Genome Characterization of a Novel Wastewater Bacteroides fragilis Bacteriophage (vB_BfrS_23) and its Host GB124

Abstract

Bacteroides spp. are part of the human intestinal microbiota but can under some circumstances become clinical pathogens. Phages are a potentially valuable therapeutic treatment option for many pathogens, but phage therapy for pathogenic Bacteroides spp. including Bacteroides fragilis is currently limited to three genome-sequenced phages. Here we describe the isolation from sewage wastewater and genome of a lytic phage, vB_BfrS_23, that infects and kills B. fragilis strain GB124. Transmission electron microscopy identified this phage as a member of the Siphoviridae family. The phage is stable when held at temperatures of 4 and 60 • C for 1 h. It has a very narrow host range, only infecting one host from a panel of B. fragilis strains (n = 8). Whole-genome sequence analyses of vB_BfrS_23 determined it is double-stranded DNA phage and is circularly permuted, with a genome of 48,011 bp. The genome encodes 73 putative open reading frames. We also sequenced the host bacterium, B. fragilis GB124 (5.1 Mb), which has two plasmids of 43,923 and 4,138 bp. Although this phage is host specific, its isolation together with the detailed characterization of the host B. fragilis GB124 featured in this study represent a useful starting point from which to facilitate the future development of highly specific therapeutic agents. Furthermore, the phage could be a novel tool in determining water (and water reuse) treatment efficacy, and for identifying human fecal transmission pathways within contaminated environmental waters and foodstuffs.

One Health Assessment of an Urban Temporary Settlement Reveals Gut Microbiome Serving as Antimicrobial Resistance Gene Reservoir

“…Chlamydia gallinacea which causes slow growth and reduced body mass in chickens was detected in two poultry samples collected from the backyard farms. Infection with this organism is also known to cause mild symptoms in humans as well (Salas and de Vega, 2008; Tariq et al, 2020). Additionally, Helicobacter pullorum which causes enteritis in poultry and zoonotic colitis in humans was also detected, along with Gallibacterium anatis that impacts egg production by triggering oophoritis, salpingitis and peritonitis in hens (Narasinakuppe Krishnegowda et al, 2020; Crisci et al, 2021).…”

“…Since enterobacteria such as E. coli, Klebsiella, Shigella , and gut bacteria like Bacteroides, Prevotella, Roseburia, Lachnospira were mostly present in the samples, phages that infect those bacteria were also found. Most of the phages that infects genera of Enterobacteria, Prevotella and Bacteroides fall into the families of Siphoviridae (Tariq et al, 2020; Thakali et al, 2021a), Podoviridae (Manandhar et al, 2020) and Myoviridae (Salas and de Vega, 2008; Crisci et al, 2021). The Stx-2 converting bacteriophage (Table 2) is phage of much importance.…”

TEM Experiment and Complete Genome Sequencing with Comparative Genomic Analysis to Uncover Potential Probiotic Features of IsolatedLactobacillus delbrueckiisubsp.indicusTY-11

“…ClpP proteases contribute to survival and growth of diverse bacteria under conditions of stress [54]. The perfect role of Thymidylate synthase (TS or ThyA) is unidentified within the phage genome but its extra copies probably important for survival of its host by increasing growth [55]. FtsH is not only for the proteolytic removal of unessential proteins, but also in the proteolytic control of some cellular functions [56].…”

Complete Genome Sequence of a Bacteroides fragilis Bacteriophage, vB_BfrS_NCTC

“…This sewage concentrate was added to 5 ml semisoft agar (0.35% [wt/vol]) containing 200 μl B. fragilis NCTC 9343 in mid-exponential growth phase. The plate was incubated for 16 h in an anaerobic cabinet, and resulting single plaques were purified an additional three times before propagation using the Bacteroides phage recovery medium (BPRM) top agar method ( 3 ). In brief, purified phage lysate was mixed with 200 μl mid-log-growth-phase bacterial culture in semisoft BPRM agar (0.35% [wt/vol]) and incubated for 16 h in an anaerobic cabinet (5% CO 2 , 5% H 2 , and 90% N 2 at 37°C and ∼25 lb/in 2 ).…”