Kirn - Gram Negative Rods

Question 1

What do HOK stand for and what are they used for?

Answer 1

H-flagella
O-LPS
K-Kapsule

Used for stereotyping to describe the different characteristics of the bacteria

Question 2

What is the name and difference between the three types of intestinal infections?

Answer 2

1) non inflammatory - bacteria in lumen
2) inflammatory - bacteria invade wall
3) penetrating - bacteria beyond wall

Question 3

What kind of culture do u use to cholera

Answer 3

TCBS - stool sample will show up as green/yellow

Question 4

Mechanism of action of cholera vibrio

Answer 4

A unit adds ADP-ribose group to Gs to permenantly activate it
Gs stimulates adenylyl Cyclase
This causes high levels of cAMP
CFtR pumps a lot of chlorine out of cell into lumen
This causes osmotic inflow of water

Question 5

ETEC

Answer 5

Common cause of travelers diarrhea.
Two exotoxins - acid labile and acid stable

Acid labile - like cholera, causes increased cAMP
Acid stable - causes increased cGMP
“eL Agua del San Gabriel”

Question 6

EPEC

Answer 6

Type III secretion
- causes brush border to disappear in intestine and pedestals to form via that whole mechanism in the video

• Basically the bacteria comes down and the brush border just dissapears to make way for landing. The pili attach to the epithelial lining allowing for a smooth landing. A tube like structure comes down and spits proteins into the epithelium which then come back up and live in the epithelial lining. They built actin filaments that become very long and push up on the epithelial lining. The original microbe then has these pedestals that cup the top of the proteins and pull it up.

Question 7

Shigella

Answer 7

Painful, bloody, low volume stools with WBC and mucus
- transocytosis by M cells –> invade enterocytes via type III system —> lyses phagocytic vacuole so that the enter cytosol –> actin polymerization causes actin tail to form that pushes bacteria through palmsa membrane into adjacent tails

Question 8

Shiga toxin

Answer 8

A subunit cleaves RNA of large ribosomal subunit causing the ribosome to be inactive
- causes hemolytic uremic syndrome (HUS)- micro vascular damage in the kidneys that cause red cell lysis

Question 9

EHEC

Answer 9

Shiga like toxin
Causes HUS
Causes bloody diarrhea 
Predominant serotype is O157:H7
Sorbitol it from undercooked meat

Question 10

Non-typhoidal salmonella

Answer 10

Get it from meat and eggs
Can get it from pet reptiles
Causes gastroenteritis
Exit M cells and invade enterocytes to multiply locally
Induce apoptosis via type III system
Non bloody diarrhea, fever, nausea, vomiting

Question 11

Campylobacter jejuni

Answer 11

Association with guillan barre
Gullwing morphology
Transmitted from chicken

Question 12

Helicobacter pylori (H pylori)

Answer 12

Causes peptic ulcers
Resides below mucus layer of stomach
Has urease which converts urea to ammonia
Diagnosis: gastric biopsy, breath test with labeled carbon to test for ammonia, stool antigen assay

Question 13

Typhoidal salmonella

Answer 13

Has capsule
Penetrate intestine via m cells
May be cultured from bone marrow
Can establish chronic state in gall bladder

Question 14

P-fimbrae

Answer 14

Allows E. coli to adhere to bladder epithelium

Question 15

Additional things that E. coli causes

Answer 15

K1 causes neonatal meningitis

S fimbrae adheres to endothelium and choroid plexus

Question 16

What are the common nosocomial infections?

Answer 16

Enterobacter

Klebsiella

Serratia

“Sloan Kettering entrance”

Question 17

Haemophilus influenzae

Answer 17

Chocolate agar
- with NAD and hemin

Common in upper respiratory

Virulence factor - Type b capsule, IgA capsule, iron acquisition mechanisms

Causes otitis media, epiglottitis, pneumonia, meningitis, septic arthritis

Question 18

Hib vaccine

Answer 18

Vaccine for haemophilus influenza that is given to all kids at 2 months of age.

Question 19

Treatment for haemophilus influenzae

Answer 19

Ceftriaxone or other 3rd gen cephalosporins

Question 20

Haemophilus ducreyi

Answer 20

School of fish gram stain morphology

Chancroid - genital infection that spreads to the lymph node

Question 21

Bordatella pertussis

Answer 21

Small colonies in blood agar
Usually use NAAT for diagnosis
Small colonies on blood agar
Causes whooping cough
Long lasting disease
Virulence factors - filamentous hemagglutinin (binds integrins on ciliated epithelial cells), fimbrae phase variation, BrkA protein (causes complement resistance). Tracheal toxin, adenylate Cyclase toxin, pertussis toxin.
Prevention - DTaP vaccine ( diphtheria, pertussis, acellular pertussis)

Question 22

Legionella pneumophila

Answer 22

Respiratory infection usually coming from aerosol for a bad water supply.
Pontiac fever is milder form
Needs BCYE agar with iron and cysteine, highly fastidious
Usually use Urine Ag test to detect

Question 23

Brucella

Answer 23

From livestock and dairy

Systemic febrile illness

Question 24

Pasteurella multocida

Answer 24

Normal oral flora of domestic animals such as cats and dogs.

• causes snuffles in rabbits
• infections associated with animal bites
• causes soft tissue Infection

Question 25

Francisella tularensis

Answer 25

Transmission from wild animals, usually rabbits.
- low infectious dose so a irks to la workers

Causes:
ulceroglandular - ulcer at inoculation site, lymphadenopathy
Oculoglandular - eye is site of inoculation, lymphadenopathy
Oral or pharyngeal - contaiminated food/water
Respiratory infection - aerosol transmission

Question 26

Yersinia Pestis

Answer 26

Cause of bubonic plague
Transmitted from rodents to humans by flee bite
Prairie dog
Flee bites sick animal and then the blood clots in its stomach. Upon biting a human the flea regurgitates the blood into us.
Causes bubous, enlarged lymph nodes.
Bipolar staining that looks like a safety-pin using Wayson stain
Can get into lungs and cause “pneumonic plague” which can lead to human to human transmission.
Has a capsule

Question 27

Pseudomonas aeruginosa

Answer 27

Present in soil, water, vegetation
Forms biofilms
Siderosphores Smell like grapes/OJ
- community acquired infection
- hot tub folliculitis
- otitis externa
- more common in burn victims and incubated patients 
- in CF patients you will see chronic respiratory infection

Question 28

What does P. Auruginosa look like when plated?

Answer 28

Produces greenish pigment that looks slimy due to the presence of an extracellular polysaccharide capsule.