title: Transmission electron microscopic morphological study and flow cytometric viability assessment of Acinetobacter baumannii susceptible to Musca domestica cecropin.
abstract: Multidrug-resistant (MDR) Acinetobacter baumannii infections are difficult to treat owing to the extremely limited armamentarium. Expectations about antimicrobial peptides' use as new powerful antibacterial agents have been raised on the basis of their unique mechanism of action. Musca domestica cecropin (Mdc), a novel antimicrobial peptide from the larvae of Housefly (Musca domestica), has potently active against Gram-positive and Gram-negative bacteria standard strain. Here we evaluated the antibacterial activity of Mdc against clinical isolates of MDR-A. baumannii and elucidate the related antibacterial mechanisms. The minimal inhibitory concentration (MIC) of Mdc was 4 μg/mL. Bactericidal kinetics of Mdc revealed rapid killing of A. baumannii (30 min). Flow cytometry using viability stain demonstrated that Mdc causes A. baumannii membrane permeabilization in a concentration- and time-dependent process, which correlates with the bactericidal action. Moreover, transmission electron microscopic (TEM) examination showed that Mdc is capable of disrupting the membrane of bacterial cells, resulting in efflux of essential cytoplasmic components. Overall, Mdc could be a promising antibacterial agent for MDR-A. baumannii infections.
authors.affiliation: Intensive Care Unit, Shenzhen Second People's Hospital, Shenzhen, Guangdong 518031, China.
authors.forename: Shuiqing
authors.initials: S
authors.lastname: Gui
authors.affiliation: Department of General Surgery, Xixiang People's Hospital, Shenzhen, Guangdong 518102, China.
authors.forename: Rongjiang
authors.initials: R
authors.lastname: Li
authors.affiliation: Intensive Care Unit, Shenzhen Second People's Hospital, Shenzhen, Guangdong 518031, China.
authors.forename: Yongwen
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Vascular Surgery, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, China.
authors.forename: Sanming
authors.initials: S
authors.lastname: Wang
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000648:ultrastructure; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D054807:Cecropins / Q000494:pharmacology*; D005434:Flow Cytometry; D019476:Insect Proteins / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054807:Cecropins; D019476:Insect Proteins; C000595275:cecropin protein, Musca domestica