Mycobacterium bovis (M. bovis) is implicated in 0.1-1.4% of cases of tuberculosis in industrialized countries. This study describes the prevalence and manifestations of M. bovis infections in a Bronx hospital.
Microbiology records were reviewed from 1/98 until 2/04 to identify patients with culture isolates of M. bovis.
Of 78 patients with tuberculosis in a 6-year period, 10 patients (1.3%) were identified with M. bovis infections. The mean age of the patients was 36±22 (range 4-76). Seven patients were male and 9 were immigrants. Patients immigrated 4.5±4 years before their illness. A child 4 years of age, who was born in the US, without any travel history, was exposed as an infant to visitors from Mexico who were coughing. One of 8 patients tested HIV positive. In addition, a woman was diagnosed during the third trimester of her pregnancy. Extrapulmonary involvement occurred in 7 patients. The following sites were affected: cervical lymphadenitis (1), salivary gland enlargement (2), genital (1), CNS(1), peritoneal (1) and pelvic abscess with osteomyelitis (1). Of these patients, only 2 had abnormal chest x-rays. There were 3 patients with isolated pulmonary involvement. Four patients had isolates resistant to pyrazinamide. All 10 patients were successfully treated with chemotherapy.
The prevalence for M. bovis of 1.3% at our hospital may be due the large immigrant population. Extrapulmonary manifestations were common and patients were not likely to have comorbidities. Clinical disease was indistinguishable from M. tuberculosis. These patients probably have reactivated M. bovis, which was acquired in endemic countries. The case of the child without a travel history may be suggestive of human-to-human transmission.
Clinicians should suspect M. bovis in patients who are from endemic regions,younger, immunocompetent and present with extrapulmonary granulomatous disease. Continued surveillance for this organism is important given intrinsic resistance to PZA in many isolates.
A. Chandra, None.