Antimicrobial resistance genes and virulence gene encoding intimin in Escherichia coli and Enterococcus isolated from wild rabbits (Oryctolagus cuniculus) in Tunisia

Abstract

The spread of antimicrobial-resistant bacteria in wildlife must be viewed as a major concern with serious implications for human and animal health.Escherichia coliand enterococcal isolates were recovered from faecal samples of 49 wild rabbits(Oryctolagus cuniculus)on specific media and were characterised using biochemical and molecular tests. For all isolates, antimicrobial susceptibility testing was performed, and resistance genes were detected by PCR. Molecular typing of isolates was carried out by pulsed-field gel-electrophoresis, andE. colistrains were also tested for the presence of intimin (eae) gene characteristic of rabbit enteropathogenicE. coli.A total of 34E. coliand 36 enterococci [E. hirae(52.8%) andE. faecalis(47.2%)] were obtained. ForE. coli, resistance to tetracycline (94%), streptomycin (62%), ciprofloxacin (47%), trimethoprim-sulphamethoxazole (35%) and chloramphenicol (6%) was observed. Resistance to third-generation cephalosporins was detected in oneE. colistrain that carried theblaCMY-2andblaTEM-1genes. Class 1 integrons were detected in eight isolates. For enterococci, resistance to tetracycline (63.9%), erythromycin (30.5%), streptomycin (18.2%), and chloramphenicol (5.5%) was detected. Thetet(M)+tet(L),erm(B) and ant (6)-Ia genes were identified in thirteen, seven and three resistantEnterococcusstrains, respectively. Molecular typing showed a high diversity among our strains. Wild rabbits could represent a reservoir ofE. coli, and enterococci carrying antimicrobial resistance genes andE. coliadditionally carrying theeaegene of enteropathogenic pathotypes could both contaminate the environment. our finding seems to represent the first report ofeae-positiveE. coliin wild rabbits.