title: Gene-silencing antisense oligomers inhibit acinetobacter growth in vitro and in vivo.
abstract: BACKGROUND
  Peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) are synthetic DNA/RNA analogues that silence expression of specific genes. We studied whether PPMOs targeted to essential genes in Acinetobacter lwoffii and Acinetobacter baumannii are active in vitro and in vivo.
  
  
  METHODS
  PPMOs were evaluated in vitro using minimum inhibitory concentration (MIC) and viability assays, and in vivo using murine pulmonary infection models with intranasal PPMO treatment.
  
  
  RESULTS
  MICs of PPMOs ranged from 0.1 to 64 µM (approximately 0.6-38 µg/mL). The most effective PPMO tested was (RXR)4-AcpP, which is targeted to acpP. (RXR)4-AcpP reduced viability of A. lwoffii and A. baumannii by >10(3) colony-forming units/mL at 5-8 times MIC. Mice treated with ≥0.25 mg/kg of (RXR)4-AcpP survived longer and had less inflammation and bacterial lung burden than mice treated with a scrambled-sequence PPMO or phosphate-buffered saline. Treatment could be delayed after infection and still increase survival.
  
  
  CONCLUSIONS
  PPMOs targeted to essential genes of A. lwoffii and A. baumannii were bactericidal and had MICs in a clinically relevant range. (RXR)4-AcpP increased survival of mice infected with A. lwoffii or A. baumannii, even when initial treatment was delayed after infection. PPMOs could be a viable therapeutic approach in dealing with multidrug-resistant Acinetobacter species.
authors.affiliation: Department of Microbiology, Oregon State University.
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Geller
authors.forename: Kimberly
authors.initials: K
authors.lastname: Marshall-Batty
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Schnell
authors.forename: Mattie M
authors.initials: MM
authors.lastname: McKnight
authors.forename: Patrick L
authors.initials: PL
authors.lastname: Iversen
authors.forename: David E
authors.initials: DE
authors.lastname: Greenberg
mesh_terms: D000150:Acinetobacter / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D000151:Acinetobacter Infections / Q000382:microbiology / Q000401:mortality / Q000628:therapy; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004195:Disease Models, Animal; D005260:Female; D020868:Gene Silencing; D051379:Mice; D008826:Microbial Sensitivity Tests; D060172:Morpholinos / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics*; D018410:Pneumonia, Bacterial / Q000382:microbiology / Q000401:mortality / Q000628:therapy
chemical_list: D000900:Anti-Bacterial Agents; D060172:Morpholinos; D016376:Oligonucleotides, Antisense
keywords: Acinetobacter; MIC; PPMO; antisense; baumannii; infection; lwoffii; mouse; phosphorodiamidate morpholino oligomer; respiratory infection