Spirochetes

Question 1

Spirochete cell shape

Answer 1

elongated gram negative helix with thin cell wall, endoflagella and an outer membrane

Question 2

What is the causative agent of syphilis

Answer 2

Treponema pallidum

Question 3

How do you visualize syphilis bacteria

Answer 3

dark field microscopy with a darkfield condenser on an ordinary microscope or fluorescent antibody stains on a fluorescent microscope

Question 4

How do you differentiate primary Herpes simplex ulcers and syphilis primary lesions

Answer 4

Herpes ulcers are painful while syphilis lesions are not

Question 5

Three categories of diagnostic tests for syphilis

Answer 5

direct visualization tests, non-specific antibody tests (non-treponemial screening test, detect Abs against tissue damage antigens), and confirmatory specific antibody tests

Question 6

2 common assays for a non-specific antibody test for syphilis

Answer 6

Rapid Plasma Reagin and Venereal Disease Research Lab tests

Question 7

Why must the physician collect and read the darkfield exam for syphilis right away?

Answer 7

They must observe living organism from a moist lesion to see the characteristic corkscrew motion

Question 8

Describe the technique for darkfield prep

Answer 8

Do not wash lesion, gently adrade a primary lesion or area with the heaviest rash for secondary syphilis while applying gental pressure to exude fluid, if needed add pure warm saline to float coverslip and observe at 400X

Question 9

Describe the non-specific antibody test for syphilis

Answer 9

A synthetic reagin (lipoidal material relased in damaged tissues) is used to detect IgM and IgG antibodies in a patients serum, antigen antibody complexes form a visible precipitate, results reported as titer

Question 10

What titer level for a non-specific syphilis antibody test is considered reactive

Answer 10

1:2 or higher

Question 11

Do non-specific or specific syphilis antibody titers change after treatment

Answer 11

non-specific antibody titers change to reflect severity of disease while specific antibody titers do not change and persist for life

Question 12

What can cause a false positive for a non-specific syphilis antibody test for less than 6 months

Answer 12

acute infections/conditions: hepatitis, mono, viral pneumonia, chicken pox, pregnancy, and some immunizations

Question 13

What can cause a false positive non-specific syphilis antibody test for more than 6 months

Answer 13

autoimmune or connective tissue diseases: lupus, Ig abnormalities, malignancy, narcotic addiction, and aging

Question 14

What is VDRL used to detect

Answer 14

neurosyphilis antibody in CSF

Question 15

Name and describe the most popular specific syphilis antibody test

Answer 15

Fluorescent treponemia antibody test/FTA-ABS: killed Treponema pallidum put on a glass slide with serum of patient, fluorescent-tagged antibody to human Ig added then slide is rinsed, presence of flourescence is a positive result

Question 16

What is different about specific syphilis antibody testing for early or congenital syphilis

Answer 16

IgM only FTA test used because IgM indicates more recent infection

Question 17

Describe primary syphilis

Answer 17

incubation for 10-90 days then painless indurated palpule that progresses to chancre with regional lyphadenopathy

Question 18

Why is darkfield the preferred diagnostic test for primary syphilis

Answer 18

It will be positive before the presence of antibodies and the patient can get the results immediately

Question 19

Describe secondary syphilis

Answer 19

disease is silent after primary lesion for 2-10 weeks then secondary lesions appear on trunk, palms, soles, and face that can progress to warty erosions called painless condyloma lata

Question 20

3 possible outcomes of untreated secondary syphilis

Answer 20

about equal chance of 1.becoming spontaneously cured, 2.progressing to non-infections tertiary stage after many years where the body harbors organisms ant delayed hypersensativity may cause tissue damage, and 3.entering latent stage with positive serology and infections capacity but no symptoms

Question 21

Commplications of tertiary syphilis

Answer 21

Monocytic infiltrates and tissue damage cause gummatous lesions that cause anneurysms, valve incompetence, pressure necrosis, and rupture in the aorta; bacteria may also infect CNS causing meningovascular syphilis with decrease memory, psychosis, and shuffling gait

Question 22

When is a fetus susceptible to syphilis infection from the mother

Answer 22

After 4 months gestation

Question 23

What body structures are affected by congenital syphilis

Answer 23

eyes, meninges, bones, and skin; can develop anemia, jaundice and thrombocytopenia

Question 24

What is the treatment for congenital syphilis

Answer 24

Usually penicillin and doxycycline

Question 25

Nonvenereal treponemal diseases

Answer 25

Bejel, Yaws and Pinta, caused by Treponema pallidum sub-species, same diagnostic techniques and treatment as syphilis

Question 26

How is Leptospira interrogans transmitted from animals to people and how is it killed

Answer 26

Bacteria are in water (survive for weeks) and food contaminated by animal urine and can enter the body through the skin; acid, drying and soap kill it

Question 27

Who is at risk for leptospirosis and how can the disease be prevented

Answer 27

sewer workers, miners, farmers, veterinarians, meat packers, and athletes/children that swim together in natureal bodies of water are at risk; animal immunizations, rodent control, draining water, hygiene, and avoiding contact with dirty water can prevent

Question 28

Clinical course of Leptospirosis

Answer 28

incubation of 7-13 days, flu-like phase for 1 week caused by the bacteremic phase, second stage with aches rash and further complications for 3 weeks

Question 29

Diagnosis of Leptospirosis

Answer 29

culture from blood and CSF during bacteremic phase, culture urine during second phase (imediately before urine acidity kills bacteria), or rise in antibody from acute to convalescent sera

Question 30

Treatment of Leptospirosis and why it is a challenge

Answer 30

tetracycline and penicillin must be given by 4th day of bacteremic phase which is difficult because definitive lab diagnosis takes to long with slowly culturing bacteria

Question 31

cell structure of Borrelia recurrentis

Answer 31

irregular gram negative spiral that has microaerophilic metabolism

Question 32

How are endemic and epidemic Borrelia recurrentis spread

Answer 32

Endemic form rodent reservoir by ticks and epidemic form spread from person to person my body louse in overcrowding, poverty and war

Question 33

How does Borrelia recurrentis cause relapsing fever

Answer 33

Antibodies end symptoms but organism can develop a new antigenic coat and symptoms resume, incubation is about 7 days, usually 2-4 relapses each less severe than the last

Question 34

Diagnosis of relapsing fever

Answer 34

Geisma or Wright stain of blood smears, culture in specialty labs

Question 35

Treatment for Borrelia recurrentis

Answer 35

erythromycin and tetracycline with short regimen

Question 36

Jarisch-Herxheimer reaction

Answer 36

B. recurrentis and syphilis so susceptible to antibiotics that in massive infections, the rapid and widespread cell death causes a backlash of TNF and Il that can be fatal if unanticipated

Question 37

cell structure of Borrelia burgdorferi

Answer 37

Large irregular spiral that has toxic lipopolysaccharide and stain with silver and immunofluorescent dyes

Question 38

What is the causative bacteria of Lyme disease and how is it spread

Answer 38

Borrelia burgdorferi is spread by prolonged bite from Ixodes ticks that fed on infected white-footed mice when they were larva

Question 39

Describe stage 1 Lyme disease

Answer 39

primary lesion at bite site with slowly expanding red ring ring called erythema chronicum migrans rash and constitutional symptoms like fever and muscle/joint aches

Question 40

Describe secondary Lyme disease

Answer 40

dissemination of bacteria, neurological and heart symptoms

Question 41

Describe tertiary Lyme disease

Answer 41

fluctuating intermittent arthritis and mild neurological symptoms or encephalitis

Question 42

Lab diagnosis of Lyme disease

Answer 42

ELISA: negative is significant if positive do a western blot BUT only PCR of joint fluid or fresh tissue or growth is confirmatory, culture or stains of tissue biopsy are not useful

Question 43

Treatment for Lyme disease

Answer 43

doxycyclin, amoxicillin and erythromycin are effective in early disease and prophylaxis for multiple prolonged Ixodes tick bites (careful of overuse because not all bites transmit disease), antibiotics less affective in late disease and repeat therapy may be needed