Nitric oxide is better at blocking E.coli growth than silver

Published: 18-Aug-2011

Does not have the drug resistance issues of antibiotics, study finds


Canadian scientists have demonstrated the superior ability of nitric oxide-releasing devices to block growth of E.coli on the surface of medical devices compared with silver-coated catheters.

The paper, Comparative efficacy of commercially available and emerging antimicrobial urinary catheters against E. coli infection in vitro, by Professor Yossef Av-Gay's lab at the University of British Columbia, reports results from an investigation into the ability of four different types of catheters to prevent growth of micro-organisms suspended in fluid medium (planktonic growth) and on the surface of catheters in the form of a biofilm. It is published in the August issue of Urology journal.

The study compared a non-antimicrobial catheter, an Enox nitric oxide releasing catheter, a silver coated catheter and an antibiotic coated catheter.

The research concluded that both the Enox and antibiotic catheters were effective in preventing planktonic growth and biofilm formation, whereas the silver and uncoated catheters were not.

“This study confirms the superiority of nitric oxide as an antimicrobial,” said Professor Av-Gay, president and founder of Enox Biopharma, an emerging Canadian biotechnology company that sequesters nitric oxide into medical devices to make them antimicrobial.

“Silver proved to be as ineffective as a non-antimicrobial catheter, whereas both the Enox and antibiotic catheters were very effective in reducing and eliminating microorganisms.”

He added that Enox's ability to do this without antibiotics is a significant advantage.

Enox's nitric oxide device technology renders medical devices such as catheters and endotracheal tubes antimicrobial by sequestering nitric oxide within them in a stable state.

Nitric oxide, which is released by the device over a period of about 2 weeks once used clinically, is a potent antimicrobial agent without the drug resistance issues that plague antibiotics, the firm says.

John Rewcastle, chief executive of Enox, commented: “Recently published clinical results completely independent of Enox have shown silver not to perform as well as hoped in a clinical setting. The results from the current study substantiate these observations.”

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