Background: Bordetella bronchiseptica is commonly encountered as both a commensal and a cause of respiratory tract disease in many wild and domestic animals, and it has rarely been implicated as a cause of infection in humans.
The genus Bordetella comprises several species causing symptoms like pertussis (whooping cough) in human, among them: B. pertussis, B. parapertussis, B. holmesii and B. bronchiseptica. B. bronchiseptica is a small, Gram negative, rod-shaped, obligate aerobe bacterium. Unlike B. pertussis, B. bronchiseptica is generally resistant to macrolides and cephalosporins antibiotics. Some human cases have been successfully treated with trimethoprim/sulfamethoxazole and fluoroquinolones.
Methods: Bordetella bronchiseptica was isolated from sputum cultures arriving to the bacteriology lab at Haifa and Western Galilee, Clalit Health Services during the last ten years. Cultivation of the samples which grew Bordetella bronchiseptica was performed on TSBA, MacConkey agar and Chocolate agar (Hy-Labs and Novamed, Israel).. Suspected colonies were identified by Vitek 2 and Maldi-Tof Vitek-MS technology (bioMerieux, France). Sensitivity tests were done by Vitek 2 (bioMerieux, France). Gram staining (Aerospray, ELITech) as well as oxidase, catalase and motility tests were also performed.
Results: During the last 10 years only 5 cases of Bordetella bronchiseptica were identified from 10,785 sputum samples arriving to our lab (0.05%). The appearance of those bacteria in Gram staining was Gram negative coccobacilli and they were catalase, oxidase and motility positive. Most of the isolates were sensitive to aminoglycosides (gentamycin), 3rd generation cephalosporin (ceftazidime) and fluoroquinolones (ciprofloxacin). Half of the isolates were resistant to trimethoprim/sulfamethoxazole.
Conclusions: B. bronchiseptica is rarely isolated from humans despite the considerable exposure of humans to animal sources of the bacterium and yet it should be considered, in the differential diagnosis, in immunocompromised patients presenting with respiratory symptoms, especially those with known contact with animals.It is considered as a commensal but when encountered as a probable pathogen, part of the patients have a severely compromised clinical status. Specific guidelines for treatment do not exist, thus the duration and choice of antibiotic is determined on a case by case basis.