Multiple Antibiotic Resistance and Heavy Metal Resistance Profile of Bacteria Isolated from Giant Freshwater Prawn (Macrobrachium rosenbergii) Hatchery

In this article, antibiogram and heavy metal resistance profile of bacteria isolated from giant freshwater prawn (Macrobrachium rosenbergii) hatchery in Malaysia are described. Although giant freshwater prawn was introduced into Malaysia since the 1980s, there was no database information on antibiogram and heavy metal resistance profile of bacteria from giant freshwater prawn (M. rosenbergii) hatchery in Malaysia. Therefore, this study was carried out to determine the effectiveness of antibiotic and heavy metal resistance profile to control bacterial diseases in M. rosenbergii hatchery. The results can provide valuable information for local M. rosenbergii post-larval producer. Antibiotic sensitivity test was carried out by disk-diffusion method against 15 types of antibiotics as follows: oxolinic acid (2 mu g), ampicillin (10 mu g), erythromycin (15 mu g), furazolidone (15 mu g), lincomycin (15 mu g), amoxicillin (25 mu g), colistin sulphate (25 mu g), doxycycline (30 mu g), florfenicol (30 mu g), flumequine (30 mu g), nalidixic acid (30 mu g), tetracycline (30 mu g), oleandomycin (15 fosfomycin (50 mu g), and spiramycin (100 mu g), whereas heavy metal resistance profile of the present bacterial isolates was determined by 2-fold agar dilution technique. In this study, 5 types of bacteria were successfully isolated; they were Aeromonas spp. (n=77), Escherichia coli (n=73), Edwardsiella spp. (n=62), Salmonella spp. (n=75), and Vibrio spp. (n=43). The result showed that furazolidone was the most effective antibiotic to control the bacteria isolated in this study, approximately 89.7% of the bacterial isolates were sensitive to this antibiotic. Multiple antibiotic resistance (MAR) index indicated that the hatchery water source and M. rosenbergii post-larval and sediment tanks were at high-risk exposure to the tested antibiotic. Furthermore, all the tested heavy metals (Cd2+, Cr6+, Hg2+, and Cu2+) failed to inhibit the growth of the bacterial isolates. Therefore, it indicated that the water source of the hatchery is contaminated with both antibiotic residues and heavy metal.