Salmonella Infections

Question 1

What Salmonella strains cause typhoid fever

Answer 1

S. Typhi, S. Paratyphi

Question 2

How is NTS spread?

Answer 2

Animal contact
Contaminated food - poultry, eggs, dairy, ground beef, produce, sprout seeds, tomatoes
Contaminated water

Question 3

What is the incubation period for NTS

Answer 3

12-48h - maximum 7 days

Question 4

How does NTS present

Answer 4

Nausea, vomiting non-bloody diarrhea +/- fever

6-8% have bacteraemia

Question 5

Who is at risk for disseminated NTS? And how does it present?

Answer 5

<3mo old, immunocompromised, asplenic

• Bacteremia: 6-8%
• Meningitis, brain abscess in <12mo
• Endocarditis, arthritis (rare)
• OM, SA - patients with SCD
• Renal abscess (rare)

Question 6

How do you diagnosis NTS

Answer 6

Stool culture +

Blood cultures IF febrile or immunocompromised or <3mo (consider up to 6mo IF stool positive)

Question 7

How is afebrile, uncomplicated NTS treated

Answer 7

No antibiotics
May need exclusion from daycare while symptomatic
Counsel family to take any reptiles out of the home, or at least keep them out of the kitchen/bathtub
Advise careful hand washing

PH is notified of all infections

Question 8

How is febrile, complicated NTS managed initially

Answer 8

Send BCx

• CSF if <3mo
• Admit to hospital
• IV ceftriaxone (or azithromycin if fever only concern)

If BCx negative and patient continues to look unwell- consider:

• repeat BCx
• continue antibiotics
• ID consult

If BCx negative and patient well - d/c antibiotics

If BCx positive - continue abx until BCx clears, and then step down to azithromycin 10mg/kg/d x 5-7d

Question 9

How is typhoid fever spread?

Answer 9

Water or food contaminated with feces from a carrier

Direct person-to-person spread

Question 10

What is the incubation period for typhoid fever?

Answer 10

7-14 days

Range 3-60d

Question 11

How does typhoid fever present?

Answer 11

Bacteraemia —> sepsis, MOF

Present with fever, abdominal manifestations (diarrhea then constipation and abdo pain), eventually HSM develops

Rose spots (abdo macular rash) - 30%

Question 12

What are the complications of typhoid fever?

Answer 12

GIB - 10% of hospitalized patients
Encephalopathy
Myocarditis, endocarditis (rare)
Can lead to urinary stones

Question 13

When should typhoid fever be suspected?

Answer 13

Children with onset of unexplained fever within 2mo of returning from resource poor country

Question 14

How is typhoid fever diagnosed?

Answer 14

• Stool culture + in 30%

- BCx (may need multiple)

Question 15

How is typhoid fever treated?

Answer 15

Send BCx

• Admit to hospital
• IV ceftriaxone (or azithromycin if fever only concern)

If BCx negative and patient continues to look unwell- consider:

• repeat BCx
• continue antibiotics
• ID consult

If BCx negative and patient well - d/c antibiotics

If BCx positive - continue abx until BCx clears, and then step down to azithromycin 10mg/kg/d x 7d

Question 16

What are other step down agents for typhoid fever?

Answer 16

Quinolone: 3-7d
Cefixime: 7-14 d
Ceftriaxone: 10-14d
Amoxicillin: 14d
Sentra: 14d

Question 17

How often due relapses in typhoid fever occur?

Answer 17

17% relapse within 4wk

Question 18

Do patients with typhoid fever need to be afebrile to go home?

Answer 18

NO! Fever can continue for 6-8d after antibiotics started

As long as blood culture negative and patient well - can go home

Question 19

Does NTS or typhoid fever need follow up stool cultures?

Answer 19

NTS - no

Typhoid fever: 2-3 negative, 24 hour apart before returning to work or child care

Question 20

What is needed if a patient was in an area also endemic for schistosomiasis?

Answer 20

Urine culture

• Salmonella-schistosoma - promotes long-term survival of S. Typhi/paratyphi with intermittent bacteriuria

Question 21

How can typhoid fever be prevented?

Answer 21

1. Careful food and beverage selection
2. Good hand hygiene
3. Typhoid vaccine if >24mo

Question 22

What vaccine option are there? What is their efficacy?

Answer 22

1. Vivotif (oral, live) - for >5yo, need booster in 7y
2. Typherix or Typhim Vi (IM, inactivated), for >2y, booster in 3y
3. ViVaxim (IM inactivated, +hepatitis A) - for >16yo, typhoid booster in 3y

All are ~50% efficacious

Question 23

What medical conditions increase risk for typhoid fever?

Answer 23

1. Achlorhydria
2. Asplenia
3. SCD
4. Immunocompromised

Question 24

What locations require the typhoid vaccine? (8)

Answer 24

1. Afghanistan
2. Bangladesh
3. Bhutan
4. India
5. Nepal
6. Maldives
7. Pakistan
8. Sri Lanka

Question 25

Which children need a minimum of 10 days antibiotics in hospital?

Answer 25

Disseminated disease
Blood cultures take >48h to clear
Child is still unwell after cultures cleared