1. Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
2. Department of Microbiology & Plant Pathology and Institute for Integrative Genome Biology, University of California—Riverside, Riverside, California, USA
3. Dartmouth-Hitchcock Medical Center, Section of Pulmonary and Critical Care Medicine, Lebanon, New Hampshire, USA