Tripyridylporphyrin in photodynamic inactivation of biofilm

Legionella pneumophila Gram-negativna je bakterija koja spada u porodicu Legionellaceae. Uzročnik je pontijačke groznice i legionarske bolesti. Obitava u vodenom okruženju kao što su jezera, rijeke, ali i umjetno stvoreni vodeni sustavi kao što su sustavi s visokim temperaturama vode, sustavi rashladne vode, spa i wellness centri, hoteli, bolnice, vodeni sustavi u stomatološkim ordinacijama. U takvom okruženju stvaraju se biofilmovi koje nastanjuje L. pneumophila i u njima se razmnožava. Biofilmovi su otporni na dezinfekcijska sredstva i termičku obradu vode što otežava eradikaciju legionele. Zbog toga potrebno je razviti nove metode dezinfekcije voda, a jedna od tih metoda je fotodinamička inaktivacija. Fotodinamička inaktivacija temelji se na upotrebi fotosenzibilizatora, u ovom radu 5-(4-oktadec-9-enamidofenil)-10,15,20-tris(3-piridil)porfirina (TMPyP3-C17H33), u aerobnim uvjetima. Izlaganje amfifilnog porfirina izvoru svjetlosti određene valne duljine rezultira stvaranjem singletnog kisika (1O2) i/ili ostalih kisikovih reaktivnih vrsta (ROS) koji dovode do oksidacije i stanične smrti patogena. Cilj ovoga istraživanja bio je ispitati učinkovitost fotodinamičke inaktivacije amfifilnog porfirina na razaranje 6-dnevnog biofilma Legionella pneumophila soj 130b. Korištena je sterilna vodovodna voda, a kao izvor svjetlosti korištena je ljubičasta svjetlost intenziteta 40 mW/cm2. Koncentracije amfifilnog porfirina od 0,176 μM, 0,351 μM, 0,702 μM i 1,404 μM su dovele do uništavanja biofilma L. pneumophila u vodovodnoj vodi. Istraživanjem je dokazano da spoj učinkovito razara bakterijski biofilm pa bi se metoda mogla primijeniti u praksi.Legionella pneumophila is a Gram-negative bacteria of the family Legionellaceae. It is a causative agent of Pontiac fever and Legionnaires' disease. It resides in water environment like rivers, lakes as well as in artificially created water systems like high temperature systems, cooling water systems, spa and wellness centres, hotels, hospitals, water systems in dental offices. In such environment biofilms are formed and inhabited by L. pneumophila that multiplies within them. Biofilms are resistant to disinfectants and thermal processing what makes eradication of Legionella more difficult. Consequently, new methods for water disinfection need to be developed and photodynamic inactivation is one of those methods. Photodynamic inactivation is based on usage of photosensitizer, in this case 5-(4-octadec-9-enamidophenyl)-10,15,20-tris(3-pyridyl)porphyrin (TMPyP3-C17H33) in aerobic conditions. Exposure of amphiphilic porphyrin to light of specific wavelength results in generation of singlet oxygen (1O2) and/or other reactive oxygen species (ROS) that lead to oxidation and cell death of pathogen. Focus of this research was determining effectiveness of photodynamic inactivation of amphiphilic porphyrin on destruction of 6 day-old biofilm of Legionella pneumophila strain 130b. Sterile tap water and violet light with intensity of 40 mW/cm2 were used. Concentration of amphiphilic porphyrin of 0.176 μM, 0.351 μM, 0.702 μM and 1.404 μM led to destruction of Legionella pneumophila biofilm in tap water. This research demonstrated that compound effectively destroys bacterial biofilm therefore this method could be put into practice