Intro

Question 1

7 Classical Methods for Microbial Classification

Answer 1

Morphology
Staining characteristics
Environmental requirements
Nutritional requirements
Antimicrobial resistance profiles
Bacteriophage susceptibility
Antigenic properties

Question 2

Gram Stain

Answer 2

Stain blue w/ crystal violet, fix peptidoglycan w/ iodine, delocolorize w/ acetone-alcohol, red counterstain w/ saffranin.
Those that resist decolorization remain blue, Gram +

Question 3

Fungi in Gram Stain

Answer 3

Don’t have peptidoglycan so nonspecific coloring, never do

Question 4

Acid-Fast Stain

Answer 4

Stain red, then use acid/acid-alcohol to delocolorize and restain with blue-green. Mycobacteria and others have mycolic acids and other lipids in cell walls that retain dye. Stain red and called Acid-Fast. Non acid fast stain blue

Question 5

How to Tell Gram from Acid Fast Stain

Answer 5

Gram BG is pink, acid-fast is blue

Question 6

Cording

Answer 6

Mycobacterium forms in acid fast stain

Question 7

5 Environmental Requirements for Microbes

Answer 7

pH
NaCl conc
Temperature
CO2 - capnophilic
O2

Question 8

4.1 Categories of Redox Environment Bacteria

Answer 8

Aerobic - high redox potential
Microaerophilic - need O2 at reduced levels
Facultative - most, high or low redox
Anaerobic: aerotolerant, moderate obligate, strict obligate (very low redox)

Question 9

3 Nutritional Requirements

Answer 9

Which carbs as sole C source
Requirement for unique nutrient (like AA)
For cofactor or mineral

Question 10

Emden-Meyerhoff-Parnas pathway

Answer 10

Glycolitic pathway that oxidizes carbs to pyruvate

Question 11

Difference b/w Respiration and Fermentation

Answer 11

Respiration has inorganic final e- acceptor, fermentation has organic

Question 12

Difference b/w Aerobic and Anaerobic Respiration

Answer 12

O2 final e- acceptor or NO3/SO3

Question 13

Nucleic Acid Analysis

Answer 13

Just amplify and sequence highly conserved regions, not whole thing

Question 14

3 Benefits of Genetypic Method of Classification

Answer 14

Independent of viability or growth in culture
Independent of phenotypic expression
Allows for recognition of previously unknown species

Question 15

4 Components of Microbial Cell Envelope

Answer 15

Capsule
Outer Cell Membrane (G- only)
Cell Wall (gives shape)
Inner (cytoplasmic) membrane

Question 16

Capsule (5)

Answer 16

Some but not all bacteria
Production may depend on nutritional/environmental conditions
Most are carbohydrate polymers
Antigenic, called “K” antigens (enteric G- bacilli)
Protects organisms from phagocytosis

Question 17

Opsonizing Abs

Answer 17

Act on capsules

Question 18

Capsule Antigenic Types and Vaccines

Answer 18

Most specs have a lot of different antigenic types, vaccines only hit the major ones, but that selects for rarer ones so vaccines have to be revisited

Question 19

Peptidoglycan (Murein) Layer (5)

Answer 19

In G+ (more), G-, and acid fast cells
Provides shape and rigidity to cell wall
Assembled in cytoplasmic membrane and transported to outside and linked
Composed of interconnected alternating NAGs and NAMs that cross link
Contain teichoic acids (communicate w/ host cell) and lipotechoic acids (surface antigens)

Question 20

Peptidoglycan Linkages

Answer 20

Lys and Ala (in 2nd to last position) cross link w/ cleavage of Ala in last position

Question 21

3 Things that Prevent Peptidoglycan Linkages

Answer 21

Penicillin and similar drugs: inactivate the linkage forming proteins
Vancomycin prevents cleavage of terminal Ala
5-7 Gene Cassette replaces last Ala w/ Ser

Question 22

Result When Interfere w/ Peptidoglycan Linkage w/out Killing Cell

Answer 22

Just changes shape and elongates

Question 23

4 Components of G- Cell Envelope

Answer 23

Outer membrane
Thin Peptidoglycan
Periplasmic space
Inner (cytoplasmic) Membrane

Question 24

Porins

Answer 24

Proteins in outer membrane of G-s that can mutate to allow/exclude stuff in

Question 25

Endotoxin (2 long)

Answer 25

Component of outer cell membrane of G-s that has highly conserved Lipid A and Core Pollysaccharide and then highly variable side chains Can be liberated and cause massive problems if contaminate drugs as LPS can bind markers of immune cells and cause responses

Question 26

6 Clinical Manifestations of LPS Action (and other point)

Answer 26

Fever Leukopenia/leukocytosis Thrombocytopenia Disseminated intravascular coagulation Decreased peripheral circulation and perfusion to organs Hypotension Sometimes tricky bc lipotechoic acid interactation can mimic this

Question 27

Acid Fast bacteria Cell Wall

Answer 27

Lipid rich hydrophobic cell wall w/ peptidoglycan overlaid by FA (mycolic acids) layer w/ free lipids, polypeptides, and sulfolipids (cord factor)

Question 28

3 Characteristics from Complex Acid Fast Cell Wall

Answer 28

Relatively slow growing bc have to synthesize and build a lot Very resistant to disinfectants Resistant to dessication - can survive when vehicle dries out

Question 29

2 Forms of Flagella

Answer 29

Extend outwards around cell (peritrichous) or on ends of bacilli (polar)

Question 30

H Antigens of Enteric Bacteria

Answer 30

On flagella

Question 31

Pili or Fibriae

Answer 31

Fine protein fibrils that mediate attachment to host membranes (colonization factors or adhesions). Often necessary for pathogenicity

Question 32

Spores (3)

Answer 32

Form of cell differentiate for some G+, not replication bc leads to cell death. Dormant for many years and resistant to dessication, UV, heat, or germicidal agents

Question 33

Endosporulation

Answer 33

Some DNA separates and forms septum Two membranes and thick peptidoglycan layer built around it Endospore released w/ cell lysis

Question 34

2 Notable Spores

Answer 34

Clostridium in hospitals | Anthrax

Question 35

3 Kinds of Compromised Host (& examples)

Answer 35

Immunologic - AIDS, immunosuppressing treatment Physiologic - diabetes, malnutrition Physical - foreign body in wound

Question 36

4 Elements of Microbial Infection (& major point)

Answer 36

Expression of specific adherence mediators Invasive capabilities (what can penetrate) Resistance to the Host Immune Responses Production of Exotoxins (some) Invasive factors work together to have greater, combined effects

Question 37

8 Resistances to Host Humoral Immune Response

Answer 37

``` Agic mimicry to host Ag Antigenic drift/shift Production of anti-Ig proteases (usually IgA) Anti-complementary outer surface components block function of Abs Inhibition of phagocytosis Inhibition of chemotaxis Inhibition of intracellular killing Intracellular replication ```

Question 38

Microbial Exotoxins (4)

Answer 38

Usually produced by G+ Produced, released, and actively excreted by living structures w/out rupture Most affect specific targets May affect distant targets

Question 39

5 Mechs of Microbial Exotoxins

Answer 39

Inhibition of prot synth Interruption of internal cellular signals Interruption of neuromuscular interactions Destruction of euk cell membranes Nonspecific agic stimulation (superantigens)

Question 40

Vitek and Microscan

Answer 40

Automated biochemical ID of bacteria, just does all the tests and looks up biotype number

Question 41

Biochemical ID of Microorganisms

Answer 41

Determination of + or - rxns of unknown organism from various biochemical substrates Numerical scoring results in "Biotype Number" Look up biotype number in database

Question 42

4 Chemical and Molecular Methods of Microbial ID

Answer 42

Chromatography of metabolic products or cell wall FAs Electrophoretic analysis of whole cell prots or enzymes Matrix-Assisted Desorption Ionization-Time of Flight kind of mass/charge ratio Direct probing or amplification w/ hybidization or sequencing