The many faces of human-to-human transmission of brucellosis: Congenital infection and outbreak of nosocomial disease related to an unrecognized clinical case

Background. Because person-to-person transmission of brucellosis is exceptional, physicians who care for patients with this disease are not considered to be at increased risk. A woman in her 24th week of pregnancy who had received a diagnosis of placenta previa presented to the hospital with massive vaginal bleeding and hypovolemic shock, requiring performance of an emergency Cesarean delivery. Two physicians who assisted the surgical delivery developed culture-proven Brucella melitensis infection. The organism was also recovered from cultures of blood samples obtained from the mother and the premature newborn. The mother had been observed since early pregnancy because of an undiagnosed febrile hepatitis, but no specific tests for brucellosis had been performed. Retrospective testing of serum samples obtained at the onset of disease were positive for Brucella antibodies, indicating that the disease could have been diagnosed earlier. Methods. Hospital records of the obstetric, intensive care, and surgical departments were examined to identify all staff members who took care of the mother and her offspring. The identified personnel were interrogated about exposure to potentially infective blood and fomites and were screened by blood cultures and serologic tests for Brucella species. Results. An additional physician who assisted in the resuscitation of the newborn had a blood culture positive for B. melitensis and a positive result of a diagnostic serological test. Ninety-five other members of the hospital staff, who were potentially exposed to the organism, were found to be uninfected. Conclusions. Although rare, transmission of B. melitensis from patients to medical personnel may occur. Strict adherence to universal precautions, especially during performance of medical procedures characterized by massive blood exposure, should be reinforced.