Objectives: In the light of increasing drug resistance in Staphylococcus aureus, bacteriophage endolysins [peptidoglycan hydrolases (PGHs)] have been suggested as promising antimicrobial agents. The aim of this study was to determine the antimicrobial activity of nine enzymes representing unique homology groups within a diverse class of staphylococcal PGHs.
Methods: PGHs were recombinantly expressed, purified and tested for staphylolytic activity in multiple in vitro assays (zymogram, turbidity reduction assay and plate lysis) and against a comprehensive set of strains (S. aureus and CoNS). PGH cut sites in the staphylococcal peptidoglycan were determined by biochemical assays (Park-Johnson and Ghuysen procedures) and MS analysis. The enzymes were tested for their ability to eradicate static S. aureus biofilms and compared for their efficacy against systemic MRSA infection in a mouse model.
Results: Despite similar modular architectures and unexpectedly conserved cleavage sites in the peptidoglycan (conferred by evolutionarily divergent catalytic domains), the enzymes displayed varying degrees of in vitro lytic activity against numerous staphylococcal strains, including cell surface mutants and drug-resistant strains, and proved effective against static biofilms. In a mouse model of systemic MRSA infection, six PGHs provided 100% protection from death, with animals being free of clinical signs at the end of the experiment.
Conclusions: Our results corroborate the high potential of PGHs for treatment of S. aureus infections and reveal unique antimicrobial and biochemical properties of the different enzymes, suggesting a high diversity of potential applications despite highly conserved peptidoglycan target sites.
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http://dx.doi.org/10.1093/jac/dku552 | DOI Listing |
Int J Biol Macromol
December 2024
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China; Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Chinese Academy of Agricultural Sciences, Beijing 100193, China; Key Laboratory of Agro-Products Processing, Ministry of Agriculture and Rural Affairs, Chinese Academy of Agricultural Sciences, Beijing 100193, China. Electronic address:
The development of functional hydrogel dressings with robust mechanical properties has posed a significant challenge in expediting the healing process of MRSA-infected wounds. To address this, a composite hydrogel, comprising carboxylated soybean cellulose nanocrystals (CNCs), poly(N-isopropyl acrylamide) (PNIPAM), dimethyl diallyl ammonium chloride (PDADMAC), and kaolin (CN/P-K) was synthesized. CNCs served to stabilize the interpenetrating polymer networks of PNIPAM and PDADMAC through hydrogen bonding and electrostatic interactions, respectively, while the kaolin interlayer improved the material toughness.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Marine College, Shandong University, Weihai, Shandong 264209, China. Electronic address:
Managing wounds infected with multi-drug-resistant (MDR) bacteria remains a significant public health challenge in clinical settings. While multifunctional hydrogels are commonly employed to treat skin infections, there is a scarcity of hydrogels that effectively combine cationic guar gum (CG) with both potent antimicrobial and safe therapeutic actions. This study introduces a novel pH responsive, dual-dynamically crosslinked hydrogel (CFC-PDA/Ag), synthesized by crosslinking CG with polydopamine (PDA)-coated silver nanozymes (PDA/PM-AgNPs).
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
School of Veterinary Medicine, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu 225009, PR China. Electronic address:
The excessive utilization of antibiotics gives rise to the development of bacterial resistance, the deterioration of animal immune functions, the increase in mortality rates, and the undermining of human immunity. Therefore, there is an urgent necessity to explore new antimicrobial agents or alternatives to tackle bacterial resistance. We investigated tea tree oil (TTO), a pure natural plant essential oil extracted from Melaleuca leaves, which exerted efficient antibacterial activities.
View Article and Find Full Text PDFMicrobiol Res
December 2024
College of Food Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, China; Yangzhou Engineering Research Center of Food Intelligent Packaging and Preservation Technology, Yangzhou University, Yangzhou, Jiangsu 225127, China. Electronic address:
Temperate bacteriophages are crucial for maintaining the pathogenicity and fitness of S. aureus, which also show promise as a biocontrol agent for S. aureus.
View Article and Find Full Text PDFTrials
December 2024
Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
Background: Vancomycin, an antibiotic with activity against methicillin-resistant Staphylococcus aureus (MRSA), is frequently included in empiric treatment for community-acquired pneumonia (CAP) despite the fact that MRSA is rarely implicated in CAP. Conducting polymerase chain reaction (PCR) testing on nasal swabs to identify the presence of MRSA colonization has been proposed as an antimicrobial stewardship intervention to reduce the use of vancomycin. Observational studies have shown reductions in vancomycin use after implementation of MRSA colonization testing, and this approach has been adopted by CAP guidelines.
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