Utility of PCR assays for rapid diagnosis of BCG infection in children.

We report Mycobacterium bovis BCG infection in two children vaccinated with BCG (Tokyo strain) on the first day of life. Their diagnoses were made by biopsy of skin lesions and pus from an anterior chest wall abscess, respectively, yielding a positive culture of mycobacteria fully susceptible to rifampicin, isoniazid and ethambutol, but resistant to pyrazinamide. M. bovis BCG was identified by a negative niacin test, absence of nitrate reductase and resistance to pyrazinamide and cycloserine. The diagnoses were further confirmed by a combination of an allele-specific polymerase chain reaction ated strain of Mycobacterium bovis, is the only available vaccine for the prevention of tuberculosis. Although complications are rare after BCG vaccination and the outcome is usually favourable, serious BCG infections can occur. We report two cases of M. bovis BCG infection in children, a 4-year-old immunocompetent girl and an 8-month-old immunodeficient boy. To our knowledge, this is the first report of BCG complications in children in which two recently developed polymerase chain reaction (PCR) based methods were used for rapid identification of M. bovis BCG infection. (PCR) and a multiplex PCR method. Based on the drug susceptibility results, treatment with rifampicin, isoniazid and ethambutol was instituted. One patient (Case 1) improved clinically and is well after treatment. However, the other patient with severe combined immunodeficiency died of disseminated BCG infection in spite of intensive anti-tuberculosis therapy. Although BCG is considered to be a safe vaccine, it should be kept in mind that complications related to BCG do occur.