During the last decade antimicrobial resistant pathogens have become a major medical problem. Internationally, multiresistant enterococci have increased nosocomial morbidity and mortality. Such ...strains are often resistant to ampicillin, aminoglycosides, and glycopeptides such as vancomycin. The spread of these strains has been shown to correlate to the use of antibiotics and the practice of suboptimal infection control within health care facilities. The current situation in Norwegian hospitals is presented, including the only six cases with infections and the three carriers of vancomycin resistant enterococci found to date. Surveillance in the hospitals shows that such strains are uncommon in non-infected patients. To maintain this favourable situation it is necessary to continue to practice effective methods of infection control and to employ sound antibiotic policies.
Legionella strains produce extracellular proteases. One method to demonstrate these is through the activity of broth culture filtrates on para-nitroanilide (pNA)-derivatized peptides. Previously, ...this method has comprised a 100-times concentration of the filtrates, in order to bring the protease activity, as measured by the liberation of free pNA from hydrolysed peptides, up to easily recordable values. By introducing a diazotation step, the sensitivity of the test has been increased sufficiently to omit the time-consuming concentration procedure. Accordingly, the analysis of extracellular Legionella proteases by pNA-derivatized peptides has become rapid and straight-forward.
Enterotoxigenic reference strains of Staphylococcus aureus were cultivated in sterile whole and skim milk for 18 h at 37°G. Staphylococcal enterotoxin A, B, and C were detected directly in the milk ...by an enzyme linked immunosorbent assay (ELISA), sensitive down to 1 ng/ml. Enterotoxins in the range of 1 ng–20 µg
/
ml milk were detected without any concentration or extraction. Skim and whole milk were almost identical as medium for enterotoxin production.
Crude concentrates of extracellular proteases from strains belonging to species within the genus Legionella were examined for their effect upon synthetic chromogenic tri- and tetrapeptides. For the ...species L. pneumophila, similar and reproducible substrate degradation patterns were found. Strains from the other Legionella species produced proteases with dissimilar proteolytic patterns, which were all distinct from those of the L. pneumophila proteases.
A sensitive ELISA method for protein A detection Olsvik, O; Berdal, B P
Acta pathologica et microbiologica Scandinavica. Section B, Microbiology,
March 1981, Volume:
89, Issue:
4
Journal Article
Crude, concentrated extra-cellular supernatants from Legionella pneumophila produced a soft-tissue necrosis, demonstrated by intraperitoneal or sub-cutaneous injections into infant mice. The reaction ...was rapid and gave a hemorrhagic tissue necrosis within minutes. Being heat-labile, this tissue reaction is different from those of a heat-stable cytotoxin and a heat-stable hemolysin previously described.
One hundred and seventy-seven Escherichia coli strains isolated from food, pigs and humans were tested for the production of heat-labile and heat-stable enterotoxin at 4, 22, and 37 degrees C. ...Heat-labile enterotoxin was detected in culture supernatants by an enzyme-linked immunosorbent assay, and heat-stable enterotoxin by the infant mouse bioassay. Thirty strains produced heat-labile enterotoxin, and twenty heat-stable enterotoxin. None of the strains isolated from food were enterotoxigenic. Fifty-seven per cent of the human and porcine strains producing heat-labile enterotoxin at 37 degrees C also produced the toxin at 4 degrees C. The fact that Escherichia coli enterotoxin may be present in food at consumption must be considered pathogenetically relevant.
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