الفهرس 
cover englishOnly 14 pages are availabe for public view
 |  | from | 108 |  |  |
| | | from | 108 | | |
Abstract
Neonatal calf diarrhea is one of the most important problems in young calves causing great
economic losses., The objective of this study was to investigate serotypes, virulence genes, and
antibiotic sensitivity testing of Escherichia coli isolated from buffalo and cattle calves at some
places in Egypt. A total number of 160 fecal samples from diarrheic cattle and buffalo calves
under one months old were examined bacteriologically for isolation of E. coli. All isolates were
confirmed by PCR using 16SrRNA gene. Results showed that Overall 44 isolates typed as E. coli
(27.5%); were belonged to serogroup O146 (50%), followed by O1 and O119 (13.5%) then
O78(9.25%) and later O26 and O127 (6.8%). Epidemiological studies of E. coli were as the
following: prevalence rate of enteric colibacillosis in the present study was (27.5 %). A higher
prevalence rate was recorded in cattle calves (32.46 %) than buffalo calves (22.89%). The present
study recorded a higher incidence in female calves (34.6%) than male calves (21.1%).
Considering seasons; The results showed that the higher incidence was in summer (38.7%)
followed by winter (31.5%) then spring (22.5%) then autumn (21.5%). Susceptibility was also
evaluated for the incidence in calves of different ages; the results showed that the calves were
more susceptible during the 1 st then 2nd then 3 rd then the 4th week post calving. The antibiotic
sensitivity test showed that the isolates exhibited a high resistance to Enrofloxacin (91%). In the
same time the isolates were sensitive to Sulphmethoxazole/Trimethoprim (54.5%), followed by
amoxicillin /Clavulanic acid (29.5%). Field trial for treatment was done by using the results of
antibiotic sensitivity test on ten diarrheic calves by using Sulphmethoxazole/Trimethoprim. The
treatment trial was evaluated by clinical and bacteriological improvement of the treated calves. It
was concluded that the colibacillosis is prevalent among calves in the first month of age and the
prevalence differ according to sex and age of calves, season and feeding system. The most
common strain of the isolated E. coli was O146. The most sensitive anti-E. coli antibacterial drug
was Sulphmethoxazole/Trimethoprim.