Wednesday, July 23, 2014

Should you wear a hazmat suit when you operate an elevator?

In their quest to culture every object on planet Earth, researchers have found that hospital elevator buttons are more contaminated with bacteria than restroom surfaces.

Of 120 randomly cultured elevator buttons, 73 (61%) grew bacteria. Washroom surfaces were cultured 96 times with 41 (43%) showing microbial growth.

As is customary with papers like this, the media sensationalized the findings with headlines like "Why you should never ever touch that hospital elevator button."

Most stories eventually mentioned the fact that the authors said the majority of bacteria found ”had low pathogenicity," but some, including,,, and, did not. In fact, the MRSAID blog also confused the benign streptococcus found in this paper with the pathogen that causes strep throat.

I've written several posts about the culturing of various inanimate objects and pointed out that disease transmission has not been documented for almost all surfaces on which bacteria are found. If you click on the "Infection" label to your right, you can read as many as you wish.

Like most papers in this genre, this one has some flaws. You can read the full text here.

It was published in an open-access journal called "Open Medicine." It is not among the top 40 internal medicine journals listed by impact factor. It has no discernible impact factor at all and is not listed PubMed.

The title of the paper "Elevator buttons as unrecognized sources of bacterial colonization in hospitals" overstates the case a bit.

This table shows the types of bacteria found on both the elevator buttons and surfaces in the restrooms.
You can see that pathogens were few. Multiple organisms were found in several instances accounting for some of the numerical discrepancies. I could not figure out how the percentages were calculated. In neither column did the percentages add up to 100%.

Samples of restrooms surfaces were taken "a few months" after the elevator buttons were cultured. The authors conceded that this may have confounded the results.

Washroom sample swabs were taken from the exterior and interior entry-door handles, the privacy latch, and the toilet flusher. They did not swab toilet seats, which previous studies have shown are the gold standard to which all inanimate surfaces should be compared.

It may surprise you to learn that most of the bacteria found on elevator buttons and restroom surfaces can also normally be found ON YOUR HANDS!


Terry Murray said...

Gold standards for comparison:
Ickiness/bacteria: Toilet seats
Area: Football fields
Mass casuality/epidemic mortality: 747s or non-specific "jumbo jets"
Smallness: pinhead
Narrowness: hair's breadth

I predict these will never be dislodged from headline writers' bag of cliches or from public use.

Emily said...

I've noticed people using their knuckles to push elevator buttons or the walk button when crossing the street, and their shoulders when opening a swinging door. Prudent or overkill, I don't know, but now I catch myself doing it..

Skeptical Scalpel said...

Terry, that's an excellent list. It reminds me of a Washington Post article about journalistic cliches. Here's the link:

Skeptical Scalpel said...

Emily, I've seen the knuckle trick but not the shoulder push. I hope people who do it don't put their knuckles in their mouths. Do most people wash their knuckles when they wash their hands? I wonder.

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