title: 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.
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.
authors.affiliation: JMI Laboratories, North Liberty, Iowa, USA rodrigo-mendes@jmilabs.com.
authors.forename: Rodrigo E
authors.initials: RE
authors.lastname: Mendes
authors.affiliation: JMI Laboratories, North Liberty, Iowa, USA.
authors.forename: Amy A
authors.initials: AA
authors.lastname: Watters
authors.affiliation: JMI Laboratories, North Liberty, Iowa, USA.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Rhomberg
authors.affiliation: JMI Laboratories, North Liberty, Iowa, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Farrell
authors.affiliation: JMI Laboratories, North Liberty, Iowa, USA.
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
mesh_terms: D001426:Bacterial Proteins; D001431:Bacteriological Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000235:genetics; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D046915:Penicillin-Binding Proteins / Q000172:deficiency*; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000382:microbiology; D014481:United States
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus