Phenotypic Identification and Antibiotic Resistance Profile of Escherichiacoli Isolated from Lambs with Colibacillosis in Mosul, Iraq

Abstract

Neonatal diarrhea and colibacillosis generally lead to critical morbidity and mortality rates
in affected sheep flocks caused by Escherichia coli (E. coli). The aim of this study was to detect and
isolate E. coli from lambs with dysentery and their antibiotic resistance profile. 67 Rectal swabs from
affected lambs in different regions of Mosul city were collected and cultured in MacConkey broth
and incubated aerobically for 24 hours at 37ºC to cultivate and decrease the growth of undesired
bacteria. Then, each sample was cultured on MacConkey, EMB, and HicromTM E. coli agar at the
same incubation conditions for isolation of E. coli. Growing and purified isolates were identified
based on Gram's staining reaction and biochemical IMViC tests (Indole, Methyl Red, Voges-
Proskauer, and Citrate). E. coli was isolated from 65 samples (97.01%). Then, an antibiotic resistance
profile was performed on all 65 isolates by using the disk diffusion method on 12 common antibiotics.
The results of the research showed a high distribution of E. coli in affected cases, with varying
resistance patterns, especially all isolates showed absolute resistance to spiramycin, lincomycin, and
ceftriaxone. These findings point to the immediate requirement to reform antibiotic administration
policies in veterinary medicine and ensure the importance of antibiotic resistance in E. coli isolates
to find the most effective treatment strategies for colibacillosis in lambs. Future studies are needed to
find alternative treatment options and the role of antibiotic management in veterinary lines.