[Epidemic outbreak of tuberculosis in a primary and secondary school in Granada (Spain)]

To describe the diagnosis and early treatment of an epidemic outbreak of tuberculosis and determine the utility of polymerase chain reaction (PCR) compared with routine culture in gastric juice.

A computer studies teacher, with clinical features suggestive of tuberculosis and caverns on X-ray, was diagnosed with bacilliferous tuberculosis. Primary health care services carried out a Mantoux test on the school's 387 students as well as on teachers and other staff. The children with a positive Mantoux test underwent laboratory, radiological, and microbiological investigations for one week in the Pediatric Respiratory Unit of Hospital Clínico in Granada. In the teaching and non-teaching staff, active tuberculosis was ruled out through bacilloscopy of sputum samples, Mantoux test, and chest X-ray.

In the first screening, the Mantoux test was positive in 67 children. Of these, 7 children were diagnosed with tuberculosis and 60 were found to be infected. Of the 7 children with tuberculosis, five presented positive gastric juice culture in Lowenstein medium while Roche COBAS PCR was negative. In the second screening, 9 children became tuberculin positive. Of these, 8 were diagnosed with tuberculosis and one was infected. Cultures were positive in 3 and PCR was negative. In 77.6 % of the children (59/76), the Mantoux induration was equal to or higher than 18 mm. All of the 15 children with tuberculosis were aged between 9 and 14 years old, except one who was 5 years old.

The Mantoux test remains a basic screening method in diagnosis and epidemiological research, whereas the results of microbiological investigation remain poor and in our study the results DNA were disappointing. The screening of tuberculosis and of other infectious diseases should be more closely monitored in professional groups, such as teachers, that are in contact with large numbers of children. This would identify infected adults and prevent epidemics such as that described in the present study.