Using a Novel Lysin To Help Control Clostridium difficile Infections

Abstract

c As a consequence of excessive antibiotic therapies in hospitalized patients, Clostridium difficile, a Gram-positive anaerobic spore-forming intestinal pathogen, is the leading cause of hospital-acquired diarrhea and colitis. Drug treatments for these diseases are often complicated by antibiotic-resistant strains and a high frequency of treatment failures and relapse; therefore, novel nonantibiotic approaches may prove to be more effective. In this study, we recombinantly expressed a prophage lysin identified from a C. difficile strain, CD630, which we named PlyCD. PlyCD was found to have lytic activity against specific C. difficile strains. However, the recombinantly expressed catalytic domain of this protein, PlyCD 1-174 , displayed significantly greater lytic activity (>4-log kill) and a broader lytic spectrum against C. difficile strains while still retaining a high degree of specificity toward C. difficile versus commensal clostridia and other bacterial species. Our data also indicated that noneffective doses of vancomycin and PlyCD 1-174 when combined in vitro could be significantly more bactericidal against C. difficile. In an ex vivo treatment model of mouse colon infection, we found that PlyCD 1-174 functioned in the presence of intestinal contents, significantly decreasing colonizing C. difficile compared to controls. Together, these data suggest that PlyCD 1-174 has potential as a novel therapeutic for clinical application against C. difficile infection, either alone or in combination with other preexisting treatments to improve their efficacy.

Gram-Negative Bacterial Lysins

“…Minimal resistance to lysins has been observed to date in in vitro studies [31]. Another key feature that distinguishes lysins from many standard-of-care (SOC) antibiotics is their narrow-spectrum of activity that allows the targeting of pathogenic antibiotic-resistant bacteria, as well as those that are antibiotic-sensitive, while sparing the healthy host microbiome and preventing dysbiosis [32]. The potent, narrow-spectrum, rapid bactericidal and biofilm-disrupting effects of lysins make them promising antimicrobials [22,31,33,34].…”

“…In the last twenty years, numerous lysins have been identified and recombinantly expressed to target a number of Gram-positive bacteria such as Bacillus anthracis, methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile, etc. [22,32,[34][35][36]. Exebacase, an anti-staphylococcal recombinant lysin is the first lysin in the United States to currently undergo human clinical trials to treat S. aureus bacteremia and endocarditis [37].…”

“…Antibiotics 2020, 9, 74 3 of 14 dysbiosis [32]. The potent, narrow-spectrum, rapid bactericidal and biofilm-disrupting effects of lysins make them promising antimicrobials [22,31,33,34].…”

“…LysABP-01 has synergy with various antibiotics such as colistin, an antibiotic of last resort that is used to treat MDR infections [47]. Another lysin, PlyAB1, was isolated from A. baumannii bacteriophage ABp1, has bactericidal activity against 48 hospital-derived pan drug-resistant A. baumannii isolates [32,48]. Lysin ABgp46 isolated from A. baumannii phage Øvb_AbaP_CEB1 has bactericidal activity against several multidrug-resistant A. baumannii strains [49].…”

The dawn of phage therapy

“…Instead of direct isolation of phage enzymes, researchers and biotechnologists also use genetic engineering and recombinant DNA technology to identify some more hidden potentials of phage antibacterial activity. A prophage lysin PlyCD, from Clostridium difficile , was expressed recombinantly and was found to be very effective against C. difficile and engineered endolysin Artilysin against P. aeruginosa has also been investigated . In an experiment, tomato seeds were transformed with endolysin genes encoding a peptidase isolated from phage CMP1.…”