Antibiotic-resistance patterns of bacterical pathogens isolated from ornamental fish in Trinidad and Tobago

ABSTRACT

Ornamental fish farming forms an important part of the local aquaculture industry in Trinidad and Tobago, and the number of farms has been increasing annually. This study was designed to ascertain the prevalence of bacterial pathogens from fish and pond water, and determine the resistance of the bacteria to commonly used antimicrobial agents. A total of 1204 bacterial isolates were recovered from 575 fish slurry and 111 water samples from 17 aquaculture farms. Isolates from fish were identified as belonging to 19, and those from water samples were grouped in 18 genera. The predominant genera isolated were (in descending order) Aeromonas spp., Pseudomonas spp., Plesiomonas spp., Chromobacterium spp., Enterobacter spp. and Serratia spp. Screening against 8 antimicrobial agents showed that 95.1 percent (774 of 814) of isolates from fish slurry, and 98.4 percent (254 to 258) of isolates from pond water were resistant to one or more antimicrobial agents ( P> 0.05, X2). The highest resistance (55-94 percent) were to ampicillin, oxytetracycline and erythromycin, but relatively lower resistance (4-14 percent) occurred to gentamycin and norfloxacin (P< 0.05; X2). It was concluded that the high prevalence of bacterial pathogens in ornamental fish coupled with their high levels of resistance to antimicrobial agents may pose therapeutic problems as well as health risks to farmers, workers and fish hobbyists