TSPphg Lysin from the Extremophilic Thermus Bacteriophage TSP4 as a Potential Antimicrobial Agent against Both Gram-Negative and Gram-Positive Pathogenic Bacteria

Abstract

New strategies against antibiotic-resistant bacterial pathogens are urgently needed but are not within reach. Here, we present in vitro and in vivo antimicrobial activity of TSPphg, a novel phage lysin identified from extremophilic Thermus phage TSP4 by sequencing its whole genome. By breaking down the bacterial cells, TSPphg is able to cause bacteria destruction and has shown bactericidal activity against both Gram-negative and Gram-positive pathogenic bacteria, especially antibiotic-resistant strains of Klebsiella pneumoniae, in which the complete elimination and highest reduction in bacterial counts by greater than 6 logs were observed upon 50 µg/mL TSPphg treatment at 37 • C for 1 h. A murine skin infection model further confirmed the in vivo efficacy of TSPphg in removing a highly dangerous and multidrug-resistant Staphylococcus aureus from skin damage and in accelerating wound closure. Together, our findings may offer a therapeutic alternative to help fight bacterial infections in the current age of mounting antibiotic resistance, and to shed light on bacteriophage-based strategies to develop novel anti-infectives.

Lysins breaking down the walls of Gram-negative bacteria, no longer a no-go

“…A. baumannii appears as the most sensitive species for currently unknown reasons [7,8]. Some of these lysins have an unusually broad spectrum covering both Gram-negative and Gram-positive strains [9,10]. Based on analyses of truncated lysin variants, there is a growing consensus that the mechanism of action of many of these lysins is based on a self-promoted uptake mechanism induced by a Cterminal amphipathic helix that interacts with the OM, followed by active peptidoglycan degradation by the Nterminal enzymatic domain.…”

“…An exception to this rule are lysins from extremophilic Thermus bacteriophages. These lysins have intrinsic antibacterial activity based on a protruding N-terminal cationic peptide [10,17 ] (Figure 1).…”

“…Whereas some studies report moderate antibacterial activities (<1-3 log reductions), other studies report a high bactericidal in vitro effect (>5 log reductions) [10,18,19 ]. However, assessing and comparing the potential of these lysins is complicated by the lack of standardized protocols and the variety of conditions used.…”

Molecular Characterization of a Novel Lytic Enzyme LysC from Clostridium intestinale URNW and Its Antibacterial Activity Mediated by Positively Charged N-Terminal Extension

“…It is also possible, that having the pI of 9.96 and a highly positively charged N -terminal region, LysC destabilizes bacterial membranes by electrostatic interactions. This scenario was postulated for recently discovered TSPphg lysin [ 32 ].…”

Viruses in Extreme Environments, Current Overview, and Biotechnological Potential

“…For example, from a whole genome study of Thermus phage TSP4 isolated from Tengchong hot spring in Yunnan Province of China at a temperature of 70 °C with a pH of 7.0, was identified a novel phage lysin named TSPphg and assessed in vitro and in vivo its antibacterial activity against a panel of antibiotic-resistant strains. TSPphg is able to cause bacteria destruction and has shown bactericidal activity against both Gram-negative and Gram-positive pathogenic bacteria, especially antibiotic-resistant strains of Klebsiella pneumoniae [ 109 ].…”