Bài giảng Vai trò của Linezolid trong điều trị MRSA

Nội dung text: Bài giảng Vai trò của Linezolid trong điều trị MRSA

1. Vai Trò Của Linezolid Trong Điều Trị MRSA BS Nguyễn Phương Thùy 1
2. TỔNG QUAN  1.MRSA  2. Cấu trúc và cơ chế tác đông của linezolid  3.Vai trò linezolid trong điều trị MRSA  4. Kết luận 2
3. MRSA  Methicillin-resistant Staphylococcus aureus (MRSA) was first identified in the United Kingdom in 1961, only 2 years after the introduction of methicillin  Over the next few decades MRSA became established in hospitals throughout North America and Europe, and subsequently Northeast, then Southeast, Asia  Extensive use of vancomycin to treat infections caused by MRSA led to the emergence of vancomycin- and methicillin-resistant S. aureus (VRSA).  To date, 11 VRSA strains, which have acquired the vanA operon from glycopeptide-resistant enterococci, have been isolated in the United States (Staphylococcus aureus VRSA-11B Is a Constitutive Vancomycin-Resistant Mutant of Vancomycin-Dependent VRSA-11A - Antimicrob Agents Chemother. 2012 Sep) 7
4. Linezolid  Linezolid was discovered in the mid 1990s and was approved for commercial use in 2000  Linezolid is a member of the oxazolidinone class of medications. The oxazolidinones are protein synthesis inhibitors: they stop the growth and reproduction of bacteria by disrupting translation of messenger RNA (mRNA) into proteins in the ribosome.  As a protein synthesis inhibitor, it affects the ability of bacteria to produce protein. Linezolid binds to the 23S portion of the 50S subunit (the center of peptidyl transferase activity),close to the binding sites of chloramphenicol, lincomycin, and other antibiotics. Due to this unique mechanism of action, cross-resistance between linezolid and other protein synthesis inhibitors is highly infrequent or nonexistent.  Linezolid is metabolized in the liver, by oxidation of the morpholine ring, without involvement of the cytochrome P450 system. Clearance of linezolid varies with age and gender; it is fastest in children (which accounts for the shorter half-life), and appears to be 20% lower in women than in men 9
5. Spectrum of activity  Linezolid is effective against all clinically important Gram- positive bacteria—those whose cell wall contains a thick layer of peptidoglycan and no outer membrane  Enterococcus faecium and Enterococcus faecalis (including VRE)  Staphylococcus aureus ( MRSA)  Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes, the viridans group streptococci,  Listeria monocytogenes  Corynebacterium species 10