Colibacillus Diarrhoea in Calves, Sheep and Goats

Abstract

Rectal swabs from 82 cases of diarrhoeic calves, sheep and goats in Khartoum State were subjected to bacteriological examination to investigate aerobic bacteria and to do studies on colibacilli associated with diarrhoea. The total number of bacterial isolates was 137. Ninety two percent of the isolates were Gram-negative and the rest (8%) were Gram-positive bacteria. Bacterial isolates from 48 swabs were subjected to further identification. Gram-positive bacteria were 3 (4%) Eneterococcus spp., 2 (3%) Streptococcus spp. and 2 (3%) Bacillus spp., Gram-negative isolates were E. coli 44 (64% of the total isolates and 70% of the Gram negative bacteria), Klebsiella pneumoniae 8 (12% of Gram-ve bacteria), Proteus spp. 5 (8%), Yersinia enterolitica 2 (5%) and Alcaligenes faecalis 1 (2% of the Gram negative bacteria). E. coli was isolated from 94% of the samples. Bioassays were used to test some E. coli isolates for enterotoxigenicity. Infant mouse test was positive for two out of three E. coli isolates and the ligated rabbit ileal loop test was positive for three out of four isolates. Eleven goat kids, naturally infected with coccidia were inoculated with an E. coli isolate that was positive for both bioassays. Seven kids showed consistency changes in faeces, which varied, from soft to watery and four of the kids died accordingly. On postmortem examination, gross lesions of the dead kids were mainly congestion of the intestinal mucosa and enlargement of the mesenteric lymph nodes. Histopathological sections of the intestines showed capillary congestion, haemorrhage, and infiltration of intestinal mucosa with lymphocytes and polymorphonuclear cells. Lymph nodes sections showed oedema, congestion, haemorrhage and depletion of lymphocytes. Intestinal mucosa scraping of one kid slaughtered after onset of diarrhoea showed clumps of Gram-negative rods. Haematological findings on the goat kids after experimental infection with E. coli were increase in leukocyte count, neutrophilia, lymphocytopnoea, decrease in haemoglobin concentration and fluctuations of packed cell volume and red blood corpuscles count. Eimeria spp. oocysts count showed increase with varying rates post infection. Sensitivity tests of some E. coli isolates to 9 different antibiotics showed a considerable variation in pattern of sensitivity among the isolates tested. All isolates were sensitive to gentamicin and resistant to penicillin, cloxacillin, and erythromycin. Sensitivity to streptomycin was considerably low among the isolates. Sensitivity to tetracycline and co-trimoxazole was more or less the same and the pattern of sensitivity to ampicillin and chloramphenicol was comparable.