as independent risk factors associated with yeast carriage. Candida albicans was the dominant (74%) species (497.5 per 1000 cancer admissions) followed by C. glabrata (11.5%), C. tropicalis (2.6%), C. krusei (2.6%) and C. parapsilosis (1.9%). The overall resistance to azoles was 28.2% (75/266). Resistance to specific drugs was seen for fluconazole (4.5%), itraconazole (11.7%), ketoconazole (11.3%), voriconazole (0.75%) and caspofungin (41.1%) but none to amphotericin B or nystatin.

CONCLUSIONS

The highest incidence of oral candidiasis amongst cancer patients was seen in head neck cancers. The majority of infections were caused by C. albicans but almost one third of patients harbored non-C. albicans strains such as C. glabrata which were often more resistant to anti-fungal agents.

Synergy of caspofungin with human polymorphonuclear granulocytes for killing Candida albicans

The influence of caspofungin on polymorphonuclear leukocyte (PMN) phagocytosis and intracellular killing of Candida albicans was investigated. Caspofungin, at all of the concentrations tested (2, 3.2, and 8 microg/ml), significantly increased intracellular killing by PMNs through its direct action on both yeast cells and PMNs, indicating the potential ability of caspofungin to synergize with phagocytes for candidal killing. Caspofungin may therefore constitute an effective therapeutic option for the treatment of invasive fungal infections, including those refractory to conventional treatment with azole agents.

Candida parapsilosis: a review of its epidemiology, pathogenesis, clinical aspects, typing and antimicrobial susceptibility

The Candida parapsilosis family has emerged as a major opportunistic and nosocomial pathogen. It causes multifaceted pathology in immuno-compromised and normal hosts, notably low birth weight neonates. Its emergence may relate to an ability to colonize the skin, proliferate in glucose-containing solutions, and adhere to plastic. When clusters appear, determination of genetic relatedness among strains and identification of a common source are important. Its virulence appears associated with a capacity to produce biofilm and production of phospholipase and aspartyl protease. Further investigations of the host-pathogen interactions are needed. This review summarizes basic science, clinical and experimental information about C. parapsilosis.