E coli infection in poultry is one of the principle causes of mortality and morbidity in chickens and turkeys resulting in retardation
of growth and decreased feed conversion rate . The most common form of collibacillosis is characterized as an initial respiratory
infection (air sacculitis) followed by generalized septicemia, perihepatitis and pericarditis. The present study aimed to identify the
bacteria associated with pericarditis , airsacculitis and perihapatitis in Egyptian broiler chickens. A total 300 samples of diseased
and dead broilers from 3-6 weeks age were collected. The isolated bacteria included E. coli, Klebsiella spp., Shigella spp. And
Enterobacter spp. Sero-grouping of the isolated E. coli strains revealed O125, O158, O55,O129, O20 , O6 , O8 , O27, O115,
O142 and un-typed strains with prevalence of 16%, 12%, 8%, 8%, 8% , 8% , 8% , 8% ,4%,4% and 16% respectively. The
majority of E coli isolates were sensitive to colistin sulphate (38%) and Norofloxacin (38%) followed by ciprofloxacin (19%),
cefotaxim (19%) and Ofloxacin (19%). On the other hand, E coli were resistant (100%)to amoxicillin, clindamycin ,
Erythromycin and streptomycin. PCR analysis for antibiotic resistance genes of E coli detected that 12 serogroups isolates were
positive using the specific primers for Aada2 , BlaCTX and TetA(A) genes. The current study demonstrated the high prevalence
of E. coli indeed broilers suffered from pericarditis , perihepatitis and airsacculitis . Measures are needed to control E. coli
contamination in poultry farms to reduce economic losses caused by infection of E.coli.