Que devraient savoir les cliniciens au sujet de la microbiologie des pneumocoques ?

Pneumococci, encapsulated Gram-positive cocci whose polysaccharidic capsule is a key factor in their virulence, are aerotolerant anaerobic micro-organisms that require specific growth conditions. S. pneumoniae is a transformable species with a highly plastic genome. In the nasopharynx, in contact with other streptococci such as S. mitis or S. oralis, it is the key to numerous interspecifictransfers of genetic material, contributing to capsule diversification and protein modifications, including penicillin-binding proteins (PLPs). Molecular identification methods, which are more sensitive than conventional diagnostic methods, aim to detect one or more pneumococcal-specific genes (pneumolysin, autolysin, part of the capsule, etc.). The specificity of these molecular investigation methods increases with the number of genes targeted. © 2024 The Author(s). Published by Elsevier Masson SAS.