NAME: Salmonella typhi
SYNONYM OR CROSS REFERENCE: Typhoid fever, Enteric fever, Typhus abdominalis, Salmonella choleraesuis serotype typhi, Salmonella enterica serotype typhi
CHARACTERISTICS: Family Enterobacteriaceae; Gram negative rod; motile, aerobic and facultatively anaerobic; serological identification of somatic, flagellar and Vi antigens
PATHOGENICITY: Generalized systemic enteric fever, headache, malaise, anorexia, enlarged spleen, and constipation followed by more severe abdominal symptoms; rose spots on trunk in 25% of Caucasian patients; complications include ulceration of Peyer's patches in ileum, can produce hemorrhage or perforation; Common enterocolitis may result without enteric fever; characterized by headache, abdominal pain, nausea, vomiting, diarrhea, dehydration may result; case fatality of 16% reduced to 1% with antibiotic therapy; mild and atypical infections occur
EPIDEMIOLOGY: Worldwide; sporadic cases in North America; most cases represent importation from endemic areas; multi-drug resistant strains have appeared in several areas of world
HOST RANGE: Humans
INFECTIOUS DOSE: 100,000 organisms - ingestion; variable with gastric acidity and size of inoculum
MODE OF TRANSMISSION: Person-to-person; by contaminated food or water; by food contaminated by hands of carriers; flies can infect foods in which the organisms may multiply to achieve an infective dose
INCUBATION PERIOD: Depends on size of infecting dose; usually 1-3 weeks
COMMUNICABILITY: Communicable as long as typhoid bacilli appear in excreta; usually 1st week throughout convalescence; 10% of patients discharge bacilli for 3 months after onset; 2-5% become chronic carriers, may shed bacteria for years
RESERVOIR: Humans - patients with acute illness and chronic carriers
ZOONOSIS: None
VECTORS: Possibly flies (mechanical only)
DRUG SUSCEPTIBILITY: Susceptible to chloramphenicol, ampicillin, amoxicillin, TMP-SMX, fluoroquinolones; Multi-drug resistant (MDR) strains are on the rise; drug susceptibility testing is required
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to many disinfectants - 1% sodium hypochlorite, 70% ethanol, 2% glutaraldehyde, iodines, phenolics, formaldehyde
PHYSICAL INACTIVATION: Sensitive to moist heat (121° C for at least 15 min) and dry heat (160-170° C for at least 1 hour)
SURVIVAL OUTSIDE HOST: Ashes - 130 days; rabbit carcass - 17 days; dust - up to 30 days; feces - up to 62 days; linoleum floor - 10 hours; ice - 240 days; skin - 10-20 min
SURVEILLANCE: Monitor for symptoms; bacteriological examination of blood, excreta; serology not effective
FIRST AID/TREATMENT: Antibiotic therapy for enteric fever; determine appropriate antibiotic with drug susceptibility testing
IMMUNIZATION: Two typhoid vaccines licensed in Canada, one injectable one oral; vaccine administered for occupational exposure or travel to endemic areas for greater than 4 weeks; does not offer complete protection, immunity may be overwhelmed by large inoculum; oral vaccine is contraindicated in immunocompromised and pregnant individuals
PROPHYLAXIS: Antibiotic prophylaxis
LABORATORY-ACQUIRED INFECTIONS: Typhoid is the second most commonly reported laboratory infection; at least 256 reported cases with 20 deaths
SOURCES/SPECIMENS: Feces, urine, bile, blood
PRIMARY HAZARDS: Ingestion, parenteral inoculation; importance of aerosol exposure not known
SPECIAL HAZARDS: None
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices, containment equipment, and facilities for all activities utilizing known or potentially infectious clinical materials and cultures
PROTECTIVE CLOTHING: Laboratory coat; gloves when contact with infected materials is unavoidable
OTHER PRECAUTIONS: Good personal hygiene and frequent hand washing; vaccination for those regularly working with S. typhi cultures or clinical materials
SPILLS: Allow aerosols to settle; wearing protective clothing; gently cover spill with paper towels and apply 1% sodium hypochlorite, starting at perimeter and working towards the centre; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate before disposal; steam sterilization, chemical disinfection
STORAGE: In sealed containers that are appropriately labelled
Date prepared: March, 2001
Prepared by: Office of Laboratory Security, PHAC
Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Health Canada, 2001