Tests show that ‘friendly’ bacteria in a simple cleaning fluid can eliminate harmful bacteria
Sean Derrig reports on the results of trial at a London-based NHS Trust
Trials of a natural and cheap alternative to traditional hygiene practices could spawn a new approach to the fight against hospital superbugs, according to UK-based hygiene specialist Chemex International, based in Smethwick, West Midlands.
The firm reported that the unique properties of biofilms could be used in a healthcare setting to exclude clinically significant pathogens as well as producing enzymes to digest dirt, grease and grime.
In its trials, the results of which were reported today (20 September) at a conference of more than 600 members of the Infection Protection Society in Bournemouth, the firm found that replacing traditional cleaning chemicals with a product based on Bacillus subtilis resulted in a visibly cleaner, more hygienic, safer environment.
The trial ran over a three-week period in a single site at a London-based NHS Trust containing a number of staff washrooms.
The normal janitorial products used for daily cleaning were removed and replaced with a product containing B. subtilis.
The strain chosen was selected for its ability to grow over a wide range of physical and chemical conditions and its production of a battery of enzymes for the breakdown of organic matter. These include amylases (for starch), cellulase (for cellulose, plant & vegetable matter), lipases (for fats oils & greases), proteases (for proteins) and uricase (for uric acid).
The replacement product’s active ingredients were a blend of B. subtilis spores at a concentration of 1x108 CFU ml-1 and 3% surfactant. Non-active ingredients included an opacifier, fragrance and buffer.
This concentrated product was automatically diluted 20:1 in a Venturi-based chemical proportioner to assure consistency of dilution.
The dilute solution was used by cleaning staff as both a ‘spray and wipe’ cleaning product as well as for mopping floors. The cleaning frequency, protocols and procedures remained unchanged. The only change to the regime was the substitution of the product used for cleaning.
Staff reported that the washrooms were visibly cleaner and more pleasant to use, and that the malodours that air fresheners had struggled to mask had disappeared.
The overall bacterial load had decreased and the Gram negative species found in the original samples had been completely excluded in under 21 days.
The only other organism detected after treatment was S. aureus in a shower tray drain.
Based on these results, Sean Derrig, scientific director of Chemex International and a co-author of the study, said the efficacy of B. subtilis as a cleaning product is clear cut; it also appears effective at competitively excluding other organisms including those that pose significant challenges in infection control.
“Since the days of Lister and Florence Nightingale science has put a lot of effort into killing bacteria. This approach certainly has its place but we have now proved that nature’s methods can be more effective,” he said.
“It’s fighting fire with fire. The ‘friendly’ bacteria chase out germs and form a protective biofilm that is tougher than Teflon and keeps the bad bacteria away permanently.”