title: The toxic role of alpha-haemolysin in the pathogenesis of experimental Escherichia coli infection in mice.
abstract: Filtrates from strains of Escherichia coli possessing plasmid-cloned haemolysin (Hly) genes and from strains possessing 'wild' Hly plasmids were lethal for mice on intravenous inoculation; similar doses of preparations from derivatives of these strains in which the Hly genes had been rendered non-functional or which did not possess the 'wild' plasmids were not. Live cultures of both kinds of Hly+ strain usually had a lower lethal dose for mice on intraperitoneal inoculation than the corresponding Hly- forms. Mice that had been inoculated with Hly+ forms had shorter survival times and lower numbers of organisms in peritoneal washings, lungs and blood at point of death than mice that had been inoculated with the corresponding Hly- forms; this was also so for mice pre-treated with FeSO4, a procedure which rendered mice equally susceptible to the lethal effects of the Hly+ and Hly- forms of a strain. In FeSO4-treated mice the numbers of organisms in the tissues of those dying from infection with Hly+ organisms were no higher than they were at the same time after inoculation in others given the corresponding Hly- forms; before mice of the latter category died the numbers of organisms in their tissues increased greatly. The clinical and pathological signs exhibited by mice inoculated with Hly+ organisms, but not with Hly- organisms, resembled those exhibited by mice inoculated with bacteria-free haemolysin preparations. These results suggest that haemolysin played a significant role in the pathogenesis of the disease produced by the Hly+ organisms by having a direct toxic action on the host.
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000633:toxicity*; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000209:etiology* / Q000401:mortality; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D006460:Hemolysin Proteins / Q000235:genetics / Q000633:toxicity*; D008168:Lung / Q000382:microbiology; D051379:Mice; D010537:Peritoneum / Q000382:microbiology; D010957:Plasmids
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; C036507:Hlya protein, E coli