Photodynamic inactivation of bacteria: Why it is not enough to excite a photosensitizer.

Background: The development of multidrug resistance (MDR) in infectious agents is one of the most serious global problems facing humanity. Antimicrobial photodynamic therapy (APDT) shows encouraging results in the fight against MDR pathogens, including those in biofilms.

Methods: Photosensitizers (PS), monocationic methylene blue, polycationic and polyanionic derivatives of phthalocyanines, electroneutral and polycationic derivatives of bacteriochlorin were used to study photodynamic inactivation of Gram-positive and Gram-negative planktonic bacteria and biofilms under LED irradiation.

On the possibility of photodynamic inactivation of tracheobronchial tree pathogenic microbiota using methylene blue (in vitro study).

Background: The treatment of patients after mechanical ventilation of lungs suffering from a multi-species infection of the tracheobronchial tree can be complicated.. The situation is aggravated in patients with post-intubation tracheal stenosis, where infection plays a leading pathogenetic role in damage to the tracheal wall.

Membrane tubules attach Salmonella Typhimurium to eukaryotic cells and bacteria.

Using scanning electron microscopy techniques we measured the diameter of adhesive tubular appendages of Salmonella enterica serovar S. Typhimurium. The appendages interconnected bacteria in biofilms grown on gallstones or coverslips, or attached bacteria to host cells (human neutrophils).