An epidemic CC1-MRSA-IV clone yields false-negative test results in molecular MRSA identification assays: a note of caution, Austria, Germany, Ireland, 2020
Stefan Monecke, Elisabeth König, Megan R. Earls, Eva Leitner, Elke Müller, Gabriel E. Wagner, David M. Poitz, Lutz Jatzwauk, Teodora Vremeră, Olivia Dorneanu, Alexandra Simbeck, Andreas Ambrosch, Ines Zollner‐Schwetz, Robert Krause, Werner Ruppitsch, Wulf Schneider‐Brachert, David C. Coleman, Ivo Steinmetz, Ralf Ehricht
Abstract
We investigated why a clinical meticillin-resistant Staphylococcus aureus (MRSA) isolate yielded false-negative results with some commercial PCR tests for MRSA detection. We found that an epidemic European CC1-MRSA-IV clone generally exhibits this behaviour. The failure of the assays was attributable to a large insertion in the orfX /SCC mec integration site. To ensure the reliability of molecular MRSA tests, it is vital to monitor emergence of new SCC mec types and junction sites.