Candida Infections: An Update on Host Immune Defenses and Anti-Fungal Drugs
Ning Gao, Changbin Chen
From Key Laboratory of Molecular Virology and Immunology, Unit of Pathogenic Fungal Infection and Host Immunity, Institute Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Guide Infections by pathogenic fungi have become an increasing problem in human health, although their effects are not widely recognized and deaths caused by such infections are often overlooked. Based on reports from the World Health Organization, most people have experienced superficial fungal infections in their lifetimes. In most cases, these infections are easy to cure, but millions of individuals worldwide are suffering from life-threatening invasive infections that are hard to diagnose and treat, a situation possibly attributable to the immunosuppression caused by HIV-AIDS, cancer, metabolic disorders like diabetes, and long-term antibiotic use. Invasive fungal infections are coming under the spotlight because of their unacceptably high mortality rates and because more than 90% of all the fungal-related deaths reported result from species that belong to one of the following four genera: Candida, Cryptococcus, Aspergillus, and Pneumocystis. These fungi are saprophytes in soil and the general environment or can be present as commensals in healthy organisms. Among them, candidemia, which is caused by infection with Candida species, is one of the leading causes of blood-stream infections and has a mortality rate of more than 30%. There is an increased incidence of infections caused by non-albicans Candida species such as Candida tropicalis, Candida parapsilosis, and Candida glabrata. Although these fungi are isolated much more frequently as the causative agents of invasive candidiasis worldwide, Candida albicans remains the most common isolate from hospitalized patients. In this review, we will focus on Candida species as pathogens by dividing our discussion into three parts: the first part concentrates on fungal infection mechanisms, the second part focusses on host–fungus interactions, and the final part looks at anti-fungal drugs.
Abstract Infections by fungal pathogens such as Candida albicans and non-albicans Candida species are becoming increasing prevalent in the human population. Such pathogens cause life-threatening diseases with high mortality, particularly in immunocompromised patients. Host defenses against fungal infections are provided by an exquisite interplay between innate and adaptive immune responses. However, effective anti-fungal agents for Candida infections are limited, and fungal drug resistance is a significant treatment challenge. In this review, we summarize the current understanding of host–fungal interactions, discuss the modes action of anti-fungal drugs, explore host defense mechanisms, and define the new challenges for treating Candida infections.
Received: 02 January 2016
Published: 01 February 2016