Gram Funky Flashcards
1
Q
Spirochetes
A
- thin, regular, coiled cells
- live in the oral cavity, intestinal tract, and perigenital regions of humans and animals -pathogens are strict parasites with complex growth requirements
- require live cells for cultivation
2
Q
Treponema pallidum - spirochete
A
- think regular coiled cells
- live in oral cavity, intestinal tracts, and perigenital regions of humans and animals
- pathogens are strict parasites with complex growth requirements
- require live cells for cultivation
- causes syphilis
- human is the natural host
- extremely fastidious and sensitive; cannot survive long outside of the host
- sexual and trans placental transmission
3
Q
Primary Syphilis
A
- lasts 2-6 weeks
- spirochete binds to the epithelium, multiplies, and forms a lesion called chancre at the site of inoculation - commonly mouth and genitals
- typically painless
- fluid from the chancre is highly contagious
- chancre spontaneously heals as the spirochete moves into the blood
4
Q
Secondary Syphilis
A
- spirochete is multiplying in the bloodstream
- rash forms on the skin, palms and soles with fever, headache, and sore throat
- rash does not hurt or itch and can persist for months
- rash disappears spontaneously
5
Q
Latency and Tertiary Syphilis
A
- after resolution of secondary syphilis - 30% of infections enter a latent period that can last for 20 years or longer
- if left untreated, tertiary syphilis forms
- damage to multiple tissues and organs (even neurological issues)
- gummy’s (painful swollen tumors) may develop
6
Q
Congenital syphilis
A
- Treponema pallidum can pass through the placenta to the fetus (infection possible in any of 3 trimester)
- symptoms include nasal discharge, skin eruptions, bone deformation, and nervous system abnormalities
- the later for, gives rise to stigmata in the bones, eyes, inner ear, and joints, and causes the formation of Hutchinson teeth (notched, barrel shaped)
7
Q
Syphilis diagnosis and testing
A
- stages can mimic other diseases; overlapping symptoms with other stds complicate diagnosis
- consider symptoms, medical history, microscopic, and serological testing
- staining techniques using silver make spirochetes more visible with a bright-field microscope
- serological tests detect antibodies in response to T. Pallidum (RPR, VDRL, FTA-ABS)
- TreatmentL penicillin G
8
Q
Borrellia burgdorferi - spirochete
A
- Lyme disease
- complex lifecycle involves mice, deer, and transmission by ticks
- acquired by tick bites
- non fatal, slowly progressive syndrome that mimics neuromuscular and rheumatoid conditions
- 50-70% patients get bulls eye rah
- fever, headache, stiff neck, and dizziness
- if untreated, can progress to cardiac and neurological symptoms, polyarthritis
9
Q
Chlamydias
A
- small, wall less cells with two membranes
- obligate intracellular parasites within vesicles
- gram negative
- life cycle alternates between two stages:
1. Elementary Body: small, metabolically inactive, extracellular, infectious form released by the infected host
2. Reticulate body: non infectious, actively dividing form, grows within host cell vacuoles
10
Q
Chlamydia trachomatis
A
- small gram funky
- human reservoir
- causes ocular trachoma: severe infection, deforms eyelid and cornea, may cause blindness (leading cause of non-traumatic blindness globally)
- causes inclusion conjunctivitis: occurs as baby passes through birth canal; prevented by prophylaxis
- two strains infect humans:
1. Trachoma strain: attacks the mucous membranes of the eyes, genitourinary tract, and lungs
2. Lymphogranuloma venereum (LGV) strain, which invades the lymphatic tissues of the genitalia
11
Q
Sexually Transmitted Chlamydial Diseases
A
- Chlamydiosis: most prevalent bacterial STD - long term reproductive damage - asymptomatic in women (70%) and in men (10%)
- Nongonococcal Urethritis (NGU): in makes - inflammation of urethra - mimics gonorrhea - yet do not involve gonococci
- Pelvic Inflammatory Disease (PID): in women - cervicitis with a white drainage, endometriosis, and salpingitis
- Lymphogranuloma venereum: disfiguring disease of the external genitalia and pelvic lymphatics
12
Q
Identification of Chlamydiosis
A
- sampling requires dislodging cells from mucosal surface
- direct assay of specimens using immunoflourescence and a PCR based probe most sensitive and specific tests
- giemsa or iodine stains useful in diagnosing inclusion conjunctivitis - not recommended for urogenital specimens (low sensitivity and false-negative results in asymptomatic patients
13
Q
Commas (curviform) - gram funky
A
- gram negative
- generally cause enteric diseases
- three groups share adaptations to survival in the intestine:
1. Vibrio: comma-shaped rods, single polar flagellum
2. Campylobacter: short spirals or curved rods; flagellum
3. Helicobacter: spirochete with tight spirals and several polar flagella
14
Q
Vibrio cholerae
A
- comma shaped bacteria. Fermentative and grow on ordinary or selective media containing bile at 37 degrees F
- they possess unique O (somatic), H (flagella), and membrane receptor antigens
- cause of cholera
- humans infected by ingesting contaminated food and water
- found most in areas with poor sewage and water treatment
- generally sensitive to and killed in, acidic environments
- favored by warm, monsoon, alkaline, and saline conditions
- pandemic pattern since 1961 - El tor bio type survives longer, more infectious
- in nonedemic areas can be spread by ingestion of contaminated food or water
- infects mucous barrier of small intestine, noninvasive
- cholera toxin that causes electrolyte and water loss through secretory diarrhea “rice water stool;” resulting in dehydration, and neurological symptoms
- treatment: rehydration and tetracyclines
- prevention: clean water and use peptobismol - not Tums
15
Q
Vibrio parahaemolyticus
A
- Salt-tolerant inhabitants of coastal waters, associate with marine invertebrates
- gastroenteritis from raw seafood; symptoms similar to cholera
- treatment: fluid and electrolyte replacement; occasionally antimicrobials
