Lecture 15 Flashcards
What is airborne transmission?
infection by droplet nuclei in dust
- 1 meter from the host
- sneezing and coughing
What bacteria are in dust particles?
- staphylococci
- streptococci
How does the normal microbiota suppress pathogens of the respiratory system?
competing for nutrients and producing inhibitory substances
Which part of the respiratory system is nearly sterile?
lower part
What is part of the upper respiratory system?
- nose
- pharynx
- middle ear
- eustachian tubes
What protects mucosal surfaces in the upper respiratory system?
- saliva
- tears
What are some examples of microbial diseases in the upper respiratory system?
- pharyngitis: sore throat
- laryngitis
- tonsillitis
- sinusitis
- epiglottitis
Which is the most life-threatening disease of the upper respiratory system?
epiglottitis
What are some examples of the common cold?
over 200 different kinds
- rhinoviruses (30-50%)
- coronavirus (10-15%)
- enterovirus D68
What are symptoms of the common cold?
- sneezing
- nasal secretion
- congestion
- no fever
What can the common cold lead to?
laryngitis and otitis media
How can the common cold be cured?
NOT with antibiotics
- cough suppressants
- antihistamines
What is streptococcal pharyngitis (strep throat) caused by?
streptococcus pyogenes
What is scarlet fever caused by?
streptococcus pyogenes produces erythrogenic toxin
- follow strep throat
What causes measles?
measles virus
What causes rubella?
rubella virus
What causes smallpox?
variola virus
- mostly systemic but can affect respiratory
What causes pertussis (whooping cough)?
bordetella pertussis
What causes influenza?
influenza virus
- start in upper respiratory and progresses
What is diphtheria caused by?
corynebacterium diphtheriae
What is chicken pox caused by?
varicella-zoster virus
- can also affect lower respiratory
What causes shingles?
reactivation of varicella-zoster virus
What are characteristics of streptococcus pyogenes?
- resistant to phagocytosis
- streptokinases lyse clots
- streptolysins are cytotoxic
What are symptoms of strep throat?
- local inflammation
- fever
- tonsillitis
- enlarged lymph nodes
How can strep throat be diagnosed?
rapid antigen detection tests
What is lysogeny?
strain is infected by bacteriophage
- integrates its genetic material
What are symptoms of scarlet fevr?
- pinkish-red skin rash
- high fever
- strawberry-like tongue
What is treatment of scarlet fever?
antibiotics to prevent rheumatic fever to prevent the later development of rheumatic fever
What are symptoms of measles?
- cold-like
- macular rash
- Koplik’s spots (red spots on oral mucosa opposite the molars)
- can turn into encephalitis or subacute sclerosing panencephalitis
How can measles be prevented?
MMR (measles, mumps, rubella) vaccine
Who can’t get the MMR vaccine?
- children under 1 years old
- pregnant woman
What is another name for rubella?
german measles
How is rubella transmitted?
respiratory route
- 2 to 3 week incubation
What is congenital rubella syndrome?
- fetal damage
- deafness
- heart defects
- mental retardation in 35% of cases
- 15% mortality within first year of life
How can rubella be prevented?
MMR vaccine
What are the 2 forms of smallpox?
- variola major (20-60% mortality)
- variola minor (<1% mortality)
How is smallpox transmitted?
- respiratory route
- moves into bloodstream
- infects skin
How is smallpox prevented?
vaccines
What are characteristics of monkeypox?
endemic to small animals in Africa
- related to smallpox
- jumps from animals to humans
How is monkeypox prevented?
smallpox vaccine
What is otitis media?
infection of middle ear
- formation of pus puts pressure on eardrum
What are causes of otitis media?
- streptococcus pneumoniae
- nonencapsulated haemophilus influenzae
- moraxella catarrhalis
- streptococcus pyogenes
- respiratory syncytial viruses
How can otitis media be treated?
broad-spectrum penicillins
What is part of the lower respiratory system?
- larynx
- trachea
- bronchial tubes
- alveoli
What destroys microorganisms in the lungs?
alveolar macrophages
What protects mucosal surfaces?
respiratory mucus
What is typical pneumonia caused by?
s. pneumoniae
What is atypical pneumonia caused by?
other microorganisms
What does lobar pneumonia infect?
lobes of the lungs
What does bronchopneumonia infect?
alveoli adjacent to the lungs
What is pleurisy?
pleural membranes inflamed
What is pneumococcal pneumonia caused by?
streptococcus pneumoniae
- gram-positive
- encapsulated diplococci
What are symptoms of pneumococcal pneumonia?
infected alveoli of the lung fill with fluids and RBCs
- interferes with oxygen uptake
How can pneumococcal pneumonia be diagnosed?
- optochin-inhibition test
- bile solubility test
- presence of capsular antigen in urine
How can pneumococcal pneumonia be treated?
macrolides
How can pneumococcal pneumonia be prevented?
conjugated pneumococcal vaccine
What is haemophilus influenzae pneumonia caused by?
gram-negative coccobacillus
What is the risk group of haemophilus influenzae pneumonia?
- children under 5
- adults over 65
How can haemophilus influenzae pneumonia be prevented?
Hib vaccine
How can haemophilus influenzae pneumonia be diagnosed?
isolation on special media for nutritional requirements (X and V factors)
How can haemophilus influenzae pneumonia be treated?
cephalosporins
What are the symptoms of haemophilus influenzae pneumonia similar to?
those of pneumococcal pneumonia
What is another name for mycoplasmal pneumonia?
primary atypical pneumonia
- walking pneumonia
What is mycoplasmal pneumonia caused by?
mycoplasma pneumoniae
- no cell wall
What are symptoms of mycoplasmal pneumonia?
mild but persistent respiratory symptoms
- low fever
- cough
- headache
How can mycoplasmal pneumonia be diagnosed?
PCR
How can mycoplasmal pneumonia be treated?
tetracyclines
What bacteria causes moraxella catarrhalis?
gram-negative diplococcus
What are symptoms of moraxella catarrhalis?
- cough
- increased sputum production
- wheezing
What can moraxella catarrhalis lead to?
- otitis media
- sinusitis
What are the risk groups of moraxella catarrhalis?
common in:
- children with otitis media
- adults with COPD
- those with weakened immune systems
How can moraxella catarrhalis be diagnosed?
- cultured on blood or chocolate agar
- oxidase-positive and produces characteristic “hockey-puck” colony movements
How can moraxella catarrhalis be treated?
- amoxicillin-clavulanate
- second/third-gen cephalosporins
= beta-lactamase production
How can viral pneumonia occur?
complication of influenza, measles, chickenpox
What is the most common viral respiratory disease in infants and life-threatening pneumonia in older adults?
respiratory syncytial virus (RSV)
What does RSV cause in cell cultures?
cell fusion
- synctium
What are symptoms of RSV?
coughing and wheezing for more than a week
How can RSV be diagnosed?
serological test for viruses and antibodies
How can RSV be treated?
palivizumab
What is another name for coccidioidomycosis?
Valley fever
- San Joaquin fever
What is coccidioidomycosis caused by?
coccidioides immitis
- dimorphic fungus
What are symptoms of coccidioidomycosis?
- fever
- coughing
- weight loss
How can coccidioidomycosis be treated?
- fluconazole
- itraconazole
What is pneumocystis pneumonia (PCP) caused by?
pneumocystis jirovecii
What is PCP the primary indicator for?
AIDS
Where is PCP found?
lining of the alveoli
- forms a cyst
- cyst ruptures = releases 8 trophozoites
How can PCP be treated?
trimethoprim-sulfamethoxazole
What does streptococcus pyogenes look like?
gram-positive cocci in chains
What is another name for streptococcus pyogenes?
Group A streptococcus
How can streptococcus pyogenes be diagnosed?
beta-hemolytic on blood agar
- sensitive to bacitracin
- rapid antigen tests available for strep throat
How can streptococcus pyogenes be treated?
penicillin
- clindamycin or erythromycin if allergic
What does aspergillus fumigatus cause?
aspergillosis
What are the characteristics of aspergillus fumigatus?
airborne conidia
- grows in compost piles
What kind of fungi are rhizopus and mucor?
mold spores
What is the history of bioweapons?
1346: plague-ridden bodies used by the tartar army during the siege of kaffa
- spread to the rest of Europe causing Black Death
18th century: smallpox-contaminated blankets used against Native Americans during French and Indian war
1937-1945: plague-carrying flea bombs used in sino-japanese war
What new technologies have been made to identify bioweapons?
- DNA chips
- recombinant cells
- pro strips rapid screening systems
