Hemolysin-Producing Gram-Negative Bacterial Profile in Fish Pond Wastewater

Aquaculture wastewater is increasingly recognized as a hotspot for pathogenic microorganisms. This study investigates the diversity and hemolytic characteristics of Gram-negative bacteria isolated from three fish pond effluents. Standard microbiological methods, including cultural, morphological, and biochemical tests (Gram staining, catalase, oxidase and coagulase), were used for identification, while hemolysin activity was determined using blood agar. The isolates obtained were presumptively identified as Pseudomonas spp., and Klebsiella sp., Pseudomonas sp., isolated from all three ponds showed β-hemolytic activity, whereas Klebsiella sp., showed no hemolytic activity in two water samples tested. The presence of hemolysin-producing Pseudomonas spp., suggests a strong pathogenic potential, as hemolysin is a key virulence factor that enhances bacterial survival and host tissue destruction. The detection of such organisms in fish pond wastewater highlights the risk of bacterial infections in aquaculture and possible transmission to humans. Findings reveal significant levels of hemolysin-producing bacteria, indicating potential threats to environmental safety, fish productivity, and human health. Fish ponds should be regularly screened for possible hemolysin-producing organisms to avoid possible zoonotic diseases ensure better fish production. The use of protective wear should be encouraged while visiting fish ponds.