Induction of the macrolide-resistance efflux pump Mega inhibits intoxication of Staphylococcus aureus strains by Streptococcus pneumoniae

Dissemination of Tn 916 -Related Integrative and Conjugative Elements in Streptococcus pneumoniae Occurs by Transformation and Homologous Recombination in Nasopharyngeal Biofilms

“…We found that >20-kb Tn 916 -related ICEs horizontally disseminate at high frequencies between S. pneumoniae in dual-strain biofilms (rF of 10 −4 ) established on a human nasopharyngeal cell monolayer and in a continuous flow bioreactor system, which mimics the microenvironment of the human respiratory epithelium. Previous work using the bioreactor has shown high rFs for the exchange of smaller antibiotic resistance determinants between S. pneumoniae strains ( 20 , 45 ).…”

Ultrastructural, metabolic and genetic determinants of the acquisition of macrolide resistance byStreptococcus pneumoniae

“…pneumoniae occurs in the bioreactor and that it is facilitated by the transformation machinery 19,20 . We therefore sought to compare, under the same culture conditions of the bioreactor, the rF for the acquisition of macrolide resistance encoded in genetic elements of varying sizes (∼1, ∼5.5, ∼23.5, or ∼51 kb).…”

“…This hypothesis was based on the observation that conjugative insertion of Tn 2009 or Tn 2010 in Spn strains were infrequent 28, 29 , that in vitro conjugation assays has been unsuccessful to generate transconjugants 26, 30 or that the conjugative transference of Tn 916 or Tn 916 -related ICEs, when it has been observed, it has occurred at a low (<10 -6 ) conjugation frequency 37 . In recent years, we developed in our laboratories a life-like bioreactor system that facilitates the natural transference of mutation-mediated resistance 15 , as well as macrolide resistance carried in ICEs among Spn strains 19, 20 . Using the bioreactor system, we demonstrated that the transformation machinery, specifically the Com system, facilitates the acquisition of MEGA, carried in Tn 916 -related elements, at a recombination frequency (rF) as high as 10 -3 .…”

“…We and others have demonstrated that pneumococcal strains form biofilm consortia on abiotic surfaces as well as on human nasopharyngeal cells [15][16][17][18] . Furthermore, human nasopharyngeal cells, cultivated in a bioreactor system, facilitated the swift, nature-like acquisition of antibiotic resistance genes between two Spn strains with a high recombination frequency (rF) 15,19,20 .…”