BATERIAL DISEASES Flashcards
SYPHILIS CAUSATIVE AGENT
Treponema pallidum subspecies pallidum
No natural reservoir and must multiply within a living host
Treponema pallidum subspecies pallidum
agent of nonvenereal endemic syphilis or bejel – in desert regions
T. pallidum subspecies endemicum
agent of yaws – in tropics
T. pallidum subspecies pertenue
aget of pinta – in Central and South America
T. carateum
outer membrane is a phospholipid bilayer
T. pallidum
treponemal rare outer membrane proteins (TROMPs)
T. pallidum
scarcity of such proteins delays the host immune response
T. pallidum
sexual contact through abraded skin or mucous membranes
Treponema pallidum
Congenital infections: transmission to the fetus
Treponema pallidum
parenteral exposure through contaminated needles or blood (possible but extremely rare)
Treponema pallidum
destroyed by heat, cold, and drying out
Pathologic treponemes
almost always spread by direct contact
Pathologic treponemes
Incubation Phase : 3 weeks; 10-90 days
Syphilis
primary stage: painless chancre (28-42 days) - heals without treatment
Syphilis
A person is highly contagious during the primary stage and secondary stage
Syphilis
Secondary Stage: rash (2-8 weeks) - heals without scarring in 2-12 weeks
Syphilis
rash often develops all over the body, including palms of the hands and the soles of the feet
Secondary Stage of Syphilis
Open sores may be present on mucous membranes and may contain pus
Secondary Stage of Syphilis
Pus in the Secondary Stage of Syphilis
condyloma lata
Symptoms can include nervous system abnormalities.
Secondary Stage of Syphilis
If untreated, an infected person will progress to the a stage of syphilis with no symptoms
latent period
Latent period
1 year; 5-20 years
A person is contagious during the [?] and may be contagious during the [?].
early part of the latent stage
latent period
About 20-30% of people with syphilis have a relapse of the secondary stage of syphilis during the [?].
latent stage
the person had passed through the second stage, was symptom-free, then began to reexperience secondary stage symptoms
Relapses
can occur several times
Relapses
When these no longer occur, a person is not contagious through contact.
relapses
A woman in the latent stage of syphilis may still pass the disease to her unborn baby and may have a miscarriage, a stillbirth, or give birth to a baby infected with
congenital syphilis
Most destructive stage of syphilis.
Tertiary (Late) Stage
If untreated, the tertiary stage may begin as early as 1 year after infection or at any time during a person’s lifetime. A person may never experience this stage of the illness.
Tertiary (Late) Stage
The symptoms of tertiary (late) syphilis depend on the complications that develop – gummata, large sores inside the body or on the skin, cardiovascular syphilis, or neurosyphilis.
Tertiary (Late) Stage
• Several varieties of passive hemagglutination tests have been used to detect specific treponemal antibody.
Agglutination Tests
• Particle agglutination tests such as the Serodia TP-PA test have largely replaced microhemagglutination
tests. Particle agglutination tests use colored gelatin particles coated with treponemal antigens and are more
sensitive in detecting primary syphilis.
Agglutination Tests
• It involves isolating and amplifying a sequence of DNA that is unique to a particular antigen.
Polymerase Chain Reaction (PCR)
• Currently still being studied.
Polymerase Chain Reaction (PCR)
Nichols strain of T. pallidum
FTA-ABS
Antitreponemal
FTA-ABS
EIA
Confirmatory; specific, sensitive; may be negative in primary stage
FTA-ABS
Treponemal or recombinant
EIA
Antitreponemal
EIA
Simple to perform; can be automated; not as sensitive as FTA-ABS.
EIA
Enzyme-labeled treponemal antigen
EIA
Anti-IgG or antiIgM, antitreponemal antibody from
patient
EIA
Simple to perform; sensitive in primary syphilis, but sensitivity
decreases in later stages.
EIA
Sheep RBCs or gel particles sensitized with T. pallidum sonicate
MHA-TP or Serodia TP-PA
Antitreponemal
MHA-TP or Serodia TP-PA
Not as sensitive as FTA-ABS
MHA-TP or Serodia TP-PA
Patient DNA matched to treponemal DNA
DNA probe
None
DNA probe
Technically demanding; very specific; lacks sensitivity
DNA probe
Salmonella typhi, a gram-positive bacilli from the family Enterobacteriaceae; an intestinal pathogen that causes many infections
TYPHOID FEVER
Paratyphoid fever, a disease similar to typhoid fever that tends to be milder, is caused by Salmonella paratyphi A or Salmonella paratyphi B
TYPHOID FEVER
Typhoid and paratyphoid fevers are usually spread when feces or urine from an infected person contaminates something that is transferred to another person’s mouth.
Contaminated water and food are the most common sources of infection.
TYPHOID FEVER
Mary Mallon was the first to be identified as an asymptomatic carrier of Salmonella typhi, who worked as a cook and spread the disease unknowingly, hence receiving her famous
nickname “Typhoid Mary.”
TYPHOID FEVER
The symptoms of typhoid fever may be mild or severe and may include prolonged fever, severe headache, malaise, constipation or diarrhea, rose-colored spots on the trunk and an
enlarged spleen.
TYPHOID FEVER
The time from contact with the bacteria to the start of symptoms is usually 8-14 days for typhoid fever, and 1-10 days for paratyphoid fever.
TYPHOID FEVER
Patients infected with Salmonella can become chronic carriers of the bacteria.
TYPHOID FEVER
There are three antigens that is of importance in serologic testing:
a. O antigen (cell wall)
b. H antigen (flagellar)
c. K antigen (capsular)/ Vi antigen (virulence)
This is the outer polysaccharides of the cell wall. It is used to subdivide the salmonellae into group A to I.
O antigen (cell wall)
There are two forms of H antigens, phases 1 and 2. Only one H proteins is synthesized at any one time, depending on which gene sequence is in the
correct alignment for transcription into mRNA.
H antigen (flagellar)
This is antiphagocytic and is an important virulence factor for S. typhi. This is also used for the serotyping of S. typhi in the
laboratory.
K antigen (capsular)/ Vi antigen (virulence)
• This is an enzyme immunoassay that detect IgM and IgG antibodies against the outer
membrane protein of Salmonella typhi
I. Typhidot
• This is a direct agglutination test that is used to detect a rise in the antibody titers
against S. typhi antigens in patient’s serum.
II. Widal test
• Anti-O and anti-H antibodies rise early at 1-2 weeks after infection, and peak at 3-5
weeks
II. Widal test
• Anti-A and anti-B antibodies (against Vi antigens) rise 2-3 weeks after infection and
persist for 4-5 weeks
II. Widal test
• Significant titers are 80 for unvaccinated patients and 160 for vaccinated patients
II. Widal test
play a key role in the immune response.
T cells and macrophages
show the presence of both CD4+ and CD8+ T cells, which produce cytokines that activate macrophages, leading to phagocytosis and healing the primary chancre.
Primary lesions
is capable of coating itself with host proteins, which delays the immune system’s recognition of the pathogen.
T. pallidum
