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
