New biofilm findings could lead to treatments to prevent blockages and urinary tract infections experienced by many long-term catheter users, according to Scottish researchers.
They noted that up to 50% of long-term catheter users experienced encrustations and subsequent blockage, which result in severe trauma and pain.
“In order to find ways to control and prevent catheter blockages, it is essential that we have a full understanding of biofilm formation”
Using an imaging technique called episcopic differential interference contrast (EDIC) microscopy, he Southampton University researchers identified four clear stages to the development of a crystalline biofilm, which leads to encrustations.
The findings provide information that will aid in the development of anti-biofilm materials and treatments to “manage and ultimately prevent blockage, improving the quality of life of many long-term catheter users”, they said.
The team used EDIC microscopy to study the development of the crystalline biofilm over a 24-day period on two common catheter materials – silicone and hydrogel latex.
They found four distinct stages:
- an initial foundation layer formed by individual “colonising” Proteus mirabilis cells, which occurred in less than one hour
- this was rapidly followed by a sheet-like microcrystalline material that covers this conditioning film from which
- after 24-hour exposure, large amounts of crystalline material extends out and
- within four days the entire surface (of both catheter materials) was covered with a crystalline biofilm, in which P. mirabilis was embedded throughout this structure.
The results showed that the biofilm occurred equally on silicone and hydrogel latex and that the two materials had no effect on the time progression of development.
Study lead author Dr Sandra Wilks, senior research fellow in the university’s Centre for Biological Science, said: “In order to find ways to control and prevent catheter blockages, it is essential that we have a full understanding of biofilm formation.
“When considering the various stages, it is clear that if primary attachment and development of a conditioning film can be prevented the subsequent formation of encrustations could have reduced impact,” she said.
The findings challenge traditional theories and previous findings and add further important information, said the authors.
Dr Wilks added: “The use of EDIC microscopy provides a rapid and effective method for visualising crystalline biofilm development directly on catheters.
“Previous studies also suggest that the biofilm layer primarily forms around the eye hole area of the catheter, whereas our work shows they form anywhere on the catheter surface,” she said.
“We also demonstrated that the colonising P. mirabilis cells attached themselves to the catheter surface prior to the formation of the conditioning film, which hadn’t previously been observed,” she added.
The study, published in the journal PLoS ONE, was presented yesterday at the official launch of the university’s Network on Antimicrobial Resistance and Infection Prevention.