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1

What part of the Cell wall on gram POSITIVE organisms will induce TNF and IL-1?

What part of the cell outer membrane gram NEGATIVE orgnisms induces TNF and IL-1?

Gram + cell wall makes Lipoteichoic acid--> induces IL-1 and TNF and is major surface antigen

Gram - outter membrane makes Lipid A--> inducses IL-1 and TNF and is major surface antigen

2

1. Location of B-lactamase enZ in bacteria

2. Provides rigid support and protects against osmotic gradient (has peptide side chains with x-link via transpeptidase)

3. Protects organims against phagocytosis

4. mediates adhereance to surfaces, especially foriegn surfaces

 

1. Periplasm

2. Peptidoglycan

3. Capsule

4. Glycocalyx

3

What is unique about Mycoplasm bacteria?

What about Mycobacteria?

Mycoplasma has sterols but no cell wall

mycobacteria have mycolic acid and high lipid content

4

What bugs don't Gram Stain well?

 

These Microbes May Lack Real Color. 

Treponema (too thin to be visualized).

Mycobacteria (high lipid content; mycolic acids in cell wall detected by carbolfuchsin in acid- fast stain).

Mycoplasma (no cell wall).

Legionella pneumophila (primarilyintracellular).

Rickettsia (intracellular parasite).

Chlamydia (intracellular parasite; lacks classic peptidoglycan because of low muramic acid). 

5

What bugs stain with Giemsa stain?

 

 

Certain Bugs Really Try my Patience. 

Chlamydia, Borrelia, Rickettsia, Trypanosomes, Plasmodium. 

6

What Stains with Ziehl-Neelson stain?

Inian Ink?

Silver stain?

Ziehl =Acid-fast bacteria (Nocardia, Mycobacteria), protozoa (Cryptosporidium oocysts). 

Indian ink = Cryptococcus Neoformans

Silver Stain= Legionella, H.pylori and Fungi (Pneumocystisis)

7

Cryptococcus neoformans will stain......

with India Ink

8

What organisms stains PAS+? 

What disease pathology does it cause?

Stains glycogen, mucopolysaccharides; used to diagnose Whipple disease (Tropheryma whipplei) 

9

Chocolate Agar with factors V (NAD+) and X (hematin)

H.influenza = gram - rod

10

What special culture can you use to detect N. Meningitis or N. Gonorrhea

 

Thayer-Martin (VPN) media: Vancomycin (inhibits gram-positive organisms), Trimethoprim, Colistin (inhibits gram- negative organisms except Neisseria), and Nystatin (inhibits fungi)

Very Typically Cultures Neisseria 

11

What bug do we culture on a Potatoe agar = Bordet-Gengou agar

Bordetella Pertuss

Bordet = Bordetlla

12

What cultures on Tellurite agar or Loffler medium?

What cultures on Lowenstein Jensen agar?

What cultures on Eaton Agar but requires cholesterol?

Tellurite and Loffler = Cornye Diptheria

Lowentein-Jensen agar = M.Tuberculosis

Eaton =M.Pneumonaie

 

13

What is special about Nocardia, Pseudomonas aeruginosa and Mycobacterium TB?

All Obligate Aerobes and use an O2 dependent system to generate ATP

Nagging Pests Must Breath

(reactivated TB likes to go to Apices of lung d/t high O2 content)

P.aeruginoas is aerobe seenin burn wounds, comoplication of diabetes

14

What bacteria are Obligate Anaerobes?

Why are thye anaerobes?

What antibiotics are useless against them?

Anaerobes Frankly Can’t Breathe Air: 

Fusobacterium, Clostridium, Bacteroides, and Actinomyces.

They lack catalase and/or superoxide dismutase and are thus susceptible to oxidative damage. 

AmiO2lgycosides are worthless on these guys bc they need oxygen to enter bacterial cell

15

What bugs are Obligate intracellular organims?

Stay inside (cells) when it is Really CHilly and COld. 

Rickettsia, CHlamydia, COxiella. Rely on host ATP. 

16

What bugs are facultative intracellular bugs?

Some Nasty Bugs May Live FacultativeLY. 

Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis. 

17

What are my Encapsulated Bacteria?

What doe the capsule do for them?

What pts are at risk for infections with these?

SHiNE SKiS.

Streptococcus pneumoniae, Haemophilus influenzae type B, Neisseria meningitidis, Escherichia coli, Salmonella, Klebsiella pneumoniae, and group B Strep.

Their capsules serve as an antiphagocytic virulence factor. Capsule + protein conjugate serves as an antigen in vaccines. 

Asplenics have decreased opsonizing ability and thus increased risk for severe infections. Give S. pneumoniae, H. influenzae, N. meningitidis vaccines 

18

What are my Catalase + organisms?

What does it mean to be catalase +?

What Disease is susceptible to Catalase + organisms?

Cats Need PLACESS to hide. 

Nocardia, Pseudomonas, Listeria, Aspergillus, Candida, E. coli, Staphylococci, Serratia. 

Catalase degrades H2O2 into H2O and bubbles of O2 before it can be converted to microbicidal products by the enzyme myeloperoxidase. People with chronic granulomatous disease (NADPH oxidase deficiency) have recurrent infections with certain catalase ⊕ organisms. 

19

What organsims are Urease +?

CHuck Norris hates PUNKSS. 

Cryptococcus, H. pylori, Proteus, Ureaplasma, Nocardia, Klebsiella, S. epidermidis,
S. saprophyticus. 

20

1. This bacteria produces yellow sulfur granules

2. This bacteria produces yellow pigments

3. This bacteria shows up as blue-green

4. This bacteria gives off a red pigment

Actinomyces israelii= yellow sulfur 

Staph. Aureus = yellow pigment

Pseudomonas Aeruginosa = blue-green pigment

Serratia Marcescens = red pigment

21

What is the mechanism in which Protein A promotes evasion of host immune system?

Binds Fc region of IgG. Prevents opsonization and phagocytosis.

Expressed by S. aureus 

22

What is the Mechanism of host evastion of IgA protease?

What bugs secreat this?

Enzyme that cleaves IgA in order to colonize respiratory mucosa.  

Secreted by S. pneumoniae, H. influenzae type B, and Neisseria (SHiN) 

23

What is the mechanism of host evasion by M protein

What bugs use this?

Helps prevent phagocytosis.

Expressed by group A streptococci. Shares similar epitopes to human cellular proteins (molecular mimicry); possibly underlies the autoimmune response seen in acute rheumatic fever. 

24

What is the mechanims of Type III secreation system utilized by bacteria to evade host immune system?

Also known as “injectisome.” Needle-like protein appendage facilitating direct delivery of toxins from certain gram-negative bacteria (e.g., Pseudomonas, Salmonella, Shigella, E. coli) to eukaryotic host cell. 

25

What is the Mechanism of action of the Diphtheria toxin?

Is it an endo or exotoxin?

What is it simular to?

EXOtoxin that inactivates elogation factor : EF-2

(see pharyngitis with grey pseudomemrane in back of throat + bulls neck from lymphadenopathy

Simular to Exotoxin A produced by Pseudomonas Aeruginosa

26

What is the mechanism of action of the Shiga toxin?

What disease symptoms does it cause?

What other organims produces a Shiga-like toxin?

Inactivate 60S ribosome by removing adenine from rRNA 

Shigella: GI mucosal damage--> dysentery; ST also enhances cytokine release, causing hemolytic- uremic syndrome (HUS) 

EHEC; 0157 releases Shiga-Like Toxin: see SLT enhances cytokine release, causing HUS but doesn't invade the host cells like Shigella 

27

What is the MOA of the Heat Labile (LT) and Heat Stable (ST) released by

Enterotoxigenic E.Coli?

Heat Labile (LT) Overactivates adenylate cyclase (Increase cAMP)--> Increased Cl− secretion in gut and H2O efflux 

Heat Stable (ST) Overactivates guanylate cyclase (Increases cGMP)--> DEcreased resorption of NaCl and H2O in gut 

Watery diarrhea: “labile in the Air (Adenylate cyclase), stable on the Ground (Guanylate cyclase)” 

28

Mechanism of Bacillius Antracis EDEMA factor EXOtoxin

Mimics the adenylate cyclase enzyme (Increase cAMP) 

Likely responsible for characteristic edematous borders of black eschar in cutaneous anthrax 

29

MOA of the Cholera Toxin (Exotoxin)

Overactivates adenylate cyclase (Increase cAMP) by permanently activating Gs-->

Cl− secretion in gut and H2O efflux with rice water diarrhea

30

MOA of Pertussis toxin (exotoxin)

Overactivates adenylate cyclase (Increasing cAMP) by disabling Gi, impairing phagocytosis to permit survival of microbe