Stability and activity in sputum of G10KHc, a potent anti-Pseudomonas antimicrobial peptide
4区 · 医学
作者: Eckert, Randal ; McHardy, Ian ; Yarbrough, Daniel K. ; He, Jian ; Qi, Fengxia ; Anderson, Maxwell H. ; Shi, Wenyuan
G10KHc, a specifically targeted antimicrobial peptide developed in our laboratory, has shown rapid and selective killing activity against Pseudomonas aeruginosa in culture medium. Because of the major role played by this pathogen in cystic fibrosis, we sought to evaluate the utility of G10KHc under more physiologic conditions in vitro. In the current study, we found that robust G10KHc activity could be maintained in expectorated sputum if serine protease-dependent digestion associated with this fluid was inhibited, either by chemical antagonists or by the construction of a D-amino acid enantiomer of G10KHc. Further investigations revealed that specifically targeted antimicrobial peptide activity in sputum could be further enhanced when samples were treated with a combination of peptide and recombinant human DNase. Our results illustrate the importance of investigating combination therapy to treat cystic fibrosis, especially if protease-sensitive peptide-based agents, such as G10KHc, are to be developed as alternatives to, or in conjunction with, conventional small-molecule antibiotics.
2006-11-01·Antimicrobial Agents and Chemotherapy2区 · 医学
Enhancement of antimicrobial activity against Pseudomonas aeruginosa by coadministration of G10KHc and tobramycin
2区 · 医学
作者: Eckert, Randal ; Brady, Keith M. ; Greenberg, E. Peter ; Qi, Fengxia ; Yarbrough, Daniel K. ; He, Jian ; McHardy, Ian ; Anderson, Maxwell H. ; Shi, Wenyuan
Pseudomonas aeruginosa is a common opportunistic human pathogen that is associated with life-threatening acute infections and chronic airway colonization during cystic fibrosis. Previously, we converted the wide-spectrum antimicrobial peptide novispirin G10 into a selectively-targeted antimicrobial peptide (STAMP), G10KHc. Compared to novispirin G10, the STAMP had an enhanced ability to kill Pseudomonas mendocina. In this study, we explored the activity of G10KHc against P. aeruginosa. G10KHc was found to be highly active (as active as tobramycin) against P. aeruginosa clinical isolates. Most interestingly, we observed a synergistic-like enhancement in killing activity when biofilms and planktonic cultures of P. aeruginosa were cotreated with G10KHc and tobramycin. The data indicate that the mechanism of enhanced activity may involve increased tobramycin uptake due to G10KHc-mediated cell membrane disruption. These results suggest that G10KHc may be useful against P. aeruginosa during acute and chronic infection states, especially when it is coadministered with tobramycin.
2006-04-01·Antimicrobial Agents and Chemotherapy2区 · 医学
Adding selectivity to antimicrobial peptides: rational design of a multidomain peptide against Pseudomonas spp
2区 · 医学
作者: Eckert, Randal ; Qi, Fengxia ; Yarbrough, Daniel K. ; He, Jian ; Anderson, Maxwell H. ; Shi, Wenyuan
Currently available antimicrobials exhibit broad killing with regard to bacterial genera and species. Indiscriminate killing of microbes by these conventional antibiotics can disrupt the ecological balance of the indigenous microbial flora, often resulting in negative clinical consequences. Species-specific antimicrobials capable of precisely targeting pathogenic bacteria without damaging benign microorganisms provide a means of avoiding this problem. In this communication, we report the successful creation of the first synthetic, target-specific antimicrobial peptide, G10KHc, via addition of a rationally designed Pseudomonas-specific targeting moiety (KH) to a generally killing peptide (novispirin G10). The resulting chimeric peptide showed enhanced bactericidal activity and faster killing kinetics against Pseudomonas spp. than G10 alone. The enhanced killing activities are due to increased binding and penetration of the outer membrane of Pseudomonas sp. cells. These properties were not observed in tests of untargeted bacterial species, and this specificity allowed G10KHc to selectively eliminate Pseudomonas spp. from mixed cultures. This work lays a foundation for generating target-specific "smart" antimicrobials to complement currently available conventional antibiotics.