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Feature Medical Devices

Laboratories and regulator misled over antibiotic susceptibility test discs

BMJ 2013; 346 doi: (Published 13 February 2013) Cite this as: BMJ 2013;346:f837
  1. Deborah Cohen, investigations editor1,
  2. Glenn Swift, freelance journalist2
  1. 1 BMJ, London WC1H 9JR, UK
  2. 2London, UK
  1. Correspondence to: D Cohen dcohen{at}

Patients may have received inappropriate antibiotic treatment as a result of quality problems with one company’s test discs, Deborah Cohen and Glenn Swift report

A leading global producer of diagnostic tests has been falsely marketing one of its products, an investigation by the BMJ shows.

Oxoid, owned by US diagnostics giant Thermo Fisher, has been selling discs for testing antimicrobial susceptibility that do not always contain the advertised amount of antibiotic. The website of the $10bn (£6bn; €7bn) a year company claims that it is “renowned for quality, accuracy, reliability and innovation.” However, internal documents seen by the BMJ show that this reputation may not be entirely justified.

A BMJ investigation shows that the company used flawed data to determine the quality of its products and misled the UK regulator when it was alerted that some discs did not contain antibiotic. The company continued in early 2012 to mislead clinicians by inaccurately labelling some of its antimicrobial susceptibility discs.

At worst, patients may have been prescribed the wrong antibiotic or moved from oral to intravenous treatment unnecessarily. This comes at a time when health agencies around the world are concerned about antibiotic resistance and the shortage of new antimicrobial treatments in the pipeline.

Only last month, the chief medical officer for England, Sally Davies, described antibiotic resistance as an “apocalyptic scenario.”1 “Antibiotics are losing their effectiveness at a rate that is both alarming and irreversible . . . I urge patients and prescribers to think about the drugs they are requesting and dispensing,” she said.

The findings also pose further questions for Europe’s in vitro diagnostics regulators.

Antimicrobial susceptibility test (AST) discs are used in hospitals around the world to guide the choice of antibiotic treatment. The Basingstoke based company—which was originally housed in the Oxo Tower on London’s …

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