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.

Pharmacokinetics of intravenous and intramuscular danofloxacin in red-eared slider turtles (<i>Trachemys scripta elegans</i>)

“…The mean t 1/2ʎz (24.17 hr) obtained after the IV administration of danofloxacin to red-eared slider turtles was longer than that reported in C. caretta (15.4 hr) [19] and consistent with previously reported value in Amur sturgeon (22.19 hr) [18]. Because t 1/2λz is a hybrid parameter, it is difficult to evaluate the differences in the elimination half-life between species [28].…”

“…It can also be preferred in bacterial diseases of red-eared slider turtles for its pharmacokinetic and pharmacodynamic properties. Although danofloxacin pharmacokinetics had been assessed for ectotherm animals species of C. caretta [19] and some fish species [18, 27], there are no studies in red-eared slider turtles. This study aimed to determine the pharmacokinetics and bioavailability of danofloxacin following intravenous (IV) and intramuscular (IM) administration at 6 mg/kg dose in red-eared slider turtles.…”

Virulence and antimicrobial resistance potential ofAeromonasspp. associated with shellfish

“…Biofilm formation was reported in A. salmonicida recovered from finfish in United Kingdom (Desbois et al 2020). Aeromonas veroni isolates were recovered from shrimp in China (Liu et al 2020) and A. salmonicida, A. veroni, A. enteropelogenes, A. caviae and A.allosaccarophila were isolated from hard shell mussels (Hossain et al 2020).…”

An update on the ornamental fish industry in Malaysia: Aeromonas hydrophila-associated disease and its treatment control

“…The main ornamental fish exporter is from the state of Johor (86), followed by Perak (49), Selangor (38), and Penang (35). Others are from Kuala Lumpur (8), Negeri Sembilan (6), Melaka (3), Kedah (2), and Sarawak (2), whereas the main ornamental fish importer is from Selangor (52), Johor (29), Penang (29), and Perak (25). Others are from Kuala Lumpur (12), Melaka (6), Negeri Sembilan (6), Kedah (2), Terengganu (2), and Sarawak (1) [11].…”

“…There is also a broad spectrum of rarely identified bacteria which may be the causative agents of diseases [3]. A. hydrophila is one of the common freshwater pathogens [24]; it leads to a great economic loss in aquaculture [25]. It has evolved in a wide range of temperatures, conductivities, pHs, and turbidities, and only few environments with extreme ranges of these parameters (extremely saline conditions, hot springs, and highly polluted waters) fail to develop aeromonads [26].…”