Distribution of Aeromonas hydrophila serogroups in different clinical samples and the development of polyclonal antibodies for rapid identification of the genus Aeromonas by direct agglutination.

We characterized a collection of 256 Aeromonas hydrophila strains isolated from blood, discharge and stool for their serogroup designation. Of these, 2.3% were untypable and 15.2% were rough strains. Among the typable strains, about 50% comprised serogroups O:11, O:16, O:18, O:34 and O:83. To develop rapid differentiation of Aeromonas from other oxidase-positive bacteria, antisera against Aeromonas were produced to establish a direct, genus-specific, agglutination test. It was found that among 105 isolates of Aeromonas, 102 showed positive results with the agglutination test. The calculated sensitivity and specificity were 97.1% and 90.7%, respectively.