06 - Salmonella Flashcards
(Salmonella Species)
- What family?
- G+ or G-
- how do they handle oxygen?
- shape?
- enterobacteriacea
- G-
- facultative aerobic
- rod-shaped bacterium
there were some corrections on this that I don’t really understand
(Salmonella)
From epidemiological point of view, Salomenella can be classified into 3 main groups…
1-3. What are they?
- those infecting only humans (ex S. typhi, paratyphia A and C)
- those adaped for particular species of vertebrates
- Salmonella types with no particular host preferences (infect both humans and animals)
1-2. What are the two species of salmonella?
- S. bongori
- S. enterica
(Genus: Salmonella)
- Approximately how many serotypes are known to exists?
Based on what?
- Members of the genus given names based on what? (4 steps)
- 2000 serotypes
67 O and numerous H antigen serotypes
- grouping by epidemiological point of view
animal or syndrome from which they first isolated
place where first reported
antigenic formula
look at slides 8-15 for growth stuff
(Serotyping of Salmonella Enterica)
Based on antigenic structure of Kaufman-White Scheme…
1-3. What are the three criteria?
- somatic antigen (O) - heat stable
- capsular antigen (Vi)
- Flagellar antigen (H - phases 1 and 2) - heat labile
(Antigenic Variation)
In Salmonella Variations in antigenic structure take place
1-4. What are the four kinds of variation?
- phase variation
- H - O variation
- S - R variation
- Form variation
a) O variation
b) V - W variation
(H - O Variation)
- Loss of what?
- Proceeds in one or two directions?
- Mutant non-motile resulting from motile one
- Is spontaneous change from HO to O forms common?
- Genetic material responsible for development of the enzyme system that synthesis the flagella is lost or altered.
- H antigen or flagella
- one (ie flagellated HO form to non-flagellated O form)
- no - is rare (and most often irreversible)
(S - R Variation)
Smooth to Rough Variation
- Change from smooth to rough forms
- Known to occur in what?
- Is it an instantatnous change? what happens?
- Rough organisms give what kind of agglutination?
- low or high in virulence?
allowing what?
- do flagellar antigens change?
- pracitally all bacteria
- no - is a gradual loss of O antigen thus exposing the core polysaccharide
- non-specific
- low
can be used as vaccine strains
- no
(O and V-W Antigen Variation)
- What is O Variation?
- quantitative variation in O antigen
(V - W Variation)
- This variation affects what?
- What happens to O and H antigens?
- Quantitative antigenic changes which take place in Vi antigen are called what?
- Vi antigen
- nothing (remain unchanged)
- the V-W variation
- is salmonella a lactose fermenter?
- do they produce hydrogen sulfide (black pigment)?
- no
- yes
(Phase Variation)
- Flagellar (H) antigens are what?
- H antigen often exists in one of two different phases. An individual bacteria will have flagella composed of antigens either in phase 1 or phase 2.
Bacteria, which are originally in one phase, may switch to the other phase when?
what is this switch called?
- Some Salmonella are monophasic and others are non-motile.
Do non-motile strains demonstrate phase variation?
- Identification of both phases is necessary for what?
- proteins localized in the flagella of motile species of Salmonella
- during multiplication
phase variation
- no
- for identification of Salmonella serotype
(Virulence)
1-5. What are the five virulence factors?
- antigenic phase variation
- sequestratino of nutritional factors
- resistance to serum killing
- antimibrobial resistance
- pathogenecitiy islands
(Salmonellosis)
- Leading Cause of human foodborne illness worldwide
- 1-5 million estimated human cases in the US yearly
- What are the three most common serotypes of Salmonella isolated from humans in the US?
- typhinurium, enteritidis, and newport
(Salmoneloosis in Humans)
- Caused by certain Salmonella serotypes
- Salmonella paratyphi A, S. paratyphi B, S. paratyphi C, and S typhi affect only what?
- Human infections are also caused by non-host adapted Salmonella
- humans
(Human Salmonellosis)
(Salmonella serotype Typhi)
- Causes what?
- Typical symptoms may be preceded by what?
- incubation?
- symptoms?
- Risk is low in the US, but it is higher among international travelers
- Typhoid fever
- acute gastroenteritis (coming on shortly after consumption of cantaminated food and water)
- 7-14 days
- fever, diarrhea, vomiting, abdominal tenderness, death in some cases (12-30%)
(Human Salmonellosis)
(Salmonella serotype Typhi)
- After ingestion…
multiplies where?
enters what?
disseminates thoughout body using what?
- Relapses may occur during convalescence due to what?
- (Carriers) typhoid bacillus may localize where?
- diagnosis?
- what are used as vaccines?
- GI tract
lymphatic system
disseminates throughout the body by blood stream
- Reinvasion of blood stream from the tissues in which typhoid bacilli are still proliferating
- in the gall bladder or bile ducts (may persist there from any years after convalescence)
- culture of blood, feces, urine or bile
- inactivated bacterins or live attenuated strains
