Mycoplasma, Lyme, Spirochetes, Chlamydia, Rickettsia (Woychick) Flashcards
Mycoplasma pneumoniae (colony appearance, unique characteristic, hallmark symptoms, diagnostic test)
- no cell wall, so penicillins dont work, cant gram stain well, “mulberry shape” colonies
- pneumoniae- adhere to lung epithelia, cause loss of cilia and cells slough, causing COUGH and SLOW ONSET (hallmarks)
- “cold agglutinins” (antibodies vs altered RBC antigens)
- diagnosis based on gradual onset, long family incubation (months)
Spirochetes (gram status, characteristic component, disease-causing genera (3))
- gram -
- endoflagella
1) Borrelia
2) Leptospira
3) Treponema
Borrelia Burgdorferi (disease, carrier, prophylactic treatment, virulence factors)
- Causes lyme disease
- Carried by Ixodes deer tick (also causes babesiosis)
- Give prophylactic doxycycline vs tick bite
- Virulence factors: OspA-F allow attachment
- vaccine, but canceled for PR issues
Lyme Disease Clinical Presentation (3 stages, treatment)
Stage 1: local infection (erythema migrans 7-10 days after bite, hot, burning, itchy, painful) on trunk, thigh, groin
Stage 2: days-weeks after bite: flu-like s/t (headache, fever, chills, achiness, skin lesions. Weeks-months: musculoskeletal pain in joints, cardiac, neurologic issues (Bell’s palsy- face droop).
Stage 3: months-years: Chronic nervous system/joint, Lyme’s arthritis
-ALL CURABLE WITH ANTIBIOTICS
Borrelia Recurrentis (disease (2), clinical presentation)
- Causes relapsing fever
- epidemic: louse transmitted during war/famine, not in US
- endemic: tick transmitted via small animals (west coast)
- symptoms: sudden fever, chills, headache 3-6 days, ends abruptly. Relapse 7-10 days later, less bad each time.
Leptospira (source, disease, clinical presentation, geography)
- comes from wild animals/dogs, shed in urine, fecal/oral route to infect humans
- Causes leptospirosis (asymptomatic/mild febrile/multisystem (meningitis, pulmonary hemorrhage syndrome, myocarditis, hepatic/renal dysfunction + mortality))
- most frequent in Hawaii
Treponema Pallidum (disease, transmission)
- spirochete, Causes syphilis
- transmitted by human contact, commonly sexual
- lesions on fingers, mouth, oral cavity, breasts, genitals (anywhere sexual)
- invades anywhere in body
Syphilis (stages/types (5))
Primary: primary lesion (chancre) at infection site
Secondary: disseminated lesions anywhere on body
-can heal on its own (30%)
Latent: No clinical manifestation but test +, blood contagious
Tertiary: slow progressing inflammatory disease affecting any organ (neurosyphilis: subacute meningitis-mental deterioration, cardiovascular syphilis: necrotic aorta, gummatous syphilis: painless lesions in skin and painful bone lesions)
Congenital: cause fetal death/miscarriage/developmental abnormalities (notched teeth, saber shins, saddle nose, hepatosplenomegaly, lesions)
Reagin (diagnostic value, tests (2))
- nonspecific treponemal test- antibodies to lipoidal antigen present in syphilis infection- add cardiolipin to patient serum, if syphilis it will react since contains reagin
- Flocculation test (above) or complement fixation (fixation if reagin present)
- Specific tests also for antibodies vs treponema
Chlamydia (species, life cycle)
- obligate intracellular parasite, need cell to make ATP
- C. trachomatosis, pneumoniae, psittaci
- infect as elementary body (EB), phagocytosed, migrate near nucleus, grow to reticulate bodies (RB), multiply, convert to EB, lyse cell
Chlamydia trachomatosis (diseases (5))
Causes diseases like
1) Ocular trachoma (chronic conjunctivitis–>scarring, most common cause of preventable blindness)
2) inclusion conjunctivitis (acute infection)
3) infant pneumonia (from birth- give prophylactic erythromycin to all newborns, also vs gonnorhea)
4) genital tract infection
5) lymphogranuloma venereum
Chlamydia pneumoniae (disease, symptoms)
- common among kids
- mild URT infection, pneumonia or bronchitis
- linked to asthma
Chlamydia psittaci (disease, clinical presentation)
- Causes psittacosis (lethal bird disease in parrots), zoonotic aerosolized transfer to humans
- ranges from severe pneumonia to asymptomatic
- fever, headache, sore throat, COUGH LATE IN DISEASE
Rickettsia (groups, organisms, characteristics, general mechanism)
Spotted Fever Group
-rickettsia rickettsi, r. akari
Typhus group
-r. prowazeckii, r. typhi, orienta tsutsugamushi
Others: erlichia chaffeensis, anaplasma phagocytophilum, Coxiella burnetti
-all obligate intracellular parasites, arthropod vectors (except coxiella, zoonosis from livestock shedding)
Unlike chlamydia (mucous membranes), rickettsia targets endothelial cells, systemic and hallmark rash
Rickettsia rickettsi (disease, hallmark feature, mechanism, vector)
- Causes rocky mountain spotted fever (RMSF)
- hallmark rash after 2-4 days illness
- attach to endothelial cells via OmpA/B, escape phagosome, multiply, cause damage, vascular permeability
- spread by dog tick, dermacenter variabilis
Rocky Mountain Spotted Fever (clinical presentation
-incubation 2-14 days. Then fever, severe headache, myalgia. Petechial rash 3-5 days after fever, starting at limb extremities TOWARD trunk (something else is opposite)
Rickettsia akari (disease, vector, target, clinical presentation)
Causes rickettsiapox
- transmitted by mouse mite
- targets macrophages/monocytes
- at bite site, papule forms, ulcerates, dark eschar. Fever and generalized rash follows
Rickettsia prowazeki (disease, vector, mechanism of spread, reservoir)
Louse-born typhus (not typhoid!!!)- causes epidemics
- outbreaks in war/famine/close quarters by body louse, lives in clothes
- mechanism: louse feeds on infected human, gets bacteria. r. prowazeki multiplies in louse, gets in louse poop. Louse goes to new host, when person scratches bacteria in louse poop gets into body
- flying squirrel is reservoir
Louse-born typhus (clinical presentation, secondary disease)
- caused by r. prowazeckii
- severe headaches, fever, myalgia, rash (spreads trunk–>limbs- opposite of RMSF
- Brill-Zinser disease (recurrence) from stress/compromised immunity
Rickettsia typhi (disease, geography, vector, reservoir, clinical presentation)
Causes murine typhus, common in tropical/subtropics
- transmitted by rat flea, rat is reservoir
- similar to RMSF but milder; fever common
Orienta tsutsugamushi (disease, vector, geography)
- Causes scrub typhus
- transmitted by chigger (mite) transovarially
- common in far east
Erlichia & Anaplasma (mechanism)
Infect via WBCs, not endothelial (HME in monocytes, HGA in neutrophils)
- like chlamydia, two forms, core and reticulate cell
- multiply in morula- membrane-bound cytoplasmic vesicles
Human Monocyte Ehrlichiosis (HME) (bacteria, vector, mechanism, clinical presentation, distinguishing)
- caused by ehrlichia chaffeensis
- transmitted by ticks in summer
- infect monocytes/macrophages
- symptoms: mild-severe illness with headache, fever, myalgia, 50% rash. LEUKOPENIA is distinguishing feature, morulae rare
Human Granulocyte Anaplasmosis (HGA) (bacteria, vector, mechanism, clinical presentation, distinguishing)
- caused by anaplasma phagocytophilum
- transmitted by Ixode tick like lyme
- occurs in neutrophils
- Like HME: fever, headache, myalgia. MORULAE IN NEUTROPHILs distinguishing
