bacterial serology (febrile disease) Flashcards
can detect antibodies in typhoid fever, tularemia and brucellosis.
widel’s test
The gold standard for the serological diagnosis of RMSF is the (?) with R. rickettsii antigen, performed on two paired serum samples to demonstrate a significant (?) rise in antibody titers.
- IFA
- four-fold
- Initial diagnosis is often made clinically after ruling out a large variety of other conditions, including typhoid fever, measles, rubella, enteroviral infection, and respiratory tract infection.
- The diagnosis is even more difficult because of its rapid course. The rash develops shortly before death, if at all; therefore, antibodies do not have time to develop.
RMSF
- Thermolabile, Flagellar antigen
- Antigens are SPECIFIC for the given species
- Prepared by suspending the bacterial growth in saline containing 2% formalin. Concentrated stock antigen is good for months, if refrigerated
- Produce floccular type of agglutination
hauch / H antigen
- Detection of (?) is the most useful diagnostic test because it likely indicates a recent infection.
- (?) have been the most widely used methods for antibodies and can detect IgM or IgG directed against M. pneumoniae
- M. pneumoniae-specific IgM immunoglobulin
- Enzyme-linked immunoassays
an agglutination test based on the cross-reactivity of rickettsial antibodies with antibodies to the somatic “O” antigens of the OX-19 and OX-2 strains of Proteus vulgaris and the OX-K strain of Proteus mirabilis.
weil-felix test
- Thermostable, Somatic antigen
- Directly associated with the bacterial body
- NON-SPECIE SPECIFIC and can divide genus into five groups (A,B,C,D,E)
- These are used to detect somatic agglutinins against Salmonella and Proteus (OX2, Ox19, Oxk)
- Prepared by extracting bacterial cultures with either phenol or alcohol. Concentrated stock antigen is good for months, if refrigerated
- Produce granular type of agglutination
ohne / O antigen
Originally, pneumonia caused by M. pneumoniae was referred to as “(?)” because the infection could not be treated with penicillin.
atypical pneumonia
standard diagnostic technique for the diagnosis of typhoid fever
culture method
- small, gram negative abligate intracellular bacteria
- MOT of infection: arthropod bite or contamination with its feces
- primary grow in endothelial cells of small blood vessels, producing vasculitis, cell necrosis, thrombosis of blood vessels, skin rashes, and organ dysfunction
rickettsia/rickettsial organism
- Thermolabile, capsular antigen
- Occur as capsules or as envelop surrounding the bacterial body
- Varieties include: B, L, Vi antigens
- Vi antigen – occurs in highly virulent strains of Salmonella typhi, S.paratyphi,and S.ballerup
- Also suggested as a means of identifying typhoid carriers who often have negative “O” and “H” titers
kapsel / K antigen
- capable of clumping RBCs at 4°C.
- The reaction is reversible when the samples are warmed to 37°C.
- develop in about 50% of patients with M. pneumoniae infection. These antibodies are produced early in the disease (7–10 days) and can typically be detected at the time the patient seeks medical attention.
- The titer peaks at 2 to 3 weeks, and antibodies are present for 2 to 3 months after infection
cold agglutinins
measures the presence of anti-O and anti-H antibodies using bacterial suspensions of killed S. typhi and S. paratyphi that have been treated so that they retain only the O and H antigens
widal agglutination test
- Ingestion of contaminated food or food products, or through contaminated hands
Infections include:
* Gastroenteritis (S.typhimurium, S.enteritidis)
* Bacteremia and Extraintestinal Infections (S.cholerasuis, S.dublin)
- characterized by prolonged fever and multisystem involvement, including lymph nodes, liver, and spleen
typhoid fever
The infection has been referred to as “walking pneumonia” because individuals often do not stay home from work or school and still participate in their daily activities
mycoplasma pneumonia
