Asian Journal of Microbiology, Biotechnology & Environmental Sciences Paper

PUTATIVE VIRULENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF AEROMONAS SPP. ISOLATED FROM MARKETED FISH INTENDED FOR HUMAN CONSUMPTION IN BANGLADESH

MD. HAZRAT ALI, MD. FARUQUE MIAH1, SHAMSUL H. PRODHAN, MD. ASHRAFUZZAMAN, MD. MAHBUBUR RAHMAN, MD. JAHIR RAIHAN, KAZI MOHAMMAD ALI ZINNAH, MD. TOASIN HOSSAIN AUNKOR, MD. JULHASUR RAHMAN, FATEMA BEGUM RUMA AND MD. AL NAYEM CHOWDHURY

Abstract

Aeromonads are widely distributed in aquatic environments and considered as primary or opportunistic pathogen of fish, aquatic animals and humans. A total of 25 strains of presumptive Aeromonas spp. were identified by using biochemical as well as molecular technique like polymerase chain reaction (PCR). The strains were isolated from 6 samples of marketed fish (Catla catla, Labeo rohita and Cirrhinus mrigala) purchased from local markets of Sylhet City. In the present study, we detected the presence of virulence genes such as hemolysin and aerolysin encoding for putative virulence factors and in vitro screening of putative virulence factors such as lipolytic, hemolytic, congo red dye uptake and proteolytic activities of Aeromonas sp. strains were also examined. In addition, antimicrobial patterns of those strains were also studied. Biochemical identification demonstrated that the prevalent species in marketed fish were Aeromonas hydrophila (36%), Aeromonas veronii (20%), Aeromonas salmonicida (16%), Aeromonas caviae (12%), Aeromonas schubertii (8%) and Aeromonas trota (8%). Hemolysin and aerolysin gene was detected in 60% (15/25) and 56% (14/25) of the strains respectively. All the Aeromonas sp. Strains showed proteolytic, hemolytic and lipolytic activity whereas most of the isolates were able to uptake congo red dye except strain H11, H14, H15 and H24 in in vitro assay. Most of the strains (>80%) were susceptible to chloramphenicol, ciprofloxacin and streptomycin. Conversely majority of the strains were resistant to co-trimethoxazole (44%), amoxicillin (32%) and gentamycin (28%). Besides these, 20% of the strains were resistant to erythromycin, novobiocin and azithromycin. Among the antibiotics used, chloramphenicol was the most effective one.