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Superficial or cutaneous mycoses
grow on keratinized tissue (hair, nails, stratum corneum)
Examples: athletes foot, ringworm
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Subcutaneous mycoses
penetrate below the skin to involve the subcutaneous muscle or lymphatic tissues
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Systemic or deep mycoses
Able to infect internal organs and become widely disseminated throughout the body. This type is often fatal.
Example: Chronic Pulmonary Aspergillosis (CPA) A slowly progressive destructive disease of the lung.
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Endoparasites
- Malaria
- Leishmaniasis
- Entamoeba & Giardia
- Intestinal Worms
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Ectoparasites
Ticks, scabies (mite), lice
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Prokaryotic characteristics:
Cell wall and no membrane-bound organelles.
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Bacterial classification: Morphology
1. Cocci
Cocci: Spherically shaped bacteria with rigid cell walls
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Bacterial classification: Morphology
2. Bacilli
Bacilli: Rod-shaped bacteria with rigid cell walls
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Bacterial classification: Morphology
3. Spirillum
elongated, helical bacteria with one or more twists
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Bacterial classification: Morphology
4. Pleomorphic
without shape, can stretch and contort similar to an ameba
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Strepto
bacteria arrange themselves in single file
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Staphylo
Bacteria tend to clump together
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Difference between gram-positive and gram-negative
Gram-positive has more layers of peptidoglycan in their cell walls
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Positive bacteria stain purple because...
They contain up to twenty times more peptidoglycan than gram-negative bacteria
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6 Gram-positive bacteria that infect humans and their shapes
- Streptococcus (cocci)
- Staphylococcus (cocci)
- Bacillus (bacilli)
- Clostridium (bacilli, protective spore)
- Corynebacterium (bacilli, no protective spore)
- Listeria (bacilli, no protective spore)
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Gram-negative bacteria have...
- A unique outer membrane
- Thinner layer of peptidoglycan
- Space between the cell wall and the membrane
- Resistant to lysozyme and penicillin attack
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Spirochetes and Neisseria are examples of...
Gram-Negative bacteria
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What inhibits bacterial growth
Penicillium
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When pathogenic bacteria overwhelm the immune system, we use antibiotics to...
decrease the bacterial population to a level the immune system can handle
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Why are antibiotics not effective against viruses?
Viruses are not living and can only reproduce when they are inside other living cells
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How does penicillin inhibit bacterial growth?
Penicillin targets peptidoglycan (gram-positive bacteria) chains in the cell walls of bacteria
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How do bacteria become resistant?
1. A mutation creates a resistance gene in one bacterium.
2. The patient takes an antibiotic, killing first the weak bacteria, then the stronger bacteria, none of whom have the resistance gene.
(It's evolution!)
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How does bacteria pass on resistance genes?
Bacteria can transfer genes like those for antibiotic resistance onto lots of other bacteria.
They use plasmids (small circular bacterial DNA)
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What are plasmids
Plasmids are circular bits of double-stranded DNA independent of chromosomal DNA. They can replicate and have between 5 and 100 genes.
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What is Conjugation?
Two bacteria join by a tube-like extension called a sex pilus that allows the transfer of DNA from one bacterium to the other.
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What is Transformation?
Plasmids can be absorbed from the enviornment
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What is transduction?
Plasmids from dead cells can be passed via viral delivery
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