UK company Oxoid has launched a new range of rapid diagnostic tests for the detection and identification of the most common non-O157 verocytotoxin-producing Escherichia coli (VTEC) serogroups.

According to the company the Oxoid Dryspot E. coli Seroscreen and Serocheck tests provide a fast and simple screening procedure for colonies isolated on culture plates, with visible results in just 60 seconds.

Although E. coli O157:H7 is the most significant VTEC serotype associated with human disease, there are a number of additional O-serogroups that are often Verocytotoxin producers, such as O26, O91, O103, O111, O128 and O145. The company stressed in a statement that standard procedures for the detection of E. coli O157 would not detect these serogroups.

Oxoid Dryspot E. coli Seroscreen is a single screening kit that will detect the presence of any of these six common serogroups. The individual Oxoid Dryspot E. coli Serocheck tests, one for each of the serogroups mentioned, are able to provide a specific identification.

Oxoid explains that for each test, the sensitive blue latex reagent is dried onto disposable reaction slides. Suspect colonies are suspended in a drop of buffer and mixed with the reagent on the slide. In the presence of the specific E. coli serogroup (any of the six serogroups for Seroscreen), the latex particles will agglutinate to provide a visible positive result. If the test is negative the latex particles remain in smooth suspension.

The company adds that the absence of 'wet' reagents allows the Oxoid Dryspot E. coli Seroscreen and Serocheck tests to be stored conveniently at room temperature. Each kit contains sufficient materials for 60 tests (Seroscreen kit) or 15 tests (Serocheck kits).