Isolation and characterization of bacteriophages against virulent Aeromonas hydrophila

Abstract

Background Aeromonas hydrophila is an important water-borne pathogen that leads to a great economic loss in aquaculture. Along with the abuse of antibiotics, drug-resistant strains rise rapidly. In addition, the biofilms formed by this bacterium limited the antibacterial effect of antibiotics. Bacteriophages have been attracting increasing attention as a potential alternative to antibiotics against bacterial infections. Results Five phages against pathogenic A. hydrophila, named N21, W3, G65, Y71 and Y81, were isolated. Morphological analysis by transmission electron microscopy revealed that phages N21, W3 and G65 belong to the family Myoviridae, while Y71 and Y81 belong to the Podoviridae. These phages were found to have broad host spectra, short latent periods and normal burst sizes. They were sensitive to high temperature but had a wide adaptability to the pH. In addition, the phages G65 and Y81 showed considerable bacterial killing effect and potential in preventing formation of A. hydrophila biofilm; and the phages G65, W3 and N21 were able to scavenge mature biofilm effectively. Phage treatments applied to the pathogenic A. hydrophila in mice model resulted in a significantly decreased bacterial loads in tissues. Conclusions Five A. hydrophila phages were isolated with broad host ranges, low latent periods, and wide pH and thermal tolerance. And the phages exhibited varying abilities in controlling A. hydrophila infection. This work presents promising data supporting the future use of phage therapy.

Bacteriophages in the Control of Aeromonas sp. in Aquaculture Systems: An Integrative View

“…The majority of marine phages are highly host-specific [ 232 , 233 , 234 ], and about 73% lyse only the original host bacterium [ 234 ]. Although phages with a broad host range are hard to find, some examples of virulent phages have shown some promise for therapeutic use in aquaculture, infecting strains of several bacterial species [ 180 , 181 , 217 , 235 , 236 ] and genera [ 92 , 237 ] ( Table S2 ). Liu et al (2020) reported that the isolated phages had a relatively broad infectivity spectrum against A. hydrophila and showed the potential to infect A. veronii , A. caviae and A. bestiarum [ 236 ].…”

Isolation and Characterization of Bacteriophage ZCSE6 against Salmonella spp.: Phage Application in Milk

“…It was reported that burst sizes are variable in Siphovirus (between 60 and 147 PFU/mL), whereas latent periods and rise times range from 16 to 55 min and 24 to 65 min, respectively [40,41]. Phages have different activities against bacteria, including (i) bacteriostatic activity that stops the bacterial growth, as in Acinetobacter baumannii after 360 min of incubation with phages [42,43], and P. aeruginosa [44]; and (ii) bacteriolytic activity, represented by the reduction in bacterial OD 600 from starting concentration, as in A. baumannii [45] and Aeromonas hydrophila [46]. In this study, phage ZCSE6 presented a bactericidal effect against Salmonella with a significant reduction rate compared to the control.…”

Isolation and Characterization of Bacteriophages Against Aeromonas hydrophila Bacteria Causing Hemorrhagic Septicemia from Striped Catfish (Pangasianodon hypophthalmus

“…Moreover, temperature determines the occurrence, viability, and storage of bacteriophages [16]. In the study of Liu., et al [26], the five bacteriophages (W3, G65, Y81, N21, Y71) maintained almost 100% infectivity after be- Knowledge of phage stability is necessary when phages are subjected to industrial processes such as manufacturing medicated feed, where high temperatures and different pH are often used [21].…”