BOSTON — High-touch areas of public restrooms — particularly
areas people touched after washing their hands — frequently contained more
than 1,000 colony-forming units per milliliter of infection-causing bacteria,
according to findings presented here.
Lennox Archibald, MD, PhD, of the College of Medicine at the
University of Florida in Gainesville, spoke to Infectious Disease News at the IDSA 49th Annual Meeting. “The six or seven bugs
that we found were the ones that cause two-thirds of infections in health care
centers,” he said.
Lennox Archibald, MD, PhD
The researchers aimed to fill a void in qualitative or quantitative data
about bacterial contamination of surfaces likely to be touched after washing
and drying hands in public restrooms. Public restroom areas included those in
hospitals, offices, lecture halls, conference centers,
department stores, restaurants, airports and resorts.
Of the multitude of organisms recovered, the predominant gram-positive
organisms recovered included Staphylococcus, Micrococcus,
Bacillus and Enterococcus. Gram-negative microorganisms were
mostly Enterobacteriaceae (eg, Escherichia coli, Klebsiella,
Cronobacter, Leclercia, Pantoea and Serratia) or
non-fermenters, according to the results.
All high-touch surfaces yielded extensive quantitative cultures. The
quantity of organisms was too numerous to count in several of the restrooms.
The research included a process of counting up to 1,000 colony-forming units
(CFU)/milliliter. Archibald said the standard measure for “too numerous to
count” is usually 250 CFU/mL.
The areas most likely to contain microorganisms that were too numerous
to count included faucets,
soap and paper dispenser operating levers, and the
exit door handle of restaurants and aircraft restrooms.
“It is especially important to note that this was in areas people
touched after they washed their hands,” he said.
This was the first phase of a three-phase study. “The first phase,
which we are looking at here, was simply a microbiologic
characterization,” Archibald said. “The second phase included
observation of hand washing practices, including the time taken to wash and dry
hands, and the third phase included information on more than 200 bathrooms
representing 40 different kinds of sites. These data are forthcoming.”
The trial was conducted from December to February. The researchers
cultured 18 public restrooms and four commercial aircraft.
Disclosure: Dr. Archibald reports no relevant financial
For more information:
- Archibald L. #314. Presented at: IDSA 49th Annual
Meeting; Oct. 20-23, 2011; Boston.
Keith S. Kaye, MD, MPH
These findings are not surprising, but are notable. Several of the
pathogens identified are known colonizers of the gastrointestinal tract, skin
or nares. What is notable is that items such as faucets and doorknobs were
contaminated — thus, even after washing your hands in the bathroom, there
is a high likelihood that they can become immediately contaminated. The role of
‘hands free’ faucets, soap and towel dispensers, and doors that can
be operated by feet or open automatically seem to be particularly relevant in
health care and food care arenas.
– Keith S. Kaye, MD, MPH
Infectious Disease News Editorial Board member
Disclosure: Dr. Kaye reports no relevant financial