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Introduction
Zygomycosis refers to a group of uncommon but aggressive infections caused by Zygomycetes, which is subdivided into two orders: the Entomophthorales and Mucorales. The angiotropic Mucorales, causing tissue necrosis, are frequently lethal in immunocompromised hosts and are grouped into the term mucormycosis [1,2]. Mucor spp, Rhizopus spp, Absidia spp and Rhizomucor spp are the most common causal agents [3]. Rhizopus oryzae, Rhizopus microsporus var. rhizopodiformis are the most commonly implicated (90%) [4], and occasionally have been implicated Absidia corymbifera (2-3%) [5], Cunninghamella spp, Apophysomyces spp and Saksenaea spp. These fungi are ubiquitous in the nature and are found in high-organic matter and soil [6,7], most of them are able to grow at more than 37’C [2]. They can be acquired by inhalation, ingestion, or infecting wounds [8], but their potential virulence in the human host is very low. They usually affect the immunocompromised patient including patients with hemato-oncologic diseases and transplant recipients, poorly controlled diabetics, iron overload states or treatment with deferoxamine [9] and extensive burns [2,10]. The use of broad-spectrum antibiotics has also been associated. Occasionally mucormycosis has been reported in immunocompetent patients following trauma. The main sites involved in cancer patients have been pulmonary, sinuses, sinopulmonary, rhinocerebral, disseminated, gastrointestinal tract, and soft tissues [11]; but rhinocerebral, pulmonary forms and disseminated disease have the highest mortality (78-100%) [8].
Discussion
Zygomycetes characteristically invade blood vessels, causing thrombosis and infarction with necrosis and scarring. This necrotic tissue favors fungal growth and limits penetration of systemic antifungals [5]. Rhinocerebral zygomycosis was classically described as occurring in patients with uncontrolled diabetes mellitus (with ketoacidosis). These patients typically present an advanced stage of the infection, and in most cases is usually fatal [12]. Nevertheless, more invasive fungal infections are being observed in immunocompromised patients over the past two decades. This trend is alarming because they are associated with significant morbidity and mortality. Two critical developments have contributed to this trend: an increase in the number of individuals with acquired immune deficits (cancer patients on systemic chemotherapy, solid and bone marrow transplant recipients and HIV disease) and aggressive therapeutic modalities like indwelling catheters, potent antineoplastic or immunosuppressive interventions and the widespread use of antimicrobial agents [13]. Along the last 50 years the classic manifestations and risk factors for zygomycosis...