HEMOLYTIC ACTIVITY AND ANTIBIOTIC RESISTANCE OF AEROMONAS SP. ISOLATED FROM MARKETED FISH.

Indu Sharma*, Deepanjali Rabha, Susmita Das and Devjani Ningombam

ABSTRACT

The present work highlights the important incidence of Aeromonas sp., with hemolytic activity, antimicrobial resistance and multiple antibiotic resistance (MAR) isolated from freshwater marketed fish (Labeo rohita) intended for human consumption in Silchar town. Hence, a total of 114 samples were collected of which 45 isolates were isolated. Strain differentiation of A. hydrophila was done on the basis of different sugar fermentation tests used in this study. The haemolytic activity tests were performed on blood agar containing 5% sheep red blood cells and of the 45 Aeromonas sp. strains that were isolated, 35 (77.7%) isolates exhibited β-haemolysis and the number of isolates showing α-haemolysis (8; 17.7%) and γ-haemolysis (2; 4.4%) was relatively small. Antibiotic resistance results revealed that all the A. hydrophila strains were 100% resistant to ampicillin. Besides this, more than 80% of the strains were found to be resistant to penicillin, ofloxacine and gentamycin. Kanamycin, nalidixic acid, chloramphenicol and tetracycline were recorded with a resistance percentage between 28-32% and resistance towards erythromycin (52%) and neomycin (8%) was also observed. Finally, the percentage occurrence of antibiotic resistance of MAR index was calculated and a MAR index value of more than 0.2 was observed, thus suggesting that all the isolates originated from high-risk source of contamination.

Keywords: Fish, haemolytic activity, antibiotic resistance.