Antibiotic resistance in pneumococcus

Antibiotic resistance is pervasive among bacterial pathogens. Simple theoretical models suggest that drug-resistant strains of common pathogens like pneumococcus should, under most circumstances, outcompete drug-sensitive strains. This is not what we observe. With Marc Lipsitch (Harvard School of Public Health), Caroline Colijn (Imperial College London), and Christophe Fraser (Imperial College London), we are evaluating several hypotheses to explain the persistence of drug-sensitive strains.