A leading health expert has said that using less sterilisation agents and avoiding excessive antibiotic use could actually reduce the level of infection in hospitals as it would allow good bacteria to remain in the atmosphere.

Jack Gilbert of Argonne National Laboratory in Chicago and head of the Earth Microbiome Project, has recommended opening windows in hospitals to allow friendly bacteria found outdoors to enter wards and reduce the amount of infections.

He believes that air conditioning and an ultra-sterile environment may cause higher level of infections has it removes organisms that fight dangerous microbes and lay an open ground for bad infections to grow.

Dr Gilbert said, “There's a good bacterial community living in hospitals and if you try to wipe out that good bacterial community with sterilisation agents and excessive antibiotic use you actually lay waste to this green field of protective layer. Then these bad bacteria can just jump in and start causing hospital borne infections.”

Dr Gilbert said that his theory is supported by findings that open windows affect the composition of microbial communities on handles and surfaces in hospitals, but it does not increase the number of dangerous pathogens, which affect patients.

His recommendations are similar to that of Florence Nightingale, who insisted upon opening windows in hospital wards to let fresh air in, about 150 years ago.