Fig. 1

Strains divided by genetic differences shown by dendrogram, farm and season of isolation, MIC, antibiotic susceptibility, biofilm formation capacity. W: weak biofilm producer. M: medium biofilm producer. S: strong biofilm producer. N: negative. MIC: Minimum Inhibitory Concentration. NFX: Enrofloxacin, SLT: Sulfonamide + Trimethoprim, CRO: ceftriaxone, GM: gentamicin, S: streptomycin, T: oxytetracycline, L: lincomycin, TY: tylosin, FF: florfenicol, AMX: amoxicillin, P: penicillin, CL: colistin, TE: tetracycline