Microbiological evaluation of a new growth-based approach designated for rapid detection of meticillin-resistant Staphylococcus aureus directly from specimens
Abstract number: P1760
von Eiff C., Maas D., Sander G., Eggemann A., Friedrich A.W., Becker K.
Background: Active screening and compliance to appropriate infection control activities have been shown to play an important role in the control of meticillin-resistant Staphylococcus aureus (MRSA). Rapid diagnostic tests make these efforts even more effective. Thus, infection prevention has taken a step forward with the introduction of various tests for rapid identification of MRSA carriers. To evaluate the reliability of a new rapid screening tool, the 3M BacLite Rapid MRSA Test, to successfully detect MRSA strains, a well-characterized S. aureus strain collection was tested in this study.
Material and Methods: All staphylococcal strains were freshly isolated from clinical material at the University of Münster or during the course of various German multicentre studies. In total, the 724 S. aureus strains tested comprised 211 meticillin-susceptible S. aureus (MSSA) and 513 MRSA strains. To determine the clonal lineages of MRSA strains, spa typing was performed as previously described. spa clonal complexes were assigned by using the BURP algorithm. The 3M BacLite Rapid MRSA Test, that is utilising growth methodology and provides results within five hours, was used according to the instructions of the manufacturer. Ten microliters of each prepared bacterial suspension (McFarland standard 0.5) was directly transferred into each vial containing the selective broth.
Results: All 513 MRSA strains tested were recognised as MRSA, while none of the 211 MSSA strains was detected positive. These results are particularly impressive as the MRSA strains used in this study, represent more than 90 different spa types covering >90% of all registered European MRSA spa types within the SeqNet network. Beside several singletons, the MRSA enrolled in this study were grouped into eight spa clonal complexes. Thus, a very large number of MRSA strains with different genetic background were recognised as MRSA using this method.
Conclusions: The new growth based rapid MRSA assay was shown to detect without exception all MRSA strains of large collections of strains comprising highly diverse genetic backgrounds. Such a phenotypic test might be potentially more likely to cope with new strains. Further studies are warranted to evaluate this method using clinical specimens.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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