Enterobacteria and Vibrio from Macrobrachium amazonicum prawn farming in Fortaleza, Ceará, Brazil

To investigate the isolation of enterobacteria associated with Macrobrachium amazonicum (M. amazonicum) farming and evaluate the in vitro antimicrobial susceptibility of Vibrio strains.

Strains were isolated from female M. amazonicum prawns and environmental and hatchery water. Biochemical assays were used to identify bacterial genera and those belonging to the genus Vibrio were submitted to further analyses for species identification, through Vitek 2 automated system and serotyping. Susceptibility test was performed according to Clinical Laboratory Standards Institute.

The following genera of enterobacteria were recovered: Enterobacter (n = 11), Citrobacter (n = 10), Proteus (n = 2), Serratia (n = 2), Kluyvera (n = 2), Providencia (n = 2), Cedecea (n = 1), Escherichia (n = 1), Edwardsiella (n = 1) and Buttiauxella (n = 1). As for Vibrio, three species were identified: Vibrio cholerae non-O1/non-O139 (n = 4), Vibrio vulnificus (V. vulnificus) (n = 1) and Vibrio mimicus (n = 1). Vibrio spp. showed minimum inhibitory concentrations values within the susceptibility range established by Clinical Laboratory Standards Institute for almost all antibiotics, except for V. vulnificus, which presented intermediate profile to ampicillin.

Enterobacteria do not seem to be the most important pathogens associated with M. amazonicum farming, whereas the recovery of Vibrio spp. from larviculture, with emphasis on Vibrio cholerae and V. vulnificus, deserves special attention due to their role as potentially zoonotic aquaculture-associated pathogens. Furthermore, the intermediate susceptibility of V. vulnificus to ampicillin reflects the importance of monitoring drug use in prawn farming.