Authors
Neeraj Kumar Singh, Mahesh Sharma
Abstract
Aspergillus fumigatus is an opportunistic pathogen causing infection in immunosuppressed patients. Its incidence is increasing since last decade and spreading fatal diseases amongst the weakened immunity patients. Aspergillus fumigatus have number of characteristics like thermotolerance, small conidiospores size, enzymes, allergens, and toxins etc. that help to protect it from host defence mechanism. Pathogenic properties of this fungus and defect in host immunity mechanism may result in dissemination of this pathogen. A better understanding about its pathogenic characteristics will help in better clinical treatment of patients. In this article, we tried to explore the characteristics that enhance its pathogenic calibre to cause infections. Key words: Aspergillus fumigatus; immune system; allergens; toxins; proteases; phospholipases
Introduction
Aspergillus fumigatus is a pathogenic fungus belonging to the genus Aspergillus. It is a saprophyte, an organism which utilizes non-living matter for their survival, and world-wide in distribution. Its natural habitat is soil and grows on dead organic matter. It is an opportunistic pathogen, which does not infect healthy host cells, but can infect immunocompromised individuals, in whom the infection can be life threatening 1.
A. fumigatus reproduces mainly through air-born conidiospores which are microscopic and free floating in environment. Its small spore size enhances its pathogenicity in host cells and an individual inhales hundreds of conidia on a daily basis but cleared up from lungs due to healthy pulmonary defence mechanisms2.
Infections from Aspergillus species has been increasing since last ten years and is one of the main causes for mortality in immunocompromised patients globally. Rise in mortality rate in patients with weakened immune response, especially due to Aspergillus species, prompted research¬ers to understand the epide¬miology of these microbes3. Inhaled conidiospores cannot be removed from lungs due to weakened immune response and leads to their growth and germination inside host cells4.
Factors such as resistance against high temperature also enhance its dimension for virulence as it can grow quickly at 37ºC whereas optimum temperature for mesophilic fungi ranges between 25-35ºC. It carries characteristics of thermotolerance and thermophilic fungi because it can maintain its growth below 20ºC and can survive up to 60ºC5.
Infection from Aspergillus fumigatus directs development of many diseases such as allergic bronchopulmonary aspergillosis, aspergilloma, or invasive aspergillosis. Incidence of invasive aspergillosis is getting worse since last twenty years and the control measures are not adequate enough to limit its prevalence completely, hence the high mortality rate6.
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| APA Style | Singh N. K. and Sharma. M. (2019). Aspergillus fumigatus and Its Weapons for Infection. Academic Journal of Microbiological Studies, 1(1), 28-35 |
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