Featured Research

from universities, journals, and other organizations

Wet breathing system filters transmit harmful bacteria and yeast, hospitals warned

Date:
July 12, 2010
Source:
Wiley - Blackwell
Summary:
UK doctors have highlighted potential problems with the breathing system filters used in anesthesia, including intensive care units, after demonstrating that they don’t provide protection from harmful bacteria and yeast when they become wet. A new study shows that when they were wet, six commonly available filters allowed substantial passage of Candida albicans (a yeast infection linked to a range of chronic illnesses) and coagulase-negative staphylococci (a common hospital-acquired bacterial infection).

Doctors have highlighted potential problems with the breathing system filters used in anaesthesia, including intensive care units, after demonstrating that they don't provide protection from harmful bacteria and yeast when they become wet.

Research in the July issue of Anaesthesia has shown that when they were wet, six commonly available filters allowed substantial passage of Candida albicans (a yeast infection linked to a range of chronic illnesses) and coagulase-negative staphylococci (a common hospital-acquired bacterial infection).

"Breathing systems filters are commonly used to reduce the passage of drug-resistant respiratory infections, but current international standards only require them to prevent bacterial transfer when dry," explains Dr David H T Scott, Consultant Cardiothoracic Anaesthetist and Intensive Care Specialist at the Royal Infirmary of Edinburgh, UK.

"The current ISO standard does not replicate the circumstances in clinical practice, where filters get wet with condensed water and airway secretions. We believe that our study shows that commonly available breathing filters cannot be relied upon to prevent bacterial transfer."

The researchers used six breathing system filters available in hospitals in Edinburgh:

  • three hydrophobic pleated filters designed for use as heat and moisture exchanging filters (PhobA, PhobB and PhobC)
  • one hydrophilic unpleated heat and moisture exchanging filter (PhilD)
  • two simple filters (FilE and FilF).

These were tested using suspensions of two microbes:

  • Candida albicans, because of its large cell unit size (12 micrometres)
  • coagulase staphylococcus, because it is a common organism and its cell unit size (one micrometre) is representative of a large range of potential pathogens.

"All the filters tested permitted substantial passage of bacteria and yeast" says Dr Scott. "Even in a one microlitre loop of filtered solution, the number of colony-forming units transmitted through the filters was too large to quantify.

"In most cases the bacterial cultures from filters could not be distinguished from the samples created using unfiltered bacteria."

The authors conclude that their study shows that viable organisms pass across all types of breathing systems filters tested under conditions that may occur in clinical practice.

"In particular, simple filters required very little pressure to permit passage of microorganisms," says Dr Scott. "Although our experiment involved saturating the filters with test fluid, it provides important proof of the principle: organisms may traverse some filters very easily and even large yeasts like Candida albicans survive the passage."

The authors are keen to point out that, although they tested six commonly available filters, the structure of gas filters suggest that products made by other manufacturers are just as likely to show the problem.

"It is important that clinicians are aware of the potential for microorganisms to pass through wet filters," says Dr Scott.

"Further studies are also required to investigate the potential for cross-contamination between patients if filters are used as the sole method of infection control in breathing systems for anaesthesia and intensive care.

"It should be pointed out that a microbe would have to make a long journey to infect a new patient by this route. Although a search of previous studies has revealed no evidence of cross-contamination relating to filter use, it could be theoretically possible in certain conditions."


Story Source:

The above story is based on materials provided by Wiley - Blackwell. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. H. T. Scott, S. Fraser, P. Willson, G.B. Drummond, J.K. Baillie. Passage of pathogenic microorganisms through breathing system filters used in anaesthesia and intensive care. Anaesthesia, 2010; DOI: 10.1111/j.1365-2044.2010.06327.x

Cite This Page:

Wiley - Blackwell. "Wet breathing system filters transmit harmful bacteria and yeast, hospitals warned." ScienceDaily. ScienceDaily, 12 July 2010. <www.sciencedaily.com/releases/2010/07/100706082056.htm>.
Wiley - Blackwell. (2010, July 12). Wet breathing system filters transmit harmful bacteria and yeast, hospitals warned. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2010/07/100706082056.htm
Wiley - Blackwell. "Wet breathing system filters transmit harmful bacteria and yeast, hospitals warned." ScienceDaily. www.sciencedaily.com/releases/2010/07/100706082056.htm (accessed April 17, 2014).

Share This



More Health & Medicine News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
Powered by NewsLook.com
Formerly Conjoined Twins Released From Dallas Hospital

Formerly Conjoined Twins Released From Dallas Hospital

Newsy (Apr. 16, 2014) Conjoined twins Emmett and Owen Ezell were separated by doctors in August. Now, nearly nine months later, they're being released from the hospital. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins