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Microbiology Exam 2

Terms in this set (96)

Goals of Diagnosis
Pure culture via isolation
Methods of Distinction
Direct examination
Molecular techniques
Serologic techniques
Antimicrobial susceptibility
Electron Microscopy
Transmission electron micrograph (TEM)
e- pass through
Steps of Gram Stain
1) CV, 2) Iodine-mordant, 3) Alcohol decolorized 4) Safranin counter stain
Importance of Timing Gram Stain
if alcohol left on too long you can decolorize and get false stain and diagnosis
Differential Stain
Positive Stain seen in endosporse
Simple Stain
Negative Stain in capsules with india ink
Catalyse
H202 into oxygen and water
Biochemical Testing
Stepwise way to get to group of bacteria
Antimicrobial Testing
Clinical isolates are tested for their sensitivity or resistance to certain antimicrobial agents
MIC
The lowest concentration (highest dilution) of the drug that can inhibit growth of the organism
Minimum bactericidal concentration (MBC)
the lowest concentration of a specific antimicrobial medication that kills 99.9% of cells of a given bacterial strain in vitro
Molecular size of agent
Solubility in medium
Stability of the agent
Speed at which the organisms grow

Affect what?
Zone Size in Disc Diffusion
Colonization by infectious agent in GI
24-72 Hours
Bacteria must grow
Food Infection
No Colonization required in GI
Less than 12 Hours
Toxin Mediated
Food Intoxication
Study of microorganisms or Microbes
Microbiology
Unicellular
Single cell
Multicellular
Cell Colony
Acellular
Lacking Cells
Bacteria and Archea are?
P rokaryotes
Parasites, Fungi, Protoza are?
Eukaryotes
Particles - not cells, have processes similar to living organism; some processes like dead things

Not part of taxonomic scheme
Viruses
No nuclear membrane
Haploid Genome
70S ribosomes
Prokaryotic
Membrane Bound nucleus & organelles
Diploid Genome in nucleus
80s ribosomes
Eukaryotic
Acellular particles
Genetic Material in protein covering
Parasitic only
Virus
Three domains are:
Bacteria, Archaea, Eukarya
5 kingdom classification system
1. Monera-Prokaryote, unicellular
2. Protista-Eukarotic-unicellular
3. Fungi-Absorption
4. Plantae-Photosynthesis
5. Animalia-Ingestion
Classification in a domain
Kingdom, Phylum, Class, Order Family, Genus Species
Cell Morphology Parameters:
Shape
Size
STRUCTURE
ARRANGEMENT
Bacterial Colony Morphology
Shape
Size
COLOR
SMELL
Tests for antibody interactions
Serotyping
antibiotic sensitivity test
Antibiogram
Phenotypic characteristics
Serotype-antibody interactions
Antibiogram-Abx sensitivity & resistance
Genotypic Characteristics
Nucleic acid sequence
G/C Ratio
Sugar Fermentation biochemical analysis differentiates what?
Lactose + or Lactose -
Enzyme production biochemical analysis tests can detect what?
Coagulase & urease
Cocci
spherical bacteria
Bacilli
rods
3 architectural regions of bacterium
Appendages-surface
Cell envelope-cell wall
Cytoplasm-genetic & organelles
Types of appendage for mobility & locomotion
Flagella
Appendage for attachement and adhesion
Fimbriae
Appendage for genetic information & conjugation
Pili
Bacterial cell wall that does not have a flagella
Atrichous
a single flagella at one end of the cell
Polar/Monotrichous
tuft of flagella at one end
lophotrichous
flagella all over
peritrichous
Tuft of flagella at both ends
amphitrichous
Motility of flagella
Straight
Tumble
Provide Locomotion
Movement toward or away oxygen
aerotaxis
Movement toward or away pressure
barotaxis
movement toward or away chemicals
Chemotaxis
Movement toward or away electrocurrent
Electrotaxis or Galvanotaxis
Movement toward or away moisture
hydrotaxis
Movement toward or away magnets
magnetaxis
movement toward or away light
phototaxis
movement by temperature change
Thermotaxis
Are flagella found on gram positive and negative?
Yes both have exposed proteins called antigenic
Where are endoflagella found
Gram negative cells only
What are shorter than flagella, hollow, and only on G- that transfer DNA
Sex Pilus
What are shorter than flagella & pilus, cover the entire bacterial cell, and are used in ADHESION & biofilm formation?
Fimbriae
What is attached to cell via basal body, has a rotating filament, and moves cell forward?
Flagellum
Components of cell envelope
Capsule
Cell wall
membranes
Functions of Capsule
Adherence-Glycocalax-sticky adhesion to surfaces
Immune Evasion-slip away-hard to grab
Components of cell wall
Cell phospholipid membrane

Peptidoglycan
Function of cell wall
Provides shape

Osmotic Balance
Types of Cell wall
Gram +
Gram -
Thick peptidoglycan layer
Purple Gram Stain
Cytoplasmic Membrane
Gram +
Teichoic Acid-Anchor
Lipoteichoic Acid
Gram +
thin peptidoglycan layer
Pink Gram Stain
Cytoplasmic/Inner membrane, Periplasmic Space
LPS
gram negative
Purpose of LPS in Gram Negative Cell Wall?
Adherence & Virulence
peptidoglycan cross bridge structure
NAG
NAM
4 AA
The Peptidoglycan is __________ in Gram Positives?
Thick
The Peptidoglycan is __________ in Gram Negatives?
Thin
Found in Gram positive & gram negative bacteria
Nutrient Uptake
Electron transport-respiration
Energy Production-PMF
Cytoplasmic Membrane Bilayer
Gram Negative Only
External to Petidoglycan
Lipid Bilayer with LPS
Outer Membrane
Gram Negative only
ENDOTOXIN
Made of:
Lipid A-toxic
Core polysaccharide
O-specific polysaccharide
LPS
Gram Negative Only
Area between outer membrane & Cytoplasmic membrane
Periplasmic Space
Nucleoid
Plasmids
Ribosomes
Granules
Endospores
Cytoplasmic Structures
Membrane-less gel
Contains Chromosome
Nucleoid
Haploid
Circular
Double Stranded
Typical Chromosome found in Nucloeid
Circular ds DNA
Replicates Indepndently of chromosome
Not necessary for survival
Plasmids
Can be transferred to daughter cells & bacterial cells
Vertical-Parent to offspring
Horizontal-Cell to cell
Plasmids
Genetic information resistance can confer advantageous traits
Plasmids
Protein Synthesis
Prokaryotes 70S-50s Large sub unit 30s small subunit
Eukaryotes 80S: 60s & 40s
Ribosome
Non-vegetative dormant form of GRAM POSITIVE bacteria

Metabolically Inactive

Handle Heat, pH, drying, freezing, radiation, chemicals

ex) Bacillus & Clostridium
Endospores
What can endospores resist?
heating, drying, freezing, radiation, chemicals
What are factors affecting cultivation?
temp.
oxygen
pH
salt
Mesophile
Microorganisms that grow 32-40
human & animal pathogens
Most common group
Psychrophilic bacteria
Prefer low temperatures 8-15 deg C
cause food to spoil in fridge
Thermophiles
heat loving microbes
grow 62-75 degrees C
Thermal vents in ocean & hotsprings
Superoxide dimutase
converts oxygen radicals to oxygen & hydrogen peroxide
Catalase
converts hydrogen peroxide to water and oxygen
obligate aerobic bacteria
require oxygen for growth
aerobic respiration
Top of test tube
obligate anaerobes
organisms that cannot live where molecular oxygen is present

anaerobic respiration or fermentation

O2 is toxic

Bottom of test tube
facultative anaerobes
Grow best with oxygen, but can grow without oxygen
Aerobic & aerobic respiration or fermentation
gather most at top but can be seen in all of tube
aerotolerant anaerobes
obligate fermentation but can grow with oxygen
Exclusive anerobic type of metabolism
insensitive to presence of O2
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