Disease causing bacteria often forms into clusters that are protected by biofilms from the body’s immune system. These biofilms have been a major topic of study in the fight against infectious diseases, but it’s been hard to come up with methods that help isolate the interaction between the biofilms and the immune system for prying microscopes to look at.
Researchers at the University of Copenhagen have reported in journal Infection and Immunity of a way of using injected hollow silicone tubes with bacteria grown on them, and scanning electron microscopy along with confocal laser scanning microscopy, to really see what the immune system is up to when it encounters biofilms.
From the study abstract:

Wild-type P. aeruginosa developed biofilms within 1 day that trapped and caused visible cavities in polymorphonuclear leukocytes (PMNs). In contrast, the number of cells of a P. aeruginosa rhlA mutant that cannot produce rhamnolipids was significantly reduced on the implants by day 1, and the bacteria were actively phagocytosed by infiltrating PMNs. In addition, we identified extracellular wire-like structures around the bacteria and PMNs, which we found to consist of DNA and other polymers. Here we present a novel method to study a pathogen-host interaction in detail. The data presented provide the first direct, high-resolution visualization of the failure of PMNs to protect against bacterial biofilms.

 

 
University of Copenhagen press statement: New scientific method unmasks chronic infections…
Abstract in Infection and Immunity: Interactions between Polymorphonuclear Leukocytes and Pseudomonas aeruginosa Biofilms on Silicone Implants In Vivo