Comparison between Patients with Chest Infection due to Klebsiella spp. and Streptococcus pneumoniae

OBJECTIVE: In Japan, the aging demographic structure is becoming pronounced, and the full-blown graying of society appears not far off, which indicates an increasing population that will require healthcare contact. Klebsiella spp. are major pathogens in healthcare-associated infections, and their importance is increasing. The aim of this study was to clarify the characteristics of Klebsiella spp. chest infections by evaluating the differences in the characteristics of chest infections caused by Klebsiella spp. and pneumoniae. METHODS: We conducted a retrospective study of consecutive patients hospitalized with pneumonia, lung abscess/necrotizing pneumonia, and empyema due to Klebsiella spp. and S. pneumoniae for 15 years at our institution in Saitama, Japan. PATIENTS: Patients with chest infections due to Klebsiella spp. (K group, n=76) and S. pneumoniae (S group, n=446) were included. RESULTS: The K group more frequently was male, older, coinfected by Pseudomonas aeruginosa, and had diabetes mellitus, a history of upper digestive system surgery, alcohol drinking habit, a smoking habit, and an impaired premorbid performance status than the S group. The percentages of lung abscesses or necrotizing pneumonia (31.6% vs. 0.9%) and empyema without pulmonary parenchymal shadow (3.9% vs. 0.7%) were higher in the K group than those in the S group. Severity on admission and mortality did not differ between the groups; however, patients in the K group required a longer duration of antibiotics administration and hospital stay than those in the S group. CONCLUSION: Klebsiella spp. chest infections have some marked characteristics when compared with pneumococcal infections, and our results serve to differentiate Klebsiella spp. infection from pneumococcal infection.