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This review describes some aspects related to the technological barriers encountered in the development and stability of probiotic cheeses. Aspects concerning the viability of probiotic cultures in this matrix are discussed and the potential of cheese as a biofunctional food carrier is analyzed, outlying some points related to health and safety. In general, the manufacture of probiotic cheese should have little change when compared with the elaboration of cheese in the traditional way. The physicochemical and technological parameters influencing the quality of these products have also to be measured so as to obtain a process optimization.

Three isolates collected from human mycetomas and showing an unusual brownish purple pigmentation on Bennett agar plates were analyzed by a polyphasic taxonomic approach, including morphological, biochemical, physiological, and chemotaxonomic properties coupled with genomic and phylogenetic analysis. It clearly appeared that these microorganisms were distinct from their closest phenotypic and genetic match, the most related species according to 16S rRNA gene sequence analysis being Nocardia pseudobrasiliensis. The data obtained indicated that the three clinical strains should be recognized as a new species for which the name Nocardia mexicana sp. nov. is proposed.The Nocardia genus consists of gram-positive, variably acid fast, strictly aerobic bacteria that form filamentous, branched cells that fragment into pleomorphic, rod-shaped, or coccoid elements (1). It is widely distributed in the environment and causes a variety of suppurative and granulomatous infections of humans and animals, including cutaneous, subcutaneous, lymphocutaneous, pulmonary, cerebral, or disseminated nocardiosis. These bacteria are increasingly recognized as a cause of opportunistic infections (28).The identification of new species was based for a long time on investigation of epidemiology, clinical disease spectrum, and/or drug susceptibility combined to culture features and biochemical or chemotaxonomic characteristics. Such a phenotypic approach was probably responsible for the low number (n ϭ 12) of species described between the first description of the genus by Nocard in 1888 (32) and 1995. In the last decade, the introduction of genomic methods based on the analysis of sequences and polymorphism of the 16S rRNA gene or of the hsp65 gene has been of value for the description of many species. Thus, 17 new species had been validated from 1995 to 2003, leading to a major taxonomic revolution for this genus. It seems that it was just the beginning of the story and that the Nocardia genus will undergo the same dramatic taxonomic changes as Mycobacterium genus, for which almost a hundred species have now been described. This promoted a radical reappraisal of nocardial systematics.According to this new taxonomic background, we decided to reevaluate the taxonomic status of the strains deposited in the culture collection of the French Observatory for Nocardiosis (OFN; Lyon, France). We observed that three of them revealed atypical characteristics. These strains originated from mycetoma samples collected from Mexican patients. The strains were initially identified as Nocardia brasiliensis but showed morphological differences compared to this species. The nocardial systematic position of these three strains was investigated extensively according to an integrated use of phenotypic, chemotaxonomic, and molecular methods. The data obtained indicated that these strains should be recognized as a new species, for which the name Nocardia mexicana sp. nov. is proposed. MATERIALS AND METHODSStrains and culture conditions. The analysis of a large number...

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