Performance of BD Max StaphSR for Screening of Methicillin-Resistant Staphylococcus aureus Isolates among a Contemporary and Diverse Collection from 146 Institutions Located in Nine U.S. Census Regions: Prevalence of mecA Dropout Mutants

J Clin Microbiol. 2016 Jan;54(1):204-7. doi: 10.1128/JCM.02047-15. Epub 2015 Nov 4.

Abstract

This study determined the performance of BD Max StaphSR and the rate of methicillin-resistant Staphylococcus aureus (MRSA) with an unrecognized staphylococcal cassette chromosome mec (SCCmec) right-extremity junction (MREJ) region among 907 methicillin-resistant S. aureus (MRSA) and 900 methicillin-susceptible S. aureus (MSSA) isolates. The rate of mecA/mecC dropout mutants was also evaluated. Only three MRSA isolates (99.7% sensitivity; 904/907) were classified as MSSA by the BD Max StaphSR assay, due to negative results for MREJ. Eight MSSA isolates (99.1% sensitivity; 892/900) were assigned as MRSA. However, six of these MSSA isolates had the mecA gene confirmed by PCR and sequencing (99.8% sensitivity; 898/900). Overall, 7.1% (64/900) of MSSA isolates showed results compatible with a mecA dropout genotype.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins
  • Bacteriological Techniques / methods*
  • DNA, Bacterial / genetics
  • Humans
  • Mass Screening / methods*
  • Methicillin-Resistant Staphylococcus aureus / genetics
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification*
  • Molecular Diagnostic Techniques / methods*
  • Penicillin-Binding Proteins / deficiency*
  • Sensitivity and Specificity
  • Staphylococcal Infections / diagnosis*
  • Staphylococcal Infections / microbiology
  • United States

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • Penicillin-Binding Proteins
  • mecA protein, Staphylococcus aureus

Grants and funding

This study was funded by BD Diagnostics grant number BDS-MXMSRSA. Rodrigo E. Mendes, Amy A. Watters, Paul R. Rhomberg, David J. Farrell, and Ronald N. Jones are employees of JMI Laboratories, which received compensation fees for manuscript preparation.