Bacteriological, Hematological and Biochemical Diagnostic Studies on Diarrheic Arabian Horse Foals Caused by Enterobacterial Infections

This study was conducted to evaluate the most important enteric bacteria causing diarrhea in Arabian horse foals and its impact on blood parameters. Identification and sensitivity tests for bacterial isolates from diarrheic foals were carried out. Complete blood counts and serum biochemical constituents were also investigated. Blood (with and without EDTA-K3), rectal swabs and fecal samples were collected from both 27 diarrheic and 73 apparently healthy horse foals located in an Arabian horse farm in Cairo, Egypt, during a period extending from 2018 to 2019. Bacteriological examination for rectal swabs was carried out using different selective and specific media followed by different routine biochemical tests. It revealed the isolation of 140 bacterial isolates, of which 120 were Gram negative enterobacterial isolates and the rest were Gram positive bacterial isolates. Enterobacter aerogens (27 isolates) was found to represent the major causative agent of diarrhea in foals among the enterobacterial isolates, followed by Proteus mirabilis (18 isolates), E. coli (10 isolates), Citrobacter diversus (9 isolates), Salmonella enterica (4 isolates) and Proteus vulgaris (2 isolates). Ciprofloxacin and gentamicin were the most effective against enterobacterial species isolated from diarrheic foals followed by amikacin, neomycin and rifamycin. In diarrheic foals, the values of RBCs, total WBCs, lymphocytes and platelets counts, and hematocrit values were markedly (P<0.05) increased, and microcytic normochromic anaemia was recorded. In diarrheic foals, serum total proteins, albumin, and total globulins; β2 -globulin, γ-globulin, urea, calcium and sodium levels were markedly (P<0.05) decreased, while the α2 -globulin, AST activity and creatinine level were significantly (P<0.05) increased. In conclusion, the major causative agents of diarrhea in the examined foals were Enterobacter aerogens. The most effective antibacterial agents were ciprofloxacin and gentamicin against Gram negative enterobacterial species isolated from diarrheic foals. In addition, hematological, metabolic and electrolytes’ disturbances were recorded in diarrheic foals.