Micro Flashcards
common characteristics of systemic fungi
dimorphic (mold in cold, yeast in heat)
endemic-confined to specific location
characteristics of blastomycosis
endemic to Ohio and Mississippi River valleys, Great Lakes and SE US
mimics bacterial pneumonia in acute
mimics TB or lung cancer in chronic
can disseminate in immunocompromised
diagnosis of blastomycosis
KOH prep
sputum, BAL, lung tissue, skin biopsy
methenamine silver stain
broad based yeast
characteristics of histoplasmosis
endemic to Ohio and Mississippi River valleys
found in soil rich in nitrogen and birds/bats
mimics TB-formation of granuloma
ARDS and histoplasmosis
10% inflammatory sequelae
persistent lymphadenopathy, bronchial obstruction, arthritis, arthralgias, pericarditis
mediastinal fibrosis-persistent host response, constriction of mediastinal structures
diagnosis of histoplasmosis
direct microscopy
yeast phase in sputum, BAL, fluid, blood films, bone marrow
tissue stained with Giemsa, GMS, PAS
small yeast
characteristics of coccidioidomycosis
endemic in Southwest (c. posadasii mostly outside Ca)
arid, alkaline soils
outbreaks after dust storm and earthquakes
spherules (can be mistaken for toxoplasma)
presentation of coccidioidomycosis
imitates syphilis and typhoid
forms necrotizing granulomas
spherules filled with endospores
presentation of paracoccidioidomycosis
granulomatous disease of mucous membranes, skin, pulmonary system
can disseminate to extrapulmonary sites
diagnosis of paracoccidioidomycosis
sputum, BAL, scrapings or biopsy of ulcers
multiple buds forming “Captains wheel”
characteristics of penicillium marneffei
opportunistic pathogen in individuals with AIDS and other immunosuppression
can mimic TB, leishmaniasis, histoplasmosis, cryptococcosis
cellular injuries due to bacterial invasion and multiplication
competitive metabolism bacterial quorum sensing virulence factors toxin production intracellular vs. extracellular growth dynamic growth biofilm formation complement activation Ab-Ag production activation of inflammation
cells in acute infection
neutrophils and macrophages
cells in acute allergies
eosinophils and mast cells
cells in chronic infection
macrophages and lymphocytes
mediators in acute infection
complement, kinins, prostaglandins, leukotrienes, acute phase cytokines, chemokines
mediators in chronic infection
cytokines from macrophages and T cells
characteristics of CF
most common genetic disease in Caucasians
AR
chromosome 7-gene product is CF transmembrane conductance regulator
most common deletion in CF
deltaF508
causes product to stay in Golgi
common complications of CF patients
pancreatic insufficiency
intestinal blockage-meconium ileus
signs and symptoms of CF
family history salty tasting skin chronic cough with sputum secretion chronic wheezing meconium ileus staph pneumonia in infancy chronic pansinusitis/nasal polyposis liver disease delayed puberty
bacterial components in CF
change from S. aureus to P. aeruginosa
characteristics of pseudomonas
gram negative aerobic and anaerobic rod shaped motile (pili and flagella) grape like odor environmental bacterium simple growth requirement
alginate
exopolysaccharide
mucoidy
requires a lot of energy
forms biofilm (exopolysaccharide matrix enclosed bacterial community)
clinical manifestations of CF
localized lung infections-excessive neutrophil infiltration
infections confined to bronchi and bronchioles
malnutrition
source of damage in CF
neutrophils in crhonic infection
type III hypersensitivity
treatment of CF
suppressive
inhaled tobramycin and oral azithromycin
combination-anti-pseudomonas penicillin, ticarcillin or piperacillin plus aminglycoside
second most common infectious cause of death in adults
TB
locations of TB
secondary-in the apex of the lung
characteristics of mycobacterium TB
obligate aerobic rod Gram + like wall infections from aerosols resistance to drying and chemicals waxes in cell wall grows slowly in vitro and vivo acid fast due to mycolic acid
mycolic acid
beta hydroxy fatty acid linked to murein
transmission of TB
prolonged close contact between susceptible with active case of TB
virulence factors of TB
grow inside macrophages and monocytes
prevents phagosome/lysosome fusion (escape of phagosome)
LLO homologue (hemolysin) allows for escape
prevents acidification of phagosome by producing NH4
mycolic acids induce immune response
TB with pigmented colonies
M. kansasii or m. marinum
characteristics of caseous granuloma
central core-multinucleated giant cells (fused macrophages)
epithelioid cell-large macrophage
CD4 T cells
can also be found in syphilis, histo, crypto, coccidio
AIDS and TB
kills more rapidly
more likely to develop extrapulmonary disease, lymph nodes, genitourinary CNS
miliary TB
reduced CD4 does not allow macrophages to be activated
more susceptible to MAI (inherently more drug resistant)
caveats to PPD
immunocompromised and AIDS may not react
cross reactive to other mycobacteria
foreign nationals who receive BCG
structure of picornavirus
single stranded, non-segmented RNA \+ polarity capsid with few structural proteins icosahedral capsid, no envelope rhino-acid labile (others acid stable)
ECHOvirus location of virus in summer aseptic meningitis
virus in CSF
new enterovirus that causes respiratory illness
type D68
especially severe in children and teenagers with asthma
incubation period for rhinovirus
24 hour
impracticality of rhinovirus vaccine
can’t grow well in tissue culture
short immunity, IgA
many serotypes
one type> one geographic area
characteristics of coronavirus
similar to negative strand viruses ssRNA, + polarity helical nucleocapsid peplomers in envelope (glycoproteins) replication in cytoplasm mature by budding
receptors for coronavirus
metalloprotease and coreceptor N-acetyl neuraminic acid
replication of coronavirus
replicative intermediate
bud from ER to acquire envelope and peplomers
strain A of coronavirus
infectious bronchitis
primarily in adults
SARS
lower respiratory tract infections
symptoms of high fever, cough, SOB
spread by coughing and sneezing
incubation period for SARS
2-7 days
cell receptor for SARS
angiotensin-converting enzyme 2 on epithelial cells
characteristics of adenovirus
capsid of 240 hexons and 12 pentons
pentons-antigenic
dense nucleoid core
linear dsDNA DNA noncovalently linked circular DNA
components of pentons
base
fiber
knob
division of adenovirus
DNA base composition
oncogenic properties
hemagglutination
cell interactions
preference of infection for adenovirus
conjunctiva, respiratory and intestinal epithelium and regional lymph nodes
restricted to ARD
adeno pneumonia in children
type 7 and type 3
oral vaccine for adeno
4 and 7
binding of viruses
strong binding does not get cleared by sweeping of the mucociliary cell system
lysis of infected cells-leads to symptoms
incubation times for primary respiratory vs secondary respiratory
longer incubation if viremia established
structure of paramyxovirus
ssRNA -polarity, nonsegmented helical nucelocapsid RNA dependent RNAP envelope 6 structural proteins
glycoprotein HN
hemagglutinin and neuraminidase
glycoprotein H
only hemagglutinin
glycoprotein F
fusion of membranes
paramyxovirus
mumps, parainfluenza virus
HN, F envelope glycoproteins
morbilliviruses
measles virus
H, F glycoprotein
pnemovirus
RSV
F glycoprotein
activation of F protein
proteolytically cleaved on viral envelope surface to yeild an infectious virus particle
located on surface of infected cells-can lead to formation of polykaryocytes (syncytia)
replication of paramyxovirus
cytoplasmic (measles has a nuclear stage)
replication requires RNA dependent RNAP
types of parainfluenza virus
type 1 croup, ARD of newborns
type 3 usually first, then 1,2,4
IgA short lived
pneumovirus (RSV)
bronchiolitis and pneumonia in infants
F glycoprotein
can also cause lower respiratory disease
common in winter
enhanced severity of RSV
maternal IgG does not protect and may enhance severity
treatment of RSV-prophylaxis
RSV immune globulin
anti-RSV monoclonal ab
palivizumab to at risk babies
killed vaccine for RSV
harmful
causes immune complex formation
structure of orthomyxovirus
ssRNA, - polarity 8 segments for A,B 6 segments for C helical nucleocapsid RNA dependent RNAP
antigens from influenza
nucleocapsid and M protein H ags (detected by hemagglutination, neutralization, C-fixation)
role of neuraminidase
important in budding
lowers viscosity of mucus
antigenic drift
point mutations
leads to epidemics
antigenic shift
H antigenic variation
due to reassortment between humans and animals
causes pandemics
antigenic sin
new infection with influenza A
response strongest to first subtype
influenza B
less frequent shift and drift
Reye’s syndrome (acute noninflammatory encephalopathy and fatty degeneration of liver, polyneuritis, hypoglycemia)
Guillain Barre
amantadine and rimantidine
block uncoating
give to those sensitive to egg proteins
ribavirin
inhibits RNA synthesis
zanamivir
inhibitors of neuraminidase
seasonal vaccines
formalin inactivated
trivalent vaccine-two A and one B
start vaccination in October/November
split vaccine
subunit
proteins H and N
non-toxic and non-pyrogenic
intranasal vaccine
not recommended due to poor protection against H1N1
produces IgA and IgG
swine flu
targeted healthy young
goal of vaccination in bioterrorism
protect against weaponized influenza extensive reduction (low baseline)
