Abstract

A total of 90 milk samples were collected from cows with clinical and subclinical mastitis from different areas in Mosul city, in a period from October 2009 to June 2010, for the detection of gram negative bacteriological causative agents. The bacteria were identified using morphological, cultural and biochemical characteristics. thirty tow (35.3%) gram negative bacterial isolates were obtained from the total count which included 14 isolates (15.5%) for Escherichia coli, 7 isolates (7.7%) for Klebsiella spp, 4 isolates (4.4%) for Pseudomonas aeruginosa, 3 isolates (3.3%) for Enterobacter aerogenes ,2 isolates for Serratia marcescens and one isolates (1.1%) for each of Aeromonas hydrophila and Pasteurella multocida. Results of antibiotic sensitivity test indicated that most of these isolates were sensitive to Ciprofloxacin following by Gentamycin and Cotrimoxazole, while most of these organisms were resistant to Ampicillin, the isolates showed different percentages of sensitivity to Doxycycline, Tetracycline, Neomycin and Chloramphenicol.