2S [LAB]: BAT Flashcards
A serologic test for the presumptive diagnosis of enteric or typhoid fever caused by the Gram-negative bacilli S. typhi
Widal test
Principle used in Bacterial agglutination test
Direct agglutination
Bacterial agglutination test uses what reagent?
Dye-treated suspensions of bacteria
Antibody produced by S. typhi exposure that appears before H abs, and is more significant of active infection
O Abs
Antibody produced by S. typhi exposure that is valuable late in the course of disease where O abs may have disappeared
H Abs
For the early phase of infection, which sample is preferred in Widal Test?
Blood
The diagnostic antibodies used in Widal test
O and H ags
Antigen in S. typhi that is heat-stable
O Ag
Antigen in S. typhi that is heat-labile
H Ag
Specimens submitted by the patient for the Widal test
Paired sera (acute phase, 2 weeks after)
Significant titer for the Widal Test
1:80 (0.02 mL)
What grading of agglutination is considered significant and positive in the Widal Test?
2+ (50% of the organisms are agglutinated)
If high titers are observed on all antigens, this is interpreted as ___
Mixed infections
A non-specific test for the detection of rickettsial fever
Weil-Felix test
Antigen used in Weil-Felix Test
Proteus OX species strains
One of the most common zoonoes that affect farmers, veterinarians, and slaughterhouse workers
Brucella
A Rickettsia species are transmitted to human by arthropod except ___
R. prowazekii
If the Weil-Felix Test yields the following results:
OX-2: +
OX-19: +
OX-K: -
Interpret which possible Proteus species is involved
P. vulgaris
If the Weil-Felix Test yields the following results:
OX-2: -
OX-19: -
OX-K: +
Interpret which possible Proteus species is involved
P. mirabilis
Significant titer in Weil-Felix test
1:160 (0.01 mL)
Significant titer in Brucella test
1:80 (0.02 mL)
OX-K strain of Proteus is the ___ strain
Kingsbury strain
The antibodies against Brucella antigens are cross-reactive with ___ agglutinins
Tularemia
A high titer of Proteus OX-K suggests what rickettsial infection?
Scrub or Tsutsugamushi fever
Brill’s disease, murine typhus, epidemic typhus, and Rocky Mountain Spotted Fever (RMSF) will yield what results in Weil-Felix test?
High titer of OX-19
Weak reaction on OX-2
Brucellosis is also known as ___
Malta fever
Give the causative agent:
Rocky mountain spotted fever
R. ricketsii
Give the causative agent:
Murine typhus
R. mooseri
Give the causative agent:
Epidemic typhus
R. prowazekii
Give the causative agent:
Brill’s disease
R. prowazekii
Give the causative agent:
Scrub typhus
R. tsutsugamushi
