day2.4革兰阴性菌的主要耐药表型.ppt

75% of N. gonorrhoeae and 26% of N. meningitis show a reduced penicillin sensitivity due to PBP modification or impermeability The A to Z of Susceptibility Testing GCS – TM – 0210 Version 3 – Revision 2004/01/06 7 - * 1. What is the Jarlier classification? 2. Klebsiella has what natural enzyme against b-lactams? 3. What types of acquired resistance can Pseudomonas aeruginosa have against quinolones? Gram-negative bacteria are protected by an outer-membrane which confers impermeability: PenG/M and MLSK are too fatty to mix with the porine (oil in water) Glycopeptides are too big to pass through the porine. Fusidic acid: non specific impermeability (inactive on Gram-negative) Acquired b-lactamase resistance mechanisms can come From mutation of chromosomic natural resistance From plasmidic acquisition The A to Z of Susceptibility Testing GCS – TM – 0210 Version 3 – Revision 2004/01/06 7 - * The Enterobacteriaceae are divided into four groups on the basis of their natural susceptibility to b-lactams following the educational classification of Jarlier. Various degrees of natural susceptibility characterize the wild type phenotypes. The A to Z of Susceptibility Testing GCS – TM – 0210 Version 3 – Revision 2004/01/06 7 - * 126 Group 1, no natural resistance, except low level cephalosporinase Group 3, natural cephalosporinase Group 2, natural penicillinase Group 4,natural cephalosporinase + penicillinase The A to Z of Susceptibility Testing GCS – TM – 0210 Version 3 – Revision 2004/01/06 7 - * AMO = Amoxicillin AMC = Amoxicillin/Clavulanic Acid TIC = Ticarcillin CFT = Cefalothin CXT = Cefotaxime Yersinia enterocolitica 结肠炎耶尔森杆菌 The A to Z of Susceptibility Testing GCS – TM – 0210 Version 3 – Revision 2004/01/06 7 - * AMPR-AMPC-基因突变，去阻遏-结构性的HLC The A to Z of Susceptibility Testing GCS – TM – 0210 Version 3 – Revision 2004/01/06 7 - * 127 PASE = Penicillinase PASE low level/ high level: The differenc