Gram (-) Bacteria

Question 1

Stephanie moved into her dorm and soon after came down with meningitis. What bacterium infected her?

Answer 1

Neisseria meningitidis

Question 2

If you see a gram (-) diplococci that looks like “kissing kidney beans” under a microscope, what genus does it belong to?

Answer 2

Neisseria

Question 3

The outer membrane of Neisseria sp. contains what lipid?

Answer 3

LPS - lipopolysaccharide

Question 4

LPS contains what toxins? What do the toxins cause?

Answer 4

Lipid A- endotoxin - causes sepsis

O antigen - used for serotyping

Question 5

Describe the main virulence factors of N. meningitidis.

Answer 5

Lipid A (endotoxin) and Polysaccharide capsule (13 serotypes)

Question 6

What is meningococcemia?

Answer 6

Meningitis and sepsis occurring simultaneously, due to infection with N. meningitidis.

Question 7

By what route is N. meningitidis spread?

Answer 7

Respiratory route. Breathe it. (That’s why people in close quarters…dorms, bunkers…. get it so easily)

Question 8

Why is the N. meningitidis vaccine not always helpful?

Answer 8

There are 13 serotypes of the polysaccharide capsule. The vaccine doesn’t cover them all.

Question 9

If your patient walks in and has “purulent urethritis or cervicitis,” what does she have and why did she get it?

Answer 9

Gonorrhea. STD.

Question 10

Gonorrhea is second only to ___________ for reported bacterial infections, and the two often occur simultaneously.

Answer 10

Chlamydia

Question 11

Leading cause of Pelvic Inflammatory Disease?

Answer 11

Gonorrhea

Question 12

Key virulence factors for N. gonorrheae?

Answer 12

PILI

Attachment, antiphagocytic

ANTIGENIC VARIATION OF THE PILI - more than 100 serotypes!

IgA protease as well.

Question 13

What member of the normal throat flora (also considered part of the Neisseria family) can cause sinusitis, otitis media, bronchitis, and pneumonia?

Answer 13

Moraxella catarrhalis

Question 14

What is the morphology of gram (-) glucose fermenters?

Answer 14

RODS!

Question 15

What is the most famous Gram (-) rod? (Also the top cause of of UTIs)

Answer 15

Escherichia coli

Question 16

What virulence factor does E. coli possess that makes it the top cause of UTI’s?

Answer 16

P-type pills lets it adhere to upper urinary tract epithelium.

Question 17

What disease can babies get from mom’s normal flora gone wild? (E.coli) What virulence factor contributes to this disease?

Answer 17

Neonatal meningitis…. K1 capsule.

Remember: all bacteria that cause meningitis are encapsulated

Question 18

T/F: Normal flora E.coli can cause enteric (diarrheal) diseases.

Answer 18

FALSE: can only get enteric diseases from external sources of E. coli.

Question 19

Bloody diarrhea is characteristic of which toxin produced by what species of bacteria?

Answer 19

Shiga toxin, produced by E. coli.

Question 20

What type of toxin is Shiga Toxin and how does it work?

Answer 20

A exotoxin that inhibits protein synthesis.

Question 21

What type of secretion system does E.coli predominately use?

Answer 21

Type 3: pilus!!

Question 22

Enterohemmorragic diarrhea is characterized by what symptom, and it caused by what specific species of E. coli?

Answer 22

Bloody diarrhea: from shiga toxin.

EHEC - enterohemorrhagic E. coli.

Question 23

Bacterial infection of the blood is called_____________. What virulence factors of E. coli contribute to this infection?

Answer 23

Bacteremia: caused by capsule and LPS

Question 24

The award for top cause of food poisoning goes to………? (name the bacterial species)

Answer 24

Salmonella

Question 25

You go camping and break your water bottle. You are forced to drink from a river. Later, it feels like the river is coming out your butt. You have traveler's diarrhea. What bacteria caused it? What toxins contributed?

Answer 25

ETEC (enterotoxigenic E.coli) - 2 exotoxins, one of which is similar to cholera toxin. Not endogenous to the gut! Remember: watery diarrhea = cholera toxin, or cholera- like toxin.

Question 26

What is Hemolytic Uremic Syndrome, and what toxin causes it?

Answer 26

Siga toxin disseminates through the blood to cause anemia and renal failure. Result of E.coli infection of the very young.

Question 27

What category of pathogens do Salmonella sp. fall under? (Frank, Opportunistic)

Answer 27

Frank.

Question 28

What are the 2 species of Salmonella that cause Entercolitis (Salmonellosis)? …. AKA food poisoning. What virulence factor is used?

Answer 28

S. Typhimurium and S. Enteriditis. Have type 3 secretion systems and the ability to kill macrophages

Question 29

What bacteria begins in the GI tract, then insidiously disseminates to reside within macrophages and kill you?

Answer 29

Salmonella Typhi. Typoid fever.

Question 30

How does death by S. Typhi occur?

Answer 30

hemorrhage at ruptured Peyer's patches.

Question 31

What are the main virulence factors of S. Typhi?

Answer 31

Ability to reside within macrophages, and Vi antigen that inhibits neutrophil phagocytosis.

Question 32

How is S. Typhi able to reside in macrophages?

Answer 32

Prevents phagolysosome fusion.

Question 33

You're on the Oregon Trail, but you don't make it. Not because your conestoga wagon got stuck in the river, but because you died of Dysentery. What is dysentery and what bacteria causes it?

Answer 33

Dysentery is bloody diarrhea caused by Shigella sp. Since the Oregon trail is in America, the specific shigella species is S. sonnei.

Question 34

If you got dysentery in another country, what species of bacterium would cause it?

Answer 34

Shigella dysenteriae. More severe symptoms than dysentery caused by S. sonnei, which id more common in the US.

Question 35

What is the virulence factor associated with Shigella?

Answer 35

Shiga Toxins

Question 36

What is the most common bacterial GI infection in developed countries? what do you eat to get it?

Answer 36

Camphylobacter jejuni Low dose needed. Undercooked meat, unpasteurized milk.

Question 37

What is the O2 requirement of Camphylobacter jejuni?

Answer 37

microaerophillic

Question 38

What kind of GI disturbance does Camphylobacter Jejuni cause?

Answer 38

Watery diarrhea that progresses to inflammatory (bloody) diarrhea. No shiga toxin though.

Question 39

Curved, gram negative rods are more commonly referred to as what morphology?

Answer 39

Vibrio

Question 40

The "rice water stool" associated with __________(disease) is caused by ____________(virulence factor).

Answer 40

Cholera - Cholera toxin.

Question 41

Cholera toxin works by what mechanism?

Answer 41

AB toxin. ADP-ribosylates G proteins, leading to release of electrolytes and water from enterocytes.

Question 42

How do you treat cholera?

Answer 42

Oral rehydration and antibiotics.

Question 43

Most common form of transmission of Cholera?

Answer 43

Fecal/oral transmission.

Question 44

What bacterial species causes cholera?

Answer 44

Vibrio cholera

Question 45

You ate fecal-contaminated shellfish while visiting Japan. What bacteria did you get?

Answer 45

Vibrio parahemolyticus

Question 46

Which bacteria has UREASE enzymes? what does Urease do?

Answer 46

Helicobacter pylori - Urease cleaves urea to ammonia and CO2 --> decreases the pH of the stomach so it can live.

Question 47

What does infection with Helicobacter pylori cause, and what is the toxin?

Answer 47

GI ulcers caused by Urease

Question 48

FACT: H pylori infection (if untreated) can lead to chronic GI ulcers, which ca lead to MALT B-cell tumors.

Answer 48

Mucosal associated lymphoid tissue B-cells tumors.

Question 49

After GI surgery, you develop an intraabdominal cyst, but tests show bacteria of your normal flora in the cyst. Name the most likely bacterium.

Answer 49

Bacteriodes - Predominant species of the colon.

Question 50

O2 requirements of bacteriodes.

Answer 50

Obligate anaerobes

Question 51

Blue/Green colonies are…. What makes them blue?

Answer 51

Pseudomonas aeruginosa - have Pyocyanin: a blue enzyme that damages lung cilia.

Question 52

Prominent diseases caused by Pseudomonas aeruginosa.

Answer 52

1- Skin of burn patients (infection) 2- Cystic Fibrosis (pyocyanin…lung cilia) 3- Nosocomial pneumonia 4- Sepsis

Question 53

If you get asked a nosocomial infection question that deals with pneumonia caused by ventilators, what bacteria will it be?

Answer 53

Pseudomonas aeruginosa

Question 54

What is the O2 requirement of Pseudomonas aeruginosa?

Answer 54

Obligate Aerobe

Question 55

What type of bacteria is Pseudomonas aeruginosa? (Primary/Opportunistic)

Answer 55

Opportunistic. MULTI-DRUG RESISTANT

Question 56

Key virulence factors of Pseudomonas aeruginosa

Answer 56

LPS endotoxin Degradative enzymes - elastase and protease Exotoxin A: AB exotoxin Type III secretion system PYOCYANIN

Question 57

Who does the AB Exotoxin of Pseudomonas aeruginosa work?

Answer 57

Similar to diphtheria toxin - tissue necrosis

Question 58

Currant jelly sputum and goopy colonies. What bacteria is it? What's the most common disease it causes?

Answer 58

Klebsiella pneumoniae - nosocomial pneumonia

Question 59

There is a resistant strain of Klebsiella pneumoniae. What is it resistant to, and what is its abbreviation?

Answer 59

KPC (Carbapenem resistant K pneumoniae)

Question 60

90% of acute diarrheas are caused by _______.

Answer 60

Viruses.

Question 61

Name the 3 gram (-) rods associated with the respiratory tract.

Answer 61

Haemophilus influenzae Bordetella pertussis Legionella pneumophila

Question 62

Under the microscope, you see a gram (-) coccobacillus. The 3-year old patient it was taken from has epiglottitis, and otitis media. What is the most likely cause of infection?

Answer 62

Haemophilus influenzae

Question 63

Haemophilus influenza is the 2nd most common cause of sinusitis and otitis media. Second to what?

Answer 63

Strep pneumoniae

Question 64

Meningitis caused by Haemophilus influenzae is less common now due to a vaccine that targets what virulence factor?

Answer 64

The Type B capsule.

Question 65

Bordella pertusis causes what?

Answer 65

Whooping cough

Question 66

What 2 toxins does Bordella pertusis utilize?

Answer 66

Pertussis toxin - AB toxin that acts like cholera toxin Cytotoxin - fragments cell walls of host. Kills lung cilia.

Question 67

The Bordella Pertussis vaccine is composed of what? REMEMBER: bordella pertussis is included in the DTaP and TdaP vaccine.

Answer 67

Acellular vaccine that contains altered pertussis toxin.

Question 68

Legionella pneumophila is usually found where? What does it cause?

Answer 68

Water. Atypical pneumonia. | Generally hospital/community acquired

Question 69

You got infected 4 hours ago and just started showing symptoms. Is this an infection or an intoxication?

Answer 69

Within 4 hours = TOXIN 8+hours = infection

Question 70

Neisseria can only be grown on what specific media?

Answer 70

Thayer Martin

Question 71

Gram (-) rods of the GI/UG tract have what oxygen requirements?

Answer 71

They are facultative anaerobes.

Question 72

Name some Gram (-) rods of the GI/UG tract.

Answer 72

E.coli, Salmonella, Shigella, Vibrio, etc… 2 1/2 pages of em.

Question 73

What is the serotype of EHEC?

Answer 73

O157:H7

Question 74

How do E/coli strains cause diarrheal disease if they are part of the normal flora of the colon?

Answer 74

External strains pickup PAI's from other strains via Pili (conjugation) and this increases their virulence.

Question 75

SHiga toxin is what type of toxin? What does it inhibit?

Answer 75

Shiga toxin is an AB exotoxin that inhibits protein synthesis.

Question 76

What is it called when shiga toxin distributes throughout the blood to fuse anemia and renal failure.

Answer 76

HUS: Hemolytic Uremic Syndrome

Question 77

Top cause of food poisoning?

Answer 77

Salmonella Typhimurium and Enteriditis.

Question 78

Your Peyer's patches rupture. What bacteria did you die of? How?

Answer 78

Salmonella Typhi. You died of Typhoid Fever. S. Typhi can survive in macrophages and move into the Peyer's patches (2ndary lymph tissues) and wreak havoc.

Question 79

How does cholera toxin work?

Answer 79

It ADP-ribosylates G-Proteins. Leads to the release of electrolytes and water from enterocytes in the gut.

Question 80

Which of the Gram (-) rods are obligate aerobes? Need air, on a ventilator… these guys will infect you.

Answer 80

Pseudomonas aeruginosa

Question 81

What specific tissue does Pyocyanin mess up?

Answer 81

Lung cilia.

Question 82

Intra-abdominal abscesses.

Answer 82

Bacteriodes

Question 83

Currant jelly sputum. Goopy colonies

Answer 83

Klebsiella Pneumoniae

Question 84

Cocobacillus?

Answer 84

Haemophilus influenzae

Question 85

The most likely cause of otitis media and sinusitis is…. Second? Third?

Answer 85

Strep pneumoniae, Haemophilus influenzae, Moraxella catarrhalis