This is the first known report of tetB or tetH in V. parahaemolyticus. One oxytetracycline-resistant V. cholerae (isolate TVC-O45) and two V. parahaemolyticus (isolates TVP-O99 and TVP-O401) isolates lost their resistance as a result of plasmid curing (Table 4). These isolates were negative by PCR for the resistance genes (tetA or tetH) after plasmid curing, suggesting that the resistance to oxytetracycline was related to R-plasmids (Table 5). Shrimp farms typically rely on rivers and canals that have some amount of seawater inflow for their supply of water. These environments are often contaminated with microorganisms and chemicals from livestock farming. Previously, we demonstrated the prevalence of oxytetracycline resistant bacteria, such as Aeromonas species, in shrimps cultured in inland ponds (Yano et al., 2011). Several samples in the previous study were also used for isolation of Vibrio species in the present study, and both oxytetracycline-resistant aeromonads and Vibrio species were found together in the same samples (data not shown). Taken together, shrimps cultured in inland ponds can be reservoirs