Presence of Mycobacterium spp. in frogs (Rana esculenta) from Albania

EC and non-European countries for now import the frogs, traditional ingredients of Italian cuisine, in order to meet the internal requirement. Not very well known are the real diffusion of MOTT and the possible role of the amphibians on the maintenance of this zoonosis in the environment. 214 Rana esculenta collected from a Turin’s Institute analysed. All the samples are of capture and were imported alive from Albania. A sample of skin, muscle and liver was taken from every animal in sterility. These aliquots are processed, decontaminated and centrifuged, and then the sediment was spread on Stonebrink and Löwenstein-Jensen medium. The test-tubes were incubated at 28°C until the development of colonies or up till sixty day. All the colonies resulted positive at ZN stain were processed for CDC Manual’s fenotyping tests. The specimens turned out to be positive, at least for one aliquot, for Mycobacterium spp. are 94 (43.9%) on 214 frogs examined. In skin 34.1% (73 subjects) of samples were positive, while at liver level 20.6% (44 frogs) were positive and only one muscle sample resulted positive (0.5%). 118 strains were isolated: 48 Mycobacterium chelonae (40.7%), 23 M. fortuitum (19.5%), 20 M. gordonae (16.9%), 13 M. flavescens (11.0%), 6 M. abscessus (5.1%), 4 M. peregrinum (3.4%), 3 M. kansasii (2.5%), and 1 M. marinum (0.8%). In skin and liver, the species must representative was M. chelonae (26 strains, 35.6%, in skin; 29 strains, 65.9%, in liver). The only Mycobacterium isolated from muscle samples was classified as M. marinum. Our results confirmed the hypothesis that frog’s muscles present a lower level of bacterial contamination than the non-edible portions. The frequent finding of mycobacteria in skin’s aliquots supports the hypothesis of external contamination of samples, due to the natural environment where the amphibians live rather than to an effective infection.