Isolation and characterization of a novelEnterococcus faecalisbacteriophage φEF24C as a therapeutic candidate

Abstract

Vancomycin-resistant Enterococcus faecalis (VRE) has become a significant threat in nosocomial settings. Bacteriophage (phage) therapy is frequently proposed as a potential alternative therapy for infections caused by this bacterium. To search for candidate therapeutic phages against Enterococcus faecalis infections, 30 Enterococcus faecalis phages were isolated from the environment. One of these, virulent phage phiEF24C, which has a broad host range, was selected for analysis. The plaque-forming ability of phiEF24C was virtually unaffected by differences in the clinical host strains. Furthermore, the phage had a shorter latent period and a larger burst size than ordinary tailed phages, indicating that phiEF24C has effective lytic activity against many Enterococcus faecalis strains, including VRE. Morphological and genomic analyses revealed that phiEF24C is a large myovirus (classified as family Myoviridae morphotype A1) with a linear double-stranded DNA genome of c. 143 kbp. Analyses of the N-terminal amino acid sequences of the virion proteins, together with the morphology and the genome size, speculated that phiEF24C is closely related to other myoviruses of Gram-positive bacteria that have been used experimentally or practically for therapy or prophylaxis. Considering these results, phiEF24C may be a potential candidate therapeutic phage against Enterococcus faecalis infections.

Characterization of Helicobacter pylori Bacteriophage KHP30

“…ORFs 13 and 11 had the second and third greatest quantities, so they were also considered structural proteins. N-terminal processing of the major structural protein, as seen in the major structural protein of the other tailed phage, has not been observed in ORF14 of phage KHP30 (43,(63)(64)(65), although the first 3 amino acid residues of ORF13 seemed to be removed. In contrast, ORFs 3, 12, 17, and 29 were present in minor amounts.…”

“…Genomic DNA was extracted from the phage particles essentially as described elsewhere (43,44). Moreover, H. pylori strain NY43, which releases phage KHP30, was cultured in BEV medium and then pelleted.…”

Bacteriophages and Their Derivatives as Biotherapeutic Agents in Disease Prevention and Treatment

“…[49], vancomycin-resistant Enterococci [50][51][52], antibiotic-resistant Staphylococci [53,54], multidrugresistant Klebsiella pneumonia [55], imipenem-resistant [56,57] and multidrug-resistant Pseudomonas aeruginosa [58,59], antibiotic-resistant strains of Escherichia coli [60], and methicillin-resistant Staphylococcus aureus [61]. Today, there are several different antibacterial strategies derived from phages including enzybiotics (cloned host-specific, phageencoded lytic enzymes introduced to combat bacteria without the whole phage) and whole-phage therapy (introducing whole, viable phage to attack the infecting bacteria) [8,[62][63][64].…”

Intragenus generalized transduction in Staphylococcus spp. by a novel giant phage

“…Electron microscopy, genome size estimation and nucleoside analysis were conducted to characterize the phage, according to published methods (Uchiyama et al, 2008(Uchiyama et al, , 2012Takemura-Uchiyama et al, 2013). Phage S6 was shown to belong to the family Myoviridae with a genome size of ca.…”