PORPHYRIN COMPOUNDS INHIBIT THE BIOFILM FORMATION OF Salmonella ENTERITIDIS

COLOCHO, FLORENCIA; FAVIER, G.; DI MARCO, N.; MAIER, MARTIN; PUNGITORE, C. R.; LUCERO ESTRADA, C.S.M.

San Juan

Congreso; SBC 2023; 2023

SBC

Salmonella spp. is one of the main causes of global outbreaks of foodborne illnesses being chicken and poultry products the most likely source of its transmission to humans. Biofilms formed by this genus, cause problems in the food industry due to their persistence and the incompetence of hygienic processing technologies. Natural and synthetic porphyrins, with antibacterial activity, can be isolated from nature or synthesized in the laboratory. The antibacterial activities of porphyrins are based on their ability to absorb photons and generate reactive oxygen species (ROS) that cause cells death by DNA damages, proteins oxidation, and lipids peroxidation. This activity and its low toxicity in humans place porphyrins in a group of compounds with exceptional potential for the discovery of new agents against pathogenic microorganisms. The objective of this work was to evaluate the ability of seven synthetic porphyrins (1-7) to inhibit the biofilm formed by a strain of Salmonella enterica serovar Enteritidis. One hundred microliter of an inoculum of 1x108 CFU/mL was seeded in a trypticase soya broth into a flat-bottom 96-well plate. Then, each porphyrin was added at an initial concentration of 100 μM and two fold serial dilutions were made. After 24 hours of incubation at 37ºC, biofilm formation was determined using the crystal violet technique. Compared to controls without any compound, a reduction higher than 40% of biofilms formation was observed with most of the evaluated porphyrins. The lowest concentrations that inhibited biofilm formation were up to 0.19 μM with porphyrins 6 and 7, up to 1.56 μM for porphyrins 2 and 3, and up to 12.5 μM with porphyrins 1 and 4. Regarding porphyrin 5, no inhibition was observed at any tested concentration. It might be possible to correlate the better activity of compounds 6 and 7 with their structure: compound 6 has a Zn2+ nucleus and compound 7 has side chains that correspond to pyridinium salts, both elements change the delocalization of electrons with a probable increase in the formation of ROS.