Molecular epidemiology of a Streptococcus pneumoniae serotype 1 outbreak in a Tunisian jail.

The microbiologic investigations of an outbreak implicating 17 inmates demonstrated the spread of a pneumococcal serotype 1 clone not only in this jail but also in the area of Tunis. This clone, which is fully susceptible to antibiotics but not included in the heptavalent conjugate vaccine, should be closely monitored.