Virulence Determinant of Enterotoxigenic E.coli and Its Relation To Adhesive Antigen K99 Associated With Diarrhea In Newly born buffalo Calves

The role played by E. coli in producing diarrhoea in calves hasreceived a great attention of many authors, the importance of otherbacteria, however, has not been fully investigated.In this study 113 out of 296 faecal samples collected from buffalo-calves showed clinical signs of diarrhoea were found to be positive forbacteriological examination and harboured Escherichia coli with anincidence of38.17%.All isolates proved to be E. coli by culture method, morphologicalappearance and biochemical reaction were submitted to serologicalidentification using O:K serotypes (Welcome) and K99 antiseraprepared in the laboratory using standard strains and the resultsobtained showed that the most predominant serovars were 055 : K59(85),0111: K58 (B4) , 026 : K60 (B6) , 0119: K6(B14) , 0126:K71 (B16) and 086 : K61 (B7) and 0125 : K70(B15). In addition to 29 strains that could not be serologically identified, this might be due to the presence of other serovars against which no diagnostic sera were available. All E. coli isolates were serologiantisera and the obtained results showed that 56 strains proved to beK99 +ve.The association between E. col i strains and calf age was present and obtained results showed that the high incidence was in the first day (44.00/0) followed by 40.3%, 39.3%, 38.5, 31.42 and