Ultrastructural, metabolic and genetic characteristics of determinants facilitating the acquisition of macrolide resistance by Streptococcus pneumoniae.

Aims: To investigate the molecular events associated with acquiring macrolide resistance genes [mefE/mel (Mega) or ermB] in Streptococcus pneumoniae (Spn) during nasopharyngeal colonization.

Methods And Results: Genomic analysis of 128 macrolide-resistant Spn isolates revealed recombination events in genes of the conjugation apparatus, or the competence system, in strains carrying Tn916-related elements. Studies using confocal and electron microscopy demonstrated that during the transfer of Tn916-related elements in nasopharyngeal cell biofilms, pneumococcal strains formed clusters facilitating their acquisition of resistance determinants at a high recombination frequency (rF).

Ultrastructural, metabolic and genetic determinants of the acquisition of macrolide resistance by .

Aim: (Spn) acquires genes for macrolide resistance, MEGA or , in the human host. These genes are carried either in the chromosome, or on integrative conjugative elements (ICEs). Here, we investigated molecular determinants of the acquisition of macrolide resistance.