|Escherichia coli, Gram-negative rods
Verotoxigenic Escherichia coli (VTEC) – verotoxins (‘Shiga’-like toxins): VT1, VT2, VTe (SLT1, SLT2, SLT2v); also causes oedema
disease in swine.
Enterohemorrhagic Escherichia coli ( (EHEC) causes hemorrhagic colitis and hemolytic-uremic syndrome.
Enteropathogenic Escherichia coli (EPEC) – bacteria adheres to intestinal epithelial cells, causing diarrhoea.
Presents the EAE, EAF & BFP factors.
It is an important cause of infant mortality.
|E. coli colonies on Mac Conkey Agar
Phylum Proteobacteria, Class Gammaproteobacteria, Order Enterobacteriales, Family Enterobacteriaceae, Genus Escherichia,
- Escherichia adecarboxylata Leclerc 1962 - transferred to genus Leclercia as Leclercia adecarboxylata Tamura et al. 1987
- Escherichia albertii Huys et al. 2003
- Escherichia blattae Burgess et al. 1973 - transfered to genus Shimwellia as Shimwellia blattae Priest and Barker 2010
- Escherichia coli – type species of the genus (Bacterium coli commune, Escherich 1885), Castellani and Chalmers 1919
- Escherichia fergusonii Farmer et al. 1985
- Escherichia hermannii Brenner et al. 1983
- Escherichia vulneris Brenner et al. 1983
Gram-negative, 1.1-1.5 x 2.0-6.0 μm, straight, bacilli or coccobacilli. Non-spore-
forming. Motile by peritrichous flagella or non-motile.
Colonies on Nutrient agar may be smooth (S type), low convex, shiny surface, entire
edge, gray. R type or mucoid forms may occur. Colonies of E. hermanii are
yellow-pigmented. Aerobic, facultatively anaerobic. Optimum growth temperature 37
ºC. Grow readily on simple nutrient media like Nutrient agar or nutrient broth. For
haemolysis use Trypticase Soy Agar + 5% sheep blood. Selective media: GEAM /
Levine - black colonies with metallic surface, Mac Conkey agar - red colonies,
Rambach agar - blue-green colonies, Leifson - red colonies, Istrati-Meitert - yellow
Widely distributed in nature. Isolated from water, soil, foods and clinical samples (feces, blood, urine, spinal fluid, milk, wound
infections) from humans & animals.
E. blattae was isolated from the cockroach intestine and do not seem to have been isolated from other sources.
-Escherichia (Leclercia) adecarboxylata is an opportunistic human pathogen,
isolated from peritonitis in a child (1 report).
-Escherichia albertii - isolated from diarrhoeal stools.
-Escherichia fergusonii - isolated from human & animal feces, blood, and urine
-E. hermanii, are yellow-pigmented, and while most have been isolated from wounds
and feces, there have also been a few isolations from spinal fluid and blood.
-Escherichia vulneris – wounds contaminant.
-Escherichia coli pathogenicity: nonpathogenic E. coli is generally located in the
intestinal lumen (colon), but some strains can cause a variety of infections (enteritis,
septicaemia, peritonitis, urinary infections, meningitis etc.) in humans and animals.
Large number of O, K, F and H antigens. F4 (K88), F5 (K99) - fimbriae - causes
enteritis in piglets & calves. Serotype O157:H7 - pathogen for humans & animals. E.
coli is a toxins producer and invasive germ. Enterotoxigenic Escherichia coli (ETEC) –
LT & ST toxins.
- J. G. Holt et al., 1994. Facultatively Anaerobic Gram-Negative Rods. Subgroup 1. Family Enterobacteriaceae. In: Begey’s Manual of
Determinative Bacteriology, 9th-edition, Williams & Wilkins, pp 175-189.
- Don J. Brenner and J.J. Farmer III, 2001. Family I. Enterobacteriaceae. In: Bergey’s Manual of Systematic Bacteriology, Second
edition, Vol two, part B, George M. Garrity (Editor-in-Chief), pp 587-897.
- Leclerc (H.): Étude biochimique d'Enterobacteriaceae pigmentées. Annales de l'Institut Pasteur (Paris), 1962, 102, 726-741.
- Huys (G.) et al. Escherichia albertii sp. nov., a diarrhoeagenic species isolated from stool specimens of Bangladeshi children. Int.
J. Syst. Evol. Microbiol., 2003, 53, 807-810.
- Sharon L. Abbott, Jennifer O'Connor, Tom Robin,Barbara L. Zimmer and J. Michael Janda: Biochemical Properties of a Newly
Described Escherichia Species, Escherichia albertii. Journal of Clinical Microbiology, October 2003, p. 4852-4854, Vol. 41, No. 10.
- Burgess (N.R.H.) et al.: Aerobic bacteria occurring in the hind-gut of the cockroach, Blatta orientalis. Journal of Hygiene
(Cambridge), 1973, 71, 1-7.
- Farmer III (J.J.) et al.: Escherichia fergusonii and Enterobacter taylorae, two new species of Enterobacteriaceae isolated from
clinical specimens. J. Clin. Microbiol., 1985, 21, 77-81.
- Brenner (D.J.) et al.: Atypical biogroups of Escherichia coli found in clinical specimens and description of Escherichia hermannii
sp. nov. J. Clin. Microbiol., 1982, 15, 703-713.
- Brenner (D.J) et al.: Escherichia vulneris: a new species of Enterobacteriaceae associated with human wounds. J. Clin. Microbiol.,
1982, 15, 1133-1140.
Glucose and other carbohydrates are fermented with the production of pyruvate, which
is converted into lactic, acetic and formic acids. Part of the formic acid is split into CO2
Positive results for catalase, nitrate reduction, acid production from: L-arabinose,
D-mannitol, D-mannose & trehalose.
Negative results for oxidase, H2S production, urease, Voges-Proskauer reaction,
DN-ase, lipase, gelatinase, citrate utilization, phenilalanine & acid production from
(c) Costin Stoica
Differential characters of the species:
Legend: + positive 90-100%, - negative 90-100%, [+] positive 75-89%, [-] negative 75-89%, d positive 25-74% of strains