Applied Microbiology and Biotechnology

, Volume 95, Issue 4, pp 939–945

Bactericidal activity of Musca domestica cecropin (Mdc) on multidrug-resistant clinical isolate of Escherichia coli

  • X. Lu
  • J. Shen
  • X. Jin
  • Y. Ma
  • Y. Huang
  • H. Mei
  • F. Chu
  • J. Zhu
Biotechnologically relevant enzymes and proteins

DOI: 10.1007/s00253-011-3793-2

Cite this article as:
Lu, X., Shen, J., Jin, X. et al. Appl Microbiol Biotechnol (2012) 95: 939. doi:10.1007/s00253-011-3793-2

Abstract

The housefly (Musca domestica) larvae have been used clinically to cure osteomyelitis, decubital necrosis, lip boil, ecthyma and malnutritional stagnation ever since the Ming/Qing Dynasty (1368 Anno Domini) till now, in China. In prior research, we have cloned and characterized a new gene of antimicrobial peptide cecropin from M. domestica larvae. This peptide was potently active against Gram-positive and Gram-negative bacteria standard strain. In the present study, we evaluated the possibility of Mdc to be a potential bactericidal agent against clinical isolates of multidrug-resistant (MDR) Escherichia coli and to elucidate the related antimicrobial mechanisms. Antimicrobial activity assays indicated a minimal inhibitory concentration (MIC) of 1.56 μM. Bactericidal kinetics at MIC showed that Mdc rapid killing of MDR E. coli. Lipopolysaccharide (LPS) dose-dependently suppressed Mdc antibacterial potency indicates that LPS is the initial binding site of Mdc in E. coli. Propidium iodide-based flow cytometry revealed that Mdc causes E. coli membrane permeabilization. Transmission electron micrographs further indicated that a remarkable damage in the bacteria’s outer and inner membrane, even the leakage of cytoplasmic contents induced by Mdc. DNA binding experimental result implies that DNA is one of the possible intracellular targets of Mdc. Of note, Mdc did not show a perceptible cytotoxic effect on human red blood cells. Altogether, these results suggest that Mdc could be an excellent candidate for the development of more efficacious bactericidal agents.

Keywords

Musca domestica cecropinMultidrug resistantFlow cytometryTransmission electronLipopolysaccharide

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • X. Lu
    • 1
    • 2
  • J. Shen
    • 1
    • 2
  • X. Jin
    • 1
  • Y. Ma
    • 1
    • 2
  • Y. Huang
    • 1
  • H. Mei
    • 1
  • F. Chu
    • 1
    • 2
  • J. Zhu
    • 1
  1. 1.Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive SubstancesGuangdong Pharmaceutical UniversityGuangzhouChina
  2. 2.School of Public Health and Tropical MedicineSouthern Medical UniversityGuangzhouChina