Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. C URRENT O PINION Pathogenesis of invasive fungal infections Carolina Garcia-Vidal, Diego Viasus, and Jordi Carratala ` Purpose of review Invasive fungal infection (IFI) is increasingly being recognized as a significant cause of morbidity and mortality in immunosuppressed patients. This review focuses on the latest literature reports concerning the pathogenesis of IFI in this population. Recent findings New virulence factors of Candida and Aspergillus have recently been identified. The past few months have brought significant advances in our understanding of how the immune system acts against fungal infection, especially with regard to the role of mucosa in the innate immune system, the arsenal of innate immune recognition receptors and the pathways connecting innate and adaptive immunity. Summary Knowledge of fungal pathogenesis and host immune response can help to optimize the management of fungal infections. Greater understanding of these processes may aid physicians in developing better prophylactic measures and antifungal or immunomodulatory therapies. Keywords aspergillosis, candidiasis, fungal infections, pathogenesis INTRODUCTION The risk of invasive fungal infections (IFIs) in healthy individuals is low because the immune system prevents the development of invasive dis- ease. However, IFIs are one of the leading infection- related causes of death among severely immuno- suppressed patients and patients admitted to ICUs [1–4]. In fact, the rising incidence of IFI in devel- oped societies in recent years is mainly linked to the increase in immunocompromised individuals, specifically, neutropenic patients with cancer, and recipients of solid organ or hematopoietic stem cell transplants. This close relationship between IFI and the immune system has stimulated efforts to under- stand the interactions between the host and the fungi. However, it remains hard to transfer the results of basic science research from bench to bedside. Basic investigators and clinical physicians should work together to understand how the immune system acts against the most common fungal pathogens and how we can use this knowl- edge to improve the clinical management of these infections. The purpose of this review is to summarize the latest information regarding the most significant Candida and Aspergillus virulence factors and the pathogenesis of IFI. CANDIDA Candida species are normal commensals of humans and are frequently isolated from skin, gastrointesti- nal tract, and urine. There are more than 150 species of Candida, but few are pathogenic to humans. The most frequent species that cause invasive infections are C. albicans, C. glabrata, C. parapsilosis, C. tropi- calis, and C. krusei. The step from asymptomatic colonization to invasive infection may occur when the patient presents certain risk factors, the micro- organism has virulence factors, or the host immune system is compromised. Candida virulence factors The pathogenicity of Candida species is mediated by a number of virulence factors that facilitate adher- ence to mucosa, the ability to evade host defenses, Infectious Disease Service, Hospital Universitari de Bellvitge, Institut d’Investigacio ´ Biome ` dica de Bellvitge (IDIBELL), University of Barcelona, L’Hospitalet de Llobregat, Barcelona, Spain Correspondence to Dr Carolina Garcia-Vidal, Infectious Disease Service, Hospital Universitari de Bellvitge, Feixa Llarga s/n, 08907 L’Hospitalet de Llobregat, Barcelona, Spain. Tel: +34 932 607 625; fax: +34 932 607 637; e-mail: carolgv75@hotmail.com Curr Opin Infect Dis 2013, 26:270–276 DOI:10.1097/QCO.0b013e32835fb920 www.co-infectiousdiseases.com Volume 26  Number 3  June 2013 REVIEW