Post-Vaccination Disseminated Bacillus Calmette Guerin Infection Among Children in Southern Iran.

BACKGROUND Disseminated bacillus calmette guerin (BCG) infection is a rare but life threatening complication of BCG vaccination. It has been mainly seen in severe immune deficiency. A precise and rapid diagnosis is crucial for prompt initiation of an aggressive anti-mycobacterial treatment. Polymerase chain reaction (PCR) is directly applicable to smear-positive clinical specimens, proven to be a rapid and specific diagnostic test. OBJECTIVES The aim of this study was to investigate disseminated BCG infection among 34 children in southern Iran, mainly confirmed by PCR. PATIENTS AND METHODS We included all the patients hospitalized with disseminated BCG infection at a referral teaching hospital in southern Iran between years 1990 and 2007. The clinical and laboratory data including the immunological workups were obtained through a review of the medical files. We recalled all pathology samples from pathology specimen banks and used an in-house PCR specific for Mycobacterium bovis BCG substrain to confirm the diagnosis. RESULTS From the total of 34 children hospitalized with disseminated BCG infection, 21 were categorized as definite and 13 probable. Thirty-one patients (91%) were under two years of age and 41% were male. The most common clinical findings were fever in 31 (91.2%), axillary's lymphadenopathy in 26 (76.5%), hepatosplenomegaly in 25 (73.5%), stunted growth in 21 (61.8%), and distant lymphadenopathy in 16 (47.1%). Polymerase Chain Reaction positivity rate was 100% (9 of 9) in bone marrow smear slides and 84.2% (16 of 19) for formalin-fixed and paraffin-embedded tissue specimens. Immunodeficiency state was detected in 50% and the overall mortality rate was 58.8% (20 of 34). CONCLUSIONS Disseminated BCG infection should be considered in the differential diagnosis of infants and young children with fever, hepatosplenomegaly, lymphadenopathy, and history of BCG vaccination. The PCR method has a high positivity rate and can serve as a useful tool for the rapid and specific identification of M. bovis BCG substrain infection.