Salmonella infections in Canadian children Flashcards
What are sources of non-typhoidal salmonella infection?
* animals (reptiles)
* food: poultry, eggs, dairy products, ground beef, produce, melons, sprout seeds, tomatoes (in contaminated water)
* water contaminated
What are sources of typhoid/paratyphoid fever?
* source: water/food contaminated from feces of carrier (Typhoid Mary)
* Asia (less commonly Africa)
What is the incubation period for NTS?
* incubation: 12-48 h (up to 7 days)
What is the incubation period for typhoid fever?
* incubation period: 7-14 days (3-60 days)
How does non-typhoidal salmonella typically present?
- Asymptomatic
- acute gastro
- N/V/D (non-bloody, persists 3-7 days)
+/- fever
How does typhoidal salmonella typically present?
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
What is a RF for being a chronic carrier of salmonella? (> 12 mo)
Gallstones (for TS and NTS)
What is disseminated disease for salmonella?
- 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
What can salmonella UTI cause?
NTS: renal abscesses
TS: urinary stones
Who should stool cultures for NTS be sent on?
Bloody diarrhea
persistent diarrhea
severe non-bloody diarrhea
Who should cultures for suspected TS be sent on? And what kind of cultures?
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%
What percent of kids with TS have positive stool cx?
30%
- gut infection often resolved by time of presentation
- Positive stools but negative BCx were presumably all bacteremic at some point
How do you treat NTS?
* 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)
How do you treat TS?
* 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
What is duration of therapy for TS?
- azithro
- quinolones
- cefixime
- CTX
- amoxil/septra
* 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
Which abx is best to prevent relapse in TS?
* relapse rates lower with 5-7 day course of azithro than with quinolones or CTX
When can a child with TS return to work?
* 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
When can a child with NTS return to work?
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
How effective are vaccines for salmonella?
All three vaccines have only about 50% efficacy for S Typhi.
Only oral vaccine is thought to provide some protection against S Paratyphi.
How do you prevent salmonella infections?
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
What vaccines are available for salmonella?
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)
What is the best step down antibiotic for Typhoid fever?
Azithromycin - intracellular killing and less resistance - possibly less relapse as per CATMAT
Where do intestinal perforations occur in typhoid fever?
Terminal ileum
When do you treat salmonella infections with antibiotics?
- 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
When can patients with NTS return to work/childcare?
When can patients with TS return to work/childcare ?
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
When can you step down from IV antibiotics to PO antibiotics in Salmonella?
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
Stool culture positive for salmonella. What do you do?
- Travel to resource poor-country in preceding 2 months?
- Febrile, <3 mo, immunocompromised, asplenia, unwell?
*** must do CSF if =< 3 months b/c NTS is at higher risk of meningitis
Blood culture positive for salmonella. What do you do?
- Admit unless completely well and caregivers reliable
- start CTX
- repeat BCx q24-48 hours
Why does relapse occur in salmonella disease?
17% relapse
Residual reticuloendothelial system disease, not abx resistance
Optimal management is not clear
Which kids with positive stool culture for Salmonella get a CSF?
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!
What is the percent of kids with stool positive for typhoid salmonella who will have bacteremia?
80%
