title: Photodynamic inactivation of Klebsiella pneumoniae biofilms and planktonic cells by 5-aminolevulinic acid and 5-aminolevulinic acid methyl ester.
abstract: The treatment of Klebsiella pneumoniae, particularly extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae, is currently a great challenge. Photodynamic antimicrobial chemotherapy is a promising approach for killing antibiotic-resistant bacteria. The aim of this study was to evaluate the capacity of 5-aminolevulinic acid (5-ALA) and its derivative 5-ALA methyl ester (MAL) in the presence of white light to cause photodynamic inactivation (PDI) of K. pneumoniae planktonic and biofilm cells. In the presence of white light, 5-ALA and MAL inactivated planktonic cells in a concentration-dependent manner. Biofilms were also sensitive to 5-ALA and MAL-mediated PDI. The mechanisms by which 5-ALA and MAL caused PDI of ESBL-producing K. pneumonia were also investigated. Exposure of K. pneumonia to light in the presence of either 5-ALA or MAL induced cleavage of genomic DNA and the rapid release of intracellular biopolymers. Intensely denatured cytoplasmic contents and aggregated ribosomes were also detected by transmission electron microscopy. Scanning electron microscopy showed that PDI of biofilms caused aggregated bacteria to detach and that the bacterial cell envelope was damaged. This study provides insights into 5-ALA and MAL-mediated PDI of ESBL-producing K. pneumoniae.
authors.affiliation: Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, People's Republic of China.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Liu
authors.affiliation: The First Affiliated Hospital of College of Medicine, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, People's Republic of China.
authors.forename: Yingli
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: The First Affiliated Hospital of College of Medicine, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Han
authors.affiliation: Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, People's Republic of China.|The First Affiliated Hospital of College of Medicine, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, People's Republic of China.
authors.forename: Jin'e
authors.initials: J
authors.lastname: Lei
authors.affiliation: Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, People's Republic of China.
authors.forename: Hafiz Muhammad
authors.initials: HM
authors.lastname: Ishaq
authors.affiliation: Department of Microbial Diseases, UCL Eastman Dental Institute, 256 Gray's Inn Road, London, WC1X 8LD, UK. sean.nair@ucl.ac.uk.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Nair
authors.affiliation: Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, People's Republic of China. xujiru@mail.xjtu.edu.cn.
authors.forename: Jiru
authors.initials: J
authors.lastname: Xu
mesh_terms: D000622:Aminolevulinic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000528:radiation effects; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D008027:Light; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D010933:Plankton / Q000187:drug effects / Q000528:radiation effects; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D011838:Radiation-Sensitizing Agents; C114767:delta-aminolevulinic acid methyl ester; D000622:Aminolevulinic Acid
keywords: 5-ALA; Biofilms; Klebsiella pneumoniae; MAL; PACT