The present update on the global distribution of Mycobacterium tuberculosis complex spoligotypes provides both the octal and binary descriptions of the spoligotypes for M. tuberculosis complex, including Mycobacterium bovis, from >90 countries (13,008 patterns grouped into 813 shared types containing 11,708 isolates and 1,300 orphan patterns). A number of potential indices were developed to summarize the information on the biogeographical specificity of a given shared type, as well as its geographical spreading (matching code and spreading index, respectively). To facilitate the analysis of hundreds of spoligotypes each made up of a binary succession of 43 bits of information, a number of major and minor visual rules were also defined. A total of six major rules (A to F) with the precise description of the extra missing spacers (minor rules) were used to define 36 major clades (or families) of M. tuberculosis. Some major clades identified were the East African-Indian (EAI) clade, the Beijing clade, the Haarlem clade, the Latin American and Mediterranean (LAM) clade, the Central Asian (CAS) clade, a European clade of IS6110 low banders (X; highly prevalent in the United States and United

Total mycolic acid methyl ester fractions were isolated from 24 representatives of Mycobacterium tuberculosis, Mycobacterium bovis (including BCG), Mycobacterium microti, Mycobacterium kansasii and Mycobacterium avium. The total mycolate functional group composition was estimated from 1 H-NMR spectra. Mycolates were separated into α-mycolates, methoxymycolates and ketomycolates and each class was further separated by argentation chromatography into mycolates with no double bonds, with one trans-double bond and with one cis-double bond. Mass spectrometry revealed the mycolate chain lengths and 1 H-NMR the cis-and trans-double bond and cyclopropane ring content. The same species had similar mycolate profiles ; the major type of each class had cis-or trans-cyclopropane rings and lacked double bonds. Minor proportions of possible unsaturated precursors of the cyclopropane mycolates were commonly encountered. Among unusual α-mycolates, many strains had tricyclopropyl components with chains extended by 6 to 8 carbons.Significantly, M. tuberculosis (Canetti) and M. avium had α-mycolates with a trans-double bond and cyclopropane ring, whose chain lengths suggested a relationship to possible precursors of oxygenated mycolates. The methoxyand ketomycolates from a majority of M. tuberculosis strains had minor amounts of components with additional cyclopropane rings, some of whose chains were also extended by 6 to 8 carbons. These latter mycolates were major components in the attenuated M. tuberculosis H37Ra strain, whose mycolate profile was distinct from those of other strains of M. tuberculosis.Keywords : mycobacterial mycolates, cyclopropane rings, double bonds, stereochemistry, tuberculosis INTRODUCTIONMycobacterial mycolic acids, whose general structures are indicated in Fig. 1, are high-molecular-mass 2-alkyl branched, 3-hydroxy fatty acids, which are characteristic components of the cell envelope of mycobacteria.Although they are present in the extractable lipids, mostly as trehalose dimycolates, the major portion is covalently bound in the cell envelope esterified to the 5-hydroxy groups of arabinofuranosyl residues to form the terminal [5-mycoloyl-β-Araf-(1 2)-5-mycoloyl-α-Araf-(1 )] units of a major arabinogalactan polysaccharide (McNeil et al., 1991 galactan is, in turn, attached to the shape-forming peptidoglycan. Schematic models of mycobacterial envelope structure have been proposed to show possible arrangements for the mycolic acids and other lipid components (McNeil & Brennan, 1991 ;Minnikin, 1991 ;Paul & Beveridge, 1994). According to the currently accepted structural model (Brennan & Nikaido, 1995 ;Daffe! & Draper, 1998 ;Draper, 1998), the long hydrocarbon chains of the mycolic acids are arranged in an orderly fashion, in parallel, with the methyl ends towards the outside surface. This arrangement results in the electrontransparent layer of the cell envelope, the presence of which is revealed by electron micrographs of ultra-thin sections of mycobacterial cells (Paul & Beveridge, 1992 in the major ' merom...

Mycobacterium abscessus has been isolated increasingly often from the respiratory tracts of cystic fibrosis (CF) patients. It is not known whether these organisms are transmitted from person to person or acquired from environmental sources. Here, colony morphology and pulsed-field gel electrophoresis (PFGE) pattern were examined for 71 isolates of M. abscessus derived from 14 CF patients, three non-CF patients with chronic respiratory M. abscessus infection or colonization, one patient with mastoiditis, and four patients with infected wounds, as well as for six isolates identified as environmental contaminants in various clinical specimens. Contaminants and wound isolates mainly exhibited smooth colony morphology, while a rough colony phenotype was significantly associated with chronic airway colonization (P ‫؍‬ 0.014). Rough strains may exhibit increased airway-colonizing capacity, the cause of which remains to be determined. Examination by PFGE of consecutive isolates from the same patient showed that they all represented a single strain, even in cases where both smooth and rough isolates were present. When PFGE patterns were compared, it was shown that 24 patients had unique strains, while four patients harbored strains indistinguishable by PFGE. Two of these were siblings with CF. The other two patients, one of whom had CF, had not had contact with each other or with the siblings. Our results show that most patients colonized by M. abscessus in the airways have unique strains, indicating that these strains derive from the environment and that patient-to-patient transmission rarely occurs.

We present a short summary of recent observations on the global distribution of the major clades of the Mycobacterium tuberculosis complex, the causative agent of tuberculosis. This global distribution was defined by data-mining of an international spoligotyping database, SpolDB3. This database contains 11,708 patterns from as many clinical isolates originating from more than 90 countries. The 11,708 spoligotypes were clustered into 813 shared types. A total of 1,300 orphan patterns (clinical isolates showing a unique spoligotype) were also detected.

Mycobacterial α-, methoxy-and keto-mycolic acid methyl esters were separated by argentation chromatography into mycolates with no double bond, with one trans double bond or with one cis double bond. Meromycolic acids were prepared from each methyl mycolate fraction by pyrolysis, followed by silver oxide oxidation, and analysed by high-energy collision-induced dissociation/fast atom bombardment MS to reveal the exact locations of the functional groups within the meromycolate chain. The locations of cis and trans double bonds, cis and trans cyclopropane rings, methoxy and keto groups, and methyl branches within the meromycolate chain were determined from their characteristic fragment ion profiles, and the structures of the meromycolic acids, including those with three functional groups extracted from Mycobacterium tuberculosis H37Ra, Mycobacterium bovis BCG and Mycobacterium microti, were established. Meromycolic acids with one cis double bond were structurally closely related to those with one cis cyclopropane ring, whereas the meromycolic acids with one trans cyclopropane ring were closely related to the corresponding meromycolic acids with one cis cyclopropane ring. A close relationship between methoxy-and keto-meromycolic acids was also implied. The relationship between the meromycolic acids with a trans double bond and the other meromycolic acids was not clearly revealed, and they did not appear to be immediate substrates for trans cyclopropanation.