The Screening of the Protective Antigens of Aeromonas hydrophila Using the Reverse Vaccinology Approach: Potential Candidates for Subunit Vaccine Development

Abstract

The threat of bacterial septicemia caused by Aeromonas hydrophila infection to aquaculture growth can be prevented through vaccination, but differences among A. hydrophila strains may affect the effectiveness of non-conserved subunit vaccines or non-inactivated A. hydrophila vaccines, making the identification and development of conserved antigens crucial. In this study, a bioinformatics analysis of 4268 protein sequences encoded by the A. hydrophila J-1 strain whole genome was performed based on reverse vaccinology. The specific analysis included signal peptide prediction, transmembrane helical structure prediction, subcellular localization prediction, and antigenicity and adhesion evaluation, as well as interspecific and intraspecific homology comparison, thereby screening the 39 conserved proteins as candidate antigens for A. hydrophila vaccine. The 9 isolated A. hydrophila strains from diseased fish were categorized into 6 different molecular subtypes via enterobacterial repetitive intergenic consensus (ERIC)-PCR technology, and the coding regions of 39 identified candidate proteins were amplified via PCR and sequenced to verify their conservation in different subtypes of A. hydrophila and other Aeromonas species. In this way, conserved proteins were screened out according to the comparison results. Briefly, 16 proteins were highly conserved in different A. hydrophila subtypes, of which 2 proteins were highly conserved in Aeromonas species, which could be selected as candidate antigens for vaccines development, including type IV pilus secretin PilQ (AJE35401.1) and TolC family outer membrane protein (AJE35877.1). The present study screened the conserved antigens of A. hydrophila by using reverse vaccinology, which provided basic foundations for developing broad-spectrum protective vaccines of A. hydrophila.

Revealing the associated microflora hosted by the globally significant parasite Trichostrongylus colubriformis

“…The prevalence of AMR genes in both stains identified, could be used for control strategies. Another study for example concluded the identification of two highly conserved proteins in Aeromonas species suggesting their potential selection as candidate antigens for developing of vaccines 22 .…”

Characterization of Three New Outer Membrane Adhesion Proteins in Fusobacterium necrophorum

“…Studies employing reverse vaccinology, in silico analysis, and bioinformatics to predict antigenic vaccine candidates have recognized outer membrane proteins as significant virulence factors. These proteins have been investigated as vaccine candidates in various bacterial species, such as Aeromonas hydrophila [22], Salmonella typhi [32], and Klebsiella pneumoniae [33], due to their capacity to elicit an effective immune response. Here, using host-cell-binding and pull-down assays, we identified four putative OMPs from F. necrophorum subspecies necrophorum (17 kDa, 24 kDa, 43 kDa, and 74 kDa) and one CSP (66.3 kDa), which may function as important adhesins to mediate host-cell attachment, based on results from our in vitro study.…”

“…A unique facet of this research involves modern bioinformatics and in silico investigations, which place greater emphasis on exploring OMPs and secretory elements. This emphasis highlights these components as promising candidates in identifying vaccine targets [21,22]. OMP-mediated adherence is often the first step in infection, and thus, inhibiting this essential interaction represents a possible infection-prevention strategy [23,24].…”

Identification and specificity validation of unique and antimicrobial resistance genes to trace suspected pathogenic AMR bacteria and to monitor the development of AMR in non-AMR strains in the environment and clinical settings

“…It can also be used to develop new strategies for preventing and treating antmicrobial resistance and virulence ( Beceiro et al 2013 ) in Pseudomonas, Helicobacter, Campylobacter, Enterococcus, Klebsiella, Acinetobacter, Salmonella, Haemophilus, Bacillus, and Aeromonas infections. Research from several groups in the last ten years ( Martino et al, 2011 , Liang et al, 2022 , Zhang et al, 2023 ) backs up the idea that some genes found in other genera were unique to Aeromonas or even to certain strains of Aeromonas. This was the prime reason to explore the genus Aeromonas in the later part of the investigations.…”