Premise
In microbiology, the genus " Fusarium " includes a rather numerous group of hyphal fungi, omnipresent molds in the soil capable of causing damage to roots, tubers and rhizomes.
Due to its ability to generate rot and other plant diseases, Fusarium molds are classified as phytopathogenic fungi. Despite this, some forms of symbiosis between Fusarium molds and some plants are documented.
Microbiological description
The genus Fusarium includes numerous deuteromycetes fungi, molded mycelium molds that reproduce by means of conidia. These fungi have single-celled or multicellular, transparent conidia (spores) with a fusiform structure. The more or less swollen cylindrical body is called fialide; the phialides are simple or arranged in clusters. Conidiophores, grouped in bearings, produce hyphae.
The pathogens of the genus Fusarium are feared for the production of toxins, called fumosinins and trichothecenes .
The classification of molds belonging to the genus Fusarium is the subject of discussion: in fact, it is rather complex to find an agreement on the precise cataloging of these fungi. Many biologists are engaged in analyzing many differential parameters, thus identifying many different species and varieties; others consider it more appropriate to catalog these mushrooms in a more restricted number of stocks, driven by the conviction that the concept of "synthesis" is of greater applicative utility, especially for the purpose of fighting Fusarium fungi.
Most important species
In general, it is possible to affirm that the genus Fusarium contains about 50 different species, grouped into 12 sections.
In terms of virulence, the main species is Fusarium oxysporum, followed by Fusarium solani, Fusarium verticillioides and Fusarium proliferatum .
In plants, Fusarium cerealicole attacks plants, producing mycotoxins in kernels; these toxins are subsequently transferred to feed and food until they reach animals and humans.
Fusarium oxysporum is implicated in the so-called Panama disease, which affects bananas by destroying the crop.
Fusarium graminearum commonly infects barley, especially during rains: this infection has a strong economic impact, since barley is an essential ingredient for beer production.
Fusarium solani is the species responsible for keratitis in tropical areas: it seems that the pathogenicity of this mold derives both from the production of a particular mycotoxin, and from the marked ability to reproduce at a temperature of 35 ° C.
Fusarium and infections
Fusarium- supported infections are called fusariosis . The human target of these pathogens are those with serious impairments of the immune system: cancer patients suffering from hematologic malignancy and those suffering from neutropenia, lymphopenia or treated with corticosteroid drugs, represent the population most at risk.
Among the immunocompetent subjects, therefore in the absence of an immune alteration, it is believed that Fusarium mold infections occur more frequently in case of tissue degradation, in particular from trauma, severe burns or perforation of the tissue by a foreign body.
The infections that are most often documented following contact with Fusarium are:
- keratitis
- onychomycosis
- peritonitis
- infectious cellulite
Newly reported diseases are often associated with fever, various types of skin sores (eg ectima) and lung lesions.
Unlike Aspergillus infections, those carried by Fusarium can be easily diagnosed on blood agar medium. Histopathological investigation may reveal hyaline ramifications of septate hyphae.
Fortunately, Fusarium- supported infections are of simple resolution for healthy patients: different speech should be given to severely immunocompromised patients; in this case, the probability of survival following a Fusarium infection varies from 30 to 50%.
The therapy consists of the administration of specific drugs that can remove or break down the pathogenic fungus. Some sources report voriconazole as the drug of choice for the treatment of fusariosis; from what is reported in other sources (including the journal Clinical Microbiology And Infection ), it is believed instead that there is no first-line drug to treat these mycoses, despite amphotericin B, itraconazole and voriconazole - used alone or in combinations - report excellent results.
The conditions of the host's immune system, therefore the degree of integrity / impairment, are two very important elements for predicting the prognosis of a patient suffering from Fusarium infections.
