microbio 2125 unit 5 (part 19) Salmonella Infections (Typhoid Fever and Animal Salmonelloses)

etiological agent

Salmonella typhi

Distinguishing characteristics of etiological agent:

• Flagellated, gram-negative rods

• Primary, true pathogens

• Resistant to chemicals (bile, dyes)

• Survive outside host

Virulence Factor(s):

• Well-developed virulence factors

• Adherence to small intestine

• Invasive diarrhea and ulceration of intestinal wall

Predisposing Factors:

• Consumption of fecally contaminated food or water

• Contact with carriers or contaminated fomites

• Exposure to animal carriers (poultry, cattle, reptiles)

Transmission:

• Fecal-oral route via contaminated food, water, fomites

• ID (infectious dose) = 1,000–10,000 cells

Syndrome (signs + symptoms):

• Diarrhea

• Fever

• Abdominal pain

• Septicemia (in typhoid fever)

• Asymptomatic carriers (especially in typhoid fever)

Affected body region/system:

• Gastrointestinal tract

• Gallbladder (chronic carriers)

Treatment:

• Typhoid fever: chloramphenicol or sulfatrimethoprim

• Chronic carriers: gallbladder removal

• Animal salmonelloses: rehydration therapy and/or antibiotics

Prevention:

• Vaccines for typhoid fever (temporary protection)

• Proper handling and cooking of poultry and dairy products

• Hygiene to avoid fomite transmission

Other notes:

• Typhoid fever caused by Salmonella Serotype Typhi

• Animal salmonelloses caused by many serotypes of Salmonella enterica

• Safe assumption: All poultry products are contaminated

Salmonella typhi

most serious pathogen of the genus; cause of typhoid fever; human host

Salmonella cholerae-suis

zoonosis of swine

S. enteritidis

includes 1,700 different serotypes

all salmonella species grouped together called what?

Salmonella enterica