Lecture 19 Respiratory Infections Flashcards
Rebecca Lancefield
Demonstrated that streptococci can be clasified based on cell wall carbohydrates
Rebecca Lancefield discovered ______ protein on streptococcus pyogenes
M protein
Upper respiratory tract
head and neck
Lower respiratory tract
Chest
What are the parts of the upper respiratory tract
Nose, nasal cavity, pharynx, epiglottis
in URT, ______ cells produce mucus
Goblet
______ propels mucus, trapped particles away from lungs
Mucociliary escalator
______ are lymphoid organs that come into contact with microbes entering URT
Tonsils
Approx 30% of healthy people carry
Staphylococcus aureus
Corynebacterium characteristics
Pleomorphic, gram positive rod, non-motile, club-shaped
Haemophilus characteristics
Small, gram negative rods
Staphylococcus characteristics
Gram positive cocci in clusters
Streptococcus characteristics
Gram positive cocci in chains
tears are rich in ______ and ______
Lysozyme, secretory IgA
External ear is protected by
Cerumen (ear wax)
Infection in middle ear occurs in
Otitis media
Inner ear is ______
microbe-free
What happens to throat in streptococcal pharyngitis
Red with patches of pus, tiny hemorrhages
causative agent of streptococcal pharyngitis
Strep. pyogenes
Strep pyogenes result on blood agar
Beta hemolysis
What is the lancefield group of strep. pyogenes
Group A strep (GAS)
GAS is distinguished by
M protein
in S. pyogenes, ______ acts as adhesin
______ adheres to fibrin of epithelial cell
protein ______ binds to ______ region of ______
M protein
Protein F
Protein G, Gc region, IgG antibodies
______ breaks down tissue of throat in S. pyogenes
DNase, hyaluronidase, proteases
streptokinase breaks blood clots
A few strains of S. pyogenes produce ______ which leads to a high fever
Streptococcal pyrogenic exotoxins (SPEs)
______ prevents opsonization via C3b
M protein
______ is an Fc receptor, binds to IgG, prevents IgG mediated phagocytosis
Protein G
C5a peptidase
Inhibits recruitment of phagocytes
______ make holes in membanes of erythrocytes and leukocytes, yields Beta hemolysis
Streptolysins O and S
Hyaluronic acid capsule
Interferes with phagocytosis by causing inactivation of C3b
S. pyogenes only infects ________
hhumans
How is S. pyogenes spread
respiratory droplets, contaminated food
S. pyogenes can be a source of ________ infections
healthcare associated
How is S. pyogenes treated
penicillin prevents post-strep sequelae
What is post-streptococcal sequelae
Complications after strep infections, results from autoreactive immune response
Acute rheumatic fever can begin________
3 weeks after recovery from step
________ are involved with susceptibility of acute rheumatic fever
MHC class II
ACute post-streptococcal glomerulonephritis causes
Fever, fluid retention, high BP, blood and protein in urine… KIDNEY failure
Sign and symptoms of strep. sequelae
sore red throat
pus and tiny hemorrhages
enlargement of lymph nodes in neck
rheumatic fever
glomerulonephritis
Incubation period of strep. sequelae
2 to 5 days
Causative agent of strep. sequelae
S. pyogenes, lancefield group A
Beta hemolytic
Epidemiology of strep. sequelae
Direct contact, droplet infection, ingestion of contaminated food
causative agent of diptheria
Corynebacterium diptheriae
Shape of corynebacterium
Pleomorphic
Motility of corynebacterium
non motile
gram rxn of corynebacterium
gram positive rod
C. Diptheria releases
diphtheria toxin
C. diptheria is isolated on what medium
Selective and differential
contains potassium-tellurite
also grown on Loeffler’s
Symptoms of C. diptheria
Mild sore throat, slight fever, extreme fatigue, malaise
C. diphtheria causes formation of ________ on tonsils, throat, nasal cavity
Pseudomembrane
Diptheria results from
Exotoxin absorbed into bloodstream
in diptheria, ________ attaches to cell receptors, entire molecule is taken up by endocytosis
B subunit
________ catalyzes reaction covalent modification of cellular factor 2 required for movement of ribosome on mRNA
A subunit, ADP-ribosyl-transferase
in diptheria, ________ are reservoir
humans
How is diptheria spread
by air, inhalation or from fomites
Cutaneous diptheria
Caused from touching or handling infected materials from carrier to patient
Treatment of Diptheria
injection of antiserum to toxin
Incubation period of C. diptheria
2 to 6 days
For lower respiratory tract infections, location is usually ________
sterile
Parts of LRT
larynx, trachea, bronchi, lungs
What happens in pneumonia
Alveoli fill with fluids like pus and blood
Pneumonia is an inflammatory response to ________
microbial infection
What is the leading cause of death due to infection
Pneumonia
Symptoms of pneumonia
Cough, chills, SOB, fever, chest pain, cyanosis
in pneumonia, ________ comes up from lungs
sputum
Pneumonia is caused by opportunists when ________ is compromised
Mucociliary escalator
Pneumonia may affect ________ in pleura, causing pain
Nerve endings
________ collects in alveoli in pneumonia
Fluids, leukocytes, mucus
Causative agent of pneumonia
Streptococcus pneumoniae
Gram rxn of S. pneumoniae
Gram positive diplococci
for S. pneumoniae, ________ is responsible for virulence
Thick polysaccharide
Incubation period of pneumococcal pneumoniae
1 to 3 days
________ accounts for 60% of adult community acquired pneumonia requiring hospitalization
Pneumococcal pneumonia
Symptoms of pneumococcal pneumonia
cough, fever, chest pain, sputum production
for pneumococcal pneumonia, ________ interferes with C3b of complement system, blocks phagocytosis
PspA, pneumococcal surface protein
________ damages ciliated epithelium
pneumolysin
pneumococci may enter ________, lead to sepsis of blood, endocarditis, meningitis
blood stream
There is an increased of pneumococcal pneumonia during ________
Influenza A infection
Treatment of pneumococcal pneumonia
Penicillin
________ strains of S. pneumonia is the causative agent of pneumococcal pneumoniae
Encapsulated
Causative agent of pertussis
Bordtella pertussis
Gram rxn of B. pertussis
Gram negative rod
When bacteria are inhaled of pertussis, they ________
attach to ciliated cells of epithelium
Pertussis can lead to small areas of ________
collapsed lung
decreased ________ results in severe cough in pertussis
Ciliary action
________ toxins are released in pertussis
three
Stages of pertussis
Catarrhal
Paraxoysmal
convalescent
Catarrhal stage
inflammation of mucous membrane
What happens in catarrhal stage
1 to 2 weeks of signs resembling UR infection
Paroxysmal
Repeated, sudden attacks
Whoop sound of forced inhalation
Convalescent stage
Recovery
not contagious, coughing decreases
pertussis toxin is ________ toxin
A-B
What does pertussis toxin do?
B attaches to cellular receptors
A moves through cytoplasmic membrane
Pertussis toxin icnreases ________
cAMP
Adenylate cyclase toxin
Lyses leukocytes, catalyzes ATP conversion to cAMP
Tracheal cytotoxin
Causes release of fever-inducing interleukin-1
Toxic to ciliated epithelial cells
Epidemiology of pertussis
Highly contagious
Treatment of pertussis
Macrolides during catarrhal stage
intensive support therapy
prevented with DTap
Incubation period of pertussis
1 to 2 weeks
Tuberculosis causative agent
Mycobacterium tuberculosis
Initial infection of tuberculosis by M. tuberculosis is usually ________
asymptomatic
M. tuberculosis yields ________
Latent tuberculosis infection LTBI
LTBI may later develop into
tuberculosis disease
TB primarily infects ________
lungs
Shape of M. tubercuolsis
Rod shaped bacteria
How does tuberculosis infection start
airborne cells inhaled into lung
Pathogenesis of TB
alvelolar macrophate engulfs airborne cells
lympocytes wall off infected area
granuloma forms (tubercles)
effector helper T cells release cytokines
in TB, after infection, ________ forms around macrophage, keeps lymphocyte out of tubercle
Fibrous layer
Ghon foci
Fibrous layer calcifies in adjacent lymph nodes
in TB, tubercle ________ after macrophage in tubercle dies
ruptures, spreads bacteria in lungs
How is TB identified
Tuberculin skin test, blood test
Treatment of TB
multiple drugs over a long period of time
combination therapy
What vaccine is used against TB
BCG, but it is discouraged because it causes positive tuberculin test
Causative agent of legionellosis
Legionella pneumophila
Gram rxn of L. pneumophila
Gram negative rod, fastidious
Symptoms of L. pneumophila
Headache, muscle aches, high fever, confusion, shaking chills
How is legionellosis acquired
Inhaling aerosolized water with organism
MIP
Macrophage invasion potentiator
How does bacteria survive in legionellosis
by preventing phagosome-lysosome fusion, multiple within macrophages
Epidemiology of legionellosis
widespread in warm, natural waters with protozoa
There is no ________ spread for legionellosis
Direct person to person
treatment of legionellosis
appropriate antibiotic that produces B-lactamase
some patients need O2 therapy
incubation period of legionellosis
2 to 10 days
pathogenesis of legionellosis causes ________ of cells lining alveoli
Necrosis
causative agent of influenza
Influenza A, member of orthomyxoviridae
Influenza A is an ________ virus with ________ segments of single stranded, negative RNA
enveloped, 8
Which type of flu is most serious
Influenza A
Incubation period of influenza
2 days
Influenza does NOT cause
Vomiting and diarrhea,
different from stomach flu
How is influenza contracted
inhalation of aerosolized secretions or from contaminated fomites
in influenza, virion is attached by ________ to respiratory epithelial cells, enters by endocytosis
HA spikes
Epidemiology of influenza A
only a small percent of cases are fatal
Antigenic drift is responsible for seasonal flu
Treatment of Influenza A
antiviral medications like neuraminidase inhibitors
RSV infects ________
Lower respiratory tract
Incubation period of RSV
1 to 4 days
RSV causes ________, high-pitched cough and noisy inhalation from airway obstruction
croup
Causative agent of RSV
enveloped, ss RNA
Pneumoviridae
pneumoviridae causes cells in culture to fuse into v
Syncytia
how is RSV contracted
inhalation, replicates nasopharynx
Where does RSV replicate
in nasopharynx
When is RSV common
Late fall, early spring
Treatment for RSV
no antivirals
no vaccine
incubation period of RSV
1 to 4 days
Hantavirus symtoms
fever, fatigue, muscle aches
hantavirus incubation period
7 days to 8 weeks
Causative agent of hantavirus
Sin nombre virus (SNV)
SNV genome consists of how many segments of ss RNA?
3
How is hantavirus contracted
Inhalation of airborne dust contaminated with urine, feces, saliva of infected rodents
Pathogenesis of hantavirus
Viral antigen localizes in capillary walls in lungs
Epidemiology of hantavirus
Zoonosis
Treatment of hantavirus
no treatment
