0521779407-19 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:21
Salmonella Infections Other Than Gastroenteritis 1317■Ubiquitous in nature, found primarily in the gastrointestinal tracts of
wild and domestic animals; exceptions areS. typhiandS. paratyphi,
which only colonize humans
■Humans become infected by eating contaminated food (poultry,
eggs, ice cream, other dairy products, meat) or by direct contact
with infected animals (particularly reptiles).
■Serotypes commonly causing human disease areS. typhi,S. paraty-
phi,S. enteritidis,S. typhimurium,S. heidelberg, andS. choleraesuis.Signs & Symptoms
■Gastroenteritis – see GI section
■Enteric Fever – an illness characterized by systemic and gastroin-
testinal symptoms that can be caused by any serotype; when caused
by S. typhi it is called typhoid fever; when caused by S. paratyphi
it is called paratyphoid fever. Incubation period 5–20 days; early in
course, there may be a brief period of diarrhea (invasion of mucosa
by bacteria) followed by increasing fever, malaise, headache, cough,
abdominal pain, constipation and confusion; symptoms peak in
10–14 days. Even without therapy there is slow improvement over
the next 2 weeks. Anorexia, weight loss and lassitude can persist for
several months and in 10% relapses occur. Physical findings may be
minimal, even in the acutely ill patient. Findings include bradycardia
(50%), abdominal tenderness and distention, cervical adenopathy,
hepatosplenomegaly (50%) and in 50%,an evanescent, pink, macu-
lar rash primarily on the trunk that lasts 3–4 days (rose spots).
■Bacteremia – can be due to any serotype, but S. choleraesuis and S.
dublin are the most common; <5% of patients with gastroenteritis
develop bacteremia; increased risk in immunocompromised (HIV)
and the elderly; presents with prolonged or recurrent fevers
■Localized infections – seeding of any organ system can occur as a
result of bacteremia; bone and joint (especially in patients with sickle
cell disease), genitourinary, central nervous system and atheroscle-
rotic abdominal aneurysms are the most common sites
■Asymptomatic chronic carrier – defined as presence of salmonella
in the stool for >1 year; associated with biliary stonestests
■Enteric fever diagnosed by obtaining positive blood culture; highest
yield in first week (70–80%) and by third week only 20% positive; bone
marrow aspirate sometimes positive when blood culture negative;
stool culture, urine culture and duodenal aspirates also may be