[Human and bovine tuberculosis in Latin America: from the studies about virulence to some tools for its control]. / Tuberculosis humana y bovina en Latinoambérica: de estudios sobre virulencia hacia herramientas para su control.

Human and bovine tuberculosis (TB) are currently a serious health problem in Latin America. Although the causal agents were discovered more than one century ago, the control of these illnesses is still beyond our reach: human TB accounts for more than one hundred deaths each day in this region, whereas bovine TB represents a public health risk as well as a major economic problem. We herein analyze the situation of human and bovine TB in Latin America, and present studies from our laboratories on bacterial virulence factors, intrinsic resistance features in the host, and the protective response induced in cattle through vaccination or immunization. Finally, the convenience for implementing and/or revising the use of currently available tools for TB control in the region is discussed.

Seroreactive species-specific lipooligosaccharides of Mycobacterium mucogenicum sp. nov. (formerly Mycobacterium chelonae-like organisms): identification and chemical characterization.

Strains of the new species Mycobacterium mucogenicum exhibit physiological and biochemical features very similar to those of the other species of the Mycobacterium fortuitum complex. To define taxonomic criteria for easy identification of M. mucogenicum, the glycolipid patterns of the reference strains and of 32 environmental and clinical isolates were examined by TLC. It was concluded that all M. mucogenicum strains of smooth colony morphology contained species-specific alkali-labile glycoconjugates. Three different patterns were observed among the strains of the smooth colony type. Fractionation followed by conventional chemical analyses of the purified glycolipids showed the specific glycolipids to be lipooligosaccharides (LOS). The three LOS showed a similar fatty acid composition consisting of straight chain (dodeca-, tetradeca-, hexadecanoyl and hexadecenoyl) and methylbranched (2,4-dimethyleicosanoyl and 2,4-dimethyleicosenoyl) fatty acyl substituents. The most commonly encountered LOS (present in 76% of the smooth strains) contained a tetraacylated pentasaccharide composed of four moles of glucose and one mole of a 2,4-di-O-methylhexose. A LOS composed of arabinose, glucose and mannose was present in 20% of the smooth strains, whereas the newly proposed type strain of M. mucogenicum (ATCC 49650) was the only strain that contained a LOS composed of glucose and galactose. Serological studies clearly differentiated most of the strains of M. mucogenicum from those of the other members of the M. fortuitum complex, and demonstrated the existence of serovars within the former species. Altogether, these data confirm the validity of the new species but show ATCC 49651 to be the most representative strain.