A Novel Antimicrobial Endolysin, LysPA26, against Pseudomonas aeruginosa

Abstract

The global increase in multidrug resistant (MDR) bacteria has led to phage therapy being refocused upon. A novel endolysin, LysPA26, containing a lysozyme-like domain, was screened against Pseudomonas aeruginosa in this study. It had activity against MDR P. aeruginosa without pretreatment with an outer-membrane permeabilizer. LysPA26 could kill up to 4 log units P. aeruginosa in 30 min. In addition, temperature and pH effect assays revealed that LysPA26 had good stability over a broad range of pH and temperatures. Moreover, LysPA26 could kill other Gram-negative bacteria, such as Klebsiella pneumonia, Acinetobacter baumannii and Escherichia coli, but not Gram-positive bacteria. Furthermore, LysPA26 could eliminate P. aeruginosa in biofilm formation. Our current results show that LysPA26 is a new and promising antimicrobial agent for the combat of Gram-negative pathogens.

Expression of a Peptidoglycan Hydrolase from Lytic Bacteriophages Atu_ph02 and Atu_ph03 Triggers Lysis of Agrobacterium tumefaciens

“…The use of exogenously applied peptidoglycan hydrolases to directly kill bacteria is more established for Gram-positive bacteria, since they lack an outer membrane barrier; however, in at least some cases, the exogenous application of endolysins has been shown to effectively lyse Gram-negative bacteria (25). Additional strategies for targeting Gram-negative pathogens include the coapplication of an endolysin with an outer membrane permeabilizer such as EDTA (26) or engineering an endolysin to gain the ability to lyse bacteria from the outside by absorption through the outer membrane (27).…”

Gram-Negative Bacterial Lysins

“…While the cell wall binding domain is responsible for the high specificity of lysins, some Gram-positive catalytic domains are still very active when expressed on their own, with bacterium specificity then relying on the presence or absence of the targeted bonds in the cell wall. Likewise, Gram-negative lysins usually do not contain a cell wall binding domain, but are composed of an individual catalytic domain with terminal-charged residues for binding ( Figure 1B) [22,25,26]. The independent activities and the modular nature of lysins allow for efficient catalytic or binding domain swapping with other lysins or antimicrobial components, fusion with antimicrobial peptides, etc., leading to the development of lysins that have enhanced bactericidal properties ( Figure 1B) [22,25].…”

“…The Gram-negative bacterial cell envelope is composed of protein, sugars and complex lipid arrangements [39]. Different approaches have been employed to increase the membrane permeability to lysins, such as the simultaneous addition of membrane destabilizing agents like poly-l-lysine, polymyxin B, or ethylene diamine tetraacetic acid disodium salt (EDTA), or modification of the lysins themselves, to include highly charged/hydrophobic aa residues [25,[40][41][42][43] (Table 1). The success of these approaches has been varied, with few showing in vivo efficacy in animal models (Table 1) [22].…”

“…Additional lysins with antipseudomonal activity have been identified and tested mostly in in vitro bactericidal assays in the presence of OM permeabilizers (Table 1) [25,41,42]. Lysin gp144 (KZ144), isolated from the P. aeruginosa phage phiKZ, has one of the few Gram-negative modular lysins.…”

Diversity, specificity and molecular evolution of the lytic arsenal of Pseudomonas phages: in silico perspective

“…Among these improvements, endolysins have also been modified to permeabilize the outer membrane (OM) of Gram-negative bacteria, or used in combination with permeabilizers (EDTA, citric and malic acid; Briers et al, 2014;Oliveira et al, 2014;Heselpoth et al, 2019). Although infrequent, the property of permeabilizing OM was also found to be intrinsic to some native phage lysins (Walmagh et al, 2013;Guo et al, 2017).…”