Flashcards in (1/22/15) Streptococci (Bailey) Deck (47):
streptococcus sp. is a gram ____ cocci that is composed of chains and is non-_____ forming. it is a _____ ____ and catalase (test) ______
what are the three ways to classify streptococcus?
-species (often not necessary)
hemolysis pattern that has partial hemolysis and green discoloration of hemoglobin
hemolysis pattern that shows a clear zone of COMPLETE hemolysis
hemolysis pattern that has NO zone of clearing
what group of Beta hemolysis streptococci is responsible for causing the most human diseases
acute pharyngitis, pyoderma, streptococcal pneumonia, necrotizing fascitis, childbed fever, and foodborne outbreaks are all characteristics of which group of streptococcal diseases
the S progenies in group A streptococci (GAS) are responsible for what two diseases?
-streptococcal acute pharyngitis (strep throat)
-scarlet fever (strep throat + red skin rash)
fever that was fairly common until the mid-20th century and is rarely seen in developed countries now. the US outbreaks in the 80's and 90's were due to the emergence of virulent strains
Acute Rheumatic Fever
where is the only site of infection that is followed by Acute Rheumatic Fever (1-4 weeks past strep throat)
in reference to acute rheumatic fever, infection must invoke _____ response
-(could be considered an auto immune disease)(no more than 10% of ppl are susceptible)
you can completely prevent acute rheumatic fever infection by treating strep throat with a full course of _____
actue rheumatic fever has a high susceptibility to recurrence, thus ______ antibiotics into adulthood or for life
active inflammation in the glomeruli of the kidney that turns urine smokey due to proteins, leukocytes and erythrocytes, and renal failure (dialysis)
acute post-streptococcal glomerulonephritis
what are four ways that acute post-streptococcal glomerulonephritis is different that acute rheumatic fever?
-can follow pharyngitis or pyodermal infections
-recurrent attacks are rare
-not reliably prevented by penicillin
what ages do not get strep throat?
1-2 year olds
____ % of school aged children may carry Group A infections without symptoms
what two ways does a person encounter group A infections?
-live on the skin and mucous membranes
-person to person transmission (respiratory drops, hand to hand, food, skin wounds....)
Group A infections CANNOT penetrate ____ ____
intact skin (enter through bites, wounds, lesions, cuts, abrasions....)
in group A infections, bacteria bind to epithelial cells using _____
what are the three types of adhesions that group A bacteria use?
-lipoteichoic acid (LTA)
type of group A infection adhesion that makes the streptococci sticky and then binds to fibronectin on epithelial cell surfaces
lipoteichoic acid (LTA)
type of group A infection adhesion that is a high affinity fibronectin binding protein
type of group A infection adhesion that is a keratinocyte (outer skin) adhesion
what does the spread of a group A infection depend on?
how the infection was acquired
if a group A infection was acquired on the skin or mucous membranes, it usually _____ ____
if a group A infection was acquired through deeper tissue infections then there is _____ ____
_____ is an enzyme that binds to the inactive host plasminogen to create a catalytic complex that breaks down fibrin (blood clots)
what are three things that aid group A bacteria in avoiding phagocytosis
-M proteins (most important antiphagocytic factor)
-hyaluronic acid capsule
used by bacteria to avoid phagocytosis, is the most important antiphagocytic factor and is required for virulence
used by bacteria to avoid phagocytosis, is a mucoid capsule and makes the strep slippery, interfering with phagocyte attachment
hyaluronic acid capsule
used by bacteria to avoid phagocytosis, it inactivates phagocyte chemotaxin
forms a dense coating on bacteria's surface and blocks complement from binding to the cells. it then binds the host complement control proteins
super antigens that activate macrophages and cause T cells to release cytokines (three types: SpeA, SpeB, SpeC)
streptococcal pyrogenic exotoxins (SPE's)
the super antigens of streptococcal pyrogenic exotoxins (SPE's) are responsible for what two things?
-red rash of scarlet fever
-streptococcal toxic shock syndrome
Group that is actually more common but less notorious than group A streptococci
Group B strep inhabit _____ ____ and female _____ ____ and are the leading cause of _____ _______ and _______
group B bacteria use what type of capsule?
what are three similarities between group A strep and the other group strep?
-secrete similar extracellular enzymes
Group of strep that is normal flora of GI and genitourinary tracts. has a low virulence and usually accompanies other bacterial infections
"world's toughest pathogenic bacteria" that grows in high salt concentrations and in bile. is resistant to most antibiotics including penicillin
_____ _____ is required for effective killing of enterococci
antibiotic synergism (usually between penicillin and aminoglycoside)
makes up 30-60% of the oropharyngeal flora, has a low virulence, but is the most common cause of subacute bacterial endocartidis (affects abnormal heart valves) AND IS RESPONSIBLE FOR DENTAL CARIES (mutan group)
viridians streptococci produce ____ for adherence
the surface proteins of viridans streptococci "mutans group" bind salivary _____ on teeth
amounts to ~50% or more of bacteria in plaque
viridians streptococci "mutans group"