IDENTIFICATION OF VIBRIO SPP WITH THE STRING TEST

The 'string' test has been described as a test for the initial charact erization of Vibrio spp., in particular, to differentiate between Vibr io and Aeromonas spp. Despite early literature questioning the validit y of the test, its use has continued to be recommended. In this study, 49 Vibrio spp., 32 Aeromonas spp. and 47 enteric Gram-negative bacill i were tested and it was found that four genera gave a positive 'strin g' test, including Vibrio, Aeromonas, Pseudomonas and Klebsiella. The sensitivity and specificity of the test for separating Vibrio spp. fro m other Gram-negative bacilli were 86% and 70%, respectively. Hence th e use of the string test in the initial characterization of Vibrio spp . should be supported by appropriate confirmatory tests.