GeneXpert Captures Unstable Methicillin-Resistant Staphylococcus aureus Prone to Rapidly Losing the mecA Gene ▿

A cefoxitin-susceptible Staphylococcus aureus strain was identified by the Cepheid GeneXpert as methicillin-resistant S. aureus (MRSA). This strain was highly unstable and rapidly lost SCCmec upon subculturing in vitro, indicating that unstable MRSA is best detected by gene amplification-based methods

Systematic Internal Transcribed Spacer Sequence Analysis for Identification of Clinical Mold Isolates in Diagnostic Mycology: a 5-Year Study▿ †

The implementation of internal transcribed spacer (ITS) sequencing for routine identification of molds in the diagnostic mycology laboratory was analyzed in a 5-year study. All mold isolates (n = 6,900) recovered in our laboratory from 2005 to 2009 were included in this study. According to a defined work flow, which in addition to troublesome phenotypic identification takes clinical relevance into account, 233 isolates were subjected to ITS sequence analysis. Sequencing resulted in successful identification for 78.6% of the analyzed isolates (57.1% at species level, 21.5% at genus level). In comparison, extended in-depth phenotypic characterization of the isolates subjected to sequencing achieved taxonomic assignment for 47.6% of these, with a mere 13.3% at species level. Optimization of DNA extraction further improved the efficacy of molecular identification. This study is the first of its kind to testify to the systematic implementation of sequence-based identification procedures in the routine workup of mold isolates in the diagnostic mycology laboratory