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318 Cards in this Set

  • Front
  • Back
what S&S are associated with bronchitis?
fever, cough, sputum production
sore throat, runny or stuffy nose, headache
how should you treat acute bronchitis?
it is almost always self-limited thus should NOT be treated with antimicrobials
What are 2 infxns caused by RSV? in what population can these infxns be dangerous?
infants because the inflammation can cause airway obstruction
Characteristics of RSV.
ss-sense RNA
Paramyxoviridae family
F fusion protein used at PM for pH independent fusion and formation of syncitia cells
G protein attachment
**NO hemagluttinating acitivty as compared to mumps
how do you differentiate RSV from Mumps?
F fusion protein in RSV does NOT have hemagluttinating activity
how many subtypes of RSV are there? most dangerous?
2: A and B
more sever clinical illnesses involve subtype A
Is RSV systemic or localized infxn?
LOCALIZED infxn of resp tract
*most common cause of LRT infxns in children
(as compared to MUMPs which is systemic)
what is the most common cause of acute, fatal resp tract infxns in infants?
action of RSV?
infects epithelial cells and macrophages, sloughing of cells plugs bronchioles and alveoli.develop bronchiolitis b/c of immune response
why is RSV more dangerous in children?
b/c airways of chilren are narrow leading to easy obstruction
S&S of bronchiolitis
progreses to cough, wheeze, *onset of dyspnea, increased respiratory rate (tachypnea), rales**(sounds like clicking b/c of plugged up alveoli), and retractions of intercostal or sub-sternal mm
what sign of RSV bronchiolitis indicates LRT involvement?
prominent intercostal or sub-sternal retraction due to airway obstruction
Long term sequelae of RSV?
reactive airway disease (asthma)
how is RSV LRT disease partly due to host's inflammatory response?
when RSV invades epithelium, the epithelium releases Nerve GF that binds to NK1 R activating T to produce cytokines (IL6, 10, RANTES, MIPalpha, IL8), PMNs to chemotax, edema from mast cell release
what cytokines are found in abundance in respiratory secretions of RSV pts?
IL-6, IL-10 (down reg TH1), RANTES, MIPalpha, IL-8
how will you Tx RSV bronchiolitis?
bronchodilators to help relieve chest congestions and wheezing
O2 therapy
RSV IG (passive immunity)
aerosol Ribavin (nucleoside analogue)
IS RSV seasonal?
yes, oct-april
prevention of RSV?
natural infxn may still allow re-infxn
**NO vaccine
RSV prophylaxis with RSVIG (IV) or Palivizumab (IM monoclonal Ab that is a chimera)especially for infant population that is at high risk (premies)
whta is Palivizumab that is given for RSV?
humanized anti-F recombinant mAb: specific to F protein preventing fusion
*highly specific to RSV
RSV-IG (Respigam) is what? from where?
anti-RSV from pooled human sera (selected donors with high anti-RSV titers)
in the large syncytia caused by RSV, what do the cells contain?
pale eosinophilic** inclusions in cytoplasm **NOT nuclear inclusions
all paramyxoviruses have what?
all have F protein for fusion
HN of which paramyxoviridae viruses have both hemagluttinin and neuramindase activity?
parainfluenza and mumps
**both activities in HN while H of measles has just hemagglutin activity and G of RSV lacks these activities
____ causes many of the symptoms of paramyxovirus, but is essential for control of the infxn?
cell-mediated immunity
which paramyxoviruses cause a viremia and which are localized?
mumps and measles produce a viremia , RSV and parainfluenza produce only respiratory infxn
are paramyxoviruses or orthomyxoviruses segmented?
orthomyxoviruses are segmented
both are ss-sense RNA
what is the exception to the statement: all paramyxoviruses and orthmyxoviruses have Hemagglutinin activity?
except RSV
what is the difference in fusion b/n paramyxoviruses and orthomyxoviruses?
para: fusion at neutral pH
ortho: HA mediates fusion at acidic pH
where do paramyxoviruses replicated? ortho?
para: solely in cytoplasm
ortho: needs nucleus
do both paramyxoviruses and orthomyxoviruses have F protein?
no! only para. Ortho have one Hemagglutinin spike that binds R and undergoes conformational change exposing part of H that allows fusion
of the 3 types of influenza, which types cause epidemics?
A and B
characteristics of influenza?
ss - sense RNA
segmented genome
spikes: HA, NA
helical hucleocapsid
Reservoirs: species specfic-humans, birds, pigs
fxn of HA spike in influenza?
recognizes and binds sialic acid residues on glycoproteins
the virus is then endocytosed in acidic vesicles which changes the conformation of HA
where does influenza replicte?
in nucleus after genome relesed into cyto
S/S of influenza
fever of 101.5F or higher AND
1 of the following:
-sore throat
-muscle ache
how do the S/S of influenza differ from common cold?
no fever in common cold(coryza)
what is the most common cuase of atypical or viral pneumonia in adults?
complications of influenza?
pneumonia or other viral superinfxn that occur in young, elderly, and person with chronic cardio-pulm diseases
consits of: pneumonia caused by influenza
and pnuemonia caused by bacteria
other viral superinfxn: Adenovirus
what are the top 3 bacteria after influenza that cause pneumonia?
staph. aureus
strep. pneumoniae
h. influenzae
when influenza changed from H2N2 to H3N2 what did this mean?
those with Ab to H2N2 have Ab that still recognize and neutralize N2
current circulating subtypes of influenza?
H1N1 and H3N2 and H1N2***
diff of fxn of HA and NA in influenza?
Neuraminidase is an enzyme involved in the release of progeny virus from infected cells, by cleaving sugars that bind the mature viral particles. By contrast, hemagglutinin is a lectin that mediates binding of the virus to target cells and entry of the viral genome into the target cell
which type of influnza undergoes antigenic shifts (pandemics) and drifts (epidemics) in the HA and NA:
type A
what is an antigenic drift?
accounts for the yearly differences in influenza vaccine b/c have minor mutations causing different aa seq in HA and NA but still recognized by Ab (this doesn't mean they are neutralized) still can have cross-reacting Ab
H1N1 to H2N2 is an example of what?
antigenic shift (pandemic) b/c serologically different with NO cross-reacing Ab
how do antigenic shifts in influenza arise?
b/c it has a segmented genome, there can be mix/match of parts creating new Ag therefore there will be no cross-reacting Ab
how do antigenic drifts in influenza arise?
minor changes so HA evades recognition by neutralizing Ig (there will still be cross-reactive Ab but not neutralizing)
what must happen for antigenic shift to occur?
2 influenza viruses infect same cell creating a mixed variant never seen before
dianosis of influenza? problem? when do you use them?
rapid antigen detection, IFT, EIA
rapid Ag detection has low sensitivity but useful if used for Tx descisions in ~30mins**
use ELISA but takes 2-3hrs but has highr spec/sensitivity
what type of serology tests are used for influenza Dx?
serum Ab by HAI b/c has HA
Tx for influenza?
Amantadine and Rimantadine for Influenza A
Oseltavmivir, Zanamivir (both NA inhibitors) for both Influenza A and B
why are Amantadine, Rimantadine now not recommended?
due to resistant strains
Oseltamivir and Zanamivir are what?
antiviral medications that are NA inhibitors used for Influenza A and B
*approved for prevention as well as Tx
mxn of Amantadine, Rimantadine?
interfere with M2 ion channel of Influenza A viruses that affects uncoating and decreases Influenza A shedding
mxn of Oseltamivir and Zanamivir?
block active site of NA reducing the amt of viral particles released from infected cells
*limit contagous spread
peak influenza season?
peak: feb-march
what does the influenza vaccine consist of?
pick two most freq A strains and 1 most freq B strain
ex: 2006-07 A-H1N1 and H3N2 +B
describe influenza vaccine? where grown?
chicken egg grown
inactivated *recommended
live attenuated Influenza Vaccine (LAIV), cold-adapted, nasal spray for mucosal immunity (Flumist)
how is a reassortant virus created?
take attenuated donor master strain that has the propery of growing well in chicken eggs
combine with epidemic new virulent antigenic strain to obtain glycoprotein spikes
now you have reassortant that grows well in eggs and surface Ag are epidemic strains HA and NA
what are the best months to get influenza vaccine?
october and november
priority groups for influenza vaccination? w
children 6-23 months
adults > 50yrs
2-64yrs if have underlying chronic medical conditions
healthcare providers
who should receive the inactivated influenza vaccine? why?
unhealthy individuals with chronic illnesses
can't give live b/c it was only tested in healthy individuals
who should receive LAIV ?
healthy persons 5-49 yrs
healthcare workers
what was removed from the influenza vaccine in a single dose vial?
thimerosol prservative b/c of fear of autism
*still exits in multidose b/c too expensive to have single dose worldwide
why is it less possible to have pandemic avian flu?
b/c of the host range: H5 prefers sialic acid located only on avian R of ciliated cells rather than the human R
what confers enhanced replication in H5N1 (avian flu)?
it has polymerase
what is SARS caused by?
also the 2nd most common cuase of common cold
hallmark symptoms of SARS?
fever >38C (100.4)
cough (dry)
difficulty breathing**
what is the host cell recepotr responsible for mediating infxn by SARS-CoV?
SARS Tx with what disrupts the interaction b/n virus and R?
soluble ACE-2 or
anti-ACE-2 antibodies
a person presenting after 1 Nov 2002 with history of high fever (>38) AND cough or breathing difficuly who traveled during the 10days prior to onset of symptoms possibly has what disease?
*exposure 10 days prior to symtomse could also be due to close contact with ppl suspected to have SARS or living in area with local transmission of SARS
a person with unexplained acute resp illness resulting in death after 1 Nov 2002 and exposed to traveling 10 days before symptoms probably has what?
waht is a considered a positive SARS diagnostic test finding?
confirmed postive PCR for SARS with 2 different clinical speicmens OR
same specimen collected on 2 or more different days
OR 2 different assays or repeat PCR on same specimen
what is the primary bacterial cause of typical community aqd pneumonia in ppl with no predisposing conditions?
strep pneumo
typical pneumonia is caused by what?
typical bacteria
atypical pneumonia is cuased by what?
viral, fungal, parasitic
Strep. pnuemonia can cause what?
prmay cause typical comm aqd pneumonia
primary cause of sinusitis and otitis media
what is the most common bacterial pathogen following influenza infxn?
strep. pneumo
characteristics of strep. pneumo?
Gram +
lanct shaped cocci
**No group specific carbohydrate therefore untypeable by Lancefield
virulence factors of strep. pnuemo?
polysaccharide capsule
IgA proteases
Pneumolysin (alpha hemolysis)
Neuraminidase (thins secretions)
waht is the purpose of Neuraminidase in strep. pneumo?
thins sputum therefore cough up thin sputum
what is the action of pneumolysin in strep. pneumo?
cholesterol binding toxin
assembles into oligomeric pores on target cell
clinical S/S of pneumonia caused by s. pneumo
productive cough
blood-tinged (rust or cherry colored) sputum
pleurisy common (inflam of pleura)
sever shaking chills
sustained fever: 39-41
Lobar pneumonia
what is red hepatization? gray?
in the case of lobar pneumo as caused by strep. pneumo
red hepatization first bc RBC are extravasating and lung looks like a liver
then Gray hepatization due to fibrin deposits and inflammatory exudate
what microscopic test confirms strep. pneumo?
Neufeld rxn: Quellung capsule: add Ab to bacteria of specimen that coats capsid and looks like capsule has swelled
what type of hemolysis for strp pneumo?
alpha hemolysis therefore see green
which bacteria is Optochin sensitive and catalase negative?
strep pneumo
is Strep pneumo or strep viridans optochin sensitive?
Strep pneumo
both Lancefield non-typeable
what is the vaccine for strep pneumo that is given to high risk indiduals greater than 2yrs old?
POLYVALENT anti-pneumococcal capsular polysachharde vaccine (23 serotypes) for high risk individuals over 2 yrs and adults >65
what is the vaccine for strp pneumo that is given to infants 2months?
HEPTAVALENT pneumococcal CONJUGATE vaccine
when can you say that a pneumonia is nosocomial?
greater than 5 days of hospitalization. less than that is considered community
what are the common causes of nosocomia pneumo?
P aeruginosa
E coli
S pnuemo
H influenza
what are some risk factors predisposing ppl to nosocomial pneumo?
risk of aspiration
grape cluster groupings describes what bacteria?
staph aureus
characteristics of staph aureus?
Gram +
grape clumps
nostrils are main carrier site
what are the imt extracellular proteins and enyzmes of staph aureus?
Coagulase that binds prothrombin causes blood to clot by converting fibrinogen to fibrin now resist phagocytosis making the bacteria more virulent
Catalase +
what are the toxins of Staph aureus?
5 cytotoxins: Panton-Valentine Leukocidin that kills PMNs
2 exfoliative toxins: ETA and ETB
8 enterotoxins
Toxic Shock Toxin
is Stap aureus part of normal flora?
yes, skin, oropharynx, GI tract and urogenital tract
which bacteria is a major cause of nosocomial infxn of surgical wounds?
staph aureus
what is empyema?
pus formation in pleural cavity: assoicated with staph aureus
what types of pneumonia can staph aureus cause?
community aqd after influenza infxn**
aspiration pnuemo (nosocomial)
Hematogenous pneumo: see patchy infiltrates or abscesses
individuals that develop Hematogenous pneumo from staph. aureus recently had what?
body related infxn of endocarditis
*the pneumo is secondary to the skin infxn
hematogenous means via the blood therefore it is systemic
although empyema can be a complication of s. pneumo and H. influenza, the primary cause is?
staph aureus
characteristics of Pseudomonas aeruginosa?
Gram - bacilli
oxidase +
cystic fibrosis and individuals on mechanic ventilation are prone to what type of pneumoia pathogen?
Pseudomonas aeruginosa
what virulence factor is unique to Pseudomonas aeruginosa?
Pigments: pyocyanin (blue), pyochelin (yellow-green), pyoverdin (green)
Pseudomonas aeruginosa causes what type of pneumo?
nosocomial: primary or aspiration pneumo in pts on mechanical ventilation
what is the 2nd most common cuase of nosocomial pnuemo?
psudomonas aeruginosa
clincial disease of Pseudomonas aeruginosa?
LRT infxns: nosocomial pneumo
what is at risk for Psudomonas aeruginosa?
CF pts
unlike other G- bacteria, which pneumo causing bacteria is not a lactose fermenter?
Pseudomonas aeuruinosa
do you see lobar pneumo in staph aurues?
NO! think strep pnuemo
that is unique about the Tx for Pseudomonas aeruginosa?
2drug combo therapy to inhibit drug resistance (this org is very resistant)
beta lactam + beta lactamase inhibitor (clavulanate)
which Burkholderia spp is zoonotic transmission?
B. mallei
in which country is Melioidosis (causd by Burkholderia psedomallei) endemic?
Southeast Asia
what is hallmark of meliodosis disease caused by Burkholderia?
cough with normal sputum
characteristics of Actinomyces isreali?
Gram +
fungus like: crooked, filamentous branches
pathogenic prolif is usually a result of trama
Dx lab test for actinomyces isreali?
sulfur granueles where bacteria is growing
Catalase +
Nocardia spp belong to what family?
characteristics of Nocardia spp?
aerobic rods
branching, filaments
**weakly acid fast
Catalase +
what is teh unique virulence factor to Nocardia spp?
cell wall of peptidoglycan PLUS mesodiaminopimelic acid therefore it is weakly acid fast
what species fall under the category Enterobacteriaceae?
Klebsiella pneumoia (community and nosocomial)
Proteus spp. (Nosocomial)
Serratia spp. (nosocomial)
E. coli (nosocomial)
general characteristics of Enterobacteriacea?
Gram -
ubiquitous in soil, water, vegetation
part of normal intestinal flora
which of the Enterobacteriacea cause lobar pneumo in immunocompromised?
Klebsiella pneumo
what is a unique virulence factor of Enterobacteriacae?
Type III secretion systems: syringe like mxn for proteins to move from bacterial membrane into host cell membrane directly- no extracellular phase therefoe they are hard to block
what are the largest group of medically impt gram - bacilli usually associated with intestinal infxns?
Enterobacteriacea: KEPS
which of the enterobacteriacea are associated with pneumo in elderly and those with underlying disease?
Proteus spp
which of the Enterobacteriacea appear as swarming colonies?
how do you distinguish G- rod family members like Enterobacteriacea?
look at fermentation
virulence factors of Proteus spp
lysine -
hydrogen sulfide +
urease +
why do you not want to Tx E coli infxns with antibiotics?
they may actually place the pt in severe shock which could possible lead to death due to the fact that the bacteria's toxins are released when the cell dies
is E. coli lactose fermentor?
yes. see purple color
What agar is E coli grown on? what is unique about this?
Eosin-methylene blue agar
selective and differential
selective b/c it has components that inhibit some org and differential b/c factors look diff for diff org
how is Serratia spp distinguished from other Enterobacteriaceae?
producton of 3 enzymes:
how does serratia spp apear on culture?
red b/c produces red pigment
why are most strains of serratia spp resistant to several antibiotics?
b/c of presence of R-factors on plasmids
how is klebsiela differentiated from Proteus?
klebsiella is non-motile
proteus is motile
what unique virulence factor does Klebsiella have?
large polysaccharide capsule
which bacteria produce a mucoid, blood tinged sputum?
Klebsiella :currant jelly
thick as compared to thin blood tinged sputum of strp pneumo
how do you differentiate the Enterobacteriacae family?
why are drug susceptibility tests essential for Dx of Klebsiella infxn?
b/c it produces beta lactamase
*very drug resistant
which bacteria causes walking pneumo?
mycoplasma pneumo
what are the 3 most common community aqd Atypical pneumo?
mycoplasma pneumonia
Psittacosis: Chlamydophilia, Chlamydia
Legionnaire's spp
what is the most common cuase of atypical community aqd pneumo?
mycoplasma pneumo
characteristics of Mycoplasma pneumo?
cell wall less rod
growth medium contains serum (unusual growth medium)
virulence factors of mycoplasma pneumo?
P1 Ag- attachment to resp epithelium b/n cilia and villi
incubation pd for mycoplasma?
1-4 weeks
clinical disease of mycoplasma pneumo?
looks like URT infxn that lingers b/c incubation pd is 1-4 weeks
Atypical pneumo
what is the leading cause of pneumo in school-age children and young adults?
mycoplasma pneumo
usually in healthy individuals with no predisposing risk factors *lingering
s/s of mycoplasma pneumo?
fever, cough, malaise, headache
on chest auscultation: scattered rhonchi (course rattling, gurgling bronchitis), and localized rales (fluid in air sacs)
**wheezing (like RSV)
how do mycoplasma pneumo colonies look on agar?
fried egg or mulberry appearance
what serological test is classic for Mycoplasma pneumo?
Cold agglutination-IgM Ab bind Ag (RBC) at 4C
*not sensitive
what does it mean if a serological test is specific or non specific?
specific: looking for Ab
non-specific:looking for incease in cold agglutinins at 4C-Ab that bind RBC at low temp
Sequelae associated with mycoplasma pneumo?
persistent cough
fatal cases in elderly and ppl with sickle cell disease
Raynaud phenomenon or disease is associated with what pneumonia pathogen? what is it?
mycoplasma becuse produces cold agglutinins
reversible ischemia of peripheral arterioles in response to cold or stress
what is the diff b/n Raynaud disease and phenomenon?
disease: vasospasm of arterioles in extremities in response to cold
phenomenen: vasospasm secondary to other illness
characteristics of Chlamydia spp.
"energy parasites"-use host cell ATP
*obligate intracellular (unusal)
avoid intracellular killing by preventing fusion of phagosome with lysosome
reservoir for chlamydophila pneumonia? psittaci?
pnuemonia: humans
psittaci: birds
how do chlamydia spp avoid intracellular killing?
they prevent fusion of phagocome and lysosome
what does growth of Chlaymydia spp in culture require that is unique?
cells: won't grow on normal bacteriological medium. needs cell cultures like viruses
what type of growth do Chlamydia spp have?
biphasic growth: infexs elementary body (EB) that is the extracellular form and a noninfxns reticulate body (RB) that is the obligate intracellular form
is the EB or RB of chlaymdia spp the extracellular form?
EB: elementary body is the infectous extracellular form
RB: reticulate body is the NON infectous intracellular form that replicates
what is the only infectous stage of chlamydial developmental cycle?
elementary body (E = extracellular) that fxns as tough spore to permit chlamydial survival in the environment outside the host cell. Though to be **metabolicaly inert until it attaches to and endocytosed by host cell
which stage of biphasic growth of chlaymydia is replicating form and which is metabolicaly inert?
replicating: RB so cytoplasm is rich in ribosomes*
inert: EB
describe the life cycle of Chlamydia.
EB attaches to host cell R
EB endocytosed into phagosome
EB reorganizes into RB w/n phagosome
RB multiply by fission and phagosome enlarges into inclusion
RB inclusion condenses into EB
lysis of host cell and release of EB
takes 48-72 hrs
most common cuase of pneumonia in newborn?
chlamydia trachomatis
how is a definite case of C phenumona infxn confimred?
4 fold increase in C pneumo-specific MIF (microimmunoflueresence) Ab at 3-4weeks
HEp2 cells are used for immunofluerescence antinuclear Ab tests for what pneumonia causing pathogen?
C. pneumonia
Cells from a human tissue culture line (Hep2) were used for these tests
Sequelae of C pnemo (4 A's)?
atherosclerotic vascular disease
Alzheimer's disease
what pathogen is responsible for the Woolsorters disease?
Bacillus Anthrax: Inhalational anthrax
what is impt about the structure of Bacillus anthracis? it is a virulence factor
encapsulated poly D glutamate (not polysachharide)
characteristics of Bacillus anthrasis?
Gram +
spore forming **
transmission of Bacillus anthrasis?
zoonotic: sheep
what are the virulence factors of Bacillus anthrasis?
poly D glutamate capsule that is antiphagocytic
Anthrax toxin: Edema Factor (EF), Lethal Factor (LF), Protective Ag (PA)
is the anthrax toxin an AB exotoxin?
NO, PA EF and LF do not assemble into a unit
what are the plasmids that endode EF, LF, and PA sensitive to?
temperature: have pH thresholds
action of EF?
EF: adenyly cyclase activity
PA: binds to anthrax toxin Rs on host cell
LF: Zn MAPKK activity
PA + LF combine to produce what?
lethal activity
EF + PA combine to produce what?
PA + EF + LF combine to cause what?
edema and necrosis and is lethal
explain how anthrax toxin enters host cells
PA binds 2 different R and is endocytsosed into acidic vesicle. when in vesicle it creates a pore and translocateds EF or LF into cytoplasm where they affect host proteins
incubation period for bacillus anthrax?
2 days to 2 months
CXR of pt infected with bacillus anthrasis?
widened mediastinum
CXR with widenend mediastinum is indicative of what?
inhalational anthrax
Dx of bacillus anthracis? (5)?
CXR with widened mediastinum
lysis by gamma phage
gamma hemolysis
poly D glutamate capusule staining with India ink
lack of motility
is there a vaccine for anthrax?
yes, a cell-free filtrate containing PA
what pathogen cuases Tularemia? characteristics?
Francisella tularensis
Gram -
requires cysteine for growth
what does Francisella tularesis require for growth?
how is tularemia transmitted?
via arthropoid: bites of ticks and deer flies therfore zoonotic disease via direct handling of cottontail rabbits or ingestion of contaminated food
Dx of bacillus anthracis? (5)?
CXR with widened mediastinum
lysis by gamma phage
gamma hemolysis
poly D glutamate capusule staining with India ink
lack of motility
is there a vaccine for anthrax?
yes, a cell-free filtrate containing PA
what pathogen cuases Tularemia? characteristics?
Francisella tularensis
Gram -
requires cysteine for growth
what does Francisella tularesis require for growth?
how is tularemia transmitted?
via arthropoid: bites of ticks and deer flies therfore zoonotic disease via direct handling of cottontail rabbits or ingestion of contaminated food
high risk population of tularemia?
microagglutination and Forshay's test are used in Dx of what?
Forshays test is waht?
skin test for Tularemia that elicits DTH response in 90% of pts w/n first 7 days
what pathogen will grow on cysteine heart agar?
Legionnaire's disease is what type of pneumo?
atypical pneumo both community and nosocomial
characteristics of Legionella?
fastidious growth: cysteine and Fe
Intracelllar parasite
what type of habitat does Legionella live in ?
aquatic habitat-Parasitizes amoebae
cooling towers
95% of ppl infected with Legionella develop what clinical disesae?
pontiac disease: similar to influenza, NO GI tract manifestations, NO CNS manifestations, self limiting
what type of culture will you grow Legionella on?
Buffered Charcoal Yeast Extract agar (BCYE) containing increased amts of Fe and cysteine
vaccine for legionella?
prevent by hyperchlorination, increased water temperatures
what are the most impt reservoirs for Yersinia pestis?
urban rats
most impt vector for transmission of plague from Yersinia pestis is?
rat flea
most impt virulence factor of Yersinia?
YOPs injected via Type III secretion system
greatest concentration of plaque (states)?
4 corners
how is Bubonic plague transmitted?
flea bite to rodent
rodent has direct contact with human or flea directly
tramission of pnuemonic plague?
from person that previosly had bubonic plague to another person
*most deadly >90% mortality
what is the selective and differential culture media for Yersinia?
CIN-cefsulodin, irgasan, novobiocin
aslo cold enrichment (4c for 1-3 wks)
smears of yersinia typically show what?
bipolar or "safety pin" appearance
what pathogen causes Q Fever?
Coxiella burnetii
what is the only rickettsia not transmitted by arthropod?
Coxiela burnetii
where does coxiella burnetii live?
in domestic animals via tick and is transmitted by exposure to contaminated food or raw milk
ppl at risk for Q fever?
slaughterhouse workers
food processors
sheep and cattle workers
why is Tb so worldwide even though it is curable and inexensive?
many drug resistant strains therefore can be difficult to Tx
how will mycobacterium Tb appear on gram stain?
appear gram + but is acid fast
virulence factors of mycobacterium Tb ?
intracellular growth in Macrophages
no enzymes or toxins to cause destrxn
where is primary Tb in the lungs compared with secondary/active?
primary: middle to lower lungfields
secondary: upper lobe reactivation
what are 2 things you see in primary Tb?
tubercule formation: granuloma around infected macrophages
Ghon Complex: primeary lesion plus associated swollen lymph node
is a CXR diagnostic for primary Tb?
no, it is for secondary
see opacity due to widespread hematological dissemination resulting in shot gun pellet type lesions
when does primary Tb become active?
becomes active/secondary after 2 yrs of latency and is now contagious
is primary or secondary Tb systemic?
hematological disseminateion to CNS, GI, kidney, bone
what is a postiive PPD Dx for?
secondary Tb if >15mm
(purified protein derivative, Tuberculin)
measure diamter of induration (raised area)
the Ghon complex is indicative of what type of Tb?
see granuloma near lymph node
miliary Tb is what ?
secondary Tb in which there is widespread hematological dissemination
see "millet seed" or shot gun pellet lesions in lungs that are granulomas
what isthe Mantoux Test? what is this done for?
10 PPD Tuberculin units are injected intradermally and read 48-72 hrs later by measuring the diamter of induration
Erythema should not be measured
what type of test is the Mantoux test?
screening test for close contacts (exposure) of someone with Tb
**not diagnostic
a 5mm or more PPD induration is positive for Tb in what population?
HIV positive
recent contacts of Tb case
organ transplants
a 10mm or more PPD induration is positive for Tb in what population?
recent arrivals from high prevalent countries
injxn drug users
employees of prisons,nursing homes
diabetics, leukemia pts
a 15mm or more PPD induration is positvie in what population?
ppl with no known risk factors for Tb
what is the Tx for Tb? (4)
6-9 months on "RIPE"
what prevents Isoniziad toxicity?
pyridoxine (Vit B6) for Tb Tx
what is the vaccine for Tb? what countries?
BCG (Bacillus Calmette-Guerin) live attenuated org that prevent or limit disease but not infxn in Europe and Asia
what is one of the most impt notifiable diseases?
poor control and prevention programs and incomplete adherence to Tx of Tb has led to what? how is this prevented?
MDR-Tb strains
DOT: directly observed therapy to guarantee adherence to Tx
characteristics of Hantavirus (Bunyaviridae family)
ss - sense RNA
segmented: small, medium, large
symptoms of Hantavirus Pulmonary syndrome (HPS)?
flu like: fever, chills, severe myalgia
geography associated with Hantavirus?
4 corners
how is Hantavirus transmitted?
by infected rodents through urine, droppings, or saliva
high risk populations for Hantavirus?
campers, forest rangers, woodsmen
Cytomegalovirus is what type of virus? what does this mean in terms of its genome?
Human Herpes Virus
ds DNA
what are the routes of transmission of Cytomegalovirus?
congenital infxn: from infected mother or from maternal blood
Perinatal infxn: birth canal, breast milk
In adults via sexual route
what happens after CMV infects epithelial cells and lymphocytes?
it attains a latent state and persistent infxn
latent means it has chance of reactivation
congenital infxn from CMV has what s/s?
what is the concern for CMV infxns in immmunocompromised pts?
reactivation and primary infxns
what is CMV pneumo present simultaneeoulsy with?
pnuemocystis pneumonia
how does CMV appear histologically?
owl's eye
enlarged cells contain intranuclear and intracytoplasmic inclusions
what type of inclusions are present in CMV?
intranuclear and intracytoplasmic inclusions
the owl's eye inclusions of CMV stain what color? cytoplasmic inclusions?
pink b/c they are intranuclear eosinophilic inclusions
cytoplasmic inclusions: blue
Tx for CMV? (3)
Ganciclovir: inhibts viral DNA pol
Hyperimmune human anti-CMV Ig
Antiviral medications to stop viral replication but DO NOT destroy it (will not clear the infxn)
prevention of CMV?
prophylactic or preemptive therapy for transplant pts
what are the 3 systemic mycosis that cause LRT disease?
Histoplasma capsulatum
Blastomyces dermatitidis
Coccidiodes immitis
*all dimorphic fungi
what are the 2 opportunistic mycosis that cause LRT disease?
Aspergillus spp.
Pneumocystis jeroveci (carinii)
the 3 systemic mycosis cause what clinical disease? in what populations?
primarily pulmonary diseases (healthy hosts)
dissemination in immunocompromised (lethal)
*occur in specific geo areas
What are the 3 B's of Blastomyces?
broad based budding yeast
in vitro (25C) what is the dimorphic form of the 3 systemic mycoses?
Histoplasma: mold
Blastomyces: mold
Coccidiodes: mold
in vivo (37C) what is the dimorphic form of the 3 systemic mycoses?
Histoplasm: yeast, narrow based
Blastomyces: BBB yeast
Coccidiodes: spherule
what do you think when you hear Histioplasmosis?
caves (Cave disease)
birds and bat droppings
Ohio, Missouri and Missippi River Valleys
geo affected area for Histioplasmosis?
Mississipi River Valleys, Ohio, Missouri
what is Cave Disease?
splunchers in Missipii River Valleys would be susceptible to what disease?
Cave Disease: Histioplasmosis
whre does Histioplasmosis replicate?
in phagosomes of alveolar macrophages (intracellularly)
stain for all fungi?
Gomori's methenamine SILVER stain
which form of pulmonary histioplasmosis is 90% asymptomatic?
chronic pulm Histioplasmosis occurs in what ppl?
those with underlying lung disease
what do 90% of ppl with chronic pulmonary histioplasmosis develop?
Ex: emphysema
what will you see on CXR of person with Histioplasmosis?
healed pulmonary coin-like lesions
coin-like lesions
Histioplasmosis (systemic mycosis)
Tx for Histioplasmosis? (2)
Ketoconazole, Amphotericin B
transmission of Blastomycoses?
inhalation of spres from contaiminated soils
where is Blastomycosis endemic?
southeastern and midwesterd US
(also River Valleys-overlapping geo as Histioplasmosis)
who is at risk for exposure to BBB yeast?
thos with exposure to wooded sites (farmers, forestry workers, hunters, campers)
what will CXR of BBB infected person reveal?
lobar infiltrates w/ or w/o cavitations
Histoplasmosis 90% have cavitations
how do you mount Blastomycosis for microscopic analysis?
wet KOH mount of sputum sample
culture for BBB?
Tx for BBB?
Amphotericin B +/- sulfadiazine or azoles up to 6 months
chronic pulmonary infxn by BBB will show what?
skin lesions
*skin is the most common disseminated site of infxn in chronic pulm by BBB
what is the most virulent fungal pathogen? why?
Coccidiodes immitis b/c a single pore can initiate infxn
what climate/area will you find Coccidiodes immites?
hot, semi-arid areas of SW US
what do you call the infectous particles of Coccidiodes immitis
other name for Coccidiomycosis?
Valley Fever of Desert Fever
Desert Fever?
disease of Coccidiomycosis?
erythema nodosum (pic of legs-appears as skin infxn-do CXR to confirm)
*disseminated disease in <1%
what will you see microscopically if suspecting Coccidiomycosis?
spherules in sputum
what will you see in culture if suspecting Coccidiomycosis?
Tx for Coccidiomycosis?
amphotericin B, azoles
what 3 clinical diseases can Aspergillus spp cause?
allergic rhinitis*
*=URT with underlying condition such as asthma
who does Aspergillus cause problems in ?
pathogenic in normal host
disease in immunocompromised and cancer pts
what is diagnostic of Pulmonary Aspergilloma?
fungus balls in lungs, sinuses
(present in already existing cavities)
Allergic Bronchopulmonary aspergillus (ABPA) is a syndrome occuring in what pop?
CF pts
result from HSR to Aspergillus colonization
Symptoms of invasive Aspergillus
pleuritic chest pain (from fungal balls)
Dx of aspergillus infxn?
KOH wet mount
Silver stain
septate branching**
45 degree angle**
growth on SDA agar
how does mucor differentiate from aspergillus on microscopic Dx?
mucor: aseptate, 90degrees, sporangium sac
aspergillus: septate, 45 degrees, conidiospores (linear arrays of free spores)
how is serology used to Dx aspergillus?
allergy via detection using specific IgM
skin testing
Galactomannan antigen positivity can be used for what mycosis?
positivity can be detected 5-8 days before clinical signs develop
Drug Tx for Aspergillus?
inhaled Amphotericin B and azoles for invasive aspergillosis
oral corticosteriod for allergic bronchopulm aspergillosis
what was Pneumocystis jiroveci orginally thought to be?
thought to be protozoa, but is really an opportunistic fungi
who is infected by Pneumocystic jiroveci? when does disease occur?
ubiquitios org-most have Abs by early childhood
~100% of children-world wide
*disease due to reactivation (seen in AIDS pts)
what is one of the most common infxns in immunocompromised pts with AIDS?
pneumocystic jiroveci
how is pneumocystic jiroveci unlike other fungi? reason it was originally thought to be a protozoa?
will not grow on agar
Amphotericin B not effect
*but can be seen in silver stain
what does silver stain, stain in p, jiroveci?
the cysts wall and trophozoites
*call cyst b/c originally thought to be protozoa
transmission of Ascaris lumbricoides?
parasite egg ingestion
** not inhalation
clinical disease of infxn by ascaris lumbricoides?
pnuemonitis (similar to asthema)
the early stage (4-16days) of Ascarsis lumbricoides infxn has what type of symptoms? compared with late phase?
early: tissue MIGRATORY phase causing pulmonary syndrome: fever, cough, wheezing
late: GI symptoms
where are the Ascaris lumbricoides mature?
in the GI tract
immature larva in lungs
pathology from Ascarcis lumbricoides egg ingestion results from what?
pneumonia cuaed by the worm larvae migration through the lungs
explain the life cycle of Ascarcis lumbricoides?
After infective eggs are swallowed, the larvae hatch, invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs . The larvae mature further in the lungs(10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed . Upon reaching the small intestine, they develop into adult worms
Loeffler's syndrome?
ascarsis lumbricoides
see pulmonary infiltrates with eosinophilia
Tx for ascarsis lumbricoides?
antiparasitic meds
CBC of ascarsis lumbricoides will reveal what? sputum smear?
large amts of eosinophils
sputum: larva
Threadworm disease?
Strongyloidiasis stercoralis
tramission of Stronglydiasis (Threadworm)?
skin penetration by larva in soil
Threadworm disease can progres to fatal outcome in who? cause what?
autoinfxn can lead to "hyperinfxn syndrome", pneumonia
early infxn of Threadworm disease can be id how?
this is the larval migration phase
identified by eosinphilia on microscope
patchy infiltrate on CXR
Tx for threadworm disease?
which parasite trails under the skin indicating the migration of the worms?
Strongyloides infxn (threadworm disease)