Bacteria Flashcards
(26 cards)
what is the mnemonic for things associated with endotoxin
ENDOTOXIN=Edema, Nitric oxide, DIC/Death, Outer membrane, TNF-alpha, O-antigen, eXtremely heat stable, IL-1, Neutrophil chemotaxis
what does C3a cause in reaction to endotoxin
edema, hypotension due to vasodilation
what does C5a cause in reaction to endotoxin
neutrophil chemotaxis
list the phases of bacterial growth in order
lag phase, exponential / log phase, stationary phase, death phase
what characterizes the stationary phase
nutrient depletion slows growth, spore formation in some bacteria
what characterizes the lag phase
metabolic activity without division
what characterizes the exponential growth phase
rapid cell division
at what stage are penicillins and cephalosporins most effective
exponential growth phase; this is the stage when peptidoglycan is being made
what leads to death in the death phase
prolonged nutrient depletion and build up of waste products
how is bacteria undergo transformation
DNA is taken up from the environment
what are the two types of bacterial conjugation
=F+ plasmid transfer from F+ bacteria to F-
=high-frequency recombination (Hfr): F plasmid is part of bacterial chromosome
what is transposition
a DNA sequence that can be excised then reintegrated (either in plasmid or in chromosome); this allows for new plasmids to be made
what are the two types of transposition and what characterizes them
generalized: lytic phages cleave bacterial DNA and can transfer it from one bacteria from another when it is packaged in the viral capsid
specialized: lysogenic phages insert their genes into bacterial DNA and when it is excised it takes some bacterial DNA with it to be packaged in viral capsid
name 5 bacterial toxins that are encoded by lysogenic phages
ShigA-like toxin Botulinum toxin Cholera toxin Diptheria toxin Erythrogenic toxin from S. pyogenes
list four beta-hemolytic bacteria
listeria monocytogenes
Group A strep
Group B strep
Staph aureus
what are the Jones criteria and what are they used to diagnose?
Jones criteria for diagnosing rheumatic fever: J- (joints) polyarthritis O- (heart) carditis N- nodules E- erythema marginatum S- Sydenham's chorea
name the three main categories of conditions S. pyogenes causes and what are the conditions of each?
pyogenic: cellulitis, impetigo, pharyngitis
toxigenic: scarlet fever, toxic shock- like syndrome, necrotizing fasciitis
immunologic: rheumatic fever, acute glomerulonephritis
how can strep pyogenes infection be detected
ASO titre (antistreptolysin O antibody)
antibodies against which S. pyogenes antigen can cause rheumatic fever?
M protein
what three conditions does S. agalactiae cause in babies
sepsis, pneumonia and meningitis
at how many weeks gestation should women be screened and what is done if they test positive for S. agalactiae?
35-37 weeks; mothers who test positive receive intrapartum penicillin prophylaxis
does S. agalactiae test positive or negative for Hippurate?
positive Hippurate test
what factor allows S. agalactiae to completely hemolyze the area around it?
CAMP factor
what conditions do enterococci cause?
UTI’s, biliary tract infections, subacute endocarditis
