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This paper was the first report on pathogenic bacteria isolated from golden pompano (Trachinotus blochii) with the antibiogram, as well as the heavy metal resistance pattern. Golden pompano becomes popular among Malaysian fish farmers due to its high value and demand from local and oversea markets. However, the baseline information on antibiogram of pathogenic bacteria associated with golden pompano is not well established. Therefore, the information from this study may be useful to fish farmers in selecting appropriate antibiotic for treatment and prophylactive purpose in golden pompano culture. Isolation of bacterial isolates was carried out using 5% of Horse Blood agar, Tryptic Soy Agar (TSA), Mac Conkey, Thiosulphate Citrate Bile Salt (TCBS), Eosin Methylene Blue (EMB), Glutamate Starch Pseudomonas (GSP), Xylose Lysine Deoxycholate (XLD), and Baird Parker media. The bacterial isolates were then identified using conventional biochemical tests and confirmed by commercial bacterial identification kit. Antibiotic susceptibility test of bacterial isolates against 21 antibiotics (oxolinic acid 2 µg, ampicillin 10 µg, erythromycin 15 µg, furazolidone 15 µg, lincomycin 15 µg, oleandomycin 15 µg, amoxicillin 25 µg, colistin sulphate 25 µg, sulphamethoxazole 25 µg, chloramphenicol 30 µg, doxycycline 30 µg, florfenicol 30 µg, flumequine 30 µg, kanamycin 30 µg, nalidixic acid 30 µg, novobiocin 30 µg, oxytetracycline 30 µg, tetracycline 30 µg, nitrofurantoin 50 µg, fosfomycin 50 µg, and spiramycin 100 µg) was determined using disk diffusion method, whereas the heavy metal resistance pattern (mercury Hg2+, cadmium Cd2+, chromium Cr6+, and copper Cu2+) of the bacterial isolates was characterized using two-fold agar dilution method. Five bacterial species were successfully found from 50 diseased golden pompano. They were Streptococcus spp. (n = 12), Escherichia coli (n = 30), Salmonella spp. (n = 20), Pseudomonas spp. (n = 36), and Vibrio spp. (n = 50). More than 80% of the bacterial isolates were found sensitive to 11 out of 21 antibiotics (tetracycline, nitrofurantoin, florfenicol, chloramphenicol, oxytetracycline, nalidixic acid, doxycycline, furazolidone, flumequine, fosfomycin, and oxolinic acid. However, all bacterial isolates were found resistant to all tested heavy metals except for copper and cadmium. The multiple antibiotic resistance (MAR) index of the present study indicated that the fish samples were under high risk exposure to the tested antibiotics. Florfenicol is suggested to be used as antimicrobial agent for golden pompano culture since all bacterial isolates were sensitive to it. |
