INTRODUCTION:Bordetella bronchiseptica, a small, pleomorphic, gram-negative coccobacillus is primarily a zoonotic pathogen infecting rodents, swine, and household pets (1). This obligate aerobe is one of the six species under the genus Bordetella. B. bronchiseptica has a predilection for animal respiratory epithelium in contrast to B. pertussis or B. parapertussis, which show preferential adherence to human ciliated cells. To date, human infections with bronchiseptica have only been reported in immunocompromised patients acquired through animal contact. Pets are routinely vaccinated to prevent them from acquiring this infection. Infectious exposure occurs through aerosol or droplet transmission. Illness severity varies from mild respiratory symptoms to pneumonia. Diagnosis is established by obtaining a positive culture (2). Treatment is appropriate antibiotic therapy.
CASE PRESENTATION:A 61-year-old female status post renal-pancreas transplant taking sirolimus 2mg daily and mycophenolate 500mg twice daily presented with a chronic cough and dyspnea. Three months prior to presentation at our institution the patient had been hospitalized for small bowel obstruction requiring adhesiolysis. Her course was uncomplicated. Two weeks after the operation she developed a persistent, nonproductive cough with dyspnea. She was evaluated by her local physician, diagnosed with pneumonia, and treated with macrolide therapy. The symptoms persisted; therefore, a different antibiotic was instituted, a five day course of quinolone therapy. After two more weeks, the patient had incomplete symptom resolution so the quinolone therapy was continued for another 14 days. With only minor relief of symptoms despite one month of antibiotics, hydrocodone and acetylcysteine, the patient sought a second opinion at Mayo Clinic Jacksonville. After initial evaluation, computed tomography scan was ordered and revealed increased interstitial markings. These radiologic findings, along with persistent symptoms in an immunocompromised host, led to more invasive evaluation including bronchoscopy with bronchoalveolar lavage (BAL). Samples were sent for fungal, viral, and bacterial cultures. The bacterial cultures grew 3+ Bordetella bronchiseptica. Susceptibility testing showed pathogen sensitivity to aminoglycosides, tetracycline, and trimethoprim/sulfamethoxazole. After the pathogen was identified, further questioning revealed a pet history of recent immunizations. The veterinarian was contacted identifying the vaccination as a modified, live intranasal Bordetella bronchiseptica vaccine. Our patient was treated with a 21 day course of doxycycline 100mg twice a day. This regimen resolved her symptoms.
DISCUSSIONS:We report a case of Bordetella bronchiseptica pneumonia in a renal-pancreas transplant recipient who contracted Bordetella bronchiseptica shortly after her pet dogs received a modified live intranasal Bordetella vaccine. Zoonotic organisms are recognized as potential causes of disease in humans. It is well known that vaccines which contain live attenuated organisms should not be given to immunocompromised patients. Shedding, as with the former oral polio vaccine, likely occurs with other similar vaccination modalities be they in humans or other animals. The course of infection in our patient presents the possibility of contraction via well accepted modalities. Physicians should be aware of the potential for bronchiseptica infections in immunosuppressed patients who have contact with pets as they may pose a significant, though extremely rare, health risk.
CONCLUSION:This is the first reported case of Bordetella bronchiseptica infection in a renal-pancreas transplant after exposure to recently immunized animals. Our report expands the spectrum of immunocompromised hosts who have developed infections with Bordetella bronchiseptica and illustrates the dangers of transmission involving live vaccines, particularly in the immunocompromised patient population. While optimal therapy has not yet been determined, susceptibility testing allows appropriate antimicrobial therapy and in our patient succeeded in curing her symptoms.
DISCLOSURE:Justin Gisel, No Financial Disclosure Information; No Product/Research Disclosure Information