Isolation and Characterization of the Novel Phages vB_VpS_BA3 and vB_VpS_CA8 for Lysing Vibrio parahaemolyticus

Abstract

Accumulating evidence has indicated that the multiple drug resistant Vibrio parahaemolyticus may pose a serious threat to public health and economic concerns for humans globally. Here, two lytic bacteriophages, namely vB_VpS_BA3 and vB_VpS_CA8, were isolated from sewage collected in Guangzhou, China. Electron microscopy studies revealed both virions taxonomically belonged to the Siphoviridae family with icosahedral head and a long non-contractile tail. The double-stranded DNA genome of phage BA3 was composed of 58648 bp with a GC content of 46.30% while phage CA8 was 58480 bp with an average GC content of 46.42%. In total, 85 putative open reading frames (ORFs) were predicted in the phage BA3 genome while 84 were predicted in that of CA8. The ORFs were associated with phage structure, packing, host lysis, DNA metabolism, and additional functions. Furthermore, average nucleotide identity analysis, comparative genomic features and phylogenetic analysis revealed that BA3 and CA8 represented different isolates but novel members of the family, Siphoviridae. Regarding the host range of the 61 V. parahaemolyticus isolates, BA3 and CA8 had an infectivity of 8.2 and 36.1%, respectively. Furthermore, ∼100 plaque-forming units (pfu)/cell for phage BA3 and ∼180 pfu/cell for phage CA8 were determined to be the viral load under laboratory growth conditions. Accordingly, the phage-killing assay in vitro revealed that phage CA8 achieved approximately 3.65 log unit reductions. The present results indicate that CA8 is potentially applicable for biological control of multidrug resistant V. parahaemolyticus.

Isolation and Characterization of Six Vibrio parahaemolyticus Lytic Bacteriophages From Seafood Samples

“…These morphological characteristics resemble those of the Siphoviridae family. A recent study by Yang et al (2020) reported a similar finding that two V. parahaemolyticus bacteriophages, namely vB_VpS_BA3 and vB_VpS_CA8, isolated from the sewage were Siphoviridae bacteriophage with an icosahedral head (70 × 55 nm) and a long non-contractile tail (125 to 130 nm). Dion et al (2020) reported that double-stranded DNA (dsDNA) tailed bacteriophages accounted for the majority of bacteriophages reported in the public database.…”

“…Similarly, Ren et al (2019) reported that a bacteriophage cocktail which consisted of PVP1 and PVP2 bacteriophages was superior in preventing V. parahaemolyticus infections in sea cucumbers than the use of single bacteriophages. It was also recently demonstrated that the benefit of bacteriophage cocktails can help to overcome the development of bacteriophage-resistant pathogen strains (Yang et al, 2020). For instance, Kim et al (2020) demonstrated that a bacteriophage cocktail consists of three types of V. coralliilyticus-specific bacteriophages with greater efficiency against multiple-antibiotic-resistant (MAR) and phage-resistant (PR) V. coralliilyticus infection in oyster larvae.…”

“…Different bacteriophages may infect and kill bacteria differently, thus having different optimal MOIs. For example, Yang et al (2020) reported that two V. parahaemolyticus lytic bacteriophages, vB_VpS_BA3 and vB_VpS_CA8, were tested with optimal MOI of 0.1 from the maximum bacteriophage titer produced. A lytic bacteriophage PhVh6 showing the ability to lyse V. alginolyticus , V. harveyi , and V. parahaemolyticus was tested with an optimal MOI of 1 ( Ibrahim et al, 2017 ).…”

“…From the one-step growth curve, the latent period of bacteriophages was estimated to be around 10 to 20 min and the average burst size was anticipated to be approximately 17 to 51 PFU/cell. Previously, vibriophage BA3 and CA8 were estimated as having a latent period of around 20 to 30 min and a burst size of about 100 to 180 PFU/cell ( Yang et al, 2020 ). Another lytic bacteriophage VP06 of V. parahaemolyticus was estimated to have a latent period of approximately 30 min and 60 PFU per infected bacterial cell ( Wong et al, 2019 ).…”

Bacteriophage Therapy of Bacterial Infections: The Rediscovered Frontier

“…Phages against Shigella dysenteriae 2308 were isolated from the New York City sewage by Dubos et al [12]. B_VpS_BA3 and vB_VpS_CA8 phages against Vibrio parahaemolyticus were isolated from sewage collected in China [13]. The vB_KpnP_IME337 phage against carbapenem-resistant Klebsiella pneumoniae was isolated from hospital sewage in China [14].…”