医学PPT课件抗生素

Structure of the bacterial cell envelope. Gram-positive. Gram-negative.
Gram staining animation
http://student.ccbcmd.edu/courses/bio141/labmanua/lab6/imag es/gram_stain_11.swf
Structure of peptidoglycan. Peptidoglycan synthesis requires cross-linking of disaccharide polymers by penicillin-binding proteins (PBPs). NAMA, N-acetylmuramic acid; NAGA, N-acetyl-glucosamine.
• Gram-positive aerobic bacteria • Gram-negative aerobic bacteria • Anaerobic bacteria (both Gram + and -) • Atypical bacteria • Spirochetes • Mycobacteria
Target 3: DNA and Bacterial Replication
Bacterial synthesis of tetrahydrofolate.
Supercoiling of the double helical structure of DNA. Twisting of DNA results in formation of supercoils. During transcription, the movement of RNA polymerase along the chromosome results in the accumulation of positive supercoils ahead of the enzyme and negative supercoils behind it. (Adapted with permission from Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. New York: Garland Science, 2002:314.)
Target 1: The Bacterial Cell Envelope
Two types of bacteria
• Gram-positive: Stained dark blue by Gram-staining procedure
• Gram-negative: Don’t take up the crystal violet stain, and take up counterstain (safranin) instead, staining pink in the Gram procedure.
• Rifamycins • Aminoglycosides • Macrolides and Ketolides • Tetracyclines and Glycylcyclines • Chloramphenicol • Clindamycin • Streptogramins • Linezolid (member of Oxazolidinone Class)
An overview of the process by which proteins are produced within bacteria.
Structure of the bacterial ribosome.
Antibiotics that Block Bacterial Protein Production Include:
Leabharlann Baidu
Gram-positive Bacteria of Clinical Importance
• Staphylococci
– Staphylococcus aureus – Staphylococcus epidermidis
• Streptococci
– Streptococcus pneumoniae – Streptococcus pyogenes – Streptococcus agalactiae – Streptococcus viridans
Replication of the bacterial chromosome. A consequence of the circular nature of the bacterial chromosome is that replicated chromosomes are interlinked, requiring topoisomerase for appropriate segregation.
Antibiotics that Target the Bacterial Cell Envelope Include:
• The b-Lactam Antibiotics • Vancomycin • Daptomycin
Target 2: The Bacterial Process of Protein Production
Antibiotics that Target DNA and Replication Include:
• Sulfa Drugs • Quinolones • Metronidazole
Which Bacteria are Clinically Important?
General Classes of Clinically Important Bacteria Include:
Antibiotics
Step 1: How to Kill a Bacterium.
• What are the bacterial weak points? • Specifically, which commercial antibiotics
target each of these points?