About the Authors

Luis J. Cocka
Paul Bates

pbates@mail.med.upenn.edu

Affiliation Department of Microbiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: LJC PB. Performed the experiments: LJC. Analyzed the data: LJC PB. Wrote the paper: LJC PB.