Virulence-associated factors of uropathogenic Escherichia coli strains isolated from pigs.

Thirty one Escherichia coli strains isolated from pigs with urinary tract infections were investigated for presence of virulence factors and plasmid DNA profile. The most frequent virulence factors presented by these strains were mannose-resistant fimbriae, including P. fimbriae (54.8%) and aerobactin production (45.2%). The pap) operon, detected by PCR, was found in 54.8% of the strains, which is similar to its frequency in human strains. Other characteristics such as the presence of mannose-sensitive hemagglutinin (16.1%), indicative of type 1 pili, and production of hemolysin (25.8%), colicin (38.7%) and toxins (22.6% for LT and for VT) were less frequent. No strains were positive for STa production. Plasmid profiles were variable among isolates from either the same or different farms.

The fate of Staphylococcal exfoliatin in newborn and adult mice.

The distribution and excretion of the staphylococcal exfoliatin was investigated following in vivo administration of highly purified 125I-labelled exfoliatin fractions to adult and newborn mice. Adult mice excrete approximately one-third of a test dose by 3 hours as compared to a fifteenth of a test dose excreted by newborn mice. Accordingly, blood tracer radioactivity reaches a relatively higher peak and shows a slower decline in newborns than in adults. The urine of adult mice contains considerable biologically active exfoliating material. Both nephrectomized and carbon tetrachloride-poisoned adult mice injected with exfoliatin develop generalized exfoliation whereas comparable doses in untreated controls have no effect. On the other hand, subtotal hepatectomy, followed by injection of exfoliatin, does not lead to exfoliation. We conclude that renal immaturity is a critical factor responsible for the susceptibility of neonates to generalized staphylococcal scalded skin syndrome.