Doctors may be unwittingly spreading infections through their ties, warn US researchers.
Ties may harbour potential disease-causing bacteria
The New York Hospital Queens team found nearly half of the ties worn by medical workers harboured disease-causing bacteria.
The potential for ties to transmit the bacteria to patients must be considered, say the researchers.
Dr Steven Nurkin reported his findings at the a meeting of the American Society for Microbiology.
The researchers analysed ties worn by physicians, their assistants, medical students and security staff working at their hospital.
Almost half (47.6%) of the ties worn by clinicians were found to harbour bacteria that can cause disease.
This was eight times the odds of ties worn by security staff from the same hospital being infected.
Dr Nurkin said the findings called into question whether wearing a necktie is in the best interest of patients.
He said: "Studies such as this remind us about what we may bring to our patients' bedside.
"Being well dressed adds an aura of professionalism and has been correlated with higher patient confidence.
"Senior physicians and hospital administrators often encourage staff to wear neckties in order to help promote this valuable relationship, but in so doing, they may also be facilitating the spread of infectious organisms."
A spokesman from the British Medical Association said: "Ties are frequently handled but infrequently washed which means they can spread infection.
"Doctors should not have to wear them when seeing patients."
Dr Chris Kibbler, consultant microbiologist at University College London, thought hand hygiene was more important than worrying about clothing.
"There are other items of clothing which are likely to be relevant as well - sleeves for example. So it's difficult to know that your tie itself is more of a problem than your shirt sleeve or your trouser.
"Bearing in mind that we believe hand transmission is the most important and that we can decontaminate our hands between patients, I would rather people concentrated on that far more than worry about their tie - providing they are not daubing it in a wound," he said.