In Silico and In Vivo Evaluation of Bacteriophage φEF24C, a Candidate for Treatment of Enterococcus faecalis Infections

Abstract

Along with the increasing threat of nosocomial infections by vancomycin-resistant Enterococcus faecalis, bacteriophage (phage) therapy has been expected as an alternative therapy against infectious disease. Although genome information and proof of applicability are prerequisites for a modern therapeutic phage, E. faecalis phage has not been analyzed in terms of these aspects. Previously, we reported a novel virulent phage, EF24C, and its biology indicated its therapeutic potential against E. faecalis infection. In this study, the EF24C genome was analyzed and the in vivo therapeutic applicability of EF24C was also briefly assessed. Its complete genome (142,072 bp) was predicted to have 221 open reading frames (ORFs) and five tRNA genes. In our functional analysis of the ORFs by use of a public database, no proteins undesirable in phage therapy, such as pathogenic and integration-related proteins, were predicted. The noncompetitive directions of replication and transcription and the host-adapted translation of the phage were deduced bioinformatically. Its genomic features indicated that EF24C is a member of the SPO1-like phage genus and especially that it has a close relationship to the Listeria phage P100, which is authorized for prophylactic use. Thus, these bioinformatics analyses rationalized the therapeutic eligibility of EF24C. Moreover, the in vivo therapeutic potential of EF24C, which was effective at a low concentration and was not affected by host sensitivity to the phage, was proven by use of sepsis BALB/c mouse models. Furthermore, no change in mouse lethality was observed under either single or repeated phage exposures. Although further study is required, EF24C can be a promising therapeutic phage against E. 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.…”

The Terminally Redundant, Nonpermuted Genome ofListeriaBacteriophage A511: a Model for the SPO1-Like Myoviruses of Gram-Positive Bacteria

“…Interestingly, the extent of terminal redundancy in these otherwise similar phages varies greatly, from 3.1 kb in A511 to approximately 20 kb in K. In fact, our data indicate that this is a general feature of the SPO1-like phages. The sequence of Enterococcus faecalis phage EF24C has been published very recently (60) and features significant homologies to A511 (47% overall nucleic acid identity and 64 proteins with Ͼ33.7% identity [expectation values of Ͻ0.001]). Although EF24C was classified as being a SPO1-like phage, the authors of that publication assumed that it has a circularly permuted genome.…”

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].…”