Characterization of Vibrio parahaemolyticus strains and evaluation of shrimp cultivation conditions in a farm at the northwestern of Mexico, as risk predictors for its adaptation and dissemination

Abstract

Vibrio parahaemolyticus is recognized as a human pathogen as well as the causative agent of vibriosis in shrimp. This study determined the pathogenic, antimicrobial, and biotic potential of V. parahaemolyticus isolated from white shrimp (Penaeus vannamei) and seawater on a northwestern Mexico farm. A total of 140 samples were randomly collected, including juvenile organisms (n = 120) and seawater (n = 20). The pH, salinity, and biota of the ponds were used to correlate with bacterium presence. The strains were characterized by virulence genes presence, biofilm formation capacity, antimicrobial sensitivity, and the kinetics growth using PCR, microplates method, minimum inhibitory concentration (MIC), and spectrophotometry, respectively. V. parahaemolyticus was detected in 7.1% of the samples with a mean concentration of 3.72 ± 1.24 log CFU mL-1; 6.7% (8/120) in shrimp and 10.0% (2/20) in seawater. Cultivation conditions were not predictive of the specie (P > 0.05). V. parahaemolyticus showed an adaptation time of 1.0 h, and a growth rate of 0.375 h-1 in seawater at 30ºC. The strains were classified into two pathotypes: tlh+ /tdh-/trh-/AP2- (75%) and tlh+ /tdh-/trh-/AP2+ (25%) and three resistant profiles to clinical drugs (ampicillin, amikacin, gentamicin, and netilmicin). The MIC values against oxytetracycline (OTC), florfenicol (FFC) and enrofloxacin (ENRO) were >0.50, >0.25 and >0.06 µg mL-1, respectively. Biofilm formation was a property identified in 40% of the strains. The presence of infectious V. parahaemolyticus with high adaptative potential justifies integrating integrated aquaculture practices and management to control pathogen growth and shrimp health.