TMPyP ‐mediated photoinactivation of Pseudomonas aeruginosa improved in the presence of a cationic polymer

Alterations in the bacterial envelopes produced by the cationic polymer (Eu) increase the entry of the cationic porphyrin (TMPyP), which is distributed homogeneously into the bacterial cell: (A) schematic representation, (B) fluorescence microscopy images, (C) quantification of fluorescence images. (E) The greater internalization of TMPyP contributes to achieving the eradication ofPseudomonas aeruginosa with lower concentration of photosensitizer and lower light dose (fluence rate of 28.7  mW cm−2) compared to those required for TMPyP alone (D). AbstractPseudomonas aeruginosa is one of the most refractory organisms to antibiotic treatment and appears to be one of the least susceptible to photodynamic treatment. TMPyP is effective in the photoinactivation ofP.  aeruginosa, and the co-administration with the cationic polymer Eudragit ®-E100 (Eu) potentiates this effect against isolates both sensitive and resistant to antibiotics. The fluorescent population (>98%) observed by flow cytometry after exposure to Eu  + TMPyP remained unchanged after successive washings, indicating a stronger interaction/internalization of TMPyP in the bacteria, which could be attributed to the rapid neutralization of surface charges. TMPyP and Eu produced depolarization of the cytoplasmic membrane, which increased when both cationic compounds were combined. Using confocal laser scanning microscopy, heterogeneously distributed fluorescent areas were observed after TMPyP exposure, while...

Source: Photochemistry and Photobiology - October 27, 2023 Category: Science Authors: Luciana P. Campagno, Ezequiel D. Quiroga, Edgardo N. Durantini, Fabiana L. Alovero Tags: RESEARCH ARTICLE Source Type: research