title: Evaluation of iron dextran and mucin for enhancement of the virulence of Yersinia enterocolitica serotype O:3 in mice.
abstract: The pathogenic role of Yersinia enterocolitica serotypes O:3, O:8, and O:9 in human infections is well documented. Whereas the  virulence of the O:8 strains can be readily demonstrated in mice by 50% lethal dose determinations, the O:3 and O:9 strains have no lethal effect on mice by any route of inoculation. A mouse virulence test for the O:3 and O:9 strains is described. Y. enterocolitica strains were first tested for the presence of virulence-associated plasmid characteristics by auto-agglutination and gel electrophoresis procedures before mouse virulence determinations. The 50% lethal dose of the O:3 strains injected intraperitoneally with 2.5% mucin was about 10(7) colony-forming units. However, histological examinations showed that mucin allowed the growth of Y enterocolitica on the surface of the livers and spleens of the mice without internal lesions. The 50% lethal dose of the same O:3 strains injected intraperitoneally with 1 ml of 10% iron dextran in saline was about 10(5) to 10(6) colony-forming units, and the nonlethal infective dose with typical lesion development was 20 to 200 colony-forming units. The infected mice developed symptoms and extensive liver and spleen lesions which differed from those in mice infected intraperitoneally with the virulent O:8 strains. These results showed that the virulence of the O:3 Y. enterocolitica strains can be measured by intraperitoneal injection with iron dextran. This procedure was used to test the virulence of food isolates, plasmidless strains, and the effect of growth temperatures.
mesh_terms: D000371:Agglutination; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D005516:Food Microbiology; D007505:Iron-Dextran Complex / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009077:Mucins / Q000494:pharmacology*; D010957:Plasmids; D012703:Serotyping; D013696:Temperature; D015007:Yersinia / Q000145:classification / Q000472:pathogenicity* / Q000502:physiology
chemical_list: D009077:Mucins; D007505:Iron-Dextran Complex; D002118:Calcium