Effect of temperature on biofilm growth in the presence of an antimicrobial peptide
A biofilm formation solid-surface assay was performed in tissue culture-treated microtiter plates using Staphylococcus epidermidis clinical strain (ATCC® 35984™), and plates were individually incubated for 20 hours at 35°C, 37°C, and 39°C. Results indicate that LL-37 inhibits biofilm formation significantly at all temperatures, but when compared with the control, biofilms formed in the presence of LL-37 at 35°C showed the lowest percent decrease in the amount of biofilm present as LL-37 concentration increased, while 39°C showed the highest, meaning the least amount of biofilm was present at 39°C, and the most at 35°C. Furthermore at the minimal inhibitory concentration (MIC) of LL-37, biofilms formed at the other temperatures were significantly different to the hypothermic temperature in the presence of LL-37.
Reasons for this include the temperature specificity of mammalian proteins, and it can be assumed that hypothermic temperatures (35°C) are detrimental to LL-37's anti-biofilm activity.
These findings suggest possible immune system suppression and increased susceptibility to biofilm-related infections at hypothermic body temperatures. Findings also reiterate LL-37’s therapeutic potential, and its role at the peak of an immune response.