"Bacteria vary in their outer membrane components," which can make them more or less susceptible to adverse environmental conditions, Barbaree said. "The species also vary in their tolerance of certain environmental conditions, such as temperature and humidity."
The researchers said their next step will be to test the survival and transmission of other potentially dangerous bacteria, such as Mycobacterium tuberculosis — which causes tuberculosis — on airplanes.
Even though the new study suggested that harmful bacteria survived longer on other surfaces than they did on toilet handles, previous research has shown that airplane bathrooms are teeming with pathogens.
"It's probably the germiest toilet you'll come across," Charles Gerba, a microbiology professor at the University of Arizona, told Live Science in a 2011 interview.
In one of his studies, Gerba collected bacteria from 20 planes. Airplane bathrooms turned out to be the most bacteria-infected spots on planes. As many as 75 people use the bathrooms between cleanings, he said.
Gerba also found E. coli bacteria in the bathrooms.
The new study by the Auburn University researchers was presented today (May 20) at the 2014 general meeting of the American Society for Microbiology in Boston, and has not been published in a peer-reviewed journal. The research was funded by the U.S. Federal Aviation Administration's (FAA) Office of Aerospace Medicine.
More From LiveScience:
This story originally appeared on LiveScience.com.
Copyright 2014 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.