Micro Flashcards
If asplenic/sickle cell disease, what immunizations are needed against encapsulated m/o?
N. meningitidis, S. pneumonia, H. influenzae
What vaccines are consisted of against encapsulated m/o?
Capsular polysaccharide + protein conjugate –> serves as antigen in vaccine
What are encapsulated m/o?
S. pneumonia, B streptococcus (s. agalactie), n.meningitidis, h. influenza b, pseudomonas aeruginosa, Salmonela typhi, klebsiela pneumonia, E.coli
Why carrier protein is needed in encapsulated m/o vaccines?
To increase immunogenicity. A polysaccharide antigen cannot be presented to T cells. But protein promotes T cell activation and subsequent class switching ( thus incr. immunogenicity).
What are pneumococcal vaccines?
PCV13 (conjugated); PPSV23 (not conjugated)
What catalase does?
It converts H2O2 into H2O and O2, before it can be converted to microbicidal products by the enzyme myeloperoxidase.
What m/o (oxygen dependence) are susceptible to oxidative damage?
Anaerobes: clostridium; bacteroides; fusobacterium; actinomyces israelli. THEY LACK CATALASE and/or SUPEROXIDE DISMUTASE.
3 features of anaerobes?
Foul smelling (short chain fatty acids)
Difficult to culture
Produce gas in tissue (CO2 and H2)
What are facultative anaerobes?
Streptococci, staphylococci, enteric gram negative bacteria
how facultative anaerobes produce energy?
They use O2 as a terminal electron acceptor to generate ATP
OR
can use fermentation or other O2-independent pathways.
What antibiotic is used as a test to define staphylococci?
Novobiocin
What antibiotic is used as a test to define alpha hemolysis causing streptococci?
Optochin
What antibiotic is used as a test to define beta hemolysis causing streptococci?
Bacitracin
Alpha hemolysis m/o? Hemolysis mechanism
Strp. pneumoniae; Strp. viridans
Partial reduction of Hb –> greenish or brownish color WITHOUT CLEARING AROUND GROWTH
Beta hemolysis m/o? Hemolysis mechanism
Strp. A (pyogenes); Strp. B (agalactiae); Staph. aureus
Complete lysis of RBCs –> CLEAR AREA AROUND GROWTH
6 m/o that form spores.
Bacillus anthracis and cereus;
Clostridium tetani, botulinum, difficile, perfringens
Rusty sputum caused by …………………..
s. pneumoniae
What m/o cause subacute endocarditis?
S. sanguinis (viridans group) –> makes dextrants, that bind fibrin-platelet aggregates on damaged valves
S. bovis
Enterococci (faecalis and faecium) –> following GI/GU procedures, because it is normal colonic flora
What does pertussis toxin?
disables Gi –> impaired phagocytosis
disabled chemokine receptors for lymphocytes –> lymphocytosis –> impaired phagocytosis because lymphocytes cannot move to tissue.
What does cyclase toxin by bordetella pertussis?
increases cAMP
What does tracheal cytotoxin by bordetella pertussis?
damage cilliated epithelial tissue
Legionnaire’s disease symptoms?
severe pneumonia + GI + fever +CNS symptoms
Population of Legionnaires disease?
Smokers and chronic lung disease
What causes pontiac fever?
Legionella pneumophila. Its mild flu-like symptoms. self limiting
How to assess Legionella? (3)
- Silver stain
- Charcoal yeast extract medium with cysteine and iron
- Urine test –> antigen
