Biotipizzazione ed antibioticoresistenza di ceppi di Escherichia coli isolati da conigli selvatici (Oryctolagus cuniculus) asintomatici

Biotyping and antibiotic resistance of Escherichia coli strains isolated from asymptomatic wild rabbits (Oryctolagus cuniculus). One hundred wild rabbits hunted in Serio Regional Park (Bergamo, Italy) were examinated. Post mortem examination revealed a good body condition, even in rabbits with ecto-endoparasites (Spilopsyllus cuniculi and Cittotaenia spp.). The caecum of each animal was tested bacteriologically for Escherichia coli. Sixty per cent of samples were positive. 25 strains were identified, biotyped and checked for antibiotic sensitivity (nalidixic acid, apramycin, chloramphenicol, chlortetracycline, ciprofloxacin, colistin, sulph.+trimethoprim, enrofloxacin, flumequine, gentamicin, neomycin, norfloxacin, streptomycin and the three sulphanilamides). Nine different biotypes were identified: B2 (n.1), B8 (4), B10 (3), B12 (4), B14 (5), B18 (1), B20 (2), B26 (1) and B30 (4). Antibiotic sensitivity varied widely: only norfloxacin was active against all the strains, chloramphenicol on 17, enrofloxacin only on 12, and chlortetracycline and the sulphanilamides were virtually inactive. The presence of different pathogenic biotypes of E. coli and their multi-resistance to antibiotics has never been reported in wild rabbits. These preliminary findings need to be completed with serotype studies and identification of the gene coding for intimin and adesines, to give a fuller picture of the situation in these wild animals.