Antimicrobial Susceptibility of Bordetella bronchisetica Isolates from Pigs with Respiratory Diseases on Farms in China

Abstract

One hundred and sixty-three Bordetella bronchiseptica isolates from pigs, consisting of 65 isolated in 2003 and 98 isolated in 2007, were tested for antimicrobial susceptibility to 17 antimicrobial agents by the disk diffusion method. All 163 B. bronchiseptica isolates were sensitive to polymyxin B and cefoperazone/sulbactam; the majority of the strains were sensitive to amikacin (149/163; 91.4%), gentamicin (132/163; 81.0%), ampicillin/sulbactam (127/163; 77.9%) and ciprofloxacin (115/163; 70.6%). A high level of resistance was found for furazolidone (100%), ampicillin (90.2%), cefazolin (89.0%), streptomycin (87.7%), amoxicillin/clavulanic acid (74.2%), and tetracycline (64.4%). Comparison of the data revealed that isolates with multi-resistance to at least six or eight of 17 antimicrobials used became more frequent from 32.3 or 16.9% in 2003 to 90.8 or 41.8% in 2007.