1. Bacterial Infections HB62010

2. Bacteria are: Unicellular Unicellular Small (1-4  m) Small (1-4  m) Prokaryotes- no nucleus or membrane bound organelles Prokaryotes- no nucleus or membrane bound organelles Different metabolic reactions to us (peptidoglycan cell wall) Different metabolic reactions to us (peptidoglycan cell wall) Different sources of energy Different sources of energy Photosynthetic bacteria Photosynthetic bacteria Chemosynthetic bacteria Chemosynthetic bacteria Pathogenic bacteria are heterotrophs- get energy from other organisms Pathogenic bacteria are heterotrophs- get energy from other organisms

3. Generalised bacterial cell

4. Escherichia coli

5. Bacterial shapes

6. Bacterial naming Bacteria are usually referred to by their binomial name: Bacteria are usually referred to by their binomial name: Genus species Genus species e.g. Escherichia coli e.g. Escherichia coli This may include Latin words referring to the shape, disease caused by the bacterium, or other properties This may include Latin words referring to the shape, disease caused by the bacterium, or other properties

7. Some examples: Helicobacter pylori Helicobacter pylori Staphylococcus aureus Staphylococcus aureus Staphylococcus epidermis Staphylococcus epidermis Streptococcus pneumoniae Streptococcus pneumoniae Vibrio cholerae Vibrio cholerae Neisseria meningitidis Neisseria meningitidis Neisseria gonorrhoeae Neisseria gonorrhoeae Mycobacterium tuberculosis Mycobacterium tuberculosis Mycobacterium leprae Mycobacterium leprae

8. Gram positive Gram positive Thick cell wall containing Thick cell wall containing mostly peptidoglycan Gram negative Gram negative Cell wall contains less peptidoglycan & more lipid Cell wall contains less peptidoglycan & more lipid Aerobic Aerobic Use oxygen for metabolism Use oxygen for metabolism Anaerobic Anaerobic Don’t use oxygen for metabolism, oxygen may be highly toxic to them Don’t use oxygen for metabolism, oxygen may be highly toxic to them

9. Bacterial reproduction Bacteria have a short generation time (as short as 20min) Bacteria have a short generation time (as short as 20min) Bacteria reproduce binary fission: Bacteria reproduce binary fission: The DNA is replicated The DNA is replicated The cell elongates in the middle The cell elongates in the middle The cell wall & cell membrane pinch inwards The cell wall & cell membrane pinch inwards Two cells separate Two cells separate

10. Why are bacteria so successful? They reproduce quickly They reproduce quickly They evolve quickly (e.g. antibiotic resistance) They evolve quickly (e.g. antibiotic resistance) They can live in extreme environments (e.g. in hot pools- 90 o C) They can live in extreme environments (e.g. in hot pools- 90 o C) Some can form endospores, which can survive for many years (e.g. anthrax) Some can form endospores, which can survive for many years (e.g. anthrax)

11. Not all bacteria are bad! Lactobacillus- ferment milk to make yoghurt and cheese Lactobacillus- ferment milk to make yoghurt and cheese Bacteria are decomposers- break down dead organisms and sewage and recycle the nutrients Bacteria are decomposers- break down dead organisms and sewage and recycle the nutrients There are millions of bacteria in our digestive systems- these produce vitamin K (needed for blood clotting) There are millions of bacteria in our digestive systems- these produce vitamin K (needed for blood clotting)

12. Bacteria as pathogens Some bacteria which gain their energy from other organisms can act as pathogens Some bacteria which gain their energy from other organisms can act as pathogens The negative effects on the host are generally either from toxins produced by the bacteria or from chemicals released by damaged cells The negative effects on the host are generally either from toxins produced by the bacteria or from chemicals released by damaged cells

14. Tetanus Wound infection by Clostridium tetani Wound infection by Clostridium tetani Produces a neurotoxin which causes a prolonged muscle contraction Produces a neurotoxin which causes a prolonged muscle contraction Death due to spasm of the breathing muscles Death due to spasm of the breathing muscles About 10 cases each year in Australia, of which one will die About 10 cases each year in Australia, of which one will die Neonatal tetanus (often infection of the umbilical stump) has a death rate of approximately 75% Neonatal tetanus (often infection of the umbilical stump) has a death rate of approximately 75%

15. Gram positive Gram positive Obligate anaerobe Obligate anaerobe Forms spores which can be found in soil Forms spores which can be found in soil Rod-shaped (‘tennis racket’) Rod-shaped (‘tennis racket’)

17. Some pathogenic cocci Streptococcus pyogenes Streptococcus pyogenes Causes skin infections Causes skin infections Chains of cocci Chains of cocci Staphylococcus aureus Causes wound infections Groups of cocci

18. Neisseria gonorrhoeae Neisseria gonorrhoeae Causes gonorrhoea Causes gonorrhoea Diplococci (pairs) Diplococci (pairs) Neisseria meningitides Causes meningococcal disease Diplococci

19. Some pathogenic spirilli Treponema pallidum Treponema pallidum Causes syphilis Causes syphilis Spirochetes (long spiral shape) Spirochetes (long spiral shape)

20. Bacterial pneumonia

21. Anthrax forms spores which remain dormant in the ground until they are in hospitable surroundings. Anthrax forms spores which remain dormant in the ground until they are in hospitable surroundings.

22. Some bacterial diseases Pneumonia Pneumonia Appendicitis Appendicitis Meningococcal disease Meningococcal disease Skin infections Skin infections Food poisoning Food poisoning

23. Some pathogenic bacilli Escherichia coli Escherichia coli Normally found in human intestines & faeces Normally found in human intestines & faeces Some strains cause severe food poisoning Some strains cause severe food poisoning Haemophilus influenzae Causes some types of pneumonia