Pulm Micro Flashcards
An example of a serious pathogen converted from an avirulent organism to a virulent organism by LYSOGENIC CONVERSION in
Corynebacterium Diptheriae
What is lysogenic conversion in the context of diptheriae
Strains lacking the diptheriae toxin (carried on the TOX gene on a Lysogenic bacteriophage) can be converted to toxigenic by by lysogenization
A+B Toxin model
B subunit is an adhesin that binds while the A subunit is toxic.
Where does corynebacterium diptheriae live?
Pharynx
Why is it particularly important to do a throat swab carefully when testing for diptheriae
If you rupture the epithelial layer on the back of the pharynx, you allow quick systemic access.
Symptoms of Diptheriae
SORE THROAT, Neck Swelling in severe cases, Skin lesions in cutaneous diptheriae
What is required to establish a diagnosis of corynebacterium diptheriae infection
The isolation of cornebacterium diptheriae in culture media….YOU MUST DO THIS or find some diptheria toxin
Diptheriae Differential
Think things like pharyngiitis, mono, epiglottitis, etc..
Treatment for Diptheriae
Diptheriae antitoxoin (neutralizes the circulating toxin) if used early can help, but it cannot work against toxin that has already bound to body tissue. Cutaneous diptheriae usually just requires antibiotics AB= Erythromycin or Penicillin
If you hear gram positive aerobic spore former you think
Anthrax Bacillus
What are the 3 Category A agents of bioterrorism that we’re discussing
Anthrax, Plague, Tularemia (high mortality rate for these three)
Two Anthrax Virulence Factors
1) Antiphagocytic non-antigenic capsule
2) A+B toxin: B is the binding part and it is called the Protective antigen. A has 2 subunits which makes ANthrax unique, one is the Edema factor and one is the Lethal Factor that disrupts the hosts immune response
Two types of disease caused by BA
Cutaneous Anthrax and Inhalational Anthrax
Inhalational Anthraxhas two phases
1) Flu like–> fever, aches, chest pain, Short of Breath, Rhinorrhea
2) Fever, SEVERE SHortness of Breath, Chest pain
What characterizes cutaneous anthrax?
Swelling, non-painful…..THE INTENSE SWELLING IS WHAT SHOULD MAKE YOU THINK ANTHRAX
What is Phase 2 of Anthrax infection generally characterized as?
Hemorrhagic Mediastinitis with Pleural Effusion.
Key signs and symptoms of inhalational anthrax?
Infection of hilar/mediastinal Lymph nodes DIFFERENTIATES IT FROM PNEUMONIA.
Mediastinal widening on x-ray
In ANthrax, the spores are the infectious form. THey enter the body, are phagocytosed by macrophages, germinate, become encapsulated, disseminate through the bloodstream, ALL OF THIS CAN TAKE 6 weeks
Thats why if you’ve been exposed, you must take CIPRO for 40 days
Diagnosis procedure for Anthrax
Flu test to rule it out, blood culture (look for large boxcar chains of Gram positive rods),
Treatment
Ciprofloxacin IV or Doxy IV and Ampicillin
Lancet shaped diplococcus
Strep Pneumo
Most significant virulence factor for strep pneumo
Antiphagocytic polysaccharaide capsule
Pneumolysin virulence factor
Pore forming toxin, recruits neutrophils and T and B cells which contributes to inflammation. It breaks down hemoglobin into a green pigment. Its why pneumococcal colonies are surrounded by a green zone on blood agar plates. Picture a drill.
Strep Pneumo Hyaluronidase viirulence factor
Aids in bacterial spread through hyaluronic acid containing tissues
Neuraminidase
Strep pneumo vrulence factor that clips N-acetylneuramic acid from cell surface glycoproteins, this either causes direct damage or unmasks binding sites for pneumococci bacteria. This process occurs when pneumococci move along the eustachian tube toward the middle ear.
Pili
Strep Pneumo virulence factor that aids in adhesion to epithelium
Lipoproteins
Iron Uptake….strep pneumo virulence factors
Peptidoglycan and Teichoic Acid
Strep Pneumo virulence factors….
Choline Binding Proteins
Strep Pneumo virulence factor…Most are hydrolytic enzymes that stimulate inflammation
Competence protein
Strep Pneumo virulence…allows pneumococci to acquire DNA from the environment
Autolysin
Disrupt cell wall…release inflammatory contents…Strep Pneumo virulence
Where does strep Pneumo colonize?
Nasal cavity. Cause infection in the middle ear, sinuses, trachea, bronchi and lungs….can also cause infection elsewhere by hematogenous spread
Major symptoms of CAP caused by Strep Pneumo
Cough, fatigue, shaking, chills, sweats, SOB
GRAYISH ANXIOUS APPEARANCE
Diminished breath sounds, increased fremitus, crackles, RUST COLORED SPUTUM
Cause of death for CAP by strep pneumo
accumulation of fluid in alveoli leads to suffucation
Meningitis by strep pneumo, symptoms
Occurs when strep pneumo gets in CSF
Headache, stiff neck, photophobia
Babies may have a bulge ver the fontanelle
Progressive disease may lead to seizures, drowsiness, loss of consciousnes
Most common age range for CAP
UNder 2 and over 65
Risk factors for developing Strep Pneumo Infection
NO SPLEEN (spleen clears unopsonized pneumonia), defects in Ab formation, defects in complement system, diabetes, chronic disease, alcohol abuse, sickle cell, influenza
Diagnosis of Strep Pneumo infection
Sputum sample with only a small amt of saliva and thus very few squamous epithelial cells.
Alpha hemolysis, Catalase negativity,
Susceptibility to optochin, solubility in bile salts
CHEST X RAY
Treat strep pneumo with
A macrolide, doxycycline, amoxicilin
Strep pneumo meningitis treatment
penicillin or ceftriaxone
When you hear Nocardia Asteroides think
Normal soil microflora, assoc with water. Gram positive bacili with branching head
Pulmonary disease of immunocompromised host
How does Nocardia Asteroides differ from mycobacteria (TB)
Shorter chained mycolic acids.
Nocardia Virulence Factors
catalase and superoxide dismutase protect against Neutrophil/macrophage damage
Cord Factor prevents fusion of phagosome and lysosome
Nocardiosis is an opportunistic pathogen thatmost commonly presents as
Pulmonary Disease
The majority of pts with clinically recognized nocardiosis have?
Underlyng debilitating factors such as:
LUNG DISEASE
Can Nocardial infections be transported from person-person
NO
Diagnosis of Nocardiosis
Evaluate smears and stains for gram positive branching filaments
Treatment of Nacardiosis
SUlfas, in well ppl for no less than 6 mths, In immunocompromised ppl for 12 mths
Actinomyces Israeli is very similar to
Nocardia
Actinomyces are normal flora of
Mouth
Are Actinomyces Isrealii very virulent
No…mostly opportunist attacks when mucosa is disrupted such as dental plaque present, large peridontal pockets, trauma, etc…
I say dental procedure you say
Actinomycetes
Diseases that actinomycetes causes
Pulmonary Infection, Facial actinomycosis, Jaw actinomycosis, GI infections
Symptoms of pulmonary infection
Cough with phlegm, chest pain, night sweats, wt loss
Characteristic pathogenesis of actinomycetes
Abcess of hard yellow sulfur granules
Treatment of actinomycosis
IV penicillin for 4-6 weeks, oral penicillin after that
Diagnosis of actinomycosis
biopsy of aspiration material containing sulphur granules
Chlamydia have a biphasic life cycle
True. Elementary Body enters the cell by endocytosis. The EB, now within an endosome (or phagosome) inhibits phagolysosomal fusion and organizes into a Reticulate body. This forms doughter EBs by binary fission
Chlamydial virulence factors
Type Three secretion systems that secrete proteins into the cell cytosol and interfere with host response pathways.
Legionella virulence factors
avoids phagosome lysosome fusion, injects bacterial proteins into the host cells and alters the activity of host factors involved in vesical traffic
Chlamydia trachomatis infects what type of cells?
squamocolumnar
What is the worlds leading preventable cause of blindness?
Trachoma
Neonatal pneumonia and neonatal inclusion conjunctivitis are caused by?
Immunotypes D-K of Chlamydia trachomatis…it can be prevented with erythromycin eye drops at birth.
Chlamydia is the most prevalent STI in the developed world
The problem is that 50-70% of the infections are silent in men and women so they never get treated.
Pontiac Fever
Milder illness caused by L. Pneumophila. Causes flu-like symptoms and passes in 2-5 days.
Important symptoms of chlamydia pneumonia
relatively mild respiratory illness, symptoms of bronchitis, cough with little sputum, HOARSENSS, headache. (headache and hoarseness are both unique findings) SINUS PERCUSSION TENDERNESS
Legionella symptoms
high fever, chills, cough, muscle aches, headaches
Mycoplasma
fever, malaise, dry cough, headache, chills,scratchy sore throat
When do you get legionella
When you breathe in the contaminated mist or water vapor that has been contaminated with bacteria…Hot tub
Are legionella spread from person to person
NO
Chlamydia treatment
Doxycycline
Legionella treatment of choice
Respiratory quinolones
Whats the significance of the Rhinovirus not having an envelope
It can survive on surfaces for long periods of time
Rhinovirus grows in what kind of environment
Limited tempertaure range (33-35) and non-acidic environments which is why it can basically only live in the nasopharynx
Upon virus entry and uncoating, what happens
The positive sense RNA genome is released into the cell cytoplasm and serves as messenger RNA for translation of polyprotein
What is unique about Rhinovirus proteases>
They cleave the “cap-binding complex” of eukaryotic cells that are required for translation initiation of host mRNAs. This shuts off protein synthesis but rhinovirus translation continues since it occurs in a CAP independent manner due to the presence of VPG and IRES.
Does direct viral damage contribute to the disease symptoms of a cold?
No. Its the local inflammatory response
I say ICAM-1, LDL-R. Sialoprotein Receptors you say
Rhinovirus receptors that help determine serotype
Adenovirus causes what type of infections
Respiratory, Eye, GI
Military recruits with acute respiratory disease
May be adenovirus
Eye infection from swimming pool
Adenovirus
Contaminated opthalmic medicine
keratoconjunctivitis
Pharyngoconjunctival fever =
combo of pharyngitis and ocular infection
H. Capsulatum
Histoplasmosis agent
In tissues, what form does H Capsulatum take on
Yeast…this form resists macrophage killing
What form does Blastomyces take on in the body
yeast…but it doesnt survive in macrophages
Coccidioides immitis takes on what form in tissue
spherule
Aspergillus are rapid growing molds with BRANCHING SEPTATE HYPHAE
true….recognize branching septate hyphae
I say tornadoes and fuingi you say
murcomycosis
The vast majority of Histoplasmosis infections are…
asymptomatic
A minority of them lead to
chronic and relapsing pneumonia that resembles TB.
The hallmark of acute pneumonia from blastomyces is purulent brown and bloody sputum
true
Chronic lung infections from Blastomycosis can mimic lung cancer because of the formation of mass like lesions
truth
Blastomyces infections disseminate where>
Skin (warty lesions), bone, genitourinary tract, prostate
Coccidimycosis is also knows as
Valley FeverDevelops in 40% of infections and is characterized by feer, arthralgia, rash,
ABPA
allergic bronchopulmonary aspergillosis seen in asthma and CF patients
Pts with an underlying pulmonary conditions may form a —– ball
fungal ball…this can cause life threatening hemoptysis
Invasive aspergillosis can spread beyond the lungs and into the central nervous system
true
I say fungal infection in acidotic diabetic on corticosteroid treatment, you say
Mucormycosis
Mucormycosis can cause death in as little as two weeks how>
Rhinocerebral mucormycosis
Pneumocystis presesnts as
diffuse interstitial pneumonia. Lung infiltrates develop and lead to reduced oxygen saturation
Ohio and Mississippi river valleys
histoplasmosis
How do you diagnose fungal infections
Treat culture or tissue specimens with KOH to remove all structures except fungal walls.
First line treatment for fungal infections
Azoles. If infection still persists: Ampho B
At first suspicion of aspergillus, start
Ampho B
Mucormycosis
Ampho B
See fungal-protozoan structure think
Pneumocystosis
Treat pneumocystosis with
trimethroprim sulfamethoxazole
Koryne= club, Bacter= Little Rod
diptheria name and shape
Diptheria’s main cause of harm
Throat
Chubby gram negative rods, safety pin
yersinia pestis
F1 virulence factor in Yp
paralyzes phagocytes
Unpasteurized dairy product consumption
Brucellosis
Keys to plague diagnosis
History (exposure to groud rodents, travel to Southwest US, large painful lymph nodes, resistance to B-lactams and macrolides
Lower respiratory tract infections in infants
RSV, hpMV1 and pPIV
Sand in eye
Adenovirus
Capsid Penton Protein
Adenovirus
