Difficult-To-Detect Staphylococcus aureus: mecA -Positive Isolates Associated with Oxacillin and Cefoxitin False-Susceptible Results

The Novel Oxazolidinone TBI-223 Is Effective in Three Preclinical Mouse Models of Methicillin-Resistant Staphylococcus aureus Infection

“…MIC was defined as the lowest concentration at which no visible growth occurred. Linezolid MICs for the clinical strains generally matched those reported by the CDC ( 47 ).…”

Rapid Identification of Methicillin-Resistant Staphylococcus aureus Using MALDI-TOF MS and Machine Learning from over 20,000 Clinical Isolates

“…The lower AUC in FYH is due to a lower specificity of 0.65, which means some strains were predicted as MRSA in our trained ML predicts but they were identified as MSSA in FYH AST reports. FYH used Vitek 2 instead of Phoenix for AST; however, Gargis et al have reported that MRSA could be miscategorized into MSSA in Vitek 2 system ( 20 ), which could result in the lower specificity in our ML model when predicting MRSA using FYH data set.…”

Resistance and Molecular Characteristics of Methicillin-Resistant Staphylococcus aureus and Heterogeneous Vancomycin-Intermediate Staphylococcus aureus

“…[20][21][22] Isolates MR-hVISA-33 and MRSA-6539 were mecA positive yet phenotypically susceptible to oxacillin (OS-MRSA), indicating the likely occurrence of frameshift mutations or single base substitutions in regions of nucleotide repeats within mecA, which have the ability to reverse into resistance when exposed to antibiotics. 23,24 The other remaining 12 strains, despite exhibiting phenotypic resistance to oxacillin or/and cefoxitin, were not identified by PCR for the mecA gene and had negative results in the SCCmec typing assay, so we did not treat them as MRSA.…”