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41 Cards in this Set

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list three gram positive cocci bacteria classes?
staphylococcus, streptococcus, and enterococcus
sources of staph aureus
gram positive clusters found on people's skin, 50-80% healthcare workers, spread by hand contact
suppurative skin infections assoc with staph aureus
suppurative infections (skin) assoc – impetigo, folliculitis, furuncles, boils, carbuncles (numerous boils fused tog), cellulitis (infection of deeper layers of skin)
systemic infections assoc with staph aureus
- systemic infections - bacteremia, endocarditis (rt side of heart in intravenous drug users, 50% mortality), pneuomonia (aspiration of oral secretions, or following hematogenous dissemination), osteomyelitis (secondary to trauma. Or hematogenous dissemination to bone), septic arthritis (most common cause)
enterotoxin mediated disease assoc with staph aureus
enterotoxin mediated dx – food poisoning, toxic shock syndrome (TSST-1 super antigen or enterotoxins), scalded skin syndrome (mediated by exfoliative toxins, with intense inflammation and desquamation), bullous impetigo
virulence factors assoc with staph aureus
 capsule – inhibits phagocytosis; facilitate adherence
 peptidoglycan – endotoxin-like activity, attracts leukocytes
 teichoic acid – polymer of ribitol and glycerophosphates, involved in complement activation, facilitates adherence
 protein A – binds to Fc region of IgG, reduces binding of phagocytes via FcR, inhibits complement activation; protective factor
 catalase – converts hydrogen peroxide from neutropohils to water, counteracts neutrophil ability to kill bacteria via production of oxygen free radicals
 coagulase – converts fibrinogen to fibrin, clots plasma; bacteria can hide within the clot; white cells, Ab, and even antibiotics do not penetrate clots well
 enzymes promote bacterial spread in tissue – fibrinolysin, hyaluronidase, lipase, nucleases
 cytotoxins – membrane damaging toxins that lyse eukaryotic cells
• enterotoxins (diarrhea and vomiting)
• toxic shock syndrome toxin – cause of toxic shock syndrome
• exfoliative toxin – causes scalded skin syndrome in neonates
 some strains break down B-lactam because in antibiotic wall
how can you be exposed to staph saphyophyticus
inadequately cooked food. inhabits the GI tract.
what is the 2nd most common cause of UTI in sexually active women?
S. saphrophyticus. young women are more susceptible.
clinical manifestations of staph epidermitis
endocarditis, infections of prosthetic joints and shunts/catheters
virulence factors of staph epidermitis
oability to bind to foreign materials
obiofilm production
what are 3 methods used to differentiate streptococci?
1. hemolysis (beta clear (pyogenes, agalactiae), alpha incomplete green)
2. serologic activity (Lancefield Groups based on antigenic differences in carbohydrates on cell wall – mainly in b-hemolytic strains) – pyogenes A, agalactiae B, pneumoniae – not grouped
3. biochemical reactions
diseases assoc with S. pyogens
pharyngitis, skin and soft tissue infections (impetigo, cellulitis (involves deeper layers of skin), erysipeias (involves upper layers of skin), scarlet fever, necrotizing fascilitis), bacteremia, sepsis, toxic shock syndrome (M protein bind fibrinogen and to adhesion molec – release of heparin binding protein from neutrophil. Endothelium gate control for inflammation), strep throat, scarlet fever
sequellae assoc with S. pyogens
- sequellae – rheumatic fever (after ONLY throat infections - less than 1% cross reaction btw M protein and heart tissue – permanent damage to heart valves), acute glomerulonephritis (sequellae of throat OR skin infections that is immune mediated)
virulence factors assoc with S. pyogens
Capsule – antiphagocytic, adhesive
M protein – mediates internalization by host cells, degrades C3b,
Pyrogenic exotoxins – A (most imp), B, C; temperate phage assoc with STSS and scarlet fever
Streptolysin O – lyses cells
Streptokinase – lyses blood clots – facilitates spread
give hemolysis and group category for S. pyogenes and S. agalactiae
S.pyogens - B hemolysis; Group A (GAS)
S.agalactiae - B hemolysis; Group B (GBS)
what bacteria is the leading cause of infectious death in newborns?
S. agalactiae
what is the most common cause of community acquired bacterial pneumonia?
S. pneumoniae
what is the most common cause of bacterial endocarditis in the US?
viridans group streptococci.
what is the source of S. agalactiae?
source – colonizes GI and genitourinary tracts; transmitted neonates in utero or birthing
what are the diseases assoc with S. pneumoniae
pneumonia, otitis media in children, sinusitis, meningitis
list two commensal organisms found in GIT within the Enterococcus sp.
E. faecium, E. faecalis
what are three main groups of aerobic gram positive rods that we studied
bacillus, corynebacterium, listeria
what are unique char of bacillus
spore forming, large boxy rods; ubiquitous, found in soil
what are clinical manifestations of bacillus anthracis
a. dx primarily in herbivores. Clinical manifestations – cutaneous black eschar, inhalation – lungs, cough, chest pain, fever. GI: NV, enlarged mediastinal lymph nodes
bacillus cereus is associated with two types of food poisoning different the causes and effects of the two?
spores live in food after heating
1. diarrheal form, 6-15hrs after ingestion, rarely vomiting - heat labile toxin (caused diarrhea by inc cAMP levels in gut)
2. emetic form - 30min-6hrs; nausea and vomiting, no diarrhea, associated with heat stable toxin.
besides food poisoning, what other effect can bacillus cereus have on the body?
eye infections (follows eye trauma) – rapid blindness
what are the symptoms and clinical manifestations of corynebacterium diphtheriae?
a. symptoms toxin pseudomembrane on tonsils, edema formation, bullneck appearance – B binds to cell; A inactivates elongation factor-2; leading cause of death – cardiomyopathy
b. clinical manifestations – cutaneous (skin from microabrasions)
what are the clinical manifestations and transmission methods of listeria monocytogenes?
a. clinical manifestations – neonatal dx – congenital – stillbirth, systemic infection, septicemia, meningitis, encephalitis. Immunocompromised – fever, nausea, diarrhea.
b. neonatal sepsis, meningitis
c. transmission – feces, food-borne infection, person to person – congenital and during labor and delivery
what are three main groups of aerobic gram positive rods that we studied
bacillus, corynebacterium, listeria
what are unique char of bacillus
spore forming, large boxy rods; ubiquitous, found in soil
what are clinical manifestations of bacillus anthracis
a. dx primarily in herbivores. Clinical manifestations – cutaneous black eschar, inhalation – lungs, cough, chest pain, fever. GI: NV, enlarged mediastinal lymph nodes
bacillus cereus is associated with two types of food poisoning different the causes and effects of the two?
spores live in food after heating
1. diarrheal form, 6-15hrs after ingestion, rarely vomiting - heat labile toxin (caused diarrhea by inc cAMP levels in gut)
2. emetic form - 30min-6hrs; nausea and vomiting, no diarrhea, associated with heat stable toxin.
besides food poisoning, what other effect can bacillus cereus have on the body?
eye infections (follows eye trauma) – rapid blindness
what are the symptoms and clinical manifestations of corynebacterium diphtheriae?
a. symptoms toxin pseudomembrane on tonsils, edema formation, bullneck appearance – B binds to cell; A inactivates elongation factor-2; leading cause of death – cardiomyopathy
b. clinical manifestations – cutaneous (skin from microabrasions)
what are the clinical manifestations and transmission methods of listeria monocytogenes?
a. clinical manifestations – neonatal dx – congenital – stillbirth, systemic infection, septicemia, meningitis, encephalitis. Immunocompromised – fever, nausea, diarrhea.
b. neonatal sepsis, meningitis
c. transmission – feces, food-borne infection, person to person – congenital and during labor and delivery
what bacteria is the leading cause of infectious death in newborns?
S. agalactiae
what is the most common cause of community acquired bacterial pneumonia?
S. pneumoniae
what is the most common cause of bacterial endocarditis in the US?
viridans group streptococci.
what is the source of S. agalactiae?
source – colonizes GI and genitourinary tracts; transmitted neonates in utero or birthing
what are the diseases assoc with S. pneumoniae
pneumonia, otitis media in children, sinusitis, meningitis
list two commensal organisms found in GIT within the Enterococcus sp.
E. faecium, E. faecalis