Virulent Aeromonas hydrophila (vAh ), Flavobacterium columnare , and Edwardsiella spp. (i.e. ESC) are the three most prevalent pathogenic bacteria afflicting catfish aquaculture. It is imperative to evaluate how bottom sediments of commercial catfish ponds impact the prevalence of pathogenic bacteria. This comprehensive study aims to determine the presence of vAh, F. columnare, and Edwardsiella spp. in renovated and non-renovated commercial catfish ponds in western Alabama and the persistence and antibiotic susceptibility of isolates found in of field vAh isolate susceptibility to oxytetracycline (a), sulfadimethoxine/ormeto-prim (b), and florfenicol (c).
the pond bottom sediments. Sediments from 36 filled non-renovated ponds (NRPs) and s oil cores from 21 drained to-be-renovated ponds (RPs ) at six points from each pond were collected and combined to form one composite sample. The cores of RPs were separated into depths of 0.0-5.0 cm, 5.0-10.0 cm, and 10.0-15.0 cm. Samples were vigorously mixed with 30 mL of DI water and allowed to settle . Then, using a sterile inoculation loop, water was plated onto myo-inositol, modified shieh with tobramycin, E. ictaluri medium, and blood agar. After 24-48 h of incubation at 30oC, targeted bacterial species were streaked for isolation and frozen for later PCR confirmation. Additionally, a ntibiotic susceptibility of vAh, F. columnare , and Edwardiella spp. isolates were tested on Mueller-H inton agar following the disk-diffusion method, using oxytetracycline , sulfadimethoxine/ormetoprim , and florfenicol. Of the 99 soil samples processed, 77 were bio chemically identified as vAh , 28 as F. columnare , and 38 as Edwardiella spp . Antibiotic sensitivity of vAh isolates was determined by measuring zone of inhibition diameter and assigned a susceptibility designation of susceptible, intermediate and resistance to oxytetracycline (Fig. 1a), sulfadimethoxine/ormetoprim (Fig. 1b), and florfenicol (Fig. 1c). 19.35%, 12.67% and 25.35% of vAh isolates were resistant to oxytetracycline, sulfadi-met-hox-ine/ orm-et-oprim, and florfenicol, respectively. Sediment samples were analyzed for chemical and physical analysis. Two cations of interest, calcium (Ca2+ ) and iron (Fe2+ ) had average concentrations of 9346.4 ± 4234.6 ppm and 168.7 ± 44.9 ppm respectively across all sediments. Future research on virulence factors, genetic sequencing, and persistence of these environmental bacterial isolates are necessary in understanding the role of sediments within the pond microbiome.