Slime in the ice machine. It’s more than likely that every Houstonian has heard of it; but what news anchor Marvin Zindler — who was known for reporting on this issue — didn’t know was that the slime in the ice machine could walk.
In the Oct. 1 issue of the journal Science, UH assistant professor of chemical and biomolecular engineering Jacinta Conrad and a team of researchers announced they had translated microscopy footage of bacteria into databases of bacterial behavior, and found that bacteria can stand and walk along hard surfaces.
“What we found was that instead of crawling with their long axis, parallel to the surface, they could walk with their long axis perpendicular to the surface,” Conrad said. “And they could move in all directions this way and cover surprisingly large distances.”
This movement, supported by pilli — tiny hook-like tentacles on the surface of the bacteria — allows the organisms to more efficiently explore the surfaces they encounter to determine their suitability for forming a biofilm, Conrad said.
“They’re probably looking for food. They’re probably looking for a good place to settle down,” Conrad said. “Why do people move? They (the bacteria) are looking for a good place to live, looking for a good place to start forming a family or a biofilm. And once they find a place that might be suitable, they want to move there as quickly as possible.”
Biofilm isn’t just an ice machine phenomenon; it’s everywhere. It grows on teeth and inside water pipes. They’re on water filters, and there’s probably at least one in a household shower.
Up to 80 percent of all microbial infections, like meningitis or infections around implant sites, are caused or exacerbated by biofilm-forming bacteria, Conrad said.
The FDA estimated in 1997 that about 9,000 cases of food poisoning per year are caused by microbial contamination, costing the country about $35 billion.
Biofilms double fuel costs when they form on ships’ hulls and create drag; oil and water companies have reported significant damage to pipelines where bacteria ate through the pipes or created a significant blockage.
Conrad and her team have shed light on possible solutions to the slime problem with the discovery.
“This work shows that how individual bacteria move on a surface impacts the structure of the biofilm they form,” Conrad said in a UH news release. “Designing surfaces that change how bacteria are able to move might be a very directed and rational way of preventing biofilm formation.”