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Infections of soft tissue
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66
Microbiology
Professional
03/27/2013

Additional Microbiology Flashcards

 


 

Cards

Term
General Properties of Rickettsia
Definition

small, rod shaped bacteria

related to gram negative organisms

have diaminopimelic acid (DAP) in cell wall

obligate intracellular parasites

 can persist in the body for a long time

stains poorly with the gram stain better with Giemsa

 

Term
how does rickettsia replicate
Definition
binary fission
Term
Rickettsia rickettsii
Definition

caused by rickettsia rickettssii

most common rickettsial pathogen in US

distribution- Rocky Mountain region, Eastern and SE United States endemic in TN

Term
what is rickettsia rickettsii reservior
Definition
lower animals, rodents, birds
Term
what is rickettsia rickettsii vector
Definition

wood tick (Dermacentor andersonii)

dog tick (Dermacentor variabilis)

Term
how is borrelia burgdorferi transmitted
Definition

by deer tick, Ixodes dammini

hard ticks from mice to humans

Term
how is rickettsia rickettsii transmitted
Definition
vertical transmission from adult tick to egg (transovarian transmission)
Term
pathogenesis of rocky mountain fever
Definition

rickettsia multiply in the skin at site of tick bite

spread to blood and infect vascular endothelium in lung, spleen, brain, and skin

after week onset of fever, severe headache, myalgia and other respiratory symptoms

maculopapular rash appears a few days later often becoming petechial or purpuric

splenomegaly and neurolgical involvement is frequent with later onset of clotting defects

shock and death

Term
rocky mountain spotted fever epidemiology
Definition

individual camping, fishing, picnicking in wooded areas are highly susceptible

children playing in weeds or brush in Nashville area are highly susceptible

children are most commonly infected but their disease is milder

Term
when is rocky mountain spotter fever most common
Definition
April through October
Term
Rickettsia Rickettsii immunity
Definition

cytokine-mediated intracellular killing

clearance by cytotoxic CD8 lymphocytes

antibody response to outer membrane proteins may also be important

Term
how do you diagnosis r. rickettsii
Definition

weil-felix test positive for proteus OX2 and OX19a

microimmunoflourescence methods and demonstration of a four fold or greater rise in antibody titer (1:160 or greater)

direct fluorescent antibody and PCR

Term
how do you treat rocky mountain spotted fever
Definition

tetracycline, doxycycline, flouroquinolones chloramphenicol, erythromycin

no vaccine

Term
what is leading vector borne disease in the US
Definition
borrelia burgdorferi (lyme disease)
Term
general properties of genus borrelia
Definition

weakly staining, gram negative

stain well with Giemsa or Wright stain

can be easily seen by light microscopy in smears of patients with relapsing fever

from 7-20 periplasmic flagella

are microaerophilic and have complex nutritional needs

culture is generally unsuccessful

 

Term
what are two important diseases Borrelia cause
Definition

relapsing fever

lyme disease

Term
how do you diagnosis relapsing fever
Definition
microscopy
Term
how do you diagnosis lyme disease
Definition
serology
Term
what are the two forms of relapsing fever charcterized by
Definition

recurrent episodes fever and septicemia seperated by afebrile periods

this results from antigenic variation

Term
what is the etiologic agent of louse borne relapsing fever
Definition
borrelia recurrentis
Term
how is borrelia recurrentis transmitted
Definition
person to person by human body louse (Pediculus humanas)
Term
endemic relapsing fever
Definition

caused by as many as 15 species of borreliae

spread by infected soft ticks (Ornithodoros)

Term
what is borrelia burgdoferi reservoir
Definition
mice, deer, ticks
Term
borrelia burgdorferi vectors
Definition

Ixodes scapularis in the eastern and midwestern US

Ixodes pacificus in the western US

worldwide distribution

Term
who is at risk for lyme disease
Definition
people exposed to ticks in areas of high endemicity
Term
when do most US cases for lyme disease occur
Definition
late spring and early summer
Term
borrelia burgdorferi epidemiology/transmission in year one
Definition

adult ticks feed and mate on certain deer during late fall or winter and drop to the ground

eggs deposited on bushes hatch into larvae in the spring

in summer larvaue obtain blood meal from white-footed mouse (main reservoir)

larvae into nymphs 

Term
borrelia burgdorferi epidemiology/transmission in year two
Definition

during the following spring-summer, infected nymphs feed on vertebrate hosts including white footed mouse

infected or non infected nymphs fall off host and mature into adult males or females and then parasitize available deer to start cycle all over again

human host is usually infected by infected nymphs

Term
early signs of lyme disease
Definition

erythema migrans begins as small papule and then enlarges over the next few weeks

headache, malaise, severe fatigue, fever, chills, myalgias, lymphadenopathy

Term
three stages of lyme disease
Definition

stage 1-localized (1-4 weeks)

stage 2- disseminated (1-6 months)

stage 3- latent, persistent infection (1-30 years)

Term
stage one
Definition

erythema migrans (bull's eye)

disseminated blood (fever, headache, fever, malaise)

Term
stage 2
Definition

localized: secondary annular lesions

disseminated: meningitis, carditis musculoskeletal pain, eye

Term
stage 3
Definition

localized: no manifestations acrodermatitis chronica atrophicans

disseminated: arthritic, chronic progressive neurologic/cardiac disorders

Term
how do you diagnosis b. burgdorferi
Definition

can be cultured in NSK medium from early stage cutaneous tissues but rarely seen at later stages

takes several weeks

primarly diagnosised based on clinical presentation and known exposure

Term
francisella tularensis
Definition

small gram negative coccobacillus

intracellular obligate aeorobe (macrophages)

inhibits phagosome lysosome fusion

requires cysteine for growth; can grow on BCYE (buffered charcoal yeast extract)

Term
francisella tularensis virulence factors
Definition

facultative intracellular pathogen

LPS-appears to NOT be very toxic

lipid capsule- anti-phagocytic

factors taht inhibit phagosome-lysoome fusion and prevent acidification

Term
where is francisella tularensis primarily observed
Definition

Oklahoma, Missouri, and Arkansas,

but distributed throughout North America

Term
Francisella tularensis epidemiology
Definition
found in variety of wild animals, birds, blood-sucking arthropods, rabbits, ticks, hares, voles, muskrats, beavers
Term
how is francisella tularensis acquired
Definition

bite from infected "hard-shell" tick (Ixodes, Dermacentor)

ingestion of contaminated meat or water, inhalation of infectious aerosol, skin abrasions, skinning of animals

Term
how many types of francisella tularensis is there
Definition
two types
Term
What are the two types of francisella tularenis
Definition

A (most common)

B

Term
what are the forms of disease caused by francisella tularensis
Definition

ulceroglandular

oculoglandular

glandular

typhoidal

pneumonic

Term
ulceroglandular
Definition

cutaneous ulcer/swollen lymph node

most common following skin abrasion or tick/fly bite (2-5 days)

Term
oculoglandular
Definition
direct inoculation by conjunctivitis; cervical and preauricular lymphadenopathy
Term
glandular
Definition
usually vector borne exposure, enlarged regional lymph nodes with no skin involvement
Term
typhodial
Definition

ingestion or inhalation; baceteremic spread and seeding to lung, liver, spleen; fever, weight loss, pneumonia

mimics typhoid fever, brucellosis, tuberculosis

Term
pneumonic
Definition
results from inhalation of infectious aerosols
Term
what type of agar does f. tularensis grows on
Definition
chocolate
Term
is f. tularensis catalase postive or negative
Definition
negative
Term
is f. tularensis oxidase positive or negative
Definition
negative
Term
f. tularensis diagnosis/identification
Definition

reactivity of bacteria with specific antiserum( agglutination of organism with antibodies against Francisella)

microagglutination detects antibody titer in serum

fluoresent Ab test can detect the organism in tissue specimen

Term
f. tularensis immunity/prevention
Definition

natural infection confers long lasting and protective immunity

CMI plays a major role in resistance

vaccine is given to high risk individuals

Term
what antibiotics do you use to treat F. tularensis
Definition

streptomycin-high level of toxicity

gentamicin-alternative

fluroquinolones (ciprofloxacin)- good bactericidal activity in vitro and mouse animal models

Term
what is the etiologic agent of anthrax
Definition
bacillus anthracis
Term
bacillus anthracis
Definition

large, aerobic, non motile gram positive rods that produce lecithinase

spore formers

polypeptide capsule composed of D-glutamic acid interfers with phagocytosis (plasmid-encoded)

Term
what are the toxin components of b. anthracis
Definition

protective antigen

EF

LF (lethal factor)

Term
what is the protective antigen function in b. anthracis
Definition
binds to host cell
Term
what is the function of EF in b. anthracis
Definition
adenyl cyclase activity increase (increases cAMP) resulting in tissue edema
Term
what is the function of lethal factor in b. anthracis
Definition
a protease that targets cell signaling proteins; cleaves MAP kinase leading to cell death
Term
what are the three clinical forms of anthrax
Definition

cutaneous (eshar)

pulmonary (woolsorter's disease)

ingestion

Term
cutaneous anthrax
Definition

characterized by lesions (malignant pustule) on hands, forearms or head that may contain a dark bluish black fluid

erythematous papule develops 12-36 hours after entry of organism via breaks in skin which quickly progresses to the formation of a pustule and then a necrotic ulcer from which the infection may disseminate (eschar)

 

Term
Pulmonary anthrax (Woolsorter's disease)
Definition

aquired by inhalation of spores by handlers of raw wool, hides or horse hair

spores germinate in the lungs or the tracheobronchial lymph nodes

symptoms include non-specific malaise, mild fever, and non productive cough

progressive respiratory distress and cyanosis will follow with massive edema of the neck and chest

Term
ingestion anthrax
Definition

infection of GI tract is common in animals but rare in humans

infection in humans results in abdominal pain, nausea, vomiting, and bloody diarrhea

Term
b. anthracis lab diagnosis
Definition

gram stain, culture and immunofluorescent assays of fluid or pus from local lesions, blood and sputum

can be cultured on normal blood agar

serological tests can demonstrated the presence of agglutinating antibodies; antibodies to toxin antigen

Term
b. anthracis treatment/immunity
Definition

historically susceptible to penicillin- resistance genes to penicillin and doxycycline have been transferred to the organism

now recommend ciprofloxacin

early treatment is important

Term
what is the b. anthracis made from
Definition
purified protective antigen is available for humans at high risk
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