Results
Among all tested rectal swabs, positive growth on the selective
MacConkey medium was obtained from 55 animals (50.9%). We obtained
isolates only from the squirrels, rats, hedgehogs, roe deer, red deer,
and beaver (Table S2), and 80 strains were confirmed as E. coli .
In total, in the case of 35 individuals, resistant E. colistrains were isolated from only one selective medium (supplemented with
one antibiotic: tetracycline, kanamycin, or chloramphenicol). Samples
from 15 animals showed growth on two plates with MacConkey medium
supplemented with different antibiotics, whereas 15 isolates with
positive growth on three plates with antibiotics were recovered from the
other five animals (Table S2). Isolates obtained from samples showing
growth on two or three different media, we screened using the DDM to
eliminate duplicate strains and we reduced the number of strains by
another seven isolates (one strain from each animal marked with an
asterisk in Table S2). Finally, 73 E. coli isolates were selected
for subsequent analyses.