Screening of Polyvalent Phage-Resistant Escherichia coli Strains Based on Phage Receptor Analysis

Abstract

Bacteria-based biotechnology processes are constantly under threat from bacteriophage infection, with phage contamination being a non-neglectable problem for microbial fermentation. The essence of this problem is the complex co-evolutionary relationship between phages and bacteria. The development of phage control strategies requires further knowledge about phage-host interactions, while the widespread use of Escherichia coli strain BL21 (DE3) in biotechnological processes makes the study of phage receptors in this strain particularly important. Here, eight phages infecting E. coli BL21 (DE3) via different receptors were isolated and subsequently identified as members of the genera T4virus , Js98virus , Felix01virus , T1virus , and Rtpvirus . Phage receptors were identified by whole-genome sequencing of phage-resistant E. coli strains and sequence comparison with wild-type BL21 (DE3). Results showed that the receptors for the isolated phages, designated vB_EcoS_IME18, vB_EcoS_IME253, vB_EcoM_IME281, vB_EcoM_IME338, vB_EcoM_IME339, vB_EcoM_IME340, vB_EcoM_IME341, and vB_EcoS_IME347 were FhuA, FepA, OmpF, lipopolysaccharide, Tsx, OmpA, FadL, and YncD, respectively. A polyvalent phage-resistant BL21 (DE3)-derived strain, designated PR8, was then identified by screening with a phage cocktail consisting of the eight phages. Strain PR8 is resistant to 23 of 32 tested phages including Myoviridae and Siphoviridae phages. Strains BL21 (DE3) and PR8 showed similar expression levels of enhanced green fluorescent protein. Thus, PR8 may be used as a phage resistant strain for fermentation processes. The findings of this study contribute significantly to our knowledge of phage-host interactions and may help prevent phage contamination in fermentation.

Infection Kinetics and Phylogenetic Analysis of vB_EcoD_SU57, a Virulent T1-Like Drexlerviridae Coliphage

“…It could be hypothesized that a short latency period and small burst size is a trade-off which increases the chances of phage survival under certain ecological conditions ( Abedon et al, 2001 ; Abedon, 2016 ). Recent characterization of the T1-like phages vB_EcoS-95 and vB_EcoS-IME253 however shows a very short latency period of 4 and 5 min combined with large burst sizes of 115 PFU/cell and 186 PFU/cell, respectively ( Li et al, 2019 ; Topka et al, 2019 ). Latency periods and burst sizes are dependent on the status of their hosts and the ability to synthesize their proteins ( Helmstetter and Cooper, 1968 ; You et al, 2002 ).…”

Bacteriophage-Insensitive Mutants of Antimicrobial-Resistant Salmonella Enterica are Altered in their Tetracycline Resistance and Virulence in Caco-2 Intestinal Cells

“…As no other mutations were observed in surface-associated molecules, it is likely the LPS is the receptor site of phage SI1. Salmonella type phage Felix-O1, capable of infecting 99% of Salmonellae, has also been shown to utilize the bacterial LPS for adsorption [19], and mutations in loci responsible for LPS synthesis and structure have been observed in BIMs of numerous bacteria, including Salmonella [19], Yersinia pestis [12] and E. coli [20]. Mutations within rfaL disrupt O-antigen biosynthesis and have been reported to induce phage resistance in S. Typhimurium [21,22] and E. coli O157:H7 [21].…”

Evaluation of Novel Virulent Phages Infecting the Aeromonas Hydrophila and Escherichia coli Isolated from Sewage Water Samples

“…Phage Bp7 MOI value to infect E. coli for higher yields was about 0.001 (Zhang et al, 2013). Li et al (2019) reported that the optimal MOI for E. coli phages (IME281, IME338, IME339, IME340, and IME341) was 0.001. A low MOI is an advantage in the large-scale application, phage production and can thus effectively reduce the overall cost of a commercial phage preparation (Wong et al, 2014;Bao et al, 2015;Yildirim et al, 2019).…”