F. Fanti

Mycobactericidal Activity of Human Natural, Monoclonal, and Recombinant Yeast Killer Toxin-like Antibodies

Human natural (KTAb), murine monoclonal (KTMAb), and single-chain recombinant (KTScFv) candidacidal antibodies representing the internal image of a killer toxin from the yeast Pichia anomala (KT), characterized by a wide spectrum of antibiotic activity, exerted a lethal effect against a KT-sensitive multidrug-resistant isolate of Mycobacterium tuberculosis. KTMAb and KTScFv were produced by the hybridoma and DNA technologies, respectively, from the spleen lymphocytes of animals immunized with the idiotype of a KT-neutralizing MAb (MAb KT4), while KTAb were purified against MAb KT4 from the vaginal fluid of women infected with Candida albicans cells bearing an idiotype-like KT cell wall receptor. Mycobactericidal activity was related to the binding of KTAb, KTMAb, and KTScFv to the cell surface of KT-sensitive bacterial cells and was prevented by specific absorption of KT-like antibodies onto MAb KT4. These data identify a novel potentially useful immunotherapeutic approach to tuberculosis.

Biotyping of bacterial isolates using the yeast killer system.

Forty-four presumptive killer yeasts were tested against bacterial isolates, including rapid-growing gram-positive and gram-negative bacteria, as well as slow-growing bacteria, such as the mycobacteria. A killer system, based on the patterns of bacterial susceptibility to the action of nine selected killer yeasts, was developed for epidemiological purposes. The killer system, previously standardized for yeasts and hyphomycetes, was adapted to the specific growth conditions of the bacterial isolates. The results obtained confirm that susceptibility to the yeast killer phenomenon is widespread among microorganisms unrelated to yeasts and that it could form the basis for a convenient and adaptable biotyping method in microbiological laboratories.

Studies on the epidemiology of Aspergillus fumigatus infections in a university hospital

The impact of the airborne opportunistic fungus pathogen, Aspergillus fumigatus in patients hospitalized at the university hospital of Parma, Italy, and its outpatients was investigated during a period of six months. Sputum and bronchial washings were collected from 986 patients. The 2,437 specimens were culturally examined for the presence of A. fumigatus regardless of the patients clinical diagnosis. This fungus was isolated from 32 patients (3.2%). Subsequently, immunological tests for aspergillosis were performed on 22 of these culture-positive patients. Eight of these patients (36.4%) were serologically proven to be affected by aspergillosis. The 32 A. fumigatus isolates were epidemiologically investigated by the killer system to determine the mode of spread of these infections. Among the patients, fifteen different biotypes were differentiated, and their value in studying the epidemiology of aspergillosis in the hospital environment was investigated.

First Italian report of onychomycosis caused by Onychocola canadensis

Onychocola canadensis is a non-dermatophytic mould that has been associated with onychomycosis particularly in temperate climates. Until now, O. canadensis has been isolated from patients in Canada (14 cases), New Zealand (three), France (nine), UK (four) and Spain (two). We describe the first Italian case of onychomycosis caused by this fungus.

Biotyping of Aspergillus Fumigatus and Related Taxa by the Yeast Killer System

The yeast killer system has proven to be an effective procedure for intraspecific differentiation of filamentous fungi. This biotyping method may have an useful application as an epidemiological marker in outbreaks of mycotic infections, especially when other approaches are not readily available. The opportunistic pathogen Aspergillus fumigatus Fresenius is the most common etiologic agent of the different clinical types of human aspergillosis. Strain differentiation of either morphologically identified A. fumigatus or related species as well as related teleomorphs by the yeast killer system is described.