Prevalence and co-infections of pathogenic bacteria in Nile tilapia broodstock farms: implications for aquaculture management in Togo.

This study aimed to evaluate the prevalence of E. coli, Pseudomonas spp., and Enterococcus spp. in Nile tilapia broodstock farms in Togo and their association with fish diseases. In total, 60 samples were collected from two tilapia broodstock farms, including 40 broodstock tilapia and 20 water samples. Each farm had concrete tanks supplied with water from two drills. Of the 40 fish samples, 20 were healthy, and the other 20 were diseased. Microbiological analysis of samples was conducted using standardized methods. The study revealed significant contamination in all collected water samples, detecting multiple bacterial populations. Bacterial infections were more prevalent in symptomatic fish, with 85% exhibiting co-infections (df = 1, χ2 = 7.03, p = 0.008). Contamination levels varied among sample types, with higher counts observed in wastewater (E. coli: 0-300 CFU/mL, Pseudomonas spp.: 3-300 CFU/mL, Enterococcus spp.: 0-55 × 102 CFU/mL) compared to drilling water (Pseudomonas spp.: 0-300 CFU/mL, E. coli: 3-400 CFU/mL, Enterococcus spp.: 0-14 × 102 CFU/mL), and intestinal samples (E. coli: 0-120 × 102 CFU/mL, Enterococcus spp.: 0-170 × 102 CFU/mL, Pseudomonas spp.: 0-60 × 102 CFU/mL) (df = 21, χ2 = 59.31, p < 0.000). Our findings emphasize the significant prevalence of pathogenic bacteria in Nile tilapia broodstock farms in Togo, highlighting the importance of water quality management and infection control strategies. Further studies are required to develop appropriate prevention strategies.