1. Antibiotics and Bacteria

2. Gram Negative Cocci Neisseria meningitidis
Corticosteroids such as prednisone

3. Comparing Prokaryotic and Eukaryotic Cells
Prokaryote comes from the Greek words for prenucleus.
Eukaryote comes from the Greek words for true nucleus.

4. Fig. 4.25

5. Fill In Your Chart and Create a Definition for Each
Nucleoid
Plasmid
Ribosomes
Cell wall
Plasma membrane (cell membrane)
Capsule (outer membrane)
Flagella
Pili
Gruanules

6. Fig. 4.1

7. Flagella A) Monotrichous B) Lophotrichous C) Amphitrichous
D) Peritrichous

8. Fig. 4.4

9. Fig. 4.7

10. Fig. 4.8

11. Cell Wall Prevents osmotic lysis Made of peptidoglycan (in bacteria)
Polymer of disaccharide N-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM)
Linked by polypeptides

12. Fig. 4.9

13. Fig. i4.1

14. Fig. 4.11

15. Gram positive versus gram negative

16. Crystal violet-iodine crystals form in cell Gram-positive
Gram Staining
Crystal violet-iodine crystals form in cell
Gram-positive
Alcohol dehydrates peptidoglycan
CV-I crystals do not leave
Gram-negative
Alcohol dissolves outer membrane and leaves holes in peptidoglycan
CV-I washes out

17. Fig. i4.2

18. Fig. 4.14

19. Gram-Positive vs. Gram-Negative
Gram summary
Gram-Positive vs. Gram-Negative
Thick peptidoglycan
Teichoic acids
In acid-fast cells, contains mycolic acid
Thin peptidoglycan
No teichoic acids
Outer membrane

20. Examples Gram Positive Gram Negative
Streptococcus (cocci)
Staphylococcus (cocci)
Bacillus (bacilli, protective spore) - causes anthrax and gastroenteritis
Clostridium (bacilli, protective spore) - causes botulism, tetanus, gas gangrene, and pseudomembranous colitis
Corynebacterium (bacilli, no protective spore) - causes diphtheria
Listeria (bacilli, no protective spore) - causes meningitis
Spirochetes (spiral-shaped) - causes syphilis, lyme disease
Neisseria (cocci) - causes meningococcus, gonorrhea

21. Fig. 4.22

22. Fig. 4.23

23. Fig. 4.29

24. Structure of a Bacterial Cell
Cell Wall
-maintains cell structure
-composed of peptidoglycan, a polymer of sugars and amino acids
Flagella
-tail-like structure used for locomotion
Plasma Membrane
-phospholipid bilayer surrounding cell
-contains proteins that play a role in transport of ions, nutrients, and wastes
Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

25. Gram positive and gram negative refers to how a bacteria reacts to a gram stain. If it takes the initial stain, it will be purple and be considered gram positive. If it doesn't take the initial stain, it will be pink and gram negative. The difference is the outer casing of the bacteria. A gram positive bacteria will have a thick layer of peptidoglycan (a sugar-protein shell) that the stain can penetrate. A gram negative bacteria has an outer membrane covering a thin layer of peptidoglycan on the outside. The outer membrane prevents the initial stain from penetrating.

26. Structure of a Bacterial Cell
Nucleoid
-region DNA is found in prokaryotes
DNA
-single double-stranded circular chromosome
-no histone proteins
Plasmid
-small circular chromosome
-may carry an antibiotic resistance gene
Ribosomes
-site of protein synthesis (translation)
Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

27. Some Features of an Infectious Bacteria
virulence factors: molecules produced by a pathogen that aid in its survival in a host
capsule: surrounds bacterial cell wall; protects bacteria from phagocytosis
pili: allows bacteria to attach to and invade other cells despite mucous and cell-turnover
enzymes: break down matrix between cells allowing bacteria to spread throughout tissues
Toxins
exotoxins: cause lysis of specific host cells
enterotoxins: cause secretion of fluid into the small intestine leading to vomiting and diarrhea
endotoxins: cell-bound lipopolysaccharides; causes fever and inflammation
Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.

28. Fleming and Penicillin

29. Antibiotic/Antimicrobial
Antibiotic: Chemical produced by a microorganism that kills or inhibits the growth of another microorganism

30. Microbial Sources of Antibiotics

31. Antibiotic Spectrum of Activity
No antibiotic is effective against all microbes

32. Mechanisms of Antimicrobial Action
Bacteria have their own enzymes for
Cell wall formation
Protein synthesis
DNA replication
RNA synthesis
Synthesis of essential metabolites

33. Beta-lactam antibiotics Mode of Action
The beta-lactam antibiotics inhibit the last step in peptidoglycan synthesis
It is Bactericidal (Bacteria Killing)
Bacteriostatic = Bacteria Inhibiting
Examples:
Penicillin
Ampicillin
Amoxycillin

34. Beta-lactam antibiotics Spectrum
Some are effective against both Gram-positive and Gram-negative bacteria whereas others are more effective against Gram-positive than Gram-negative bacteria or vice versa.

35. Penicllins Derived from the fungus Penicillium
Therapeutic concentration in most tissues
Poor CSF penetration
Renal excretion
Side effects: hypersensitivity, nephritis, neruotoxicity, platelet dysfunction

36. Inhibitors of Cell Wall Synthesis

37. Tetracyclines
Tetracyclines consist of eight members, and may be considered as a group of antibiotics, obtained as byproducts from the metabolism of various species of Streptomyces .

38. Tetracyclines Tetracycline Spectrum (effective against) Mode of action
Biological source
Streptomyces species
Spectrum (effective against)
Gram-positive and Gram-negative bacteria, Rickettsias
Mode of action
Inhibit translation (protein synthesis)
Bacteriostatic

39. Tetracyclines Isolated from Streptomyces aureofaciens
Reversibly bind 30S ribosomal subunit
Penetrate sinus mucosa, saliva and tears
Metabolized in liver-->excreted in bile--> reabsorbed-->eliminated in urine
Side effects: GI upset, hepatotoxicity, photosensitivity, bony deposition
Contraindicated in pregnant or breast feeding women, children under 8 y/o

40. Sulfonamides Derived from prontosil
Act as competitive inhibitors of the enzyme dihydropteroate synthetase (DHPS), an enzyme involved in folate synthesis
Wide distribution, penetrate CSF, cross placenta
Metabolized in liver, eliminated in urine
Side effects: rash, angioedema, Stevens-Johnson syndrome, kernicterus
Avoid in pregnancy and infants

41. Inhibitors of Nucleic Acid Function/Synthesis
Fluoroquinolones (Bactericidal)
Bind to bacteria DNA
Concentrate in sinus and middle ear mucosa, penetrate cartilage and bone
Treat bone and joint infections, skin infections, urinary tract infections, inflammation of the prostate, serious ear infections, bronchitis, pneumonia, tuberculosis, some sexually transmitted diseases (STDs), and some infections that affect people with AIDS
Partially metabolized in liver-->GI or renal excretion
Side effects: nausea, dizziness, phototoxicity, nephrotoxicity
Avoid in pregnant or nursing women
Use in children--possible effect on articular cartilage

42. Antibiotic Therapy Identify infecting organism
Evaluate drug sensitivity
Target site of infection
Drug safety/side effect profile
Patient factors
Cost