The Staphylococcus aureus mec determinant comprises an unusual cluster of direct repeats and codes for a gene product similar to the Escherichia coli sn-glycerophosphoryl diester phosphodiesterase

Abstract

The DNA sequence located between mecA, the gene that codes for penicillin-binding protein PBP2', and insertion sequence-like element IS431mec has been termed hypervariable because of its length polymorphism among different staphylococcal isolates. We sequenced and characterized the hypervariable region of the methicillin resistance determinant (mec) isolated from Staphylococcus aureus BB270. Within the 2,040-bp hypervariable region, we identified an unusual accumulation of long direct repeats. Analysis of the DNA sequence revealed a minimal direct repeat unit (dru) of 40 bp which was repeated 10 times within 500 bp. The dru sequences are responsible for the length polymorphism of mec. Moreover, we identified an open reading frame that codes for 145 amino acids (0RF145), whose deduced amino acid sequence showed 57% amino acid sequence similarity to the N terminus of the glycerophosphoryl diester phosphodiesterase (UgpQ) of Escherichia coli.

Successful Multiresistant Community-Associated Methicillin-Resistant Staphylococcus aureus Lineage from Taipei, Taiwan, That Carries Either the Novel Staphylococcal Chromosome Cassette mec (SCC mec ) Type V T or SCC mec Type IV

“…4). This dru is responsible for the length polymorphism of SCCmec elements (34). There are four such dru's in strain TSGH 17 and three in strain WIS.…”

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Finland

“…The genomic DNA was digested with EcoRI and BglII restiction enzymes, and hybridized with two probes prepared from plasmid pBBB30 (233). HVR probe I is a 3.6-kb fragment that recognizes the HVR of the mec DNA, starting within the mecA gene and reaching up to IS431 mec.…”

“…An analysis of sporadic strains from the year 1995 revealed only three additional HVRtypes, each encountered in only one strain. Previous studies have shown that hypervariable region analysis by PCR and sequencing can be used to distinguish different mec DNA types (191,233,308). Five to eighteen different HVR-types have been identified in collections of 24-254 strains on the basis of differences in either the number or the sequence of dru repeats (185,191,242,246,308).…”

Tätigkeitsbericht des Nationalen Referenzzentrums für Staphylokokken im Jahr 1999

“…Für die mecA-Gen assoziierte DNS wurde dazu bisher die PCRAnalyse des mec-Regulons eingesetzt [3,4]. Im Berichtszeitraum wurde zusätz-lich der PCR-Nachweis der repetitiven dru-Sequenzen eingeführt, die Bestandteil der mecA-assoziierten DNS sind ( [5], Beispiel in Abb. 6).…”