Medical device manufacturer, BioMérieux, has issued a medical device safety alert concerning its VITEK 2 Gram-Negative AST cards.
The manufacturer has identified a performance issue with colistin (cs01n). EUCAST and CLSI recently issued a joint recommendation that broth-microdilution (BMD) is the only validated method for antimicrobial susceptibility testing (AST) of colistin. As the VITEK 2 AST-GN colistin (cs01n) was developed to agar dilution (AD), an internal bioMérieux investigation was conducted to identify any shift in performance for colistin (cs01n) since the VITEK 2 colistin (cs01n) test was developed. Investigational testing included VITEK 2, broth-microdilution and agar dilution using 290 isolates with varying degrees of susceptibility and resistance to colistin. Two QC organisms (E.coli ATCC 25922 and P. aeruginosa ATCC 27853) were also included in the testing. Minimal Inhibitory Concentration (MIC) results from the three methods were compared and evaluated.
According to the manufacturer, the investigation demonstrated a high rate of very major errors (resistant isolates calling susceptible) with the VITEK 2 AST-GN colistin (cs01n) compared to agar dilution (the reference method used for cs01n development) and compared to broth-microdilution (recommended method by EUCAST/CLSI). Since the development of VITEK 2 AST-GN colistin (cs01n), higher resistance rates have been reported. In November 2015 plasmid mediated transferable colistin resistance (mcr-1 gene) was reported and heterogeneous resistance is reported more frequently.
Evaluation of the identified issue indicates the potential for false susceptible colistin results. A false susceptible result could have a negative influence on the treatment decision as the drug may be chosen for therapy. Inappropriate treatment could be prescribed resulting in treatment failure.
The manufacturer advises users to perform an alternate method of testing prior to reporting colistin (cs01n) results.
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 19 May 2017