title: 1,2,4-Triazolidine-3-thiones Have Specific Activity against Acinetobacter baumannii among Common Nosocomial Pathogens.
abstract: Acinetobacter baumannii are Gram-negative bacilli that pose a constant threat to susceptible patients because of increased resistance to multiple antibiotics and persistence in the hospital environment. After genome analysis, we discovered that A. baumannii harbors genes that share homology to an enzymatic pathway that elongates long-chain fatty acids (LCFA) in fungi. Previously, 1,2,4-triazolidine-3-thiones (T-3-Ts) were shown to inhibit hyphae production in fungi, and this same LCFA elongation pathway was implicated as the possible target. Therefore, we investigated if T-3-Ts also have activity against multidrug-resistant A. baumannii. Surprisingly, all of the clinical isolates of A. baumannii that were tested have susceptibility to ECC145 and ECC188 with MIC90values of 8.0 μg/mL. In contrast, reference strains and clinical isolates of other common nosocomial bacteria that lack the LCFA pathway also lacked susceptibility. Time-kill experiments revealed that both ECC145 and ECC188 have a bacteriostatic effect against A. baumannii. Mass spectrometry analysis suggested that exposure to T-3-Ts resulted in less LCFA production. Supplementation of media with either 0.02% w/v oleic or linoleic acid abrogated the bacteriostatic effect of the compounds, which again implicated LCFA elongation as the target. Our results suggest these molecules could be a promising start to further exploit what appears to be an important aspect of A. baumannii membrane function and integrity.
authors.affiliation: Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research , Silver Spring, Maryland 20910, United States.
authors.forename: Brendan W
authors.initials: BW
authors.lastname: Corey
authors.affiliation: Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research , Silver Spring, Maryland 20910, United States.
authors.forename: Mitchell G
authors.initials: MG
authors.lastname: Thompson
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry , Baltimore, Maryland 21201, United States.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Hittle
authors.affiliation: Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research , Silver Spring, Maryland 20910, United States.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Jacobs
authors.affiliation: Department of Veterinary Medicine, Walter Reed Army Institute of Research , Silver Spring, Maryland 20910, United States.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Asafo-Adjei
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8024, United States.
authors.forename: William M
authors.initials: WM
authors.lastname: Huggins
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8024, United States.
authors.forename: Roberta J
authors.initials: RJ
authors.lastname: Melander
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8024, United States.
authors.forename: Christian
authors.initials: C
authors.lastname: Melander
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry , Baltimore, Maryland 21201, United States.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Ernst
authors.affiliation: Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research , Silver Spring, Maryland 20910, United States.
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Zurawski
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects*; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D055808:Drug Discovery; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D013844:Thiazoles / Q000737:chemistry / Q000494:pharmacology*; D014230:Triazoles / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; C543723:ECC 145; C543724:ECC 188; D013844:Thiazoles; D014230:Triazoles
keywords: ESKAPE pathogens; Gram-negative membrane; antibacterial; antibiotic; fatty acids; fungi