Hyperbaric oxygen suppresses growth of Klebsiella pneumoniae and enhances effect of tigecycline in vitro

OBJECTIVES: (1) To examine whether hyperbaric oxygen (HBO₂) will inhibit growth of multidrug-resistant Klebsiella pneumoniae (MDR-K. pneumoniae) and extensively drug-resistant Klebsiella pneumoniae (XDR-K. pneumoniae); (2) To determine whether the effect of tigecycline on XDR-K. pneumoniae will be enhanced by HBO₂. METHODS: The effects of 1.5 hours of treatment with normoxia (21% O₂, 1 atmosphere absolute/ATA) or HBO₂ (100% O₂, 2 ATA) on bacterial counts of eight isolates of MDR-K. pneumoniae and eight isolates of XDR-K. pneumoniae were studied. The effects of five hours of treatment with normoxia (21% O₂, 1 ATA), tigecycline (21% O₂, 1 ATA), HBO₂ (100% O₂, 3 ATA) or HBO₂ + tigecycline (100% O₂, 3 ATA) on proliferation of 10 isolates of XDR-K. pneumoniae were investigated. RESULTS: HBO₂ at 100% O₂, 2 ATA, 1.5 hours suppressed growth of MDR-K. pneumoniae but had no effect on XDR-K. pneumoniae. HBO₂ at 100% O₂, 3 ATA, five hours enhanced the effects of tigecycline on XDR-K. pneumoniae. CONCLUSIONS: HBO₂ in combination with or without tigecycline can be used to eliminate K. pneumoniae in vitro, and such treatment may be beneficial for patients with infections caused by K. pneumoniae.