title: A Putative ABC Transporter Permease Is Necessary for Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa under Aerobic and Anaerobic Planktonic and Biofilm Conditions.
abstract: Pseudomonas aeruginosa (PA) is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite ([Formula: see text], pH 6.5) at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to [Formula: see text]. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to [Formula: see text], but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with [Formula: see text] plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM [Formula: see text], and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to [Formula: see text] in biofilms. [Formula: see text] sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM) that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, [Formula: see text] as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA.
authors.forename: Cameron
authors.initials: C
authors.lastname: McDaniel
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA.
authors.forename: Shengchang
authors.initials: S
authors.lastname: Su
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA.
authors.forename: Warunya
authors.initials: W
authors.lastname: Panmanee
authors.affiliation: College of Veterinary Medicine, University of Illinois at Urbana-Champaign Urbana, IL, USA.
authors.forename: Gee W
authors.initials: GW
authors.lastname: Lau
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA.
authors.forename: Tristan
authors.initials: T
authors.lastname: Browne
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Cox
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Paul
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA.
authors.forename: Seung-Hyun B
authors.initials: SH
authors.lastname: Ko
authors.affiliation: Diagnostic and Infectious Diseases Testing Laboratory, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA.
authors.forename: Joel E
authors.initials: JE
authors.lastname: Mortensen
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph Guelph, ON, Canada.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Lam
authors.affiliation: Department of Medicine, University of Calgary Calgary, AB, Canada.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Muruve
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of MedicineCincinnati, OH, USA; Department of Research Services, Cincinnati Veteran's Association Medical CenterCincinnati, OH, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hassett
keywords: ABC transporter permease; EDTA; Pseudomonas aeruginosa; acidified nitrite; biofilms