Molecular Detection of Tetracycline Types (A) and (B) Resistant Genes in Bacteria Associated with Chrysichtys nigrodigitatus from Abeokuta, Nigeria

The study aimed at isolating and using molecular tools to characterize the bacteria found in the gills intestine and skin using Tetracycline types A and B resistant markers. A total of forty four bacteria samples were isolated from the gills, skin and intestines of fifteen Chrysichtys nigrodigitatus and their antibiotic susceptibility and resistance to tetracycline type A was determined. The bacteria isolates collected were grown on Eosin Methylene Blue (EMB) and Salmonella-Shigella Agar. The pure colony of the bacteria was inoculated on Nutrient Broth overnight at 370C and DNA extraction was done along with PCR analysis using Tetracycline resistance genes type A and B markers. The antibiotic sensitivity test was also conducted using the Maxi disc high profile (-ve) diffusion method. From the result, the mean values of the body weight, total length, and standard length of the fish samples were 147.99 ± 66.4g 126.55 ± 5.55g and 20.05 ± 4.13g respectively. The result of the physical and chemical properties of Ogun River showed temperature (29.0°C), pH (7.8), Dissolved Oxygen (4.9mg/l) and Ammonia (2.3ug/dL). The total mean bacteria count in the gill samples was 1.06 ± 0.20 X 106 CFU/g, while in the intestine samples, it was 1.36 ± 0.27 X 106 CFU/g and in the skin samples is 0.77 ± 0.21 X 106 CFU/g. The 45 samples gave 135 isolates and in total, there were five bacteria found in the gills, intestine and skin of the Chrysichtys nigrodigitatus. The five bacteria isolates included Escherichia coli, Staphylococcus aureus, Bacillus spp, Salmonella spp and Pseudomonas auregenosa. It was revealed that the isolates were sensitive to Ciprofloxacin, Pelfloxacin, and Tarivid. It was also indicated that all the bacterial isolates were susceptible to Ciprofloxacin and Sparfloxacin. The result on Escherichia coli showed susceptibility to Pefloxacin, Ciprofloxacin and Tarivid while it equally showed resistance to Streptomycin, Augmentin and Amoxacillin, Gentamycin, Septrin and Chloranphenicol. The molecular detection shows that Escherichia coli and Salmonella spp is susceptible to Tetracycline Type A while other are resistant to it, so therefore tetracycline type A can only be used to treat infection with Escherichia coli and Salmonella spp.