flora of infants
are named after
Dr. Theodore von
E. coli is a gram-negative
grows both aerobically and
Rod shaped bacterium.
Many strains are motile
ESCHERICHIA COLI: BASIC FEATURES
2.0-6.0 μm long and 1.1μm in diameter
Shiga-toxin producing Escherichia coli (STEC) is a
It causes diarrheal disease in humans and is of
public health concern because of its ability to cause
Severe disease such as hemorrhagic colitis (HC) or
hemolytic-uremic syndrome (HUS) .
E. coli O157:H7 is the most prevalent STEC
Causes secondary diseases when host defense cell
are being impaired.
E. Coli 0157:H7 present enterohemorrhagic
pathogen of human which can also be decolonized
in chicken. 6
Pathotypes of E. coli
1. Enterotoxigenic E. coli( ETEC)
2. Enteropathogenic E. coli (EPEC)
3. Enteroinvasive E. coli (EIEC)
4. Enterohemorrhagic E. coli (EHEC)
5. Enteroaggregative E. coli (EAEC)
Enterotoxigenic E. coli
Heat labile toxin
Heat stable toxin
Enteropathogenic E. Coli
Intimin an adhesin
Bind to intestinal cell
of actin in host cell
Attachment and effacement
Changes in ultrastructure of
Prime cause of diaarrhoea
affected with EPEC
1.O (somatic antigen) : 173 serotypes
2.K (capsular antigen) : 74 serotypes
3.H (flagellar antigen) : 53 serotypes
4.F (fimbrial antigen) : 70 serotypes
O1, O2, O35, 078 serotypes are more prevalent in poultry to
cause diseases(O1K1 and 02K1 cause severe disease).
O antigen polysaccharide phospholipid in nature, can be
produced by boiling of culture at 100 c for 1 hour. There is 5
polyvalent antiserum at market, after grouping by polyvalent
serum, further serogroup test is done by monovalent
K antigen generate after heating at 100 c for 1 hour or 121
c for 2.5 hour, are subdivided into L,A,N,B forms. O and K is
MAJOR CLINICAL AND POSTMORTEM FINDINGS
3.Air sac disease
5.Swollen head syndrome
9.Yolk sac infection
PICTURE: COURTESY OF PROF. DR. MASUDUZZAMAN, DPP,
PICTURE: COURTESY OF PROF. DR. MASUDUZZAMAN, CVASU.
Sample for diagnosis………….
Depends on where the lesions are located.
But liver, heart are the major samples,
In case of septicemia and osteomyelitis bone marrow is the
Confirmatory and differential diagnosis
FIG.: E. M.B
agar(colonies have a
FIG: Mac Conkey
agar(Large pink color
colony of E. coli)
Fig. E. coli on nutrient
agar( Smooth, colorless,
E. Coli can not be normally grown in colony in blood
agar because it contains protease.
E. Coli is tested positive in lactose fermentation test
and consequently E. coli is IMVic test positive which
is done after finding of typical growth.
Growth in nutrient slant agar taken by scraping
and PBS added Heated upto 100 c for 1 hour or
121 c for 2.5 hours For detection of O and K
Other detection methods
Prevention and control:
Multivalent vaccine made from pilli.
A live vaccine prepare form naturally occuring non
pathogenic piliated strain Bt7 was effacious when
used in chicken
Best way- Biosecurity and improving hygienic
Fecal contamination of water, feed must be avoided.
Hatching egg must be kept free from fecal
Karimi, V. et al (2011) reported that, The significant increase in the incidence of
resistance against antibiotics in the E. coli strains isolated from broiler chickens is
probably due to the increased use of antibiotics as feed additives for growth
promotion and prevention of diseases, use of inappropriate antibiotics for treatment
of diseases, resistance transfer among different between antibiotics used in poultry.
Lutful Kabir, S. M(2010) reported that, Avian colibacillosis and salmonellosis are
considered to be the major bacterial disease problems in the poultry industry world-
wide and these diseases constitute a major public health burden and represent a
significant cost in many countries. The economic and public health burden of these
diseases have made this topic time demanding.
Matthijs, M.G.R(1973) reported that, More insight in the pathogenesis of a
superinfection of E. coli in IBV-infected broilers and in the underlying mechanisms of
the increased susceptibility to colibacillosis might lead to new methods in prevention
or reduction of colibacillosis.
HAMMOUDI, A. and AGGAD*,H. (2008) reported that, Antibiotic resistances are
frequently encoded by conjugative plasmids or transposons, thus E. coli of avian
origin could act as a possible source for the transfer of antibiotic resistances
to other bacterial species including human pathogens.