Hand Washing Quality Important in Reducing Hospital Infections

Increasing the frequency of hand washing by healthcare workers does not necessarily result in matching reductions in staphylococcal healthcare-associated infections (HAIs), according to a new study.

Researchers at Harrogate District Hospital (UK) constructed a deterministic model and applied it to a hypothetical general medical ward. The model assumed that the transmission of Staphylococcus infection occurred after contact with the transiently colonized hands of healthcare workers. It was also assumed that healthcare workers acquired contamination only by touching colonized patients. The model demonstrated that if transmission is solely via the hands of health care workers then under most circumstances it should be possible to prevent outbreaks of staphylococcal infection from occurring at a hand cleansing frequencies of under 50%, even with imperfect hand hygiene. The analysis also indicated that the relationship between hand cleansing efficacy and frequency is not linear; as efficacy decreases, the hand cleansing frequency required to ensure outbreak prevention increases disproportionately. The researchers suggest that it is important to maximize the efficacy of hand cleansing, since this will reduce the amount of hand washing activity necessary to prevent an outbreak from occurring. The study was published in the September 2, 2008, issue of the journal BMC Infectious Diseases.

"It can therefore be concluded that it should be possible to prevent many outbreaks of staphylococcal infection through hand hygiene measures alone, even if high compliance rates are not achieved,” said lead author microbiologist Kevin Kerr, Ph.D., and colleagues. "This raises questions as to why so many outbreaks of staphylococcal infection continue to occur, despite the fact that recorded hand hygiene compliance rates are generally in the region of 40%.”

Hand hygiene is generally considered the most important measure that can be applied to prevent the spread of HAI. Continuous emphasis on this intervention has lead to the widespread opinion that HAI rates can be greatly reduced by increased hand hygiene compliance alone. However, this assumes that the effectiveness of hand hygiene is not constrained by other factors and that improved compliance in excess of a given level, in itself, will result in a corresponding reduction in the incidence of HAI. However, researchers have found the law of diminishing returns applies to hand hygiene as well, with the greatest benefits occurring in the first 20% or so of compliance.

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Harrogate District Hospital