Notice type: Advisory
The Food and Drud Administration (FDA) in the USA has become aware of an incident of VRSA from a patient in the USA, which brings the documented number of VRSA isolates to three. The investigation showed inconsistent detection of vancomycin resistance by commercial automated susceptibility system. This has raised the concern that additional VRSA infections may occur and be missed when these systems are been used for reporting Staphylococcus aureus resistance and susceptibility profiles.
The FDA indicate that until automated and other commercial systems can be evaluated for reliability with relevant organisms, clinical laboratories performing such tests should be aware of this potential short coming of these systems and should use methods that have been shown to reliably detect the strains that have been described.
The FDA recommends the use of non-automated Minimum Inhibitory Concentration (MIC) methods (e.g. broth microdilution or agar dilution) with a full 24-hour incubation before reading results. Please refer to: FDA website
The IMB is currently in the process of investigating the impact of these findings on the Irish market. We are in the process of contacting the manufacturers of the affected systems: