Fig 3 (IMAGE) Osaka University Caption Interplay between the efflux pumps and porins from E. coli and H. influenzae. AcrB efflux pumps can actively transport antibiotics out of the periplasm and cytoplasm of bacterial cells, rendering them ineffective. AcrB-Ec can also export bile salts, which are present in the enteric environment where E. coli is found. In comparison, AcrB-Hi showed only weak export of bile salts. Additionally, the efflux pump inhibitor ABI-PP did not affect AcrB-Hi but completely inhibited the efflux ability of AcrB-Ec. The wide OmpP2 outer-membrane porin from H. influenzae leaks small and elongated antibiotics such as β-lactams and novobiocin back into the cells, making Hib cells sensitive to these antibiotics. Credit Osaka 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.