Colibacillosis (coli granuloma, mushy chick disease, cellulitis)

Occurrence: Worldwide.
Species affected: All.
Age affected: All.
Causes: Gram negative bacteria- Escherichia coli. It is the most common bacterial pathogen of poultry, and the second most common of all poultry pathogens.
Effects: Low performance in older birds, or high mortality in younger birds. High embryonic mortality, respiratory distress and enteritis (dirrhoea) can be evident.



This disease has a number of names because it causes granulomas in adults and inflamed egg yolk in chicks. Coli Granuloma is chronic in mature birds of all species, and may be acute in chicks occurring as omphalitis (enlarged, smelly, and discolored yolk sac). Escherichia coli are gram-negative, non-acid-fast, non-spore-forming bacilli, and many strains have flagella.


Mode of transmission

E. coli may be a primary or secondary invader. It is the most common bacterial pathogen in poultry and second most common of all pathogens of poultry. Faecal contamination of eggs, transovarian contamination, contaminated water and feed with bacteria can occur commonly. Aerosol spread may occur. 

Clinical signs

Low performance in older birds or high mortality in younger birds, high embryonic mortality, respiratory distress and enteritis (diarrhoea) can be evident.

Colibacillosis (Coli granuloma, Mushy chick disease, cellulitis)

Postmortem lesions

Cauliflower-like nodules  on  viscera  (granuloma),  omphalitis  in  chicks-  discoloured  and misshapen yolk (mushy chick) are seen. These lesions are characteristic. Air sacculitis, salpingitis (inflammation of the oviduct), enteritis, synovitis, arthritis, pericarditis, peritonitis, panophthalmitis (inflammation of the eye), or swollen head syndrome are common.
Cellulitis, an inflammation of the cellular or connective tissue, can be caused by E. coli. The soft tissue is heavily necrotic and may be gangrenous. It can result is extensive processing plant condemnation. It is sometimes called infectious process or IP.


Isolation of the organisms.

Treatment & control

Antibiotics in the feed or water.

Special note

E. coli is a normal contaminant in the intestines and may complicate mycoplasma, IBV, LT, and/or NDV in the air sacs, heart, liver, and lungs causing air sacculitis and/or chronic respiratory disease (CRD).  Several serotypes make vaccination difficult.  E. coli is a very important cause of economic losses in poultry due to mortality, drops in weight gain, hatchability, and an important cause of Septicemia-toxemia (sept-tox), air sacculitis, and infectious process (IP) condemnations in processing plant. IP lesions include cellulitis (inflammation of the skin and muscles). Sept-tox is the leading infectious cause of condemnation in the broiler processing plant in the U.S., air sacculitis is the second, and IP the third.