K. pneumoniae colonizes the colon in 5-35% of healthy individuals and, from a medical standpoint, is the most important Klebsiella species. K. oxytoca primarily causes infections in long-term care and hospital settings. K. pneumoniae subspecies rhinoscleromatis, which causes rhinoscleroma, and K. pneumoniae subspecies ozaenae, which causes chronic atrophic rhinitis, infect pts in tropical climates.