Disease relevance of mecR1

• When a fragment of DNA inserted at the point of the mecR1 deletion was used as a probe, hybridization with multiple bands was detected for Staphylococcus haemolyticus genomic DNA [1].
• Analysis of selected Mcr strains of Staphylococcus aureus and S. epidermidis by Southern hybridization suggested that the natural occurrence of two types of mec resistance determinants differ by the presence or absence of mecR-specific sequences [2].

High impact information on mecR1

• Our results indicate that methicillin resistance under mecR control in certain staphylococcal strains could escape detection by the standard disk diffusion test and broth microdilution test because of the very slow derepression of the mecA gene [3].
• In the present report, we show that the regulation of methicillin resistance occurs primarily at the level of mecA transcription and that in the presence of intact plasmid pI524 or mecR, the gene undergoes negative control [3].
• Total RNA was used to study the effect of penicillinase plasmid pI524 and of mecR, the regulatory region located on the methicillin resistance determinant (mec), on the expression of mecA, the gene coding for the low-affinity penicillin-binding protein PBP2', in methicillin-resistant staphylococci [3].
• The distribution of the mec genes mecA, mecR1 and mecI that regulate the expression of methicillin resistance was investigated by PCR in 145 staphylococci of hospital origin [4].
• Most clinical isolates of methicillin-resistant S. aureus (MRSA) (94.3%) and S. epidermidis (MRSE) (83.9%) possessed both mecI and mecR1 genes (type I), whereas no mec regulator genes were detected in mecA-negative isolates [5].

References