Mycoplasma pneumoniae : Bacterial genetic variation and colonization of the respiratory tract of children

M. pneumoniae is regarded as a common cause of community acquired pneumonia. We posed the hypothesis that M. pneumoniae is able to colonize the human respiratory tract and, assuming that our hypothesis could be confirmed, we also set out to study whether possible asymptomatic carriage could be distinguished from infection. In the first part of the thesis we described the findings of bacterial genetic variation. M. pneumoniae subtype 1 and 2 strains represent genetically distinct lineages with a high potential for homologous DNA recombination. The second part of the thesis describes the prevalence of M. pneumoniae detected by PCR, which is just as high in symptomatic as in asymptomatic children but changes over time and season. The M. pneumoniae strains found in asymptomatic and symptomatic children do not seem to differ genetically. In the Netherlands we have not found Macrolide resistant M. pneumoniae strains. Finally the consequences of the findings in this thesis are described and we discuss that diagnostic tests for an alleged M. pneumoniae respiratory tract infection should be interpreted with caution