الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 204 |  |  |
| | | from | 204 | | |
Abstract
Mastitis remains one of the most common universal diseases in the dairy industry leading to huge economic losses. Several bacterial species, especially coliform bacteria have been identified as the most important pathogens in milk causing clinical mastitis. The β-lactam antibiotics such as penicillins and cephalosporins are the most frequently prescribed in treating Gram negative bacterial infections, especially in veterinary field.
Obviously, the production of β-lactamase enzymes is the major resistance mecha¬nism to β-lactam antibiotics. Therefore, the present study aimed to understand the effect of histidine kinase inhibitors as closantel on inhibiting the expression of genes proposed for β-lactams resistance.
In the present work, a total of 52 coliform isolates were recovered from 150 different milk samples collected from clinical mastitic cows (34.7%). The highest prevalence of coliform mastitis so far was documented for Suez Governorate (80%). However, Sharkia Governorate revealed a relatively low isolation percentage (29.6%) with the highest recovery rate in Diarb-Negm city (100%). Moreover, the high prevalence rate of coliform recovered isolates occurred in summer season (39.7%). However, winter season revealed the lowest prevalence rate (23.8%).
According to cultural and biochemical properties, all the recovered isolates were identified as coliforms species. The most predominant coliform bacterial isolate was E. coli, followed by Serratia species with percentages of 20 and 7.3%, respectively, while the lowest prevalent bacterial isolate was Enterobacter species with a percentage of 1.3%. Interestingly, E. coli isolates were the most recovered coliform species in both Suez and Sharkia Governorates with incidence rates of 26.7 and 19.3%, respectively.