The antimicrobial susceptibility of the 41 Bordetella bronchiseptica isolates was tested by using the Kirby-Bauer agar disk diffusion method. The B. bronchiseptica isolates were found to be sensitive to amoxicillin/clavulanic acid (100%), gentamicin (100%), neomycin (100%) and amikacin (97.6%), whereas they were resistant to streptomycin (100%), trimethoprim/sulfamethoxazole (100%), penicillin (100%) and ampicillin (97.6%). All the B. bronchiseptica isolates resisted to at least 4 antimicrobial agents and totally 8 different combinations of multiple antibiotic resistance patterns were noted. All of the B. bronchiseptica isolates, except one, were simultaneously resistant to streptomycin, trimethoprim/sulfamethoxazole, penicillin and ampicillin. The observed antibiotic resistance is not plasmid mediated as plasmids were absent from all the B. bronchiseptica isolates.

ABSTRACT
 Introduction
 Materials and Methods
  1. Bacterial isolates and reference strains
  2. Antimicrobial susceptibility test
  3. Detection of plasmid DNA
 Results
  1. Susceptibility to antimicrobial agents
  2. Detection of plasmid
 Discussion
 References

• 신은경(강원도가축위생시험소) | Eun-Kyung Shin (North Branch, Gangwon Veterinary Service)
• 아비히지트바레이트(강원대학교 수의과대학) | Abihijit K. Barate (College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University)
• 람쯩꽝(강원대학교 수의과대학) | Truong Quang Lam (College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University)
• 홍종해(강원대학교 수의과대학) | Chong Hae Hong (College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University)
• 한태욱(강원대학교 수의과대학) | Tae-Wook Hahn (College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University) Correspondence