Salmonella enterica

Question 1

S. eneterica

Morphology

Answer 1

Gr- rods, non-spore forming
O, K/Vi, H, pili

Question 2

S. eneterica

Antigenic structure

Answer 2

LPS - O, Vi - capsule, H - flagella & pili

Question 3

S. eneterica

Diagnostic characteristics

Answer 3

Glu fermenter, NOT lac fermenter
nitrate reducer
Catalase + and Oxidase -
H2S producer
Resistant to brilliant green

Question 4

S. eneterica

Media

Answer 4

MacConkey & Levine - no color change
Kligler’s –> red top, yellow bottom & black sediment
Bismuth sulfite –> black colonies

Question 5

S. eneterica

Non-typhoidal - source/ transmission/cause

Answer 5

1. infected poultry & dairy
2. Anthropozoonosis
3. enterocolitis

Question 6

S. eneterica

Enterocolitis - symptoms & incubation

Answer 6

nausea, vomiting, non-bloody diarrhea, headache, low grade fever & abdominal cramping
Incubation: 8-48h

Question 7

S. eneterica

Thyphoid/paratyphoidal - source/ transmission/cause

Answer 7

1. contaminated food/water, person-person
2. fecal-oral
3. typhoid fever

Question 8

S. enterica

Typhoid fever - pathogenesis

Answer 8

small intestine pass through M cells over Peyer’s patches –> macophage engulfement –> reaches blood (incubation) –> liver, spleen, bone marrow & intestinal lymphs –> early symptoms –> liver & spleen enlargement –> bacterial proliferation (bacterial emboli in skin) –> colonialization of gall bladder –> more pathogens in small intestine –> Late sympoms

Question 9

S. enterica

Typhoid fever - symptoms (early, intermediate & late)

Answer 9

Early: gradual fever, malaise, headache, delusions/hallucinations, bradycardia & myalgia.
Fever plateau (39-40) + rose spots on chest, back and abdomen (enteric fever), for ~1week
Late: abdominal symptoms; diarrhea, constipation & generalized abdominal pain, for ~3weeks
Chronic colonialization: <1year - infectious

Question 10

S. enterica

Typhoid fever - Immunity/prophylaxis/treatment

Answer 10

1. reinfection becomes milder
2. non-specific & specific
   - inactivated typhoid vaccine (intramuscular)
   - live typhoid vaccine (oral)
   - capsular Vi/polysaccharide vaccine (intramuscular)
3. symptomatic and antibiotics

Question 11

S. enterica

Septicemia (causative agent, risk groups & cause)

Answer 11

typhoidal/paratyphoidal infections
At risk: infants, immunosupressed & elderly
Cause: sepsis, blood vessel infections (less common, meningitis, septic arthitis, osteomyelitis & endocarditis)