A B S T R A C TA total of 194 milk samples from clinically mastitis cattle cows were collected from Giza, Monofia, Fayoum, Ismailia, and Beni-Suef Governorates. All samples were collected during the period from December 2016 till June 2017. Bacteriological study gave a total of 29 positive strains of Escherichia coli (E.coli) in the rate of (14.9%) from all collected samples. Twelve E.coli isolates were identified from cultured samples in a single manner (6.2%) and was isolated with Staphylococcus aureus (S.aureus) by 8/194(4.1%), with Streptococcus species (Strept. spp) by 3/194(1.57%), meanwhile it was isolated with S.aureus and Strept. spp. by 6/194(3.1%). On the other hand 18 clinical mastitic milk samples were showed no growth of any pathogenic microorganisms on ordinary and specific used media of bacteriology from all investigated milk samples by (9.3%). It was observed that several serotypes were recovered from clinical cases of milk sample with different E.coli infection as O27, O146, O125, O126, O111, O20, and O157. Concerning the sensitivity test to choice the suitable antibacterial drug(s) for treatment clinical mastitis in cattle cows the data revealed that ,Cefiquinom, Gentamycin and Amoxicillin +Clavulinic acid were the antibacterial drugs of first choice that could be used to overcome a great number of single isolated E.coli causing clinical mastitis. Vice versa, the resistant antibiotics for single E.coli infection causing clinical mastitis were Amoxicillin, Ampicillin, and Neomycin. Studied strains were gave a positive results for virulence E.coli genes: phoA ,ompA and fimH in 5 examined strains (100 %),classified as follow :(two strains of O27/28.6%) ,( one strain of O125/14.3%) ,( one strain of O126/14.3%) , and (one strain of O146/14.3% ). while Stx1 and Stx2 virulence genes were detected in only 2 studied strains of E.coli in a total percentage of 28.6 %, divided into, O111(14.3%) and O157(14.3%).

1. The paper records, for the first time, the isolation of Bact. paratyphosum C in Egypt.2. It has been isolated from the urine of nine patients and the faeces of two patients suffering from enteric fever during the summer of 1937 and the early part of the present year.3. Its frequency is comparable with that of Bact. paratyphosum A, and may exceed that of Bact. paratyphosum B.4. Its inclusion in prophylactic vaccines, along with the usual “T.A.B”. vaccine is worthy of serious consideration.

Bacteriological examination of 400 fish samples taken from Oreochromis niloticus (O. niloticus), Clarias gariepinus, Cyprinus carpio.l (Common carp) and Mugil cephalus (100 from each) revealed isolation of (317) bacterial isolates, which were identified as 171 E.coli isolates and 146 Salmonella sp isolates with an incidence of (53.94% and 46.06 %) respectively. The incidence of E.coli and Salmonella spp. differ among different species of fish under investigation, the higher percentage of bacterial isolates observed in Clarias garipinas (53.31%), followed by (29.97 %), Cyprinus carpio.l (11.99 %), and the lower incidence was observed in Mugil cephalus (4.73%). Frequency distribution of isolated bacteria from the surface lesions and internal organs of examined fish and the antibacterial susceptibility to different chemotherapeutic agents were discussed. PCR based technique was used in identification of E. coli and Salmonella sp., the results showed that E. coli O26 & O111 were positive strains for stx1, stx2 and eaeA genes, E. coli O55 was positive strain for stx2 and eaeA genes, E. coli O91 & O103 were positive strains for stx1 and stx2 genes, E. coli O119 was positive strain for stx2 gene, E. coli O124 was positive strain for eaeA gene and E. coli O128 was positive strain for stx1 gene. In case of Salmonella sp, S. Typhimurium strain was positive for stn, invA and hilA genes, S. Enteritidis strains was positive for stn, invA and hilA genes, S. Virchow strain was positive for invA gene, S. Typhi strain was positive for invA and hilA genes and S. Infantis strain was positive for invA genes.