Tics And Things Flashcards
Mycoplasma pneumoniae
Type of infection; Size; Shape; Colony; Growth
- Upper respiratory infection
- bronchitis
- pneumonia
- Smallest free-living organism (size and genome)
- Many Shapes: LACK rigid cell wall
- NO PEPTIDOGLYCAN
- Unusual colony morphology on agar plates
- Fastidious
- Very slow growing
Mycoplasma Cell Wall
Lacks rigid cell wall: NO PEPTIDOGLYCAN
- instead 3 layered cell membrane
- COMPLETELY RESISTANT TO PENICILLIN and other antibiotics that attack cell wall
- Generally stains poorly or not at all
Mycoplasma: Major Antigenic Determinants
Membrane glycolipids and proteins (because lack cell wall!)
- antibodies to mycoplasma CROSS REACT WITH RBCs
Mycoplasma Fastidious: needs…
Cholesterol/sterol
Mycoplasma pneumoniae and atypical (walking) pneumonia
General Information
- Transmitted person-person via coughing (respiratory secretions)
- Prominent in closed populations
- Laboratory confirmation rarely obtained
Mycoplasma pneumonia Virulence Factor
HIGH AFFINITY for RESPIRATORY EPITHELIAL CELLS
- attaches to cilia and leads to loss of function
- critical for virulence
Clinical Characteristics of Atypical pneumonia
Mycoplasma pneumonia
SLOW ONSET AND COUGH
- Incubation period 2-3 weeks (very long)
- Typically a GRADUAL ONSET of fever, malaise, headache, COUGH
Mycoplasma pneumonia High Risk Factor
Sickle-cell disease: leased to agglutinins and digital necrosis
M. Pneumonia Laboratory Diagnosis
- Currently problematic because so slow
- Often treat without diagnosis, which doesn’t help because could be treating for general instead of walking
- PCR-based tests most specific and rapid
Spirochete
- Don’t like to grow on cultures
- Coiled cell wall, motile, endoflagella, Gram -
Endoflagella
Found on Spirochetes; acts as cork screw to cell walls
How best to visualize Spirochete
Dark-field microscopy or immunofluorescent stains
- culturing very difficult
Spirochetes that cause Disease
BLT
Borrelia - Lyme disease - Relapsing fever Leptospirosis - Leptospirosis Treponema - Syphilis
Manifestations in stages if left untreated!
Borrelia burgdorferi vs Borrelia recurrentis
Burgdorferi: Lyme
Recurrentis: relapsing fever
Lyme Disease
Occurs in stages
- Early: rash; disseminates
- Later: heart; joins; skin; CNS
Borrelia burgdorferi (Transmission; Timing of Exposures)
LYME disease
- transmitted by small deer tick: IXODES
- most exposures from May-July: NYMPHAL STAGE: tics very aggressive
MOST COMMON VECTOR BORNE ILLNESS IN THE US AND EUROPE
Ixodes
Tic that causes Lyme
- problematic because vector for many other pathogens so often confection; need to treat both (i.e. Lyme and babesiosis)!
B. burgdorferi Virulence Factor
Surface exposed lipoproteins (OspA-F)
Bburg:OspA-f
Clinical Characteristics of B. Burgdorferi
Lyme Disease
Multi-stage infection
- Early Infection Stage 1: localized infection
-slowly expanding ERYTHEMIA MIGRANS 7-10 days after tic bite
- Early Infection Stage 2: disseminated infection
- flu-like symptoms; skin lesions
- months later: pain in joints, bones, bursar, muscles and tendons
- Bell’s paisy
- Late Infection Stage 3: persistent infection (months-years after tick bite)
- chronic nervous system and joint involvement
Lyme Disease Most Common Clinical Manifestations
EM (Erythema Migrans)>Arthritis>Bells paisy
Lyme Disease Laboratory Diagnosis
Not perfect; suggests two-test serological approach
- deals with antigen antibody binding assay
Often simply assumed in presence of EM
Borrelia Recurrentis
Relapsing Fever
- epidemic (no longer seen): body lice
- ENDEMIC: transmitted from soft body tick (diff than those from LYME)
- rodents and small animals are reservoir
- western US
Clinical Characteristics of Relapsing Fever
- sudden onset of fever with chills
- lasts 3-6 days and ends abruptly
- starts again 7-10 days later
Leptospirosis
Primarily a disease of wild and domestic animals (dogs!)
- humans get infected through direct/indirect contact
- indirect contact most common: ingestion of contaminated food or water, mucosal membranes
- rapidly disseminates into blood stream
VIABLE FRESH WATER ONLY
- wide variation fo disease; multisystem disease with high mortality
Treponema
- Multi-system disease
- Transmitted through sexual intercourse
- Patient most infectious early in the disease
- Active Lesions on fingers, breasts, lips, oral cavity, or genitals
- can invade VIRTUALLY ANY ORGAN and CNS
Clinical Characteristics of syphilis
STD divided into stages:
- Primary: primary lesion occurring at inoculation site
- heals spontaneous and without treatment
- Secondary: disseminated stage: lesions anywhere on body
- Latent: serologic test positive, but no clinical manifestation
- Late (tertiary): slow progressing inflammatory disease affecting any organ
Neurosyphilis
Symptoms range from subacute meningitis to mental deterioration
Cardiovascular Syphilis
Leads to necrosis of aorta
Gummatous Syphilis
Rare
Lesions in skin (painless) and bone (deep, gnawing pain)
Congenital Syphilis
May result in fetal death and resulting miscarriag, or stillborn at term
Can appear in childhood as DEVELOPMENTAL ABNORMALITIES
- Notched teeth
- Saber shins
- Secondary lesions on feet and face
- Saddle nose
- Large liver and spleen
How is Syphilis spread during primary and secondary stages?
ANY PHYSICAL CONTACT because live bacteria are present
- sexual of non sexual
Syphilis Diagnosis
- Dark-field microscopy: primary, secondary, and congenital lesions
- Serologic Tests
- NONTREPONEMAL TESTS: rely on fortitudes observation that AB’s to a lipoid always antigen present in a wide array of host tissues are specifically generated upon syphilis infection
- REAGIN
- observing cross reaction isn’t he body
- hemagglutination
