Real-time monitoring of the dynamics and interactions of bacteria and the early-stage formation of biofilms

Abstract

Bacterial biofilms are complex colonies of bacteria adhered to a static surface and/or one to another. Bacterial biofilms exhibit high resistance to antimicrobial agents and can cause life-threatening nosocomial infections. Despite the effort of the scientific community investigating the formation and growth of bacterial biofilms, the preliminary interaction of bacteria with a surface and the subsequent early-stage formation of biofilms is still unclear. In this study, we present real-time, label-free monitoring of the interaction of Escherichia coli and Pseudomonas aeruginosa bacteria with untreated glass control surfaces and surfaces treated with benzalkonium chloride, a chemical compound known for its antimicrobial properties. The proof of principle investigation has been performed in a standard inverted optical microscope exploiting the optical phenomenon of caustics as a tool for monitoring bacterial diffusion and early adhesion and associated viability. The enhanced resolving power of the optical set-up allowed the monitoring and characterization of the dynamics of the bacteria, which provided evidence for the relationship between bacterial adhesion dynamics and viability, as well as the ability to form a biofilm. Viable bacteria adhered to the surface exhibited noticeable sliding or rotary dynamics while bacteria killed by surface contact remained static once adhered to the surface. This difference in dynamics allowed the early detection of biofilm formation and offers the potential to quantify the efficiency of antimicrobial surfaces and coatings.

Experimental evaluation of clinical and microbiological efficacy of systemic antibiotic therapy and local phage therapy in surgical treatment of burn wound infection

“…Полученные нами данные об отсутствии микробиологической эффективности используемой противомикробной терапии в присутствии некротических тканей и инородных тел согласуются с результатами исследования in vitro, выполненного коллегами из Словакии [16], в ходе которого не было достигнуто эрадикации патогенной микрофлоры в модели ожоговой раны при начале местной антибиотикотерапии спустя 24 ч от момента инокуляции. Такое быстрое формирование устойчивости бактерий к противомикробной терапии объясняется данными исследований, выполненных коллегами из Испании, Великобритании, Китая: процесс формирования биопленки in vitro начинается спустя 2 ч от момента посева бактерий на питательную среду [17][18][19][20][21]. Важно отметить, что, помимо длительной бактериальной контаминации, в ранах животных 2-й и 3-й групп присутствовали шовный материал и кольца из медицинской стали, которые являются идеальным плацдармом для бактериальных биопленок.…”

Real-time label-free exploration of the dynamics and interactions of bacteriophages

“…The usage of caustics has been also extended to the nanoscale to visualize and track nanoparticles as small as a few nanometers in diameter without labelling or invasive preparation techniques [16]. Moreover, caustics-based optical microscopy has been used successfully in characterizing the dynamics of bacterial cells and the early stages of biofilm formation, demonstrating its potential as a tool for real-time and label-free monitoring of microorganisms [17].…”

Improving antibacterial ability of Ti-Cu thin films with co-sputtering method

“…It can be said that the most concerning complication of the implantation of biological materials in the human body is infection related to biomaterials 9 . Therefore, prevention of infection and interrupting the mechanism of bacterial adherence to surfaces and removing them is necessary to prevent related problems effectively 10 – 12 .…”