Evaluation of an alkaline phosphatase-labeled oligonucleotide probe for detection and enumeration of vibrio spp. from shrimp hatchery environment

An alkaline phosphatase (AP)-labeled genus-specific oligonucleotide probe was developed to detect and enumerate vibrios in shrimp larvae and their surrounding environment. The probe was evaluated using 35 laboratory isolates of Vibrio species and 29 isolates of non-vibrio species. The probe was specific for the Vibrio species and no cross reaction was found with the non-vibrios included in the study. The total Vibrio counts obtained by plating on thiosulfate-citrate-bile salts-sucrose agar (TCBS) and using oligonucleotide probe were compared. Total Vibrio counts obtained by probe were comparatively higher than the counts obtained by plating on TCBS agar. The difference between the counts obtained by the probe and by plating on TCBS agar ranged from 2 to 21 times. The study reveals that the use of a non-selective medium such as T1N3 agar followed by detection using a genus-specific probe would help to precisely enumerate the total Vibrio load in the aquaculture environments.