• Gram -
• aerobic or facultatively anaerobic
• asporogenous
• rod shaped
• not fastidious
• some species are atrichous, others are peritrichous, but there are non-motile varients of motile species.
• Nitrates are reduced to Nitrites
• Glucose is utilized fermentatively with the formation of acid or acid and gas.
• Oxidase Negative

Escherichia

Shigella

Salmonella

Klebsiella

Enterobacter

Serratia

Proteus

Yersinia

• Use Mueller Hinton agar
• cover entire agar with organism
• place antimicrobial disks on agar and incubate
• Measure the diameter of no growth around each disk.
• diameter determines if organism is susceptible, intermediate, or resistant.

1. Susceptibility of agent to organism
2. Allergies of patient
3. Other Medications
4. Age, weight
5. method of delivery
6. medical history
7. cost
8. site of infection
9. Gram rxn of infectious organism

Minimal Inhibitory Concentration:

The least amount of an antimicrobial agent that completely inhibits the growth of the patients microorganism.

1. Make 6 dilutions of antimicrobial agent
   1:2, 1:4, 1:8, 1:16, 1:32, 1:64
2. add patients infectious organism to each tube and incubate 35-37°C for 24 hours
3. Look for growth
   The most dilute tube with no growth is the minimal inhibitory concentration.
   
   *Physician always uses 2 dilutions higher than required

Minimal Bacteriocidal Concentration

Least amount of an antimicrobial agent that completely kills a patients microorganism.

1. Use only the inoculated dilutions from MIC test that had no growth.
2. Inoculate one loopful from each tube into a nutrient broth. Incubate 35-37°C for 24 hours.
3. Look for growth
   least concentration with no growth is the Minimal Bacteriocidal Concentration.

Sterility Control: incubate one tube of broth without inoculate to be sure the broth is sterile.

Growth Control: Incubate on tube of broth with patients organism to be sure organism isn't dead or fastidious.

Serum Killing Level

the level of antimicrobial agents in patients blood that completely kills infectious organism.

They measure SKL when anitmicrobial agents are highest in the blood (peak) and lowest in the blood (trough).

*used when patient has received treatments but they were not effective and patient is about to die**

How do you find Serum Killing Level?

What is the procedure to measure SKL and SIL?

1. Draw patients blood at peak and trough
2. make serial dilutions of of peak and trough serum and add organism to each tube.
3. incubate and look for growth
4. Most dilute tube of serum with no growth is the Serum Inhibitory Level
5. Take a loop full of serum from all the tubes with no growth and inoculate nutrient broth tubes.
6. incubate and look for growth, most dilute serum with no growth in nutrient broth is Serum Killing Level.
   *MBC: Minimal Bactericidal Concentration: dilution in broth with no growth.

mycelium

septate mycelium

aseptate mycelium

vegetative part of fungus

septate: frequent cell walls

aseptate: infrequent cell walls

[image]

Oomycota--oospores

Zygomycota--zygospores

ascomycota--ascospores

basidiomycota--basidiospores

• arthrospores: a piece of hyphae breaking off
• chlamydospores: Little spherical balls at end of hyphae
• blastospores: only yeasts: refers to a yeast cell or the bud on a yeast cell.
• macrospore and microspore: only dermatophytes
• sporangiospores: found on oomycota, zygomycota and deuteromycota
• conidium: found on ascomycota or deuteromycota

Conidiospores with associated parts of fungi

• Yeast
• Normal oral and vaginal flora in small amounts
• An overgrowth in Candida Albicans is known as thrush.
• Commonly found in newborn babies
• Can occur in adults with an inhibited immune system- often is the first indicator of HIV/AIDS

• Fungus that is found in bat and pigeon droppings
• Can cause meningitis but very rare.

Physical and chemical ways to keep microorpanisms out of the body:

Skin - eyelashes/nose hairs - oil secretions - blinking

mucus & cilia - vomiting/ diarrhea - HCl - earwax

urination - tears - cough or sneeze - perspiration

non-specific ways the body gets rid of organisms that have gotten past 1st line of defense

Liver - fever - lymph nodes - tonsils - phagocytosis

inflammation - spleen - interferon α, β, γ

complement reactions: blood clotting, phagocytosis

Specific ways the body fights foreign microorganisms that invade the body.

Antibodies - Lymphocytes B & T

Something that stimulates the body to make antibodies.

Usually is a protein but can be a polysaccharide.

O or somatic antigen

H or flagellar antigen

K or capsular antigen

• IgA- dimer- fluids other than blood
• IgG- monomer- blood fixes w/ complement
  IgG can cross the placenta
• IgM- pentamer- blood fixes w/ complement
• IgD- monomer- attached to lymphocytes
• IgE- monomer- blood
  [image] 

The lite chain

[image]

[image]

RH+: Rh or D antigen/ no RH antibody

RH-: no Rh or D antigen/ no RH antibody unless previously exposed to RH antigen

When a Rh- mother is pregnant with an Rh+ baby, the mother becomes exposed to the Rh antigen during childbirth and her blood develops antibodies against it.

During her second pregnancy with an Rh+ baby, the antibodies  in the mother's blood will attack the Rh antigens in the blood of the baby. 

Blood type O

only works for the red cells

Blood type AB

only works for red cells

[image]

Polysaccharide IgM antigen

Protein IgG antigen

Where do B Lymphocytes mature?

What are the 2 types of B Lymphocytes?

• B lymphocytes are born in the bone marrow and mature in the blood.
•  The 2 type of B lymphocytes are memory cells and plasma cells

• T Lymphocytes are born in the bone marrow and they mature in the Thymus
• The types of T Lymphocytes are:

1. Memory
2. Helper T
3. Regulator/Suppressor T
4. Cytotoxic T
5. Natural Killer T

When a specific part of an antibody grasps on to the antigen of the rbc.

[image]

When the antibody blocks the binding site of a cell where a pathogen could attach.

• Natural way: Have infection-antibodies formed can last from years or entire life.
• Acquired way:Get immunizations- often times antibodies only last years- booster required

• natural way: Fetus get IgG from mother through the placenta- lasts through pregnancy until 6 months of age.
• Child gets IgA from breast milk as long as mom breast feeds. Lasts one month after breastfeeding.
• Acquired way: Injection of gamma globulin-lasts up to 6 months
• If going to 3rd world country
• If accidently get stuck by needle
• if in military

1. Part of the infectious organism is used
2. Dead organism
3. Live, attenuated organism
• attenuated: remove its ability to cause disease
• most effective!
4. Live organism that is similar to disease causing one.
• doesn't always work.

• When the monocyte phagocytizes a foreeign invader, it displays the foreign antigens as well as it own antigens on its cell wall.
• the helper t recognizes this combination of foreign and self and attaches to the monocyte.
• It then sends signals to other T&B lymphocytes to proliferate and diversify.

• B lymphocytes create antibodies.
• Suppressor T signals stop when enough have been made.
• Cytoxic T attaches and destroys cells with their specific antigen.
• natural Killer T will kill any foreign cell, regardless of antigen

very tiny, obligate intracellular parasite that has no metabolism.

*Much smaller than bacteria-can only be seen with an electron microscope

*can only work within a host cell

*they are highly specific for the creature and cell they occupy

Icosahedron-usually infects animals

Helical-usually infects plants

Complex-infects bacteria

[image]

*20 faces *12 apexes*30 edges

DNA: double or single stranded

RNA: double or single stranded

*can be one or the other but not both.

hexagonal building blocks that make up a capsid

[image]

image of icosahedron

with

*envelope

*peplomers (spikes)envelope proteins

*capsid

*nucleic acid

*tegument

peplomers work like a lock and key. They must match the attachment site on host cell.

typically infects plants

[image]

[image]

• grasps bacteria with tail fibers
• pins make holes in bacteria
• tail compresses and forces nucleic acid into the host cell
• it uses nutrients and ribosomes of bacteria to make its proteins and forms new viruses that burst out of the bacteria.

Lytic Cycle

Lysogenic Cycle

1. Attachment
2. Penetration by pinocytosis (host cell pulls virus in)
3. uncoating: envelope or capsid comes off to release nucleic acid
4. Multiplication/ Biosynthesis: parts made are seperately and spontaneously combine to make new virions
5. burst or Bud: virions burst out or bud out of the host cell.

1. Attachment (same as Lytic)
2. Penetration (same as Lytic)
3. uncoating (same as lytic)
   **after uncoating, the viral nucleic acid combines with the hosts DNA and remains dormant until something triggers it to complete its cycle.**
4. Multiplication/biosynthesis (same as lytic)
5. Burst or Bud (same as lytic)

• They purchase cells of tissue specific to the virus they want to grow.
• Cells are kept alive in nutrient liquid, which must be changed periodically to get rid of wastes and replenish nutrients.
• When cells are split into a new bottle to grow it is called a passage.

cancer cells don't die. they live through thousands of passages.

CPE: damage to host cells during virus invasion.

CPE is different for each virus. Virologists look for CPE in tissue cultures.