: J Am Vet Med Assoc. 2005 Jun 15;226(12):2016-9, 2001. Links
Isolation of necrotoxigenic Escherichia coli from a dog with hemorrhagic pneumonia.
Breitschwerdt EB, DebRoy C, Mexas AM, Brown TT, Remick AK.
Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State
University, Raleigh, NC 27606, USA.
A 7-month-old sexually intact male Cocker Spaniel was admitted to the North Carolina State University Veterinary
Teaching Hospital for evaluation of lethargy, panting, and excessive salivation that had become progressively severe
during a 5-hour period. Despite intensive medical care, the dog died within the first 24 hours of hospitalization, and
death was attributed to acute, severe, necrotizing pneumonia. Lung tissue collected at necropsy by use of swabs was
cultured and yielded an isolate of Escherichia coli; because of the rapid progression of illness in an otherwise healthy
dog, the isolate underwent virulence typing and was determined to be a necrotoxigenic E. coli. Necrotoxigenic E. coli
produce a toxin called cytotoxic necrotizing factor and are known to be involved in extraintestinal infections, including
urinary tract infection, in humans and animals. Virulence typing of E. coli isolates from dogs with peracute pneumonia is
recommended to further characterize the epidemiologic characteristics and public health importance of necrotoxigenic
PMID: 15989184 [PubMed - indexed for MEDLINE]
German Study -- Shiga toxins create the necrotizing factor which destroys animal and human body tissue,
Characterization of Shiga Toxin-Producing Escherichia coli Strains Isolated from Human
Patients in Germany over a 3-Year Period
Today, more than 200 different E. coli O:H serotypes are known to be associated with the production of Shiga toxins
J Clin Microbiol. 1990 April; 28(4): 694-699.
Evidence for two types of cytotoxic necrotizing factor in human and animal clinical isolates of Escherichia
J De Rycke, E A González, J Blanco, E Oswald, M Blanco, and R Boivin
Station de Pathologie de la Reproduction, Institut National de la Recherche Agronomique, Nouzilly, France.
This article has been cited by other articles in PMC.
We have characterized the in vitro and in vivo toxic properties of cell sonic extracts from 22 animal and human clinical
isolates of Escherichia coli that caused both necrosis in the rabbit skin and multinucleation in tissue cultures, two toxic
properties previously reported as being specific for E. coli cytotoxic necrotizing factor (CNF). Two distinct toxic
phenotypes were observed. Type 1, which was displayed by originally described CNF strains, was characterized by
extensive multinucleation and rounding of cells in HeLa cell culture assays, moderate necrosis in the rabbit skin test,
and absence of necrosis in the mouse footpad test. Type 2, which has recently been shown to be associated with E. coli
Vir plasmid, was characterized by moderate multinucleation, by polymorphism and elongation of HeLa cells, and by an
intense necrotic response in both the rabbit skin test and the mouse footpad test. The distinction between the two
cytotoxins accounting for these effects (CNF 1 and CNF 2), together with their partial relatedness, was confirmed by
seroneutralization studies of both cytopathic effects and necrosis in the rabbit skin test. In addition, type 2 extracts were
more lethal in the mouse intraperitoneal test and induced a moderate, although not totally repetitive, fluid accumulation
in the ileal loop test. The original toxic properties of these recently recognized categories of E. coli strains, together with
their association with enteritis and septicemia, suggest that these strains may play a significant role in pathology.
Basically, in the following study, multiple strains of E. coli, producing several deadly Shiga type toxins (including the
necrotizing toxin), were isolated from the infected blood of newborn calves on the verge of death.
1: Vet Microbiol. 2001 Feb 12;78(3):241-9. Links
Virulence factors in Escherichia coli isolated from the blood of bacteremic neonatal calves.
Fecteau G, Fairbrother JM, Higgins R, Van Metre DC, Pare J, Smith BP, Holmberg CA, Jang S.
Departement de sciences cliniques, Faculte de medecine veterinaire, Universite de Montreal, C.P. 5000, Que., J2S
7C6, Saint-Hyacinthe, Canada. [email protected]
Twenty-five Escherichia coli isolates from the blood of critically ill bacteremic calves sampled in two separate studies on
a calf-rearing farm housing over 15,000 calves, in the San Joaquin Valley, California were studied.Isolates were
characterized for O serogroups and for pathotypes as determined by the presence of specific virulence factors
including heat-labile enterotoxin (LT), heat-stable enterotoxins a and b (STa, STb), verotoxins 1 and 2 (VT1, VT2),
cytotoxic necrotizing factor (CNF), aerobactin, intimin Eae and P, F17 and CS31A fimbrial adhesins, and resistance to
bactericidal effects of serum.These isolates constituted a heterogeneous group. However, isolates were mostly
aerobactin positive and often resistant to the bactericidal effects of serum. Isolates of pathotypes O78 (n=6), O119:
CS31a (n=3), and P positive but O non-typeable (n=3) were associated with a high mortality rate. The remaining
isolates belonged to diverse pathotypes, often possessing the adhesins P, F17, CS31A and Eae but belonging to O
serogroups other than O78 and O119, and were less frequently associated with mortality.Although no virulence factor
common to all isolates was identified, the capacity to use iron by the presence of aerobactin which is important to the
capture of iron was a predominant factor. Moreover, certain pathotypes appear to be associated with primary
colisepticemia whereas other pathotypes may cause a bacteremia without necessarily leading to septicemia.
PMID: 11165068 [PubMed - indexed for MEDLINE]