Salmonella infections in Canadian children

Question 1

What are sources of non-typhoidal salmonella infection?

Answer 1

* animals (reptiles)

* food: poultry, eggs, dairy products, ground beef, produce, melons, sprout seeds, tomatoes (in contaminated water)

* water contaminated

Question 2

What are sources of typhoid/paratyphoid fever?

Answer 2

* source: water/food contaminated from feces of carrier (Typhoid Mary)

* Asia (less commonly Africa)

Question 3

What is the incubation period for NTS?

Answer 3

* incubation: 12-48 h (up to 7 days)

Question 4

What is the incubation period for typhoid fever?

Answer 4

* incubation period: 7-14 days (3-60 days)

Question 5

How does non-typhoidal salmonella typically present?

Answer 5

• Asymptomatic
• acute gastro
• N/V/D (non-bloody, persists 3-7 days)

+/- fever

Question 6

How does typhoidal salmonella typically present?

Answer 6

dx often not considered b/c they present with non-specific symptoms of fever and abdo manifestations! Abdo pain, constipation with a hx of recent diarrhea is common 10% of hospitalized people have GI bleed

Question 7

What is a RF for being a chronic carrier of salmonella? (> 12 mo)

Answer 7

Gallstones (for TS and NTS)

Question 8

What is disseminated disease for salmonella?

Answer 8

• bacteremia (presumably always present in typhoidal)
• osteomyelitis (NTS: SCD, TS: rare)
• septic arthritis (NTS: SCD, TS: rare)
• CNS: meningitis/brain abscess/encephalopathy (encephalopathy in TS, brain abscess/meningitis in NTS)
• cardiac/vascular involvement (endocarditis/arteritis in NTS, myocarditis and endocarditis in typhoid)
• rare reports of anemia, DIC and pulmonary, muscle/soft tissue, hepatobiliary, splenic or genital involvement, primarily in adults with typhoidal infection

Question 9

What can salmonella UTI cause?

Answer 9

NTS: renal abscesses

TS: urinary stones

Question 10

Who should stool cultures for NTS be sent on?

Answer 10

Bloody diarrhea

persistent diarrhea

severe non-bloody diarrhea

Question 11

Who should cultures for suspected TS be sent on? And what kind of cultures?

Answer 11

Blood cultures for unexplained fever within 2 mo of returning from resource poor country

Increase yield with adequate volume and 2 blood cultures

Stool cultures only + in 30%

Question 12

What percent of kids with TS have positive stool cx?

Answer 12

30%

• gut infection often resolved by time of presentation
• Positive stools but negative BCx were presumably all bacteremic at some point

Question 13

How do you treat NTS?

Answer 13

* antibiotics only with suspected or proven bacteremia or invasive infection

* don’t decrease severity/duration of diarrhea and may increase incidence of carriage

* azithro recommended for NTS (only studies for typhoid/paratyphoid)

Question 14

How do you treat TS?

Answer 14

* azithro is drug of choice (has intracellular killing and less resistance, possibly less relapse )

* cipro was commonly used as step-down therapy but not approved for pre-pubertal children and resistance common

Question 15

What is duration of therapy for TS?

• azithro
• quinolones
• cefixime
• CTX
• amoxil/septra

Answer 15

* azithro: 7 days

* quinolones: 2-7 days

* cefixime: 7-14 days

* CTX: 10-14 days

* amoxil/septra: 14 days

* total duration unclear if stepped down to oral therapy

Question 16

Which abx is best to prevent relapse in TS?

Answer 16

* relapse rates lower with 5-7 day course of azithro than with quinolones or CTX

Question 17

When can a child with TS return to work?

Answer 17

* 2-3 negative stool tests 24 h apart over variable number of days following completion of abx before returning to work or to child care

* UCx may be required if pt in area endemic with schistosomiasis because Salmonella-schistosoma binding promotes long-term survival of S typhi or S Paratyphi with intermittent bacteriuria

Question 18

When can a child with NTS return to work?

Answer 18

Basically when symptoms are gone

* pt with diarrhea should be considered infectious.

* No need to document when stools become negative; asymptomatic carriage persists for months in young children but asymptomatic carriers don’t need to be restricted from participating in activities

Question 19

How effective are vaccines for salmonella?

Answer 19

All three vaccines have only about 50% efficacy for S Typhi.

Only oral vaccine is thought to provide some protection against S Paratyphi.

Question 20

How do you prevent salmonella infections?

Answer 20

NTS:

* safe food handling

* good handwashing after contact with animals (baby poultry, reptiles, frogs)

TS:

* careful food/beverage selection

* good hand hygiene

* all children >= 24 mo travelling to South Asia (Afghanistan, Bangladesh, Butan, India, Nepal, Maldives, Pakistan, Sri Lanka) should have typhoid vaccine

* Immunization for travellers to other resource-poor countries when likely to be exposed to contaminated food/water when they have achlorhydria, asplenia, or sickle cell disease or immunocompromised

* houshold contacts of carriers should be immunized

Question 21

What vaccines are available for salmonella?

Answer 21

Vaccines only good for S typhi (50% efficacy)

* oral, live: 5yr+ (booster after 7 yr) —> only vaccine with some protection against S. paratyphi

* Parenteral inactivated vaccine: 2 yr + (booster after 3 yr)

* Parenteral inactivated vaccine with Hep A: 16 yr + (booster after 3 yr)

Question 22

What is the best step down antibiotic for Typhoid fever?

Answer 22

Azithromycin - intracellular killing and less resistance - possibly less relapse as per CATMAT

Question 23

Where do intestinal perforations occur in typhoid fever?

Answer 23

Terminal ileum

Question 24

When do you treat salmonella infections with antibiotics?

Answer 24

• NTS: only if suspected or proven bacteremia or invasive infection.

Why? Antibiotics don’t decrease severity/duration diarrhea and may increase incidence of carriage

• TS: all cases with positive blood culture

Question 25

When can patients with NTS return to work/childcare?

When can patients with TS return to work/childcare ?

Answer 25

NTS

• pt with diarrhea should be considered infectious. (shouldn’t work as food handlers if they have diarrhea)
• No need to document when stools become negative; asymptomatic carriage persists for months in young children but asymptomatic carriers don’t need to be restricted from participating in activities

TS

• 2-3 negative stool tests 24 h apart over variable number of days following completion of abx before returning to work or to child care

Question 26

When can you step down from IV antibiotics to PO antibiotics in Salmonella?

Answer 26

TS:

* Fever persists 6-8 days from start of antibiotics

* Fever not contraindication to switch to PO antibiotics or to hospital discharge

Note: flow chart says it remains controversial whether a child with persistent fever can safely be discharged

Question 27

Stool culture positive for salmonella. What do you do?

Answer 27

1. Travel to resource poor-country in preceding 2 months?
2. Febrile, <3 mo, immunocompromised, asplenia, unwell?

*** must do CSF if =< 3 months b/c NTS is at higher risk of meningitis

Question 28

Blood culture positive for salmonella. What do you do?

Answer 28

• Admit unless completely well and caregivers reliable
• start CTX
• repeat BCx q24-48 hours

Question 29

Why does relapse occur in salmonella disease?

Answer 29

17% relapse

Residual reticuloendothelial system disease, not abx resistance

Optimal management is not clear

Question 30

Which kids with positive stool culture for Salmonella get a CSF?

Answer 30

Only kids who did not travel to a resource-poor country with a positive stool culture

and CSF =< 3 months old

(while awaiting blood culture results)

Why in this situation? Because meningitis is more common in NTS!

Question 31

What is the percent of kids with stool positive for typhoid salmonella who will have bacteremia?

Answer 31

80%