The most superficial cell wall layer present in smooth-colony-forming mycobacteria was isolated from serovar 20 of the Mycobacterium avium-Mycobacterium intracellulare-Mycobacterium scrofulaceum (MAIS) serocomplex and examined chemically and by electron microscopy. Most (70 to 80%) of the fibrillar material consisted of an array of serologically active, acetylated C-myosidic peptidoglycoplipids with the basic structure (formula, see text) but in which the location of acetyl groups and the arrangement of monosaccharides have not been defined. Apparently, all serovars within the MAIS complex are characterized by structurally related superficies in which the monoglycosyl-lipopeptide portion is invariable but the oligosaccharide attachment is peculiar to each serovar. These unique inert structures may be an important factor in shielding the pathogen within phagolysosomes from lysosomal enzymes.

The previously described thin-layer chromatography procedure (Brennan et al., J. Clin. Microbiol. 8:374-379, 1978) for identifying serovars of the Mycobacterium avium-M. intracellulare-M. scrofulaceum complex, based on their specific Cmycoside glycopeptidolipid antigens, has now been extended to all 31 known serovars. Photographs of the characteristic pattern of the glycopeptidolipids are presented. Although the procedure is fraught with the difficulties inherent to comparative thin-layer chromatography, it is particularly suitable for the screening of isolates which are not amenable to seroagglutination, such as those which autoagglutinate or for which antisera are not presently available. In this way it was possible to tell whether isolates were of the M. avium-M. intracellulare-M. scrofulaceum complex and whether or not they had previously been recognized. Knowledge of the chemical features of the typing antigens of nontuberculous mycobacteria other than M. avium-M. intracellulare-M. scrofulaceum strains also enables us to develop thin-layer chromatography systems for the identification of M. kansasii, M. szulgai, members of the M. gordonae complex, M. terrae, M. xenopi, and M. gastri.

Use of argatroban as an alternative to heparin during cardiopulmonary bypass (CPB) in patients with heparin-induced thrombocytopenia has gained some attention in the past two decades. Dosing of argatroban during CPB is complex due to lack of complete understanding of its pharmacokinetic profile and the various elements during CPB that may alter its plasma levels. We report a case where the challenges in dosing argatroban led to failure to provide adequate anticoagulation during CPB, as evidenced by clot formation in the oxygenator, and extensive bleeding in the postoperative period.

The knowledge that the surface (Schaefer) antigens of certain smooth-colony atypical mycobacteria are multiglycosylated C-mycosidic peptidoglycolipids was used to devise a sensitive thin-layer chromatographic (TLC) procedure for the identification of Mycobacterium avium/M. intracellulare/M. scrofulaceum serotypes. TLC maps of the type-specific peptidoglycolipids from 17 of the 31 serotypes are presented. The primary use of the technique is to corroborate results obtained by seroagglutination. Without the aid of seroagglutination, the TLC procedure almost invariably requires the availability of reference strains or the specific peptidoglycolipids derived therefrom.