Myoviridae Phages Research Articles

Analysis of a new phage, KZag1, infecting biofilm of Klebsiella pneumoniae: genome sequence and characterization

BackgroundThis study investigates the effectiveness of the bacteriophage KZag1 against drug-resistant Klebsiella pneumoniae, aiming to assess its potential as a therapeutic agent. The novelty lies in the characterization of KZag1, a Myovirus with specific efficacy against multidrug-resistant K. pneumoniae strains. This highlights the significance of exploring alternative strategies, particularly phage therapy, in addressing biofilm-associated infections.MethodsKZag1, characterized by a typical Myovirus structure with a 75 ± 5 nm diameter icosahedral head and a 15 ± 5 nm short tail, was evaluated in experimental trials against 15 strains of K. pneumoniae. The infection cycle duration was determined to be 50 min, resulting in an estimated burst size of approximately 83 plaque-forming units per colony-forming unit (PFU/CFU). Stability assessments were conducted within a pH range of 4 to 12 and temperatures ranging from 45°C to 60°C. Biofilm biomass reduction was observed, particularly at a multiplicity of infection (MOI) of 10.ResultsKZag1 demonstrated infection efficacy against 12 out of 15 tested K. pneumoniae strains. The phage exhibited stability across a broad pH range and at elevated temperatures. Notably, treatment with KZag1 significantly reduced K. pneumoniae biofilm biomass, emphasizing its potential in combating biofilm formation. Genomic analysis revealed a complete genome of 157,089 base pairs with a GC content of 46.38%, encompassing 203 open reading frames (ORFs) and a cysteine-specific tRNA sequence. Comparison with phage GP4 highlighted similarities, with KZag1 having a longer genome by approximately 4829 base pairs and a higher GC content by approximately 0.93%. Phylogenetic analysis classified KZag1 within the Myoviridae family.ConclusionThe efficacy of KZag1 against K. pneumoniae biofilm suggests its potential as a therapeutic candidate, especially for drug-resistant infections. Further clinical research is warranted to explore its synergy with other treatments, elucidate genomic traits, compare with Myoviridae phages, and understand its host interactions. These findings underscore the promising role of KZag1 in addressing drug-resistant bacterial infections.

Assessment of the Stability of Pseudomonas aeruginosa-specific Myoviridae Bacteriophages in Mupirocin and Abukhalsa Burnt Ointments

Assessment of the Stability of <i>Pseudomonas aeruginosa</i>-specific Myoviridae Bacteriophages in Mupirocin and Abukhalsa Burnt Ointments

A bacteriophage against Citrobacter braakii and its synergistic effect with antibiotics.

A bacteriophage BD49 specific for Citrobacter braakii was screened out and purified by double-layer plate method. It consists of a polyhedral head of 93.1 ± 1.2nm long and 72.9 ± 4.2nm wide, tail fibers, collar, sheath and baseplate. The bacteriophage was identified by morphology observed with transmission electron microscope (TEM), whole genome sequencing carried out by Illumina next generation sequencing (NGS) technique, and gene annotation based on Clusters of Orthologous Groups of proteins (COG) database. It was identified primarily as a member of Caudovirales by morphology and further determined as Caudovirales, Myoviridae, and Citrobacter bacteriophage by alignment of its whole genome sequence with the NCBI database and establishment of phylogenetic tree. The bacteriophage showed good environmental suitability with optimal multiplicity of infection (MOI) of 0.01, proliferation time of 80min, optimum living temperature of 30-40°C, and living pH of 5-10. In addition, it exhibited synergistic effect with ciprofloxacin against C. braakii in antibacterial tests.

The Development of Oral Solid Dosage Forms Using the Direct-Compression Tableting of Spray-Dried Bacteriophages Suitable for Targeted Delivery and Controlled Release

This study addresses the challenge of developing a cheap, patient-friendly alternative to antibiotics using bacteriophages for gastrointestinal applications. It explores the feasibility of manufacturing an enteric solid dosage form containing a salmonella-specific Myoviridae phage, Felix O1, encapsulated in spray-dried trehalose/Eudragit microparticles. The spray-dried powder was further formulated by combining the spray-dried microparticles with magnesium stearate to facilitate the fabrication of tablets using direct compression. The paper presents a comprehensive evaluation of the tablets with measurements of phage viability during tablet fabrication using a range of compression settings and, after tablet disintegration, dissolution and friability. Phage viability measurements were performed using storage stability testing of spray-dried powders and tablets in sealed vials at 4 °C, 20 °C and 30 °C and under different humidity conditions of 0%, 50% and 65% RH. The recommended compression force range was found to be 10–15 kN for a standard 10 mm diameter tablet. The storage of tablets at 4 °C/0% RH was found to be the most favourable condition resulting in a ~1 log loss in titre over a six-month storage period. Storage at higher temperatures and samples exposed to high levels of humidity resulted in a significant loss in phage viability. The paper highlights challenges in developing phage formulations suitable for direct-compression tableting, which afford the phages protection when exposed to temperatures and humidity levels that do not require a cold supply chain.

High-resolution cryo-EM structure of the Pseudomonas bacteriophage E217

E217 is a Pseudomonas phage used in an experimental cocktail to eradicate cystic fibrosis-associated Pseudomonas aeruginosa. Here, we describe the structure of the whole E217 virion before and after DNA ejection at 3.1 Å and 4.5 Å resolution, respectively, determined using cryogenic electron microscopy (cryo-EM). We identify and build de novo structures for 19 unique E217 gene products, resolve the tail genome-ejection machine in both extended and contracted states, and decipher the complete architecture of the baseplate formed by 66 polypeptide chains. We also determine that E217 recognizes the host O-antigen as a receptor, and we resolve the N-terminal portion of the O-antigen-binding tail fiber. We propose that E217 design principles presented in this paper are conserved across PB1-like Myoviridae phages of the Pbunavirus genus that encode a ~1.4 MDa baseplate, dramatically smaller than the coliphage T4.

In Situ Structures of the Ultra-Long Extended and Contracted Tail of Myoviridae Phage P1.

The Myoviridae phage tail is a common component of contractile injection systems (CISs), essential for exerting contractile function and facilitating membrane penetration of the inner tail tube. The near-atomic resolution structures of the Myoviridae tail have been extensively studied, but the dynamic conformational changes before and after contraction and the associated molecular mechanism are still unclear. Here, we present the extended and contracted intact tail-structures of Myoviridae phage P1 by cryo-EM. The ultra-long tail of P1, 2450 Å in length, consists of a neck, a tail terminator, 53 repeated tail sheath rings, 53 repeated tube rings, and a baseplate. The sheath of the contracted tail shrinks by approximately 55%, resulting in the separation of the inner rigid tail tube from the sheath. The extended and contracted tails were further resolved by local reconstruction at 3.3 Å and 3.9 Å resolutions, respectively, allowing us to build the atomic models of the tail terminator protein gp24, the tube protein BplB, and the sheath protein gp22 for the extended tail, and of the sheath protein gp22 for the contracted tail. Our atomic models reveal the complex interaction network in the ultra-long Myoviridae tail and the novel conformational changes of the tail sheath between extended and contracted states. Our structures provide insights into the contraction and stabilization mechanisms of the Myoviridae tail.

Exploring the potential efficacy of phage therapy for biocontrol of foodborne pathogenic extensively drug-resistant Escherichia coli in gastrointestinal tract of rat model

AimThe emergence of extensively drug-resistant (XDR) Escherichia coli leaves little or no therapeutic options for the control of these foodborne pathogens. The goal is to isolate, characterize, and assess the potential efficacy of a bacteriophage in the treatment of an induced gastrointestinal tract infection. Main methodsSewage water was used to isolate phage phPE42. Transmission electron microscope was used for the visualization of phage morphology. Lysis profile, growth kinetics, and stability studies were determined. The ability of phage to eradicate biofilms was assessed by crystal violet staining, resazurin assay, compound bright field microscope, and confocal laser scanning microscope (CLSM). Moreover, the efficacy of phage phPE42 as a potential therapy was evaluated in a rat model. Key findingsA newly lytic Myoviridae phage phPE42 was isolated and exhibited broad coverage activity (48.6 %) against E. coli clinical isolates. It demonstrated favorable growth kinetics and relative stability under a variety of challenging conditions. The resazurin colorimetric assay and CLSM provided evidence of phage potential's ability to significantly (P < 0.05) decrease the viability of biofilm-embedded cells. The bacterial burden in animal faeces was effectively eradicated (P < 0.05) by oral administration of phage phPE42. Phage-treated rats exhibited a significant decrease in tissue damage with no signs of inflammation, necrosis, or erosion. Furthermore, phage therapy significantly (P < 0.05) reduced the expression level of the apoptotic marker caspase-3 and the inflammatory cytokine TNF-α. SignificanceTreatment with phage phPE42 is considered a promising alternative therapy for the control of severe foodborne infections spurred by pathogenic XDR E. coli.

Isolation and Molecular Characterization of Two Novel Lytic Bacteriophages for the Biocontrol of Escherichia coli in Uterine Infections: In Vitro and Ex Vivo Preliminary Studies in Veterinary Medicine.

E. coli is one of the etiological agents responsible for pyometra in female dogs, with conventional treatment involving ovariohysterectomy. Here, we report the isolation and full characterization of two novel lytic phages, viz. vB_EcoM_Uniso11 (ph0011) and vB_EcoM_Uniso21 (ph0021). Both phages belong to the order Caudovirales and present myovirus-like morphotypes, with phage ph0011 being classified as Myoviridae genus Asteriusvirus and phage ph0021 being classified as Myoviridae genus Tequatrovirus, based on their complete genome sequences. The 348,288 bp phage ph0011 and 165,222 bp phage ph0021 genomes do not encode toxins, integrases or antimicrobial resistance genes neither depolymerases related sequences. Both phages were shown to be effective against at least twelve E. coli clinical isolates in in vitro antibacterial activity assays. Based on their features, both phages have potential for controlling pyometra infections caused by E. coli. Phage ph0011 (reduction of 4.24 log CFU/mL) was more effective than phage ph0021 (reduction of 1.90 log CFU/mL) after 12 h of incubation at MOI 1000. As a cocktail, the two phages were highly effective in reducing the bacterial load (reduction of 5.57 log CFU/mL) at MOI 100, after 12 h of treatment. Both phages were structurally and functionally stabilized in vaginal egg formulations.

Structure Of The Head-tail Interface Part Of Myoviridae Bacteriophage TaPaz Revealed by Cryo-EM

Structure Of The Head-tail Interface Part Of Myoviridae Bacteriophage TaPaz Revealed by Cryo-EM

Identification of a broad-spectrum lytic Myoviridae bacteriophage using multidrug resistant Salmonella isolates from pig slaughterhouses as the indicator and its application in combating Salmonella infections

BackgroundSalmonella is a leading foodborne and zoonotic pathogen, and is widely distributed in different nodes of the pork supply chain. In recent years, the increasing prevalence of antimicrobial resistant Salmonella poses a threat to global public health. The purpose of this study is to the prevalence of antimicrobial resistant Salmonella in pig slaughterhouses in Hubei Province in China, and explore the effect of using lytic bacteriophages fighting against antimicrobial resistant Salmonella.ResultsWe collected a total of 1289 samples including anal swabs of pigs (862/1289), environmental swabs (204/1289), carcass surface swabs (36/1289) and environmental agar plates (187/1289) from eleven slaughterhouses in seven cities in Hubei Province and recovered 106 Salmonella isolates. Antimicrobial susceptibility testing revealed that these isolates showed a high rate of antimicrobial resistance; over 99.06% (105/106) of them were multidrug resistant. To combat these drug resistant Salmonella, we isolated 37 lytic phages using 106 isolates as indicator bacteria. One of them, designated ph 2–2, which belonged to the Myoviridae family, displayed good capacity to kill Salmonella under different adverse conditions (exposure to different temperatures, pHs, UV, and/or 75% ethanol) and had a wide lytic spectrum. Evaluation in mouse models showed that ph 2–2 was safe and saved 80% (administrated by gavage) and 100% (administrated through intraperitoneal injection) mice from infections caused by Salmonella Typhimurium.ConclusionsThe data presented herein demonstrated that Salmonella contamination remains a problem in some pig slaughter houses in China and Salmonella isolates recovered in slaughter houses displayed a high rate of antimicrobial resistance. In addition, broad-spectrum lytic bacteriophages may represent a good candidate for the development of anti-antimicrobial resistant Salmonella agents.

EIS biosensor based on a novel Myoviridae bacteriophage SEP37 for rapid and specific detection of Salmonella in food matrixes

Recently, using bacteriophages as new molecular probes in reliable platforms for the detection of bacterial pathogens has attracted more and more increasing attentions. In this paper, a novel isolated Myoviridae bacteriophage SEP37 was covalently immobilized onto gold nanoparticles (AuNPs) modified gold disk electrode (GDE) surfaces using cysteamine (Cys) as a crosslinker. Substrates of GDE-AuNPs-Cys-Phage SEP37 and specific capture of Salmonella cells had been characterized using scanning electron microscopy (SEM) separately. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical response of the biosensor interface manufacturing and bacterial capture process. Under the optimal experimental conditions, this phage-based EIS biosensor was able to detect Salmonella with a wide linear range from 2 × 101 to 2 × 106 colony forming unit (CFU)/mL within 30 min in spiked lake water and lettuce samples, with a limit of detection (LOD) of 17 CFU/mL. The detection linear range of spiked chicken samples was 2 × 102 to 2 × 105 CFU/mL, with a LOD of 1.3 × 102 CFU/mL. In combination with a pre-enrichment process for 3.5 h, this assay could reach a LOD of 1 CFU/mL in chicken breast meat samples. Besides, this phage-based EIS biosensor provided good reproducibility and stability. This phage-based EIS biosensor opens a new opportunity for the detection of pathogenic bacteria using the inherent selectivity of bacteriophage recognition.

Gut bacterial isoamylamine promotes age-related cognitive dysfunction by promoting microglial cell death

The intestinal microbiome releases a plethora of small molecules. Here, we show that the Ruminococcaceae metabolite isoamylamine (IAA) is enriched in aged mice and elderly people, whereas Ruminococcaceae phages, belonging to the Myoviridae family, are reduced. Young mice orally administered IAA show cognitive decline, whereas Myoviridae phage administration reduces IAA levels. Mechanistically, IAA promotes apoptosis of microglial cells by recruiting the transcriptional regulator p53 to the S100A8 promoter region. Specifically, IAA recognizes and binds the S100A8 promoter region to facilitate the unwinding of its self-complementary hairpin structure, thereby subsequently enabling p53 to access the S100A8 promoter and enhance S100A8 expression. Thus, our findings provide evidence that small molecules released from the gut microbiome can directly bind genomic DNA and act as transcriptional coregulators by recruiting transcription factors. These findings further unveil a molecular mechanism that connects gut metabolism to gene expression in the brain with implications for disease development.

Substantiation of propitious “Enzybiotic” from two novel bacteriophages isolated from a wastewater treatment plant in Qatar

Lysin of bacteriophages isolated from a particular ecosystem could be inducted as a bio-controlling tool against the inhabiting pathogenic bacterial strains. Our study aims at both experimental and computational characterization of the identical lysin gene product inherent in the genomes of two novel Myoviridae bacteriophages, Escherichia Phage C600M2 (GenBank accession number OK040807, Protein ID: UCJ01465) and Escherichia Phage CL1 (GenBank Genome accession number OK040806.1, Protein ID: UCJ01321) isolated from wastewater collected from the main water treatment plant in Qatar. The lysin protein, evinced to be a globular N-acetyl-muramidase with intrinsic “cd00737: endolysin_autolysin” domain, was further expressed and purified to be experimentally validated by turbidimetric assay for its utility as an anti-bacterial agent. Comprehensive computational analysis revealed that the scrutinized lysin protein shared 85–98% sequence identity with 61 bacteriophages, all native to wastewater allied environments. Despite varied Host Recognition Components encoded in their genomes, the similitude of lysins, suggests its apparent significance in host–pathogen interactions endemic to wastewater environment. The present study substantiates the identical lysin from Escherichia Phage C600M2 and Escherichia Phage CL1 as propitious “enzybiotic”, a hybrid term to describe enzymes analogous to anti-biotics to combat antibiotic-resistant bacteria by in silico analysis and subsequent experimental validation.

Characterization of Novel Lytic Myoviridae Phage Infecting Multidrug-Resistant Acinetobacter baumannii and Synergistic Antimicrobial Efficacy between Phage and Sacha Inchi Oil.

Multidrug-resistant (MDR) strains of Acinetobacter baumannii have become a major cause of hospital-acquired infections, resulting in an increase in morbidity and mortality worldwide. Many alternative treatments, including phage therapy, are attractive approaches for overcoming problems posed by antibiotic resistance. A newly isolated phage, vWUPSU-specific MDR A. baumannii, showed a narrow host range against MDR A. baumannii. This research was conducted to isolate, characterize, and apply the phage with sacha inchi oil as an alternative antimicrobial agent. Genome analysis suggested that phage vWUPSU is a novel phage belonging to the family Myoviridae, order Caudoviridae. This phage prevented biofilm formation and eradicated preformed biofilms in a dose-dependent manner. In addition, a synergistic antimicrobial effect of the interaction between phage vWUPSU and sacha inchi oil on planktonic cells was observed. The combination of phage and sacha inchi oil significantly inhibited and removed biofilms, compared with the effects of either single treatment. The results of this work indicate that phage vWUPSU could potentially be applied to control MDR A. baumannii. The antibacterial and antibiofilm activities of the combination of phage vWUPSU and sacha inchi oil have attracted significant interests in the development of antibacterial phage products as beneficial treatment options.

Sensitizing and control of colistin-resistant E. coli O157:H7 with bacteriophage application

In these days that we are drifting into the post-antibiotic era, antibiotics called "last-resort" are begun to be used more frequently. Colistin is one of the last-resort antibiotics that act on Gram-negative bacteria. The aim of the study was to investigate antibiotic re-sensitization effect of lytic bacteriophages on colistin resistant E. coli O157:H7 in-vitro. In the study, four E. coli O157:H7 isolates (encoded 25KA, 44RA, 120RA and 168KA) were included. These isolates had different features such as harboring some of the mcr genes but not showing resistance to colistin, or demonstrating resistance to colistin without carrying any mcr genes. A lytic bacteriophage cocktail was prepared with three Myoviridae family member phages. In order to determine the effect of lytic bacteriophage application on the colistin resistance of E. coli O157:H7 strains before, during and after bacteriophage treatment, minimum inhibitory concentrations (MIC) of the isolates were determined by broth microdilution method. The results were interpreted according to EUCAST. According to the results, up to 3.6 log cfu/ml reductions in colistin resistant E. coli O157:H7 were detected within 6h incubation at 23°C. Colistin and phage combination showed synergistic effect. While strains 25KA and 168KA became susceptible to colistin, 44GA and 120RA were totally eliminated. The survivors of the phage treatment were also become sensitive to colistin. Phage-resistant mutants of 25KA and 168KA showed susceptibility to colistin (1 µg/ml and 0.5 µg/ml, respectively). In addition, 44GA and 120GA remained susceptible. The findings of this study highlight that in addition to taking advantage of the lytic activity of phages in biocontrol area, phages also play a major role in re-sensitization to a last-resort antibiotic like colistin. The results show the synergy between phage–antibiotic combination treatment and give the promising idea that this approach has the potential to extend the effective lifetime of antibiotics.

Morphological, biological, and genomic characterization of a newly isolated lytic phage Sfk20 infecting Shigella flexneri, Shigella sonnei, and Shigella dysenteriae1

Shigellosis, caused by Shigella bacterial spp., is one of the leading causes of diarrheal morbidity and mortality. An increasing prevalence of multidrug-resistant Shigella species has revived the importance of bacteriophages as an alternative therapy to antibiotics. In this study, a novel bacteriophage, Sfk20, has been isolated from water bodies of a diarrheal outbreak area in Kolkata (India) with lytic activity against many Shigella spp. Phage Sfk20 showed a latent period of 20 min and a large burst size of 123 pfu per infected cell in a one-step growth analysis. Phage-host interaction and lytic activity confirmed by phage attachment, intracellular phage development, and bacterial cell burst using ultrathin sectioning and TEM analysis. The genomic analysis revealed that the double-stranded DNA genome of Sfk20 contains 164,878 bp with 35.62% G + C content and 241 ORFs. Results suggested phage Sfk20 to include as a member of the T4 myoviridae bacteriophage group. Phage Sfk20 has shown anti-biofilm potential against Shigella species. The results of this study imply that Sfk20 has good possibilities to be used as a biocontrol agent.

In Vitro and In Vivo Assessment of the Potential of Escherichia coli Phages to Treat Infections and Survive Gastric Conditions.

Enterotoxigenic Escherichia coli (ETEC) and Shigella ssp. infections are associated with high rates of mortality, especially in infants in developing countries. Due to increasing levels of global antibiotic resistance exhibited by many pathogenic organisms, alternative strategies to combat such infections are urgently required. In this study, we evaluated the stability of five coliphages (four Myoviridae and one Siphoviridae phage) over a range of pH conditions and in simulated gastric conditions. The Myoviridae phages were stable across the range of pH 2 to 7, while the Siphoviridae phage, JK16, exhibited higher sensitivity to low pH. A composite mixture of these five phages was tested in vivo in a Galleria mellonella model. The obtained data clearly shows potential in treating E. coli infections prophylactically.

Structures of the capsid and the tail of Myoviridae bacteriophage TaPaz, revealed by cryo-EM

Structures of the capsid and the tail of Myoviridae bacteriophage TaPaz, revealed by cryo-EM

Characterization of a lytic EBP bacteriophage with large size genome against Enterobacter cloacae.

Enterobacter cloacae (E.cloacae) is an emerging nosocomial pathogen that had acquired antibiotic resistance against multiple classes of antibiotics. The current study was aimed to isolate and characterize lytic bacteriophage against E.cloacae. The bacteriophage EBP was isolated from a sewage water sample using E.cloacae as a host strain by double-layer agar technique. EBP was found stabile at a wide range of temperatures (25, 37, 60, and 80°C) and pH (5, 6, 7, 8, and 9) with antibacterial activity up to 24h of infection. The latent period of EBP was 20min with a burst size of 252 phages per cell. It showed a narrow host range and infected 12/21 (57%) isolates of E.cloacae tested. It has helical symmetry with a head size of 105 and 120nm long tail with contractile sheath. The EBP has 179.1kb long double-stranded DNA genome with 44.8% GC content. Majority of identified ORFs (187/281) were encoding putative proteins with unknown function. Necessary replication enzymes, structural proteins, and lytic enzymes were detected in the genome of EBP. Phylogenetic analysis revealed that EBP closely resembles with Coronobacter phage vB_CsaM_IeN, vB_CsaM_IeE, vB_CsaM_IeB, and Citrobacter phage Margaery. Based on electron microscopy and molecular characterization, EBP was classified as a Myoviridae phage.

Genomic Analysis of a Novel Phage Infecting the Turkey Pathogen Escherichia coli APEC O78 and Its Endolysin Activity.

Due to the increasing spread of multidrug-resistant (MDR) bacteria, phage therapy is considered one of the most promising methods for addressing MDR bacteria. Escherichia coli lives symbiotically in the intestines of humans and some animals, and most strains are beneficial in terms of maintaining a healthy digestive tract. However, some E. coli strains can cause serious zoonotic diseases, including diarrhea, pneumonia, urinary tract infections, and hemolytic uremic syndrome. In this study, we characterized a newly isolated Myoviridae phage, vB_EcoM_APEC. The phage vB_EcoM_APEC was able to infect E. coli APEC O78, which is the most common MDR E. coli serotype in turkeys. Additionally, the phage’s host range included Klebsiella pneumoniae and other E. coli strains. The genome of phage vB_EcoM_APEC (GenBank accession number MT664721) was 35,832 bp in length, with 52 putative open reading frames (ORFs) and a GC content of 41.3%. The genome of vB_EcoM_APEC exhibited low similarity (79.1% identity and 4.0% coverage) to the genome of Acinetobacter phage vB_AbaM_IME284 (GenBank no. MH853787.1) according to the nucleotide Basic Local Alignment Search Tool (BLASTn). Phylogenetic analysis revealed that vB_EcoM_APEC was a novel phage, and its genome sequence showed low similarity to other available phage genomes. Gene annotation indicated that the protein encoded by orf11 was an endolysin designated as LysO78, which exhibited 64.7% identity (91.0% coverage) with the putative endolysin of Acinetobacter baumannii phage vB_AbaM_B9. The LysO78 protein belongs to glycoside hydrolase family 19, and was described as being a chitinase class I protein. LysO78 is a helical protein with 12 α-helices containing a large domain and a small domain in terms of the predicted three-dimensional structure. The results of site-directed mutagenesis indicated that LysO78 contained the catalytic residues E54 and E64. The purified endolysin exhibited broad-spectrum bacteriolytic activity against Gram-negative strains, including the genera Klebsiella, Salmonella, Shigella, Burkholderia, Yersinia, and Pseudomonas, as well as the species Chitinimonas arctica, E. coli, Ralstonia solanacearum, and A. baumannii. An enzymatic assay showed that LysO78 had highly lytic peptidoglycan hydrolases activity (64,620,000 units/mg) against E. coli APEC O78, and that LysO78 had lytic activity in the temperature range of 4–85 °C, with an optimal temperature of 28 °C and optimal pH of 8.0, and was active at pH 3.0–12.0. Overall, the results suggested that LysO78 might be a promising therapeutic agent for controlling MDR E. coli APEC O78 and nosocomial infections caused by multidrug-resistant bacteria.