Antibiotic 1 (IMAGE) Rice University Caption This chart shows how quickly resistance to tigecycline, an antibiotic, spread through a population of Enterococcus faecalis bacteria that was exposed to increasing tigecycline concentrations over the course of 24 days in experiments at Rice University. A mutation in the ribosomal S10 protein quickly reached 100 percent frequency in the population (A). Next, a mutation leading to TetM overexpression occurred in Tn916 (B) and subsequently spread through the population by increased Tn916 horizontal gene transfers (C and D). The dashed lines show instances when Tn916 conjugation likely occurred. Credit Kathryn Beabout/Rice University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.