Photodynamic inactivation of Klebsiella pneumoniae biofilms and planktonic cells by 5-aminolevulinic acid and 5-aminolevulinic acid methyl ester

Abstract

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 MALmediated PDI. The mechanisms by which 5-ALA and MAL caused PDI of ESBLproducing 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 Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporationaggregated 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. This study provides insights into 5-ALA and MAL-mediated PDI of ESBL-producing K. pneumoniae. Powered by Editorial Manager® and ProduXion Manager® from Aries

Validation of stable reference genes in Staphylococcus aureus to study gene expression under photodynamic treatment: a case study of SEB virulence factor analysis

“…aPDI effectively eradicates a wide group of multidrug-resistant bacteria in vitro (planktonic and biofilm cultures), e.g., vancomycin-resistant Enterococcus faecalis (VRE) (5.37 log 10 unit reduction in survival) 12 , a methicillin-resistant S. aureus (MRSA) strain (5-6 log 10 unit reduction) 13 , and extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae. Effective biofilm reduction under aPDI was also documented 14 . A number of confirmatory studies on in vivo/ex vivo models have indicated the efficient reduction in viable bacterial cell numbers.…”

Photoinactivation of ESKAPE Pathogens: Overview of Novel Therapeutic Strategy

“…Only two experimental work concerns biofilm analysis upon aPDI treatment: with the use of 5-ALA/MAL and phenothiazines. Whereas in the first case appreciable efficacy of approximately 4 log 10 reduction (10 mM MAL) was obtained for both ESBL-producing and ESBL-nonproducing clinical isolate [34], there was only slight antibiofilm activity for each of phenothazines studied (TBO; Azure A, AA; and new methylene blue, NMB) [32].…”

“…From the representatives of FDA-approved drugs, 5-ALA or MAL constitute an attractive option of PSs as their application resulted in more than 3 log 10 after application of 10 mM ALA. Of interest, ESBL-producing and ESBL-nonproducing strains were killed with similar efficacy. In case of MAL applications, the results were even better, and exceeded the value of 4 log 10 reduction in cell number [34]. The 5-ALA or MAL-based aPDI application seems to be attractive from the clinical point of view as beside the fact of the FDA/EMEA approval, these PSs can be used along with white light, which constitutes universal light source.…”

Weak biofilm formation among carbapenem-resistant Klebsiella pneumoniae

“…Wells were stained with 0.1% crystal violet (CV) and resolubilized with 33% glacial acetic acid (19). K. pneumoniae (ATCC 700603) served as the biofilm positive control and media alone was the negative control (12,(23)(24)(25).…”