febrile antigens Flashcards
materials used for widal test for febrile antigens
*Antigen suspension S. typhi O
Antigen suspension S. typhi ‘BH’
*Antigen suspension S. typhi H
Antigen Suspension S. typhi ‘AH’
*Pipettes
Test tubes Antigen Vortex mixer
*Glass slides
Mixing sticks
*NSS
an infection or fever caused by salmonella spp
typhoid fever or typhoid salmonella
___ infection is caused by Rickettsia spp
ricketsiall infection
___ are reagent containing bacterial antigens
febrile antigens
*Typhoid fever, simply typhoid, caused by the bacterium ____
Salmonella enterica
subsp. enterica serovar Typhi
Salmonella enterica
subsp. enterica serovar Typhi grows in what part of the body?
intestine and blood
____ is a cook poor hygiene - fecal contaminants mixed with food
mary mallon
Typhoid is spread by ___
eating or drinking food or water contaminated with the
FECES of an infected person.
TSI tube result of salmonella spp
alk/acid - red/yellow butt with black colored (hydrogen sulfide)
*Diagnosis is made by any ___ and with
the Widal test (demonstration of antibodies against Salmonella antigens
O-somatic and H-flagellar).
blood, bone marrow, or stool cultures
a therapeutic trial time with ___ is generally undertaken while awaiting the results of the Widal test and cultures
of the blood and stool.
chloramphenicol
what are the methods used for diagnosing salmonella infection
1.) Culture (bacteria) -
2.) Kauffman and White classification scheme - 3.) Widal test
4. Typhidot -
a method of diagnosing salmonella infection which is the gold standard
culturing bacteria
a method of diagnosing salmonella infection which focused on classifying sero type
2.) Kauffman and White classification scheme
a method of diagnosing salmonella infection in which it looks for the IgG and IgM
typhidot
In Typhidot, a detection of IgG indicates the presence of what infection?
past infection
In Typhidot, a detection of IgM indicates the presence of what infection?
present infection
a method of diagnosing salmonella infection in which it Quantitatively measures the antibodies in the serum of patient with Typhoid fever
WIDAL TEST
3 kinds of antigen being detected in widal test
O antigen
H antigen
K antigen
also known as Somatic antigen
O antigen
an antigen that is heat stable
O antigen
it is an antigen that is present in the cell wall of the bacteria
O antigen
an antigen that is also known as the flagellar antigen
H antigen
Is H antigen or flagellar antigen heat stable?
nope
it is an antigen that is found in the flagella
H antigen or flagellar antigen
an antigen used for widal test
commonly is the O antigen, but sometimes with H antigen
the antigen that is a virulence factor of salmonella
K antigen
K antigen is also known as
Vi antigen
K antigen is the promoter of the ___ of the salmonella
capsulation
this antigen is resistant to phagocytosis
K antigen
the antigen that is used by the reference laboratories
K antigen
3 Types of Methods in WIDAL’s:
Rapid Slide Screening Method
Rapid slide titration method
Tube agglutination test
a *1/+ agglutiation means
Less than 25% of the organism is
agglutinated
*1+ agglutination means
25% of the organism is agglutinated
2+ agglutination means
50% of the organism is agglutinated
*3+ agglutination means
75% of the organism is agglutinated
100% of the organism is agglutinated
4+
Rapid Slide Titration Method
give the corresponding ml used each circle
0.08ml, 0.04ml, 0.02ml, 0.01 and 0.005ml
Serum Volume
0.08
0.04
0.02
0.01
0.005
give the corressponding tube dilution
1:20
1:40
1:80
1:160
1:320
incubation time for salmonella O antigens and proteus
50*C for 4 hours
incubation time for salmonella H antigens
50*C for 2 hours
It is necessary to perform all dilutions in the slide test to obviate the “prozone” effect where
higher concentrations of the serum may give a negative result but further dilutions may give a
positive result
true or false
true
A single negative test does not exclude the absence of infection
true or false
true
A single positive test is of no diagnostic value unless the titer
is sufficiently low.
true or false
sufficiently high
The considered significant titer in the Widal test is ___ while
____ in the Weil-Felix Test
1:80; 1:160
Two Types of Agglutination Test in WIDAL’S
somatic agglutination
flagellar agglutination
Compact aggregates that are not easily dispersed
Stronger agglutination than H Ag
Somatic Agglutination
Fluffy and floccular aggregates that are easily
dispersed
Flagellar Agglutination
Significant titer for widal
> 80
INC titer on OD Ag:
indicates acute/ recent typhoid fever
INC titer on OA, OB and OC:
indicates acute/ recent
paratyphoid infection
INC titer on HD Ag
indicates previous/ past infection with
typhoid fever
*-Convalescent/ vaccination against typhoid fever
INC titer on HA, HB, HC
indicates past infection on
S.paratyphi
INC titer on O and H Ag:
: indicates mixed infection
*NON SPECIFIC TEST
WEIL- FELIX TEST
Used to test for antibodies to rickettsia infections of
Typhus fever caused by: (R. prowazekii)
WEIL- FELIX TEST
Proteus ox-2 is from
Proteus vulgaris
proteus ox 19 is from
Proteus vulgaris
Proteus ox-k uses
Proteus mirabilis
*Endemic Typhus:
May agglutinate “OX-19 and OX-2”
Tick Borne Spotted Fever
May agglutinate “OX-19 and OX-2”
Scrub Typhus
OX-K strain”
TEST IS NEGATIVE IN
*RICKETSSIAL POX
*TRENCH FEVER
*Q-FEVER
___ reaction may occur in urinary or other
Proteus infection. Test maybe negative in 50 percent
scrub typhus
False Positive
rocky maintain spotted fever
ox19 and ox 2
brill zinsser disease
ox19 +-1
