Hemolysin, Protease, and EPS Producing PathogenicAeromonas hydrophilaStrain An4 Shows Antibacterial Activity against Marine Bacterial Fish Pathogens

Abstract

A pathogenic Aeromonas hydrophila strain An4 was isolated from marine catfish and characterized with reference to its proteolytic and hemolytic activity along with SDS-PAGE profile (sodium dodecyl sulphate-Polyacrylamide gel electrophoresis) of ECPs (extracellular proteins) showing hemolysin (approximately 50 kDa). Agar well diffusion assay using crude cell extract of the bacterial isolate clearly demonstrated antibacterial activity against indicator pathogenic bacteria, Staphylococcus arlettae strain An1, Acinetobacter sp. strain An2, Vibrio parahaemolyticus strain An3, and Alteromonas aurentia SE3 showing inhibitory zone >10 mm well comparable to common antibiotics. Further GC-MS analysis of crude cell extract revealed several metabolites, namely, phenolics, pyrrolo-pyrazines, pyrrolo-pyridine, and butylated hydroxytoluene (well-known antimicrobials). Characterization of EPS using FTIR indicated presence of several protein-related amine and amide groups along with peaks corresponding to carboxylic and phenyl rings which may be attributed to its virulent and antibacterial properties, respectively. Besides hemolysin, EPS, and protease, Aeromonas hydrophila strain An4 also produced several antibacterial metabolites.

Detection of 232bp Virulent Gene of Pathogenic <i>Aeromonas hydrophila</i> through PCR Based Technique: (<i>A Rapid Molecular Diagnostic Approach</i>)

“…Haemolytic toxins as haemolysin and aerolysin released by A. hydrophila [12] and pathogenicity has been linked to hemagglutinins, adhesins, several hydrolytic enzymes and enter tissue in culture [13] and play significant role in pathogenesis. EPS, (exopolysaccharides) are importantly play very important role in the bacteria and their environment interactions as they are organic molecules formed by polymerization of organic fractions, carbohydrates, proteins, and humic substances [14][15][16].…”

Determination of beta-haemolytic activity and minimum inhibitory concentrations of antimicrobial drugs against Aeromonas hydrophila strains isolated from fish products

“…Two haemolytic toxins (haemolysin and aerolysin) are described in A. hydrophila. Haemolytic proteins are isolated from microbial pathogens, and β-haemolysins are among the essential virulence factors (Pandey et al, 2010). In our study, we isolated 45 Aeromonas spp.…”

A Brief Review on the Antioxidants and Antimicrobial Peptides Revealed in Mud Crabs from the Genus of Scylla

“…The AMPs are relatively small (mostly less than 10 kDA) which are comprised of different structure, length, and sequence. Another crucial point to take note is that fish and marine invertebrates in aquatic system are largely exposed to various bacterial strains [47]. Hence, AMPs play their role in host innate immunity as a response to combat infections and diseases while living in that particular type of habitat.…”

“…The purification and characterization of the new AMPs in marine organisms are important in order to find new solution to the existence of bacterial resistances towards conventional antibiotics [51]. Recently, the antibacterial activities of mud crab from the genus Scylla have been intensively studied and reported in many researches [42,47,[51][52][53]. Furthermore, [45] in supporting the antimicrobial activity in mud crab from earlier studies, Hoq et al [52] have partially purified the antimicrobial protein from the induced hemolymph of S. serrata.…”