Background:

Bordetella bronchiseptica has been considered upper respiratory tract pathogen of many mammalian species (dogs, cats, rabbits, etc.) and some immunosupressed individuals. There are few studies about antibiotic pharmacodynamics against this microorganism; however empiric prescription is very common. So the aim of this work was to determine the antibiotic profile (susceptibility-resistance, MIC, and PAE) of B. bronchiseptica strains isolated from different mammal species.

Methodology:

B. bronchiseptica strains from pharyngeal swabs of some domestic species (dogs, cats, donkeys, horses, rabbits, pigs) and individuals were isolated and identified by biochemical, serological and PCR (using DAL1 and DAL3 primers) assays. We employed 10 antibiotics in order to determine susceptibility-resistance (by agar diffusion method), minimal inhibitory concentration (MIC) (by double dilutions of the antibiotics in microplaques and cultured on agar) and post-antibiotic effect (PAE) by method described by Craig and Gudmundsson (1996).

Results:

Forty isolates of B. bronchiseptica (18 from cat, 10 from dog, six from human, two from pig and donkey, and one from rabbit and horse) were identified by PCR amplifying 1200 pb band in agarose gel; biochemical test as urease, catalase, and oxidase positive and carbohydrates no-fermentation. Hundred per cent isolated strains were sensitive to amikacin and kanamycin, 87.5% to tetracycline, 82.5% to rifampicin, 72.5% to ampicillin, 55% to erythromycin, 12.5% to penicillin and nitrofurantoin; 7.5% to vancomycin and 0% to bacitracin. The results of MIC showed heterogeneous values (the amounts varied from: amikacin 0.25–100 mg/mL, ampicillin 16–112 mg/mL, tetracycline 0.05–150 mg/mL, penicillin 50–25 000 IU, kanamycin 0.125–32 mg/mL). Also the results of PAE showed different values among strains isolated from the same specie; e.g. strains isolated from cat show values from 1 h to 5 h 40 min, while strains from dog show values from 1 h 20 min to 6 h 50 min; and human strains show values from 16 h. In general, isolated strains from human > dog > cat > donkey showed resistance for more antibiotics.

Conclusions:

Many factors influence of development resistance against antibiotics, such as sub-optimal concentration exposition, in order to avoid this problematic and agree with the results of the present work suggests determinate profile antibiotic for each individual independently of species and give it appropriated dosing regimens.