Aquatic bacterial and antimicrobial resistance profile at different fish farms in Accra

Aquaculture expansion in Ghana has been accompanied by increased antimicrobial use, raising concerns about antimicrobial-resistant bacteria emergence. This study determined bacterial prevalence and antimicrobial resistance profiles across fish farms in Accra. A cross-sectional study was conducted at 45 fish farms in Accra. Water samples (n = 135), stool samples from farm workers (n = 42), and biological samples from fish (n = 89) were collected. Bacterial identification used standard microbiological techniques. Antimicrobial susceptibility testing followed Clinical and Laboratory Standards Institute guidelines for nine antimicrobials. Multidrug resistance (MDR) was defined as resistance to ≥3 antimicrobial classes. Diverse bacterial populations were identified across sample types. Resistance rates exceeded 70% for tetracycline, ampicillin, and penicillin. MDR prevalence was highest in water samples (68.9%), followed by biological samples (61.8%) and stool samples (57.1%). Hierarchical clustering analysis using Euclidean distance revealed distinct resistance patterns indicating common selective pressures. Similar resistance profiles across water, fish, and human samples suggested active resistance circulation within farm ecosystems. Significant antimicrobial resistance exists in Accra fish farms, with evidence of resistance dissemination across the aquaculture ecosystem. These findings suggest the need for antimicrobial stewardship programs with veterinary oversight and routine resistance surveillance to mitigate public health risks.