Typhoid Carrier State

Typhoid carrier state is persistent faecal or urinary excretion of Salmonella Typhi for over 1 year after acute infection, with chronic colonisation of the gallbladder (biliary tract) as the usual reservoir. About 1 to 5 percent of infected people become chronic carriers, more commonly women, older adults and those with gallstones.

• Urinary carriage associated with Schistosoma haematobium infection is relevant in Kenya.
• Carriers are a source of outbreaks, especially when they handle food.

Usually asymptomatic with a history of typhoid; some have biliary colic, cholecystitis or cholelithiasis.

• Intermittent excretion in stool, urine or bile.
• Differential diagnosis: temporary convalescent excretion (up to 3 months), non typhoidal Salmonella carriage, other enteric carriage, gallbladder disease unrelated to infection.
• Complications: transmission to household and community contacts, outbreaks via food handling, gallbladder carcinoma (long term association), chronic cholecystitis, urinary tract infection.

Cultures of stool, urine and bile over time.

• Stool culture on enrichment and selective media at least three times at weekly intervals (all negative for clearance); urine culture, especially with schistosomiasis; duodenal string test or bile culture.
• Anti Vi antibody titre (raised in chronic carriers), blood count, liver function, gallbladder ultrasound, schistosomiasis testing (urine microscopy) and HIV test.
• Antibiotic susceptibility testing (multidrug resistance and fluoroquinolone non susceptibility are common).

Eradicate colonisation with prolonged antibiotics and treat gallbladder or urinary tract disease.

• Supportive: exclusion from food handling, healthcare and childcare until three negative cultures at monthly intervals, strict hand washing, safe food and water, education on hygiene, counselling.
• Pharmacological: choose by susceptibility.
  • Ciprofloxacin 750 mg twice daily for 4 weeks (children 20 mg/kg/day in two doses for 4 weeks).
  • Or norfloxacin 400 mg twice daily for 28 days.
  • Or amoxicillin 100 mg/kg/day in 3 doses (adults 2 g three times daily) with probenecid 500 mg four times daily for 6 weeks.
  • Or cotrimoxazole 960 mg twice daily for 6 weeks.
  • Azithromycin 1 g daily for 14 days where quinolone and first line agents fail.
  • Typhoid conjugate vaccine 0.5 mL IM single dose (from 6 months of age) for contacts and carriers' household members.
  • Urinary carriers with schistosomiasis: praziquantel 40 mg/kg single dose, then antibiotics.
• Procedures: cholecystectomy with antibiotic cover for carriers with gallstones or chronic cholecystitis when medical therapy fails (antibiotics for 1 to 2 weeks before and 4 weeks after); endoscopic retrograde cholangiography to remove stones; lithotripsy rarely.
• Special groups: pregnancy, amoxicillin or cephalosporin (ceftriaxone 2 g IV daily for 14 days) and avoid fluoroquinolones; children, cefixime 20 mg/kg/day for 14 days or azithromycin 10 mg/kg/day; HIV, prolonged therapy and relapses; renal impairment, adjust doses.
• Red flags: fever, right upper quadrant pain, jaundice (cholecystitis or cholangitis), relapse, resistant isolate, carrier among food handlers or healthcare workers.
• Follow-up: stool cultures at 1, 2 and 3 months after therapy; annual gallbladder review; notify public health authorities; vaccinate contacts.