Duguma, Reta (Prof)Equar, Yohannes2018-07-022023-11-082018-07-022023-11-082016-06http://etd.aau.edu.et/handle/123456789/5267A total of 516 samples were collected from December 2015 to April 2016 from dairy cattle farms and slaughterhouses to investigate the prevalence and antimicrobial resistance trait of E. coli isolated from cow milk, beef, mutton, chevon and chicken meat. The overall prevalence of E. coli were found to be 79 (15.3%) from both milk and meat. Of these positive cases, the isolation of E. coli was the highest in chicken samples 27 (37.0%), followed by 17 (23.3%) in mutton, 15 (20.6%) in chevon, 16 (7.1%) from cow milk and 4 (5.5 %) in beef. Conventional and molecular method were used to identify E. coli antimicrobial susceptibility trait. The overall result by disk diffusion showed that significantly high resistance to ampicillin (70.9%) and tetracycline (40.5%). On the other hand, the antibiotic sensitivity test showed that highest number of E. coli isolates were sensitive to gentamicin (81%) and chloramphenicol (67.1%). In this study the overall multiple drug resistance was 73.4% and only 7 (8.9 %) of the isolates were sensitive to all antimicrobials tested. Identification of the genes associated with antimicrobial resistance was also done using PCR. The prevalence of E. coli isolates carrying antimicrobial resistance gene for tetracycline (tet(A)), beta lactams (blaCMY) and sulphanamide (sulI) genes found in milk, beef, mutton, chevon and chicken meat were significantly high. Fifty six out of the 79 (71%) meat and milk E. coli isolates have got multidrug resistance gene to two or more classes of drugs. The associations of antimicrobial resistance phenotypes and resistance genes was also determined. The most common drugs to which isolates demonstrated resistance were consistent with the most common resistance genes detected. Tetracycline, beta lactams and sulphamethoxazole were the top three drugs identified as being the most common for resistance measured either phenotypically or genotypically. So that the rising levels of resistance to multiple antimicrobials dictate the urgent need for frequent and close monitoring of resistance in bacterial pathogens. Key words: Antibiotic resistance, Dairy farm, Escherichia coli, Meat, Milk, Sloughter houseenAntibiotic resistanceDairy farmEscherichia coliMeatMilkSloughter houseThesis