- Typhoid Mary was a cook who infected 51 patients
- World: 13-17 million cases per year
- Most cases occur in Asia (13 Million)
- Worldwide annual deaths approach 600,000
- U.S.: 400 cases per year (70% in travelers)
- Decreased from nearly 36,000 cases in 1920
-
Salmonella Characteristics (same as non-typhoid Salmonella)
- Facultative Anaerobic Gram Negative Rod in Enterobacteriaceae family
- Grouped with SS Gram Negative Bacteria (Salmonella, Shigella)
- Salmonella is distinguished from other Enterobacteriaceae
- Motile with flagella (unlike Shigella)
- Does not ferment lactose (unlike E. coli)
- Produces Hydrogen Sulfide or H2S (unlike Shigella)
- Facultative Anaerobic Gram Negative Rod in Enterobacteriaceae family
-
Salmonellosis Pathogenesis
- Vi Antigen (Virulence Antigen)
- Also present in Non-Typhoid Salmonella
- Surrounds the SalmonellaBacterial cell surface
- Protects surface Antigen O from immune response (Opsonization, Phagocytosis)
- Salmonella invades intestinal epithelial cells
- Cellular invasion is similar to non-typhoid Salmonella
- However, typhoid Salmonella results in systemic infection
- Invades regional Lymph Nodes and then spreads to other organ systems
- Salmonella typhi can also survive within Phagocytes (Macrophages)
- Vi Antigen (Virulence Antigen)
- Systemic Bacterial Infection (Enteric Fever)
- Salmonella typhi (Typhoid Fever)
- Most common and more severe form
- Salmonella paratyphi (Paratyphoid Fever)
- Much more mild than Typhoid Fever
- SalmonellaCholeraesuis
- Salmonella typhi (Typhoid Fever)
- Transmission
- Humans are only hosts of Salmonella typhi and Salmonella paratyphi
- Asymptomatic chronic carriers can shed Bacteria in the stool
- Ingestion of contaminated food or water (via feces or urine) is primary source
- Raw fruits and vegetables (grown in fields fertilized by sewage)
- Street vendor food and drink
- Contaminated water or ice ingestion
- Flooding
- Poor Hand Washing practices
- Other sources
- May also be transmitted by patient contact in healthcare workers
- Male sexual partners may also transmit to each other
- Highly dense living conditions (e.g. Refugee camp)
- Travel to developing country
- Highest risk in Southeast Asia
- Also high risk in Africa, West Asia, Central and South America
- High risk countries: Mexico, India, Pakistan, Philippines, El Salvador and Haiti
- Incubation (first 5-21 days after ingestion depending on inoculum load, may be up to 60 days)
- Usually asymptomatic in Incubation Period
- Diarrhea may occur during Incubation Period
- Active infection
- Malaise
- Fever (75% of cases)
- Intermittent Fever initially
- Sustained Fever to high Temperatures later
- See Pulse-Temperature Dissociation described below
- Associated symptoms
- Severe Headache
- Myalgia
- Anorexia
- Nausea or Vomiting
- Generalized Abdominal Pain or right lower quadrant (may mimic Appendicitis)
- Change in stool consistency (<50% of cases)
- Child: Diarrhea most common
- Adult: Constipation most common
-
Pulse-Temperature Dissociation (Faget Sign, uncommon)
- Paradoxical and Relative Bradycardia with fever spikes
- Rose Spots (Pathognomonic, present in up to 30% of cases)
- Other findings
- Severe Infection
- Gastrointestinal Bleeding
- Bowel perforation and peritonitis
- Septic Shock
- Altered Level of Consciousness
-
Complete Blood Count
- Leukopenia
- Thrombocytopenia
- Increased liver transaminases
- Increased acute phase reactants (CRP, ESR)
- Cultures
- Blood Culture
- Best Test Sensitivity in first week (up to 40-60% Test Sensitivity)
- Bone Marrow culture (rarely used in clinical practice)
- Higher sensitivity than Blood Culture
- Fecal culture
- Low Test Sensitivity (~33%)
- Better Test Sensitivity after the first week
- Blood Culture
-
Salmonella
Serology (Widal's Test)
- Poor Test Specificity
- Low Test Sensitivity (70%)
- See Fever in the Returning Traveler
- See Traveler's Diarrhea
- Malaria
- Mononucleosis
- Brucellosis
- Tularemia
- Influenza
- Psittacosis
- Dengue Fever
- Viral Hemorrhagic Fever
- Ricketssia
- Leptospirosis
- Amoebic Liver Abscess
- Amoebic Dysentery
- Acute Hepatitis (including Viral Hepatitis)
- Acute HIV Infection
- Cholera
- Giardia
- Cryptosporidium
- Antibiotic Resistance is increasing (esp. in Asia to Fluoroquinolones)
- Severe or complicated infection
- Ceftriaxone 2 g IV/IM every 24 hours for 7-14 days OR
- Infection acquired outside Asia
- Ciprofloxacin 400 mg IV (or 500 mg orally) every 12 hours for 7-10 days OR
- Levofloxacin 750 mg IV (or 750 mg orally) every 24 hours for 7-10 days
- Infection acquired in Asia
- Ceftriaxone 2 g IV/IM every 24 hours for 7-14 days OR
- Azithromycin 1 g orally day 1, then 500 mg orally daily for 5-7 days
- Consider using Azithromycin combined WITH Ceftriaxone in ill hospitalized patients
- Alternative Antibiotics (resistance is common)
- Chloramphenicol 500 mg IV or oral every 6 hours for 14 days
- Additional measures
- Consider adding Dexamethasone in seriously ill patients
- Typhoid encephalopathy
- Peyer patch necrosis (sites of Salmonella infiltration at Small Intestine lymphoid Nodules)
- Gastrointestinal Bleeding (2-10% of cases)
- Bowel perforation and peritonitis
- Mycotic aneurysm (10% of patients over age 50 years old)
- Septic Arthritis or Osteomyelitis
- Pneumonia
- Chronic Carrier state
- Affects 2-5% of Typhoid Fever survivors after acute infection
- Salmonella typhi may continue to survive chronically in the gallbladder
- May continue to spread Salmonella to others
- Gunn (2014) Trends Microbiol 22(11):648-55 +PMID: 25065707 [PubMed]
- Mortality in untreated, prolonged cases is 12-60%
- See Foodborne Illness Prevention
- See Water Disinfection
-
Typhoid Vaccine
- Adjunctive, but not complete protection, and non-compliance with the oral Vaccine is common)
- Even when taken properly, still <75% effective
- Steam or boil shellfish at least 10 minutes
- All milk and dairy products should be pasteurized
- Control fly populations
- Anderson (2014) Crit Dec Emerg Med 28(7):11-9
- Black, Martin, DeVos (2018) Crit Dec Emerg Med 32(8): 3-12
- Butler in Goldman (2000) Cecil Medicine, p. 1681-3
- Nordurft-Froman and DeVos (2022) Crit Dec Emerg Med 36(4): 4-15
- Pearson in Mandell (2000) Infectious Disease, p. 1136
- Feder (2013) Am Fam Physician 88(8): 524-30 [PubMed]
- Maskalyk (2003) CMAJ 169:132 [PubMed]
- Wain (2015) Lancet 385(9973): 1136-45 [PubMed]