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Polymyxin E Induces Rapid Paenibacillus polymyxa Death by Damaging Cell Membrane while Ca2+ Can Protect Cells from

Zhiliang Yu1, Yuanning Cai1, Wangrong Qin1

  • 1College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China.

Plos One
|August 8, 2015
PubMed

Insights

Polymyxin E kills its producer, Paenibacillus polymyxa, by damaging its cell membrane. Divalent cations, especially calcium, protect against this damage, explaining limited antibiotic production.

Area of Science:

  • Microbiology
  • Bacteriology
  • Antibiotic Resistance

Background:

  • Polymyxin E is a crucial antibiotic effective against Gram-negative bacteria.
  • Its producer, Paenibacillus polymyxa, is a Gram-positive bacterium.
  • The self-toxicity mechanism of Polymyxin E has not been previously described.

Purpose of the Study:

  • To investigate the bactericidal mechanism of Polymyxin E against its producer, P. polymyxa.
  • To explore the protective role of divalent cations against Polymyxin E-induced cell damage.
  • To elucidate the reasons for limited Polymyxin E fermentation by P. polymyxa.

Main Methods:

  • Assessing intracellular molecule leakage to detect membrane damage.
  • Utilizing scanning electron microscopy to visualize cell surface alterations.
  • Evaluating the protective effects of magnesium and calcium ions on P. polymyxa survival.

Main Results:

  • Polymyxin E disrupts the cell membrane of P. polymyxa, leading to cell death.
  • Scanning electron microscopy confirmed extensive cell membrane damage and surface alterations.
  • Divalent cations, particularly Ca2+, significantly protected P. polymyxa from Polymyxin E toxicity.

Conclusions:

  • Polymyxin E exhibits a novel bactericidal mechanism against Gram-positive bacteria, including its producer.
  • The protective effect of divalent cations explains the limited fermentation output of Polymyxin E.
  • This study provides insights into antibiotic self-toxicity and production regulation.

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