Serogrouping and resistance gene detection in avian pathogenic E.coli isolated from broiler chickens

الملخص EN

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.