STUDIES ON SURVEILLANCE AND PATHOLOGY OF E. COLI INFECTIONS IN POULTRY IN SINDH PROVINCE OF PAKISTAN

E. coli infection in commercial broiler farms cause huge economic losses with relatively high mortality and production losses. This study was conducted to observe prevalence and identify pathological lesions in E. coli infection in commercial broiler farms, along with determination of antibiotic resistance pattern. The samples total of 600 swabs from affected birds cloacal discharges and tissue samples along with their data were collected from broiler farms and were then sent to Sindh Institute of Animal Health Karachi for analysis. The data was then recorded into a proforma regarding the location of farm and number of birds and age. A total number of 60 farms were examined out of which 31 farms were found to be positive, of which the high prevalence were from Shahdadkot (90%), Larkana (90%) Thatta (80%), moderate were from Rohri (20%), Mirpurkhas (20%) whereas low prevalence were from Sukkur (10%). Among different forms of disease, complex-form of infection had the highest prevalence (60%), followed by pericarditis (45%), omphalitis (40%), perihepatitis (36.6%), airsacculi-tis (33.3%), enteritis (31.6%) and coliseptecemia (21.6%). Prevalence of Colibacillosis was found to be higher in medium sized farms as compared to both small and large farms, whereas for age it was found to be highest up to two weeks age. Histopathological lesions of these conditions included thick fibrous layer in the pericardium due to pericarditis, leukocyte infiltration and myocardial degeneration, dilation of blood vessels due to congestion of liver and vacuolanon in hepatocytes due lo tatty degeneration in liver, fatty blunting and sloughing off villus in duodenum, infiltration of lamina propria due to inflammatory cells duodenum of broiler chick. For antibiotic sensitivity of E. coli eleven antibiotics were applied to check their sensitivity pattern. The isolates were highly sensitive to enrofloxacin (20%) and gemifloxacin (12.5%), moderately sensitive to doxycycline (32%), chloramphenicol (17.5%) and colistin (12.5%), and less sensitive to neomycin (42%), streptomycin (12.5%), gentamicin (12.5%) and penicillin (7.5%). while isolates were found to be resistant to tylosin (95%) and oxytetracycline (95%).