(II) Gram Negative Rods - (5) Salmonella spp.

Question 1

Characterize (7) : Salmonella spp.

Answer 1

(1) Gram (-) rod
(2) Motile (like a salmon lol)
(3) **H2S (+) **
(4) Encapsulated
(5) Acid labile
(6) Type III secretion system
(7) Facultative intracellular

(Acid labile = Easily destroyed in stomache = Requires high dose for infection)

Question 2

What color does Salmonella spp. turn Hektoen agar?

Answer 2

Black

Question 3

ROT: Salmonella enteriditis

Answer 3

Eating undercooked chicken

(Note: S. enteriditis is on left and S. typhi on right, it’s alphabetical)

Question 4

What is the most common symptom of Salmonella enteriditis?

Answer 4

Inflammatory diarrhea

Question 5

Reservoir: S. typhi

Answer 5

Gallbladder of humans

(Sea-‘gall’)

Question 6

Name 2 distinctive signs of S. typhi infection

Answer 6

(1) Rose-colored macules
(2) “**Pea soup” diarrhea
**
(Note: In the process of spreading systemically, it can lead to ULCERATION OF PEYER’S PATCHES. Macules only occurs 25% of the time)

Question 7

What is the most common cause of osteomyelitis in sickle cell disease?

Answer 7

S. typhi

(Note: S. enteriditis does NOT dissemiante via blood or lymphatics)

Question 8

Which species of Salmonella may warrant treatment?

Answer 8

Typhi

(Usually disease progression: Diarrea → Asymptomatic → Bacteremia & Fever. Antibiotics shorten fever phase)

Question 9

Treatment: S. typhi

Answer 9

Flouroquinolone

(Whereas S. enteriditis is usually NOT treated)

Question 10

Which species of Salmonella has a vaccine?

Answer 10

S. typhi

(A live-attenuated vaccine)

Question 11

Name 2 groups at increased risk of Salmonella infections

Answer 11

People with,

(1) Reduced stomach acid
(2) Sickle cell disease (asplenics)

Question 12

Acute Gastroenteritis can be caused by salmonella subspecies: S.[…] and S.[…]

Clinical Presentation:
[…]

Answer 12

Acute Gastroenteritis can be caused by salmonella subspecies: S.Typhimurium and S.Enteritidis

Clinical Presentation:
- Diarrhea, vomitting, abdominal pain (self-limiting)
- invasive infections (leading to osteomyelitis, artheromatous plaque in artery, meningitis)

Question 13

Salmonella spp. can be classified into two groups:

[…]

Answer 13

Salmonella spp. can be classified into two groups:

Acute Gastroenteritis Group (S. Typhimurium, S. Enteritidis) and Typhoid Fever Group (S.Typhi, S. Paratyphi)

Question 14

Typhoid Fever can be caused by S.[…] and S.[…].

What is the pathology and symptoms of Typhoid Fever?
[…]

Answer 14

Typhoid Fever can be caused by S.Typhi and S.Paratyphi.

What is the pathology and symptoms of Typhoid Fever?
1. entry into bloodstream into macrophage and multiply within macrophage of many organs (10 days incubation)
2. symptoms of fever, anorexia, epistaxis, cough, headache, abdominal pain (mimicking appendicitis), constipation, bradycardia, enlarged spleen and liver, rose spots)
3. excretion of infected bile results in second invasion of gut wall –> inflammation by typhod ulcers and ileal patches
4. Some ppl remain as chronic carriers due to infected gall bladder

“Some carriers actually require surgical removal of their gall bladder to cure them”