Molecular Analysis of Antimicrobial Resistance among Enterobacteriaceae Isolated from Diarrhoeic Calves in Egypt

The present study was designed to investigate the presence of genes that conferred resistance to antimicrobials among Enterobacteriaceae that were isolated from diarrhoeic calves. A total of 120 faecal samples were collected from diarrhoeic calves that were raised in Kafr El-Sheikh governorate, Egypt. The samples were screened for Enterobacteriaceae. A total of 149 isolates of bacteria were recovered and identified; Escherichia coli was found to be the most overwhelming species, followed by Citrobacter diversus, Shigella spp., Serratia spp., Providencia spp., Enterobacter spp., Klebsiella pneumoniae, Proteus spp., Klebsiella oxytoca, and Morganella morganii. All isolates were tested for susceptibility to 12 antimicrobials; resistant and intermediately resistant strains were screened by conventional polymerase chain reaction for the presence of antimicrobial resistance genes. Of the 149 isolates, 37 (24.8%) exhibited multidrug resistant phenotypes. The most prevalent multidrug resistant species were E. coli, C. diversus, Serratia spp., K. pneumoniae, Shigella spp., Providencia spp., and K. oxytoca. Class 1 integrons were detected in 28 (18.8%) isolates. All isolates were negative for class 2 integrons. The bla_TEM gene was identified in 37 (24.8%) isolates, whereas no isolates carried the bla_CTX-M gene_. The florfenicol gene (floR) was detected in two bacterial isolates (1.3%). The findings of this study reveal that calves may act as potential reservoirs of multidrug resistant bacteria that can be easily transmitted to humans.