The bacteria basics

Question 1

Peptidoglycan

Answer 1

repeating disaccharide base w aa side chains that are cross linked by the enzyme Transpeptidase (blocked by PCN)

• Transpeptidase = “PCN-binding-protein”
• Peptidoglycan cell walls allow bacteria to survive osmotic stres! Give PCNs, cephalosporins, or Vanco to take away this defense - bacteria would disintegrate in hypotonic solution.

Question 2

Catalase+

Answer 2

You need PLACESS for your CATs

Pseudomonas
Listeria
Aspergillus
Candida
E.coli
Staph
Serratia

Question 3

Obligate aerobes

Answer 3

Nagging Pests Must Breathe

Nocardia
Pseudomonas aeruginosa
Mycobacterium
Bacillus

Question 4

Aerobe in burns wounds, diabetes, nosocomial pneumonia, Pneumonia in CF

Answer 4

Pseudomonas Aeruginosa
(obligate aerobe)

Question 5

Capsule of D-glutamate (i.e. made of aa residues)

Answer 5

Bacillus anthracis

unique. Other capsules are made of sugar

Question 6

Periplasm enzyme

Answer 6

Beta-lactamases

Question 7

LPS

Answer 7

Gram-negative outer membrane
more inside: Lipid A (induces TNF and IL-1)
Outer: O-polysaccharide (antigen)

Question 8

Gram + cell wall

Answer 8

Peptidoglycan (support) + Lipotechoic acid (induces TNF and IL-1)

Question 9

Pilus/fimbria

Answer 9

Mediates adherence of bacteria to cell surface
Sex pilus: connect bacteria during conjugation
-Made of glycoprotein
-E.g. Meningococcal pili - responsible for epithelial attachment to nasopharynx**

Question 10

Flagella

Answer 10

Motility

-made of protein

Question 11

Spore

Answer 11

Resistant to dehydration, HEAT, chemicals

• Keratin-like coat*, dipicolinic acid, peptidoglycan
• Spores form when shortage of nutrients –> lie dormant for years
• Kill w STEAM

Bacillus (aer) and Clostridium (anaer)
found in soil

Question 12

Plasmid

Answer 12

DNA

contains genes for antibiotic resistance, enzymes, toxins

Question 13

Glycoclayx

Answer 13

Mediates adherence to surface (like pilus) esp foreign ones (catheters!!!)
-made of polysaccharide (like pilus)

Question 14

Obligate Anaerobes

Answer 14

Can’t Breathe Air

Clostridium
Bacteroides
Actinomyces

Question 15

Do not gram stain well

Answer 15

These Rascals May Microscopically Lack Color

Treponema (too thin)
Rickettisa (intracellular)
Mycobacteria (high lipid)
Mycoplasma (no cell wall)
Legionella pneumophila (intracellular)
Chlamydia (intracellular, lacks muramic acid in cell wall)

Question 16

Silver stain

Answer 16

Legionella, Helicobacter pyloria, Fugni (e.g. Pneumoncystis)

Question 17

Dark-field microscopy and fluorescent AB staining

Answer 17

Treponema

Question 18

Giemsa stain

Answer 18

Certain Bugs Really Try my Patience

Chlamydia
Borrelia
Rickettsia
Trypanosomes
Plasmodium

Question 19

PAS stain (periodic acid-schiff)

Answer 19

PASs the SUGAR (glycogen)

Stain glycogen, mucopolysaccharides
-Use to diagnose Whipples (Tropheryma whipplei)

Question 20

Ziehl-Neelsen (carbolfuchsin**) stain

Answer 20

Acid fast organisms (Nocardia, Mycobacterium)- stains mycolic acid

Question 21

India ink stain

Answer 21

Capsule not taken up by stain –> see translucent halo around the cell. Used primarily to identify:
Cryptococcus neoformans

India –> mother theresa –> halo –> capsule –> Crypto

Question 22

Chocolate agar w factors V (NAD+) and X (Hematin)

Answer 22

H. influenzae

When child has the “flu” mom goes to V/five and X/dime store to get CHOCOLATE

Question 23

Thayer-martin (or VPN) SELECTIVE media: Vnacomycin, Polymyxin, Nystatin

Answer 23

N. gonorrhoeae

Question 24

Bordet-Gengou (potato) agar

Answer 24

B. pertussis

Bordet for BORDETella

Question 25

Tellurite plate, Loffler's media

Answer 25

C. diptheriae Loffffffffler (something stuck in your throat... like a pseudomembrane)

Question 26

Lowenstein-Jensen agar

Answer 26

M. tuberculosis

Question 27

Eaton's agar

Answer 27

M. pneumoniae Mycoplasma like us: We like to EAT, have no cell wall, have cholesterol in our membranes

Question 28

Pink colonies on MacConkey's agar

Answer 28

Lactose-fermenting enterics (e.g. E. coli)

Question 29

Eosin-methylene blue (EMB) agar. Colons w metallic green sheen

Answer 29

E. coli

Question 30

Charcoal yeast extract agar buffered w cysteine and iron

Answer 30

Legionella

Question 31

Sabouraud's agar

Answer 31

Fungi Sab's a FUN GUY!

Question 32

Obligate intracellular

Answer 32

Stay inside when it's Really Cold (steal ATP from the host cell) Rickettsia Chlamydia

Question 33

Facultative Intracellular

Answer 33

Some Nasty Bugs May Live FacultativeLY ``` Salmonella Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia pestis ```

Question 34

Encapsulated organisms | positive Quelleng rxns (capsular "swelling")

Answer 34

SHiNE SKiS **The capsule prevents phagocytosis Strep pneumo H. influenza Type B Neisseria meningitidies E. coli Salmonella Klebsiella Group B Strep

Question 35

Gram + Rods

Answer 35

Crappy Bacteria Can Make Logs ``` Clostridium Bacillus Corynebacterium Mycobacterium* (acid fast) Listeria ```

Question 36

Gram + Branching filamentous

Answer 36

+ brANchers Actinomyces Nocardia (weakly acid fast)

Question 37

Urease + bugs

Answer 37

CHuck norris hates PUNKSS ``` Cryptococcus H. pylori Proteus Ureaplasma Nocardia Klebsiella S. epidermidis S. saprophyticus ```

Question 38

Pigment producing: yellow "sulfur" granules | composed of filaments of bacteria

Answer 38

Actinomyces israelii | yellow sand in israel

Question 39

Pigment producing: yellow pigment

Answer 39

S. aureus | aureus = gold

Question 40

Pigment producing: blue-green pigment (pyocyanin)

Answer 40

``` Pseudomonas aeruginosa (aerug- is green) ```

Question 41

Pigment producing: red pigment

Answer 41

Serratia marcescens (thing red maraschino cherries

Question 42

Protein A

Answer 42

Binds Fc portion of IgG - prevents opsonization and phagocytosis <-- prevents complement activation S. aureus

Question 43

IgA protease

Answer 43

Enzyme cleaves IgA - allows colonization of respiratory mucosa (SHiN): Strep pneumo, H. influenza type b, Neisseria (both mening and gonoc)

Question 44

M protein

Answer 44

Helps prevent phagocytosis and complement activation - mediates bacterial adherence - Is the target for type-specific humoral-immunity - Group A streptococci

Question 45

ENDOTOXIN

Answer 45

``` Edema Nitrous Oxide DIC (activate tissue factor) Outer membrane (LPS) TNF --> hypotension, fever O-antigen (on the outer part) eXtremely heat stable (100C for 1 hr) IL-1 --> fever Neutrophil chemotaxis <-- C5b ```

Question 46

Lysogenic phage carries genes for these 5 bacterial toxins:

Answer 46

ABCDE ``` shigA like toxin Botulinum toxin (certain strains) Cholera toxin Diptheria toxin Erythrogenic toxin of Strep pyogenes ```

Question 47

Guidelines for prevention of catheter infxn

Answer 47

- 1) Proper hand washing - 2) full barrier precautions during insertion of a central line - 3) Chlorhexidine for skin disinfection - 4) Avoidance of femoral insertion site - 5) Removal of catheter(s) when no longer needed Most common pathogens: Coag neg staph, Staph aureus

Question 48

Transformation

Answer 48

Ability to take up naked DNA and incorporate into your own. A feature of many bacteria, but esp S. pneumo, H. flu type b, Neisseria (SHiN).

Question 49

Transduction

Answer 49

Transfer of genetic information between organisms by viral phages - Generalized: a packaging event - parts of the bacterial chr may be accidentally packed in with the viral phage - Specialized: an excision event. the phage gets incorporated into bacteria, but then poorly excised out such that some of the bacterial genome is take with the viral phage.

Question 50

Transposition

Answer 50

DNA pieces w legs! can "jump" from one location to another and transfer genes from plasmid to chr and vice versa. no DNA homoogy necessary for insertion of transposon (can happen btwn different speices).