Micro Flashcards
What are common symptoms and causes of typical pneumonia
High fever Chills Chest pain Bronchioles or lobes look consolidated on CXR Causes Community acquired Strep pneumonia (most common) Staph A. Haemophilus influenzae Hospital Gram negative rods
What are characteristics of S. Pneumoniae
Gram: +
Shape: Lancet diplococci
Catalase: -
Other: Alpha Hemolytic, Capsule prevents oppsonization, makes it smooth on auger
Sensitive: Optochin and bile
Causes: pneumonia, bacteremia, Otitis media, Meningitis
how is Strep. Pneumo so virulent
The capsul! Prevents deposition of C3b on the surface. It’s a straight up compliment shield, thereby avoiding complement activation.
How do strep pneumo vaccines work
Antibodies can target specific capsules, allowing the Strep. Pneumo shield to be removed and thereby stopping virulence. Critical! Vaccine is serotype dependent and there are about 100 serotypes
What is the pathogenesis of s. Pneumonae
Inspired Into alveoli If not phagocytized Multiplies Spreads Inflames Either resolves or death Predisposing factors Sickle cell HIV Splenectomy C3b deficient
Describe serotype vaccines for strep pneumonia
We now have a T cell assisted vaccine to the 13 most common serotypes Recall that children under 2 can’t really develop t independent resistance, but by coupling a protein to the capsule, all ages can build an immune response
Describe the Chlamydia developmental cycle.
C. Pneumonae. And others Obligate intracellular bacteria
They cannot grow on agur
Divides by binary fission
Cell envelope similar to gram negative
Elementary bodies attach to cell
Reorganize to RB form while in vacuole Replication to fill the cell (expresses antigens at this point)
Regress to EB form Explode outward and infect other cells
Chlamydia pneumoniae and others.
Gram: -
Shape:Elementry bodies are small and dense
- *Other:** psittaci is from rare birds, wall lacks muramic acid
- *Sensitive:** Azithromycin > Doxycycline
- *Causes:** Atypical pneumonia (pneumoniea and psittaci), urethritis, PID, conjunctivitis, reactive arthritis (trachomatis)
Cannot grow on artificial media. Live in the phagocytic vessicles of hosts.
Chlamys = cloak
Discuss the structure of a typical Mycoplasma cell and compare it to the structure of other bacterial respiratory pathogens.
Gram: No stain
Shape: pleomorphic - can bypass filters
Cold: agglutinates (IgM)
Other: Sterols in walls, facultative aerobes
Sensative: Tetracycline or erythromycins (penicillin wont work because no wall.
Causes: Walking pneumonea, Military and prisions
Viral like features: Very small 0.15 micron Antibacterial resistant Lack cell wall and peptidoglycans (resist penicillin) Do contain sterols in walls, only bacteria that does Pleomorphic - pass filters Cold aglutinin Facultative aerobes Reproduce slowly by binary fission Smallest free living organism Pathogens M. Pneumonae M. Homonis Causes “walking pneumonia” Common in military, Requires person to person contact
List the etiologic agents associated with atypical pneumonia
Chlamydia pneumonia 10% Mycoplasma Pneumoniae Mycobacterium tuberculosis (Sometimes) Legionella and pseudomonas
Explain the pathogenesis of respiratory infections leading to atypical pneumonia including transmission, symptoms, and stages of the disease
Mycoplasmas Inhaled Attach to lower respiratory tract - P1 protein Causes cilia stasis Produces CARDS toxin Immune response leads to macrophage phagocytosis (can cause inflammatory damage) Diagnosis is virtually one of exclusion, because isolation is difficult. Chlamydia Psittaci From exotic birds Abrupt onset Constitutional symptoms
List the treatment of choice for infections caused by Chlamydia and Mycoplasma and explain the rationale behind the choice of treatment
Mycoplasma Tetracycline or erythromycin B-lactams do not work. Chlamydia Culture difficult IgM titter can diagnostic Doxycycline, azithromycin (again b-lactams don’t work)
State what the environmental niches and routes of exposure are typical for Legionella and Pseudomonas.
Both like water, forming biofilms, and are very opportunistic infections Legionella goes after immune compromise Pseudomonas goes after any exposure - CF patients
Compare the intracellular life styles of Legionella in nature and in the host
It is opsonized by a phagosome, but doesn’t bind to a lysosome. Allowing it to grow, surrounds with rough ER. Finally bursts the phagosome, than the host.
Indicate what patient factors predispose individuals to infections with these agents
Age Smoking Renal failure AIDS Male Alcoholism? Pseudo CF New borns
Describe the predominant respiratory diseases associated with each agent and the other opportunistic infections that may be seen with Pseudomonas in particular
Pseudo Swimmers ear Pneumonia in CF Burn infections Folliculitis (after contaminated hot tub )
Characteristics of legionella
Gram neg bacilli
PULMBING SYSTEMS
Leigonella Live in Lymphocytes of Lungs
Growth requirements are strict (amino acids, iron, buffered charcoal yeast) “the requirements to grow legionella are legion”
Aerosol spread
No human to human transmission
Nosocomial
Wide temperature range of replication
Diagnosis Urine sample finds LPS antigen
Bronchoalveolar lavage use silver stain
Acute and convalescent serum Treat with Macrolides (zithromycin) Quinolones (
Discuss the role of biofilms in disease and resistance to antimicrobial infections
Legionella produces strong biofilms that allow it to adhere to rough surfaces, particularly pipes,and grow. Pseudomonas Biofilms protect from antibiotics by being so adhesive
