Laboratory investigation of hemorrhagic colitis outbreaks associated with a rare Escherichia coli serotype

Abstract

Two outbreaks of hemorrhagic colitis, a newly recognized syndrome characterized by bloody diarrhea, severe abdominal pain, and little or no fever, occurred in 1982. No previously recognized pathogens were recovered from stool specimens from persons in either outbreak. However, a rare E. coli serotype, O157:H7, was isolated from 9 of 20 cases and from no controls. It was also recovered from a meat patty from the implicated lot eaten by persons in one outbreak. No recovery of this organism was made from stools collected 7 or more days after onset of illness; whereas 9 of 12 culture-positive stools had been collected within 4 days of onset of illness. The isolate was not invasive or toxigenic by standard tests, and all strains has a unique biotype. Plasmid profile analysis indicates that all outbreak-associated E. coli O157:H7 isolates are closely related. These results suggest that E. coli O157:H7 was the causative agent of illness in the two outbreaks.

RAPID detection and quantification of E. coli O157/O26/O111 in minced beef by real-time PCR

“…This study has developed and optimized a real-time PCR assay, which can rapidly detect organisms harbouring the verotoxin genes, and perhaps equally significantly, can specifically identify positive samples as being derived from one of the three (O26, O111 or O157) serogroups most commonly responsible for haemorrhagic colitis and HUS (Wells et al 1983;Johnson et al 1996). Although a small number of conventional PCR-based assays have been described for the detection of O26, O111 or O157 serogroups (Louie et al 1998;Paton and Paton 1998), these procedures are not suitable for quantification of target organisms.…”

Atypical enteropathogenicEscherichia coligenomic background allows the acquisition of non-EPEC virulence factors

“…These strains belong to the E. coli collection kept at the Laboratório de Bacteriologia (Instituto Butantan, Brazil). The other E. coli strains used here include the following DEC prototype strains: E2348/69 (tEPEC), 042 (EAEC), H10407 (ETEC), C1845 (DAEC) and EDL933 (EHEC) (Evan et al, 1975;Levine et al, 1978;Wells et al, 1983;Nataro et al, 1985;Bilge et al, 1989).…”

Experimental Infection of Specific‐Pathogen‐Free Mice with Enterohemorrhagic Escherichia coli 0157: H7

“…Hemolytic uremic syndrome (HUS) has been cited as one of the complications, and respiratory symptoms were reported in about 19" of the cases of the first two outbreaks in the United States and elsewhere (7)(8)(9)23). At least three putative virulence factors were demonstrated in E. coil 0157:H7, including the Shiga-like toxin I (SUFI), Shiga-like toxin II (SLTII) and a 60 Md plasmid which encoded pili production and was suggested to be responsible for colonization (6,8,9,23,26). Several animal models have been developed for study of the pathogenesis, including mice, infant rabbits, gnotobiotic piglets and calves (1-4, 16, 18-20, 25).…”