Antimicrobial resistance of mesophilic Aeromonas spp. isolated from two European rivers

The activity of 19 antibiotics and four antiseptics and/or disinfectants wa s studied against 138 non-redundant strains of Aeromonas spp. (104 Aeromona s caviae, 22 Aeromonas sobria and 12 Aeromonas hydrophila) isolated from tw o European rivers. Antibiotic resistance frequencies were: nalidixic acid, 59%; tetracycline, 14%; fosfomycin, 8%; tobramycin and cotrimoxazole, 7%; c efotaxime, 4%; chloramphenicol, 2%; gentamicin, 1%. Most of the nalidixic a cid-resistant strains were susceptible to fluoroquinolones (54-98%). Antibi otic resistance rates varied according to the source of the strains. All Ae romonas spp, strains were killed by 50 ppm of chlorine, cetylpyridinium chl oride and peracetic acid, and by 1600 ppm of glutaraldehyde.