Photoinactivation of multidrug-resistant Gram-positive bacteria isolated from dogs with otitis using tetra-cationic porphyrins bearing peripheral platinum(II) (3-PtTPyP) and palladium(II) (3-PdTPyP) complexes
5 affiliations
- 1Center for Rural Sciences, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul Brasil
- 2Laboratory Surfaces and Macromolecules, Department of Physics, Center for Natural and Exact Sciences, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul Brasil
- 3Chemistry Department, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina Brasil
- 4Department of Preventive Veterinary Medicine, Center for Rural Sciences, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul Brasil
- 5Laboratory of Veterinary Microbiology and Immunology, Federal Institute Farroupilha, Campus Frederico Westphalen, Frederico Westphalen, Rio Grande do Sul Brasil
Abstract
The increasing prevalence of multidrug-resistant (MDR) bacteria isolated from dogs with external otitis presents a major therapeutic challenge in veterinary medicine, and antimicrobial photodynamic therapy has emerged as a promising alternative. Meso-tetra-pyridyl porphyrins bearing peripheral platinum(II) (3-PtTPyP) and palladium(II) (3-PdTPyP) complexes have shown activity against clinically relevant Gram-positive bacteria and may represent effective photosensitizers for otitis-associated MDR pathogens. Therefore, this study evaluated the antimicrobial activity and effects on bacterial morphology and adhesive properties of 3-PtTPyP and 3-PdTPyP on MDR isolates of Corynebacterium auriscanis, Enterococcus faecalis, Staphylococcus epidermidis, and Streptococcus canis obtained from dogs with otitis. Antibacterial activity was investigated by determining the minimum inhibitory and bactericidal concentrations (MBC) and by bacterial time-kill assay under white-light irradiation for 120 min. Alterations in bacterial morphology and nanomechanical properties were investigated using atomic force microscopy (AFM). Both porphyrins promoted a marked reduction in bacterial concentrations under white-light irradiation using MBC, although their bactericidal effects varied depending on the bacterial species and porphyrin. The 3-PtTPyP exhibited a more consistent photodynamic response against E. faecalis e C. auricanis, whereas 3-PdTPyP displayed greater effected against S. canis e S. epidermidis. AFM revealed pronounced changes in surface topography and nanomechanical properties after treatment with both porphyrins. Overall, these results demonstrate that 3-PtTPyP and 3-PdTPyP are promising photosensitizers for the inactivation of MDR Gram-positive bacteria associated with canine otitis externa, and the performance against the MDR Gram-positive bacteria was dependent of species.
Related
- Emergence of vancomycin-resistant and multidrug-resistant Enterococcus spp. in freshwater aquaculture systems of southeastern Nigeria: implications for one health surveillance
- Challenges of Using a Bedaquiline-Based Regimen to Treat Multidrug-Resistant Tuberculosis in Pregnancy
- A rare case report of Rasmussen’s aneurysm in multidrug-resistant tuberculosis from Nepal
- Phenotypic Characterization of Multidrug-Resistant Pseudomonas aeruginosa Isolated From Patients With Ventilator-Associated Pneumonia: Insights Into Resistance Mechanisms and Biofilm Formation
- Nursing care of a child with cerebral palsy and multidrug-resistant bacterial pneumonia treated with bacteriophage therapy: a case report
BibTeX
@article{voigt2026photoinactivation,
title = {{Photoinactivation of multidrug-resistant Gram-positive bacteria isolated from dogs with otitis using tetra-cationic porphyrins bearing peripheral platinum(II) (3-PtTPyP) and palladium(II) (3-PdTPyP) complexes}},
author = {Tauana Fernanda Jantsch Voigt and Eduarda Martins and Junior Navarini and Matheus Gass Lopes and Paulo Ricardo de Souza and Bernardo Almeida Iglesias and Fernanda Silveira Flores Vogel and Letícia Trevisan Gressler and Juliana Felipetto Cargnelutti},
journal = {Current Microbiology},
year = {2026},
month = nov,
doi = {10.1007/s00284-026-05202-8},
url = {https://doi.org/10.1007/s00284-026-05202-8},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Photoinactivation of multidrug-resistant Gram-positive bacteria isolated from dogs with otitis using tetra-cationic porphyrins bearing peripheral platinum(II) (3-PtTPyP) and palladium(II) (3-PdTPyP) complexes
AU - Tauana Fernanda Jantsch Voigt
AU - Eduarda Martins
AU - Junior Navarini
AU - Matheus Gass Lopes
AU - Paulo Ricardo de Souza
AU - Bernardo Almeida Iglesias
AU - Fernanda Silveira Flores Vogel
AU - Letícia Trevisan Gressler
AU - Juliana Felipetto Cargnelutti
PY - 2026
DA - 2026/11/04
JO - Current Microbiology
DO - 10.1007/s00284-026-05202-8
UR - https://doi.org/10.1007/s00284-026-05202-8
AB - The increasing prevalence of multidrug-resistant (MDR) bacteria isolated from dogs with external otitis presents a major therapeutic challenge in veterinary medicine, and antimicrobial photodynamic therapy has emerged as a promising alternative. Meso-tetra-pyridyl porphyrins bearing peripheral platinum(II) (3-PtTPyP) and palladium(II) (3-PdTPyP) complexes have shown activity against clinically relevant Gram-positive bacteria and may represent effective photosensitizers for otitis-associated MDR pathogens. Therefore, this study evaluated the antimicrobial activity and effects on bacterial morphology and adhesive properties of 3-PtTPyP and 3-PdTPyP on MDR isolates of Corynebacterium auriscanis, Enterococcus faecalis, Staphylococcus epidermidis, and Streptococcus canis obtained from dogs with otitis. Antibacterial activity was investigated by determining the minimum inhibitory and bactericidal concentrations (MBC) and by bacterial time-kill assay under white-light irradiation for 120 min. Alterations in bacterial morphology and nanomechanical properties were investigated using atomic force microscopy (AFM). Both porphyrins promoted a marked reduction in bacterial concentrations under white-light irradiation using MBC, although their bactericidal effects varied depending on the bacterial species and porphyrin. The 3-PtTPyP exhibited a more consistent photodynamic response against E. faecalis e C. auricanis, whereas 3-PdTPyP displayed greater effected against S. canis e S. epidermidis. AFM revealed pronounced changes in surface topography and nanomechanical properties after treatment with both porphyrins. Overall, these results demonstrate that 3-PtTPyP and 3-PdTPyP are promising photosensitizers for the inactivation of MDR Gram-positive bacteria associated with canine otitis externa, and the performance against the MDR Gram-positive bacteria was dependent of species.
SN - 0343-8651
SN - 1432-0991
ER -