Bacteriological study in association with antibiotic and heavy metal resistance pattern of water sample from freshwater giant prawn hatchery

Abstract

The total bacterial flora, antibiotic resistance and metal resistance the diseases associated with water sample of giant freshwater prawns post larvae, Macrobrachium rosenbergii were carried out. A study was undertaken to investigate the presence and the total plate count of bacteria isolates by using non selective agar medium such as Trypticase Soy Agar (TSA) and selective agar such as Thiosulfate Citrate Bile Sucrose Agar (TCBS), Pseudomonas Aeromonas Selective Agar Base (GSP), Mac Conkey Agar, Eosin Methylene Blue Agar (EMB) and Xylose Lysine Deoxycholate Agar (XLD). The total bacterial load on TSA, Mac Conkey and GSP agar varied on 102 cfu ml--i with higher counts seen in GSP agar that was 6.1 x 102 bacteria per ml. But the total bacteriological analysis on EMB, TCBS, and XLD agar to few to determine the count. 29 bacterial isolates were identified as Vibrio spp, Escherichia coli, Pseudomonas spp, Salmonella and Aeromonas spp. Heavy metal test with different level concentration such as cadmium dichloride anhydrous (cd) (25, 5.0,10,20 and 40mg/L), cuprum (Cu) (1.5, 300, 600, 1200 and 2400mg/L), Mercuric dichloride (Hg) (2.5, 5, 10, 20, 40μg) and potassium dichromate (Cr) (25, 50, 100, 200 and 400mg/l). The results showed toxicities in the order of Cd=Hg=Cr>Cu. In this pilot study, all bacterial isolates were examined for their resistance to different 15 antibiotics. These antibiotic included: Flumequine (50μg), Nitrofurantoin (50μg), Florfenicol(30μg), Amoxycillin(25μg), Doxycycline (30μg), Oleandomycin (15μg), Tetracycline (30μg), Ampicillin ( lOμg), Lincomycin (15μg), Colistin Sulphate (25μg), Oxolinic Acid (2μg), Novobiocin (30μg), Spiramycin ( lOOμg), Erythromycin (15μg) And Fosfomycin (50μg). Bacterial isolates were indicated that hundred percent resistance to Doxycycline, Oleandomycin, Linomycin, Novobiocin, Spiramycin, Fosfomycin and Flumequine. The lowest incidence of resistance was found in Nitrofurantoin, Florfenicol, Amoxicillin, Tetracyclyin, Ampicillin, Colistin Sulphate, Oxolinic Acid, and Erythromycin. MAR index shown that >0.2 for isolate bacteria indicated that environment was more polluted. Knowledge of the qualitative and quantitative aspects of bacterial flora in the hatchery would help to understand disturbances, if any, brought about during disease outbreaks to M rosenbergii.