Efficacy of calcium-EDTA as an inhibitor for metallo-β-lactamase in a mouse model of Pseudomonas aeruginosa pneumonia.
In this study, we have evaluated the efficacy of calcium-EDTA (Ca-EDTA) as an inhibitor of bacterial metalloenzymes, such as metallo-β-lactamase (MBL) and other proteases, in a mouse model of Pseudomonas aeruginosa pneumonia. The simultaneous presence of Ca-EDTA (32 μg/ml) reduced the MICs of imipenem (IPM) in all MBL-producing P. aeruginosa isolates (IMP-1, -2, -7, and -10 and VIM-2) but not non-MBL-producing strains. In the pneumonia model, mice were intranasally infected with MBL-producing P. aeruginosa and then kept under conditions of hyperoxia to mimic ventilator-associated pneumonia. With both intranasal and subcutaneous administrations, Ca-EDTA significantly potentiated survival benefits of IPM compared to those of IPM alone. Ca-EDTA combination therapy induced a significant reduction of the bacterial burden in the lungs (P < 0.05). Furthermore, the inhibition activity of Ca-EDTA against MBL activity was confirmed by using the purified IMP-1 enzyme, which was characterized by a 50% inhibitory concentration (IC(50)) of 55 ± 8.2 μM. Finally, the protective effects of Ca-EDTA were demonstrated by culture supernatant-induced epithelial cell damage and acute lung injury in mice. These data suggest the therapeutic potential of Ca-EDTA not only by the blocking of MBLs but also by neutralizing tissue-damaging metalloproteases in P. aeruginosa infections.
Aoki
Nobumasa
N
Department of Microbiology and Infectious Diseases, Faculty of Medicine, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143-8540, Japan.
Ishii
Yoshikazu
Y
Tateda
Kazuhiro
K
Saga
Tomoo
T
Kimura
Soichiro
S
Kikuchi
Yoshiaki
Y
Kobayashi
Tetsuo
T
Tanabe
Yoshinari
Y
Tsukada
Hiroki
H
Gejyo
Fumitake
F
Yamaguchi
Keizo
K
D000818:Animals; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000737:chemistry* / Q000627:therapeutic use*; D002118:Calcium / Q000737:chemistry; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004492:Edetic Acid / Q000009:adverse effects / Q000737:chemistry* / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D011014:Pneumonia / Q000188:drug therapy* / Q000382:microbiology*; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D065093:beta-Lactamase Inhibitors
D000900:Anti-Bacterial Agents; D065093:beta-Lactamase Inhibitors; D004492:Edetic Acid; D002118:Calcium