No abstract

Slime isolated after growth of four strains of coagulase-negative staphylococci on chemically defined medium plus agar was rich in galactose. However, when sterile agar plates were extracted with saline, high-molecular-weight material with similar properties was obtained that also was galactose-rich. Most of the dry weight attributed to slime, and probably all the galactose, originated from agar. Slime isolated by gel and ion-exchange chromatography from liquid culture in the same medium contained glycerol phosphate, glucose (no galactose), glucosamine, alanine, uronate, an unidentified component, and protein. Separation of protein from carbohydrate was achieved by affinity chromatography. [14C]glucose in the medium labeled the carbohydrate polymer; [14C]amino acids chiefly labeled extracellular proteins. Slime from bacteria grown on medium solidified with silica gel or on dialysis membrane above an agar surface showed essentially the same composition and behavior after purification as the material isolated from liquid culture.

Enterococcus faecium, which was highly resistant to vancomycin (MIC 256 mg/liter), but susceptible to teicoplanin (MIC 2 mg/liter), caused two distinct episodes of infection on a renal unit in the United Kingdom. Pulsed field gel electrophoresis (PFGE) indicated that a single strain caused the first episode, while the second episode, which occurred 1 year later, involved multiple strains, all of which were distinct from the original strain. Vancomycin resistance in all but one of these strains was mediated by transferable plasmids that carried the vanB glycopeptide resistance gene. Transfer either of resistance plasmids or the vanB resistance determinant itself to different strains occurred during the second episode. Plasmid-mediated vanB resistance has not been widely documented. A retrospective study of a reference collection revealed two other vanB-encoding plasmids from an E. faecalis and an E. faecium referred from two further UK centers. Although restriction analysis indicated no similarity between the plasmids from the three different centers, all contained a 2.1-kb EcoRV fragment that hybridized with a probe for the vanB gene. This suggests that there has been dissemination of a conserved glycopeptide resistance determinant, of which vanB is a part.

We reviewed the use of liposomal amphotericin B in 30 patients receiving therapy following liver transplantation over a 2 year period. Five of these patients were treated for presumed invasive aspergillosis: four of them died despite therapy, each having combined renal and respiratory failure at the time of diagnosis of presumed aspergillosis. Post-mortem examination of three of these patients confirmed the diagnosis of aspergillosis. Twenty-five patients were treated empirically; 11 died and supportive evidence for invasive fungal infection following commencement of therapy was found in only one case. Following liver transplantation, the use of liposomal amphotericin B following confirmation of aspergillus infection or for empirical therapy is of uncertain value, and strategies based on selective prophylaxis for high-risk cases may be preferable.

Summary. Extracellular high-mo1.-wt material was separated from liquid cultures of Staphylococcus epidermidis. This material contained protein c. 20 % w/w and polysaccharide c. 80 % w/w. The polysaccharide was isolated by gel and ion-exchange chromatography and contained glycerol phosphate, glucose, N-acetylglucosamine, and D-alanine. Cell-wall teichoic acid was isolated from strain RP-62A and had a similar composition.