Medical device manufacturer, BioMérieux, has issued a medical device safety alert concerning its Mueller Hinton E Agar (MHE). [Reference numbers: 413822, 413823, 413824 and 413825].

Following quality control failures (diameter out of range - too high) when testing American Type Culture Collection (ATCC) strains for antibiotic susceptibility test by disk diffusion method when using MHE agar reported from the field, the manufacturer determined that the use of the medium MHE by disk diffusion method with the antibiotics belonging to cyclines and aminosides classes could potentially lead to failure to quality control test (out of range high) and false susceptible result for clinical isolates (whatever the strain that could be tested) instead of resistant results.

According to the manufacturer, the identified non-conformity concerns all lots manufactured using a specific formulation. New lots produced using new formulations perform within the expected specifications are not affected by the above issue.

As a result of the issue, there is a potential performance issue on strain categorization that could lead to false susceptible result for antibiotics belonging to cyclines and aminosides classes when testing patients' samples' for antibiotic susceptibility test by disk method using affected MHE agar.

Until new lots from the new formulation are available, the manufacturer advises laboratories can continue to use the affected MHE agar only when applying the following recommendations:

• Laboratory should continue to follow their current QC procedure;
• Cyclines and aminosides susceptible results (whatever the clinical strain that could be tested), should be confirmed by an alternative method;
• Results of all the other antibiotics classes can be directly reported.
• Among tests previously performed, the manufacturer is asking users to identify any possible false susceptible results, analyze the related risks and determine appropriate actions if relevant.

According to the local supplier, the affected products are distributed in Hong Kong.

If you are in possession of the affected products, please contact your supplier for necessary actions.

Posted on 12 July 2017