Striped bass (hybrid of Morone ssp.) is a fish raised in hot water; in Italy is not very common because its meat is not so appreciate. In USA and Israel M. marinum, M. shottii, M. pseudoshottii were the mycobacterial species more frequently isolated from Morone spp. The aim of the present work is to describe the first M. marinum infection in a striped bass farm of Northern Italy. In summer 2007 some gills of striped bass with yellow-brown nodules were sent to Istituto Zooprofilattico and the histopathological examination showed several granulomas with a large number of acid-fast bacilli. After this finding, some fishes from the same farm were randomly selected, sacrificed and necropsied in order to identify the mycobacterial species. The anatomopathological exams revealed lesions in various organs of all animals: ulcerative cutaneous lesions, yellow mucus with red nodules on the gills, splenomegaly and military granulomatous lesions in liver, kidney and spleen. At necropsy, liver, spleen, kidney, gills and muscle were collected and a portion fixed in formalin for the histological and immunohistochemical examination while another portion, not fixed, utilized for parasitological, virological and bacteriological investigations. Microscopically granulomas presented a central necrotic area surrounded by inflammatory cells and enclosed by a thin capsule. All granulomas were associated with a great number of acid-fast bacilli resulting positive to immunohistochemistry with a polyclonal antibody against M. bovis. From all samples, with the exception of muscle, it was possible to isolate photochromogenic colonies and the purified isolates were characterised by phenotypical and biochemical identification. All the isolates were identified as M. marinum. It is important to emphasize that, although granulomatous lesions were diffused in various organs, no fishes died for the infection and that the low death rate allowed the increase of human risk by manipulation and consumption of contaminated fishes.
Mycobacterium marinum in Italian farmed striped bass: anatomopathological and histological features / Prearo M.; Varello K.; Giorgi I.; Pezzolato M.; Florio D.; Fioravanti M.L.; Gasparri F.; Zanoni R.G.; Bozzetta E.. - STAMPA. - (2008), pp. 214-215. (Intervento presentato al convegno 29th Annual Congress of the European Society of MYcobacteriology tenutosi a Plovdiv (Bulgaria) nel 6-9 luglio 2008).
Mycobacterium marinum in Italian farmed striped bass: anatomopathological and histological features
FLORIO, DANIELA;FIORAVANTI, MARIALETIZIA;ZANONI, RENATO GIULIO;
2008
Abstract
Striped bass (hybrid of Morone ssp.) is a fish raised in hot water; in Italy is not very common because its meat is not so appreciate. In USA and Israel M. marinum, M. shottii, M. pseudoshottii were the mycobacterial species more frequently isolated from Morone spp. The aim of the present work is to describe the first M. marinum infection in a striped bass farm of Northern Italy. In summer 2007 some gills of striped bass with yellow-brown nodules were sent to Istituto Zooprofilattico and the histopathological examination showed several granulomas with a large number of acid-fast bacilli. After this finding, some fishes from the same farm were randomly selected, sacrificed and necropsied in order to identify the mycobacterial species. The anatomopathological exams revealed lesions in various organs of all animals: ulcerative cutaneous lesions, yellow mucus with red nodules on the gills, splenomegaly and military granulomatous lesions in liver, kidney and spleen. At necropsy, liver, spleen, kidney, gills and muscle were collected and a portion fixed in formalin for the histological and immunohistochemical examination while another portion, not fixed, utilized for parasitological, virological and bacteriological investigations. Microscopically granulomas presented a central necrotic area surrounded by inflammatory cells and enclosed by a thin capsule. All granulomas were associated with a great number of acid-fast bacilli resulting positive to immunohistochemistry with a polyclonal antibody against M. bovis. From all samples, with the exception of muscle, it was possible to isolate photochromogenic colonies and the purified isolates were characterised by phenotypical and biochemical identification. All the isolates were identified as M. marinum. It is important to emphasize that, although granulomatous lesions were diffused in various organs, no fishes died for the infection and that the low death rate allowed the increase of human risk by manipulation and consumption of contaminated fishes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
