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Dr. Jorge Vidal’s Research

In the Vidal laboratory, we study the molecular pathogenesis of Streptococcus pneumoniae (pneumococcus), the molecular epidemiology of pneumococcal disease, and we are engaged in studies of acquisition of antibiotic resistance.

My laboratory demonstrated that a QS system, LuxS/AI-2, was required for the pneumococcus to form biofilms on abiotic surfaces. The need of a life-like system encouraged us to design and characterize a bioreactor that mimics pneumococcal colonization of the human airways. The bioreactor allowed us to further demonstrate that both the LuxS-AI-2 and Com QS systems, this latter controls DNA release/uptake in pneumococci and other streptococci, are required for biofilm formation on human pharyngeal and lung cells. Recent breakthrough findings with collaborators described the receptor for CSP (i.e., the pheromone switching on Com) in mast human cells thereby fine-tuning a very specific immune response.

We have learned the last few years, through studies of pneumococcal biofilm consortia on human pharyngeal cells, that Spn strains regulate their density in the nasopharynx. An increased nasopharyngeal density is a risk to develop pneumococcal disease and, therefore, an important topic of study. While studying biofilm colonization, we came across with a very interesting phenomenon leading us to demonstrate that acquisition of resistance by pneumococcal strains occurs at a high frequency within nasopharyngeal biofilms and that some recipient strains “forces” unidirectional transformation occurs. The molecular basis of this unidirectional transformation is under study in the Vidal laboratory.

My laboratory, along with the CDC and international collaborators, has been developing molecular reactions to detect and quantify S. pneumoniae strains and its more than 98 serotypes. We have developed molecular technology and high-throughput platforms, including a TaqMan array card that we named “PneumoTAC”. This technology allows us to assistant Phase III clinical trials of new antibiotics, to participate in vaccine effectiveness studies, and molecular epidemiology of pneumococcal carriage and disease.