Advances in Animal and Veterinary Sciences

Research Article
Adv. Anim. Vet. Sci. 9(12): 2062-2068
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Md. Zobayer Rahman1, Arman Hossain1, Md. Moshiur Rahman1, Shamima Nasren2, Md. Abdullah Al Mamun1*, Sarker Mohammed Ibrahim Khalil1, M. M. Mahbub Alam1

1Department of Fish Health Management, Faculty of Fisheries, Sylhet Agricultural University, Sylhet- 3100, Bangladesh; 2Department of Fish Biology and Genetics, Faculty of Fisheries Sylhet Agricultural University, Sylhet- 3100, Bangladesh.

Abstract | Bacteria plays a vital role in the incidence of fish diseases both in fresh and saline water, thus antibiotics are used for controlling these diseases. For effective treatment, the causative agents of the diseases need to be identified properly. The study was carried out to identify one Aeromonas hydrophila isolated from walking catfish Clarias batrachus and to determine the sensitivity and resistance of five different strains of A. hydrophila to 15 commercially available antibiotics. Aeromonas hydrophila isolated from the diseased walking catfish (C. batrachus) was initially confirmed, using Rimler- Shotts (RS) selective medium for the isolation of A. hydrophila characterized by yellow round colonies. The obtained 16S rRNA sequence of A. hydrophila matched with 887236 – 888648 bps (Identity- 99.72%) of the 16S rRNA gene of A. hydrophila strain B11 chromosome complete genome (GB Accession number CP053859.1). The identity of the sequence with the A. hydrophila sequences in NCBI confirmed that the bacteria isolated from C. batrachus was A. hydrophila and responsible for the disease Motile Aeromonas Septicemia (MAS) or Dropsy. Five strains of A. hydrophila used in this study were completely resistant to ampicillin sulbactam (20 µg) and oxacillin (10 µg). Amoxicillin (30 µg) was moderately resistant due its variant response over antibiotics. The rest of the antibiotics were intermediate and sensitive to A. hydrophila. Ciprofloxacin (5 μg) and Levofloxacin (5 μg) can be used to treat bacterial infections caused by one of the A. hydrophila strains. The information of the present study will be helpful to identify A. hydrophila and the antibiotics to be used to control the bacterial agent in aquaculture.

Keywords | Antibiotics, Sensitivity, 16S rRNA gene, Aeromonas hydrophila, Clarias batrachus