School outbreak of Escherichia coli O157 with high levels of transmission, Staffordshire, England, February 2012.

Background: Verocytotoxin-producing Escherichia coli (VTEC) are bacteria that cause infectious gastroenteritis and in certain settings can cause widespread infection due to secondary transmission. We describe the findings of an investigation of a school-based outbreak of VTEC in Staffordshire, England.

Methods: Outbreak investigation at a school in February 2012 after two children were diagnosed with VTEC infection.

Sequences of small blaTEM-encoding plasmids in Haemophilus influenzae and description of variants falsely negative for blaTEM by PCR.

Objectives: To characterize an unidentified β-lactamase and associated genetic background in a bla(TEM) and bla(ROB) PCR-negative Haemophilus influenzae isolate, and characterize small bla(TEM)-encoding plasmids in a collection of H. influenzae.

Methods: The unidentified β-lactamase gene was identified by cloning and sequencing the encoding plasmid.