The Bacteriophage EF-P29 Efficiently Protects against Lethal Vancomycin-Resistant Enterococcus faecalis and Alleviates Gut Microbiota Imbalance in a Murine Bacteremia Model

Abstract

Enterococcus faecalis is becoming an increasingly important opportunistic pathogen worldwide, especially because it can cause life-threatening nosocomial infections. Treating E. faecalis infections has become increasingly difficult because of the prevalence of multidrug-resistant E. faecalis strains. Because bacteriophages show specificity for their bacterial hosts, there has been a growth in interest in using phage therapies to combat the rising incidence of multidrug-resistant bacterial infections. In this study, we isolated a new lytic phage, EF-P29, which showed high efficiency and a broad host range against E. faecalis strains, including vancomycin-resistant strains. The EF-P29 genome contains 58,984 bp (39.97% G+C), including 101 open reading frames, and lacks known putative virulence factors, integration-related proteins or antibiotic resistance determinants. In murine experiments, the administration of a single intraperitoneal injection of EF-P29 (4 × 105 PFU) at 1 h after challenge was sufficient to protect all mice against bacteremia caused by infection with a vancomycin-resistant E. faecalis strain (2 × 109 CFU/mouse). E. faecalis colony counts were more quickly eliminated in the blood of EF-P29-protected mice than in unprotected mice. We also found that exogenous E. faecalis challenge resulted in enrichment of members of the genus Enterococcus (family Enterococcaceae) in the guts of the mice, suggesting that it can enter the gut and colonize there. The phage EF-P29 reduced the number of colonies of genus Enterococcus and alleviated the gut microbiota imbalance that was caused by E. faecalis challenge. These data indicate that the phage EF-P29 shows great potential as a therapeutic treatment for systemic VREF infection. Thus, phage therapies that are aimed at treating opportunistic pathogens are also feasible. The dose of phage should be controlled and used at the appropriate level to avoid causing imbalance in the gut microbiota.

Isolation of a lytic bacteriophage vB_EfaS_PHB08 and its endolysin lys08 against Enterococcus faecalis biofilm

“…It is worthy note that PHB08 can lyse 15 of the 19 E. faecalis strains, with a host range of 78.9%, which has a wider lytic range than the other E. faecalis bacteriophages (7%-70.5%) [38,[40][41][42]. The average burst of PHB08 was 64 phage particles per infected, in line with the generally reported estimate of about 30-122 phage particles per infected [43,44] .The genome sequence of phage PHB08 has the highest similarity (89-98%) with those phages (IME198, HEf13, Ef7.1, EF-P29, EF-P10, VD13, IME-EF1, SAP6, EF1c55, BC-611, Entf1, and Ef2.2) with ~ 40% G + C (Table 3). Phylogenetic analysis of the complete genome sequences of PHB08 and other representative the complete Saphexavirus genome.…”

The Yersinia Phage X1 Administered Orally Efficiently Protects a Murine Chronic Enteritis Model Against Yersinia enterocolitica Infection

“…Referring to the previous study (Cheng et al, 2017), early exponential cultures of ZTYSG 21 were infected with the phage at five different MOIs (PFU/CFU ratios of 10 −6 , 10 −4 , 10 −2 , and 1), and the mixture was incubated in tubes with shaking at 180 rpm at 37 • C. In addition, the uninfected phage group was set as a negative control group. The colony count of the cultures was measured every hour.…”

The Novel Enterococcus Phage vB_EfaS_HEf13 Has Broad Lytic Activity Against Clinical Isolates of Enterococcus faecalis

“…Notably, the host range of phage HEf13 was 70.5% against all tested E. faecalis strains (12 out of 17 tested strains), which is broader than other E. faecalis lytic phages with the host range from 7.6 to 42.5% (Rigvava et al, 2013;Zhang et al, 2013;Ladero et al, 2016;Cheng et al, 2017;Rahmat Ullah et al, 2017;Wang et al, 2018). Regarding burst size, whereas the average burst size of E. faecalis phages reported previously was typically 36-122 PFU/infected bacteria, phage HEf13 has an approximately threefold higher burst size of 352 PFU/infected bacteria (Rigvava et al, 2013;Cheng et al, 2017;Wang et al, 2018). Moreover, phage HEf13 has an average latent time of 25 min after infection, which is shorter than those of other E. faecalis phages (30-50 min) (Uchiyama et al, 2008;Cheng et al, 2017;Wang et al, 2018).…”

“…Based on previously published studies, a total of 22 lytic phages targeting E. faecalis (14 Siphoviridae, 6 Myoviridae, and 2 Podoviridae phages) have been isolated from various sources, including sewage, animal farmyard effluents, and human feces (Bonilla et al, 2010;Bolocan et al, 2019;Lossouarn et al, 2019). Although previous studies have demonstrated the therapeutic potency of newly isolated phages for targeting E. faecalis, practical use of these phages has been limited by their relatively narrow host range against clinically isolated E. faecalis strains (Rigvava et al, 2013;Zhang et al, 2013;Ladero et al, 2016;Cheng et al, 2017;Rahmat Ullah et al, 2017;Wang et al, 2018). In addition, despite the importance of E. faecalis in the pathogenesis of recurrent and incurable periodontitis, curative efficiency of E. faecalis phages has not been evaluated against E. faecalis strains isolated from the oral cavity.…”