(exam 3) Ch 24 microbial diseases of the respiratory system Flashcards
The nose, pharynx, middle ear, and Eustachian tubes are considered which part of the respiratory system?
the upper respiratory system
saliva and tears protect what surfaces?
mucosal surfaces
The trachea, bronchial tubes, and alveoli are considered which part of the respiratory system?
the lower respiratory system
the double layered membrane enclosing the lungs is a protective layer called the ?
pleura
how do cilia defend against pathogens?
moving particles upward toward the throat (ciliary escalator)
how do alveolar macrophages defend against pathogens?
destroy microorganisms in the lungs
how do respiratory mucus defend against pathogens?
protects mucosal surfaces (IgA)
how do normal microbiota defend against pathogens?
outcompetes pathogens for nutrients and produce inhibitory substances
what is the infection site of pharyngitis?
pharynx
what is the infection site of laryngitis?
larynx
what is the infection site of tonsillitis?
tonsils
what is the infection site of sinusitis?
sinuses
Streptococcus pyogenes causes what disease?
Streptococcal pharyngitis (strep throat)
Streptococcal pharyngitis is a gram positive member of what group of streptococci?
group A streptococci (GAS)
Streptococcus pyogenes causes what disease?
Scarlet fever
the Streptococcus pyogenes strain produces what type of toxin?
erythrogenic (reddening) toxin that is expressed from lysogenic phage
pinkish red skin rash and strawberry like tongue may indicate what disease?
Scarlet fever
Corynebacterium diphtheriae causes what disease?
Diphtheria
what does Corynebacterium diphtheriae look like?
gram positive rod that is club shape
if a tough grayish membrane is formed in the throat made of fibrin and dead tissue that blocks the passage of air to the lungs (due to a toxin), your patient may have what disease?
Diphtheria
what type of toxin is diphtheria?
powerful exotoxin that can enter bloodstream (toxin gene is expressed from lsyogenic phage)
how is Diphtheria prevented?
DTaP vaccine (requires a booster every 10 yrs)
what does DTaP vaccine stand for?
Diphtheria, Tetanus, and acellular Pertussis
what is an infection of the middle ear?
Otitis Media
why is Otitis Media painful?
formation of pus outs pressure in the eardrum resulting in pain
who is otitis most common in and why?
common in childhood due to smaller auditory tube
what type of disease is the common cold?
viral disease and probably the most prevalent human disease - cannot treat with antibiotics
what are airways that conduct air to lungs and branch from trachea?
bronchi
what are the cavities where air exchange takes place?
alveoli
what is bronchitis (bronchiolitis)?
respiratory infection involving the bronchi
what is a severe complication of bronchitis involving the pulmonary alveoli?
pneumonia
Bordetella pertussis causes what disease?
Pertussis (whooping cough)
what about pertussis contributes to virulence and allows it to attach to ciliated cells in the trachea and destroy the ciliary escalator?
capsule
there are two toxins of pertussis; 1) _____________ of cell wall damages and ciliates cells and 2) ___________ enters the blood stream.
1) tracheal cytotoxin
2) pertussis toxin
what are the three stages of pertussis?
1) Catarrhal stage (like common cold)
2) Paroxysmal stage (violent coughing / gasping for air)
3) convalescence stage (may last for months)
how is pertussis prevented?
DTaP vaccine
Mycobacterium tuberculosis causes what diseases?
Tuberculosis
what type of microbe is tuberculosis?
acid fast rod; obligate aerobe
what feature of tuberculosis makes it resistant to drying and antimicrobials?
lipids (mycolic acid) in the cell wall
what are the four steps of tuberculosis?
1) inhaled organisms are phagocytize by alveolar macrophages (healthy individuals typically destroy bacteria at this stage)
2) bacteria multiply in macrophages (mycolic acid stimulates a inflammatory response & chemotaxis of macrophages to infection site)
3) organisms are isolated in the walled-off tubercle (inner macrophages die and can become latent, noninfectious TB)
4) Tubercle breaks down, releasing bacteria into lungs (ciliary tuberculosis = disseminated infection which is all throughout the body)
coughing up bloodstained sputum is a symptom of what disease?
tuberculosis
how is tuberculosis traditional diagnosed?
tuberculin skin test (purified protein from TB bacterium injected cutaneously) and a positive reaction could mean a current OR previous infection
what follows a positive reaction of tuberculin skin test?
X ray , CT scan, sputum staining, and bacterial culture
what are some of the newer ways to diagnose tuberculosis?
rapid blood test for IFN-y and nucleic acid amplification test (NAAT) which has higher specificity and less cross reactivity in vaccinated individuals
how do we usually treat tuberculosis?
minimum of 6 months of drug therapy using first and second line drugs
what are first lined drugs for tuberculosis?
may cure disease, resistance often develops due to patients not following long schedule
what are second line drugs for tuberculosis?
for resistant strains, often less effective with toxic side effects
what are multi-drug resistant (MDR) strains of tuberculosis?
resistant to first line drugs
what are extensively drug-resistant (XDR) strains of tuberculosis?
resistant to second line drugs (virtually untreatable and emerging globally)
Tuberculosis is the leading cause of death of patients with what other disease?
HIV (because their immune systems are depleted)
what is the vaccine available for Tuberculosis and why is it not widely used in the US?
The BCG vaccine is a live culture of avirulent M. bovis; not widely used in the US due to questionable effectiveness
what % of the world’s population has latent TB?
1/3%
Streptococcus pneumoniae causes what diseases?
Typical pneumonia (primary form) which accounts for 2/3 cases
what is lobar pneumonia?
infects the lobes of the lung
what is bronchopneumonia?
infects the alveoli adjacent to the lungs
what is pleurisy?
complication from pneumonia causing the pleural membranes inflamed (painful)
infected alveoli fill with fluids and RBCs which interferes with oxygen uptake and rust colored uptake may indicate that your patient has what disease?
You patient may have typical pneumonia
how do you diagnose bacterial pneumonias?
antibiotic disk susceptibility, bile solubility test, or presence of capsular antigen in urine
what two vaccines can prevent tuberculosis and which age group are they for?
1) conjugated vaccine (younger; 2 yrs or less)
2) polysaccharide vaccine (for older people; 65 and older)
what are the risk groups for Haemophilus Influenzae Pneumonia and how do you diagnose this?
Risk group = children under 5 and adults over 65
diagnosis = isolation on special media for nutritional requirements
what vaccine reduces the incidence of Haemophilus Influenzae Pneumonia by 99%?
Hib Vaccine
Mycoplasma pneumonia causes what disease?
Mycoplasmal Pneumonia (aka atypical pneumonia or walking pneumonia)
what is unique to Mycoplasma pneumonia?
there is NO CELL WALL which results in a fried-egg appearance on the media
Legionella pneumophila causes what disease?
Legionellosis (aka. Legionnaire’s disease)
what is important about Legionella pneumophila that we are aware of?
it grows well in water and forms biofilms
how is Legionellosis transmitted?
transmitted by inhaling aerosols not transmitted person to person
Chlamydophila psittaci causes what disease?
Psittacosis (Ornithosis)
how is Psittacosis (Ornithosis) transmitted?
transmitted to humans by elementary bodies from bird droppings that are transmitted through the air
Chlamydophila pneumoniae causes what disease?
Chlamydial Pneumonia
how is Chlamydial Pneumonia transmitted?
transmitted person to person (contact)
Coxiella burnetiid causes what disease?
Q fever
what is Coxiella burnetiid?
an obligatory parasite meaning it MUST be in a host cell in order to replicate
high fever, muscle aches, headache and coughing is what type of Q fever?
acute Q fever
endocarditis (may occur years after infection) is what type of Q fever?
chronic Q fever
how is Q fever transmitted?
transmitted to farms animals from tick bites which is then transmitted to humans from the inhalation of aerosols from animals and unpasteurized milk
what disease occurs as a complication of influenza, measles, or chicken pox?
viral pneumonia
what is the most common viral respiratory disease in infants? (so common that almost all children are infected by age 2)
Respiratory Syncytial Virus (RSV)
what does Respiratory Syncytial Virus (RSV) cause the cells to do?
causes cell fusion (syncytium) in cell culture
Influenzavirus causes what disease?
Influenza (flu)
what is unique about Influenzavirus?
contains 8 RNA segments and outer lipid bilayer (envelope)
what are the two different types of spikes that Influenzavirus can have?
1) hemagglutinin (HA) spikes
2) Neuraminidase (NA) spikes
what is the purpose of hemagglutinin (HA) spikes on Influenzavirus?
recognize and attach to host cells; help with entry
what is the purpose of Neuraminidase (NA) spikes on Influenzavirus?
helps the virus separate from the infected cells; help it leave
why can influenza easily mutate?
because of its RNA genome which makes many mistakes
if influenza mutates and it is antigenic drift what can this do?
can cause minor changes in the HA and NA spikes and allow the virus to elude some host immunity but nothing major
if influenza mutates and it is antigenic shift what can this do?
changes are great enough to evade most host immunity; leads to pandemics; and involves the reassortment of the eight RNA segments; VERY BAD
how do we prevent against influenza?
Multivalent vaccine (targeted against 3-4 strains) - composition of vaccine is determined annually by identification of circulating viruses (does not provide long term immunity you need a flu shot every year)
Pneumocytosis jirovecii causes what disease?
Pneumocystis Pneumonia (PCP) which is a fungal disease
how does Pneumocystis Pneumonia (PCP) present?
Asymptotic in the immunocompetent (good immune system) but causes pneumonia in the immunocompromised (primary indicator of AIDs/HIV)
