Studied by 1 personStrep throat
________ (streptococcalpharyngitis and tonsillitis) is the most common disease caused this organism, especially in children (most individuals build immunity as they get older)
E faecalis
________ and related organisms can occasionally cause infections of the urinary tract, wounds, blood, appendix, and endocardium.
dental procedures
Can be introduced into tissue or blood by trauma such as ________ leading to bacteremia, meningitis, tooth abscesses, and endocarditis.
Organism
________ can be growing in nasal passages in men, women or children, but this is usually due to a vaginal infection in women.They have found that the use of ultra- absorbent tampons, which absorb large amounts of Magnesium irons, leads to heavy colonization by S. aureus and therefore puts women at risk for this disease.
Chemotherapy
________- in general, penicillins are the drug of choice.
Hemolysins
________ (streptolysins)- damages RBCs, WBCs, liver, and heart muscle cells.
Viridians group
________ (means green, referring to alpha- hemolysis of RBCs)- mostly found in oral cavity.
Immunizations
________- none available at present for group A.
Penicillinase
________- destroy penicillins.
Erythrogenic
________ (pyogenic) toxin- produces red rash and fever associated with scarlet fever (only produced by lysogenized strains)
Characteristics
gram+ cocci in grape-like clusters; facultative anaerobes; catalase positive; can withstand high salt concentrations (7.5 -10 %), extremes in pH, drying, and relatively high temperature (60 °C for 60 mins)
Coagulase
cause the coagulation of blood plasma to put a layer of fibrin around cells
Staphylokinase
activates a blood plasma protein (plasminogen) to protease (plasmin) that digests fibrin in clots
Hyaluronidase
digests hyaluronic acid that binds together connective tissue to allow invasion of tissues
Nucleases
digest DNA and RNA
Lipase
allows staphylococci to colonize oily skin surfaces
Penicillinase
destroy penicillins
Hemolysisns
lyse RBCs
Leukocidin
lyses WBCs
Enterotoxins
damage intestinal epitherial cells causing water and electrolyte loss (secretorydiarrhea)
Exfoliative toxin
cause loss of epidermal layer of skin
Protein A
a cell wall-associated protein that binds antibody molecules (IgG) nonspecifically and incapacitates them
TSS (toxic shock syndrome) toxin
some strains produce a potent toxin that enters blood and causes fever, rash, vomiting, liver damage, renal failure, etc
Systemic infections
staphylococci can infect more tissues that any other organism
First get a bacteremia and then can spread to bebone (osteomyelitis), the lining of the heart (endocarditis), joints, lungs (pneumonia
rare but 50 % fatal), CNS (meningitis), or virtually any internal organ
Food poisoning
organisms common on skin and in nasal passages so can easily contaminate foods such as custards, pies, cream-filled pastries, potato salad, ham and processed meats etc
Some strains produce potent enterotoxins (act on intestinal tract tocause cramping, diarrhea, nausea, committing) that is heat resistant
takes > 100 °C for 30 minutes to inactivate, so reheating food probably will not deactivate toxin
Symptoms appear within 2
6 h and last 24 h
Immunizations
none available at present but there has been a recent breakthrough that may lead to one
Chemotherapy
most now resistant to penicillin ( 95%) due to penicillinase production; methicillin, which is resistant to penicillinases in general, was at one time the drug of choice but MRSA (methicillin-resistant S. aureus) now a major problem
Other pathogenic staphylococci
coagulase negative staphylococci also can less frequently cause disease in humans, including S. epidermidis, S. capitis, S. hominis, and S. saprophyticus.They can cause infections like those caused by S. aureus and also can cause urinary tract infections (UTIs)
S. pyogenes
most serious pathogen in group A on serotyping
Capsule
protects against phagocytosis and aide in attachment
Including teichoic acids and lipoteichoic acids
protect cells from lysozyme and aid in adherence to epithelial cells
M protein
part of fimbriae, gives resistance to phagocytosis and aids in adherence
Hemolysins (streptolysins)
damages RBCs, WBCs, liver, and heart muscle cells
Erythrogenic (pyogenic) toxin
produces red rash and fever associated with scarlet fever (only produced by lysogenized strains)
Streptokinase
activates a blood plasma protein (plasminogen) to a protease (plasmin) that digests fibrin in clots
Hyaluronidase
digests hyaluronic acid that binds together connective tissue to allow invasion of tissues
Nucleases
digest DNA and RNA
Cutaneous infections
streptococcal impetigo or pyoderma is a superficial skin infection while erysipelas is a deeper skin infection
Systemic infections
septicemia (rare); pneumonia (rare); toxic shock (rare); puerperal or childbed fever, and infection of the uterus after childbirth that can be fatal if not controlled
Rheumatic fever and acute glomerulonephritis
autoimmune diseases that are triggered by the similarity between the M protein on the surface of the streptococci and certain surface proteinsin tissues of the heart, joints and kidneys
S. agalactiae
usually only a problem if normal defenses weakened (part of our normal flora)
Enterococcus faecalis (and other related organisms)
old name was Streptococcus faecalis
Viridians group (means green, referring to alpha-hemolysis of RBCs)
mostly found in oral cavity
Immunizations
none available at present for group A
Chemotherapy
in general, penicillins are the drug of choice
How many species of staphylococcus are recognized today?
less than 30
Where is staphylococcus found?
skin and mucous membrane of warm-blooded animals (including man)
What are characterisitics of staphylococcus?
gram + cocci in grape-like clusters, facultative anaerobes, catalase positive
What conditons can staphylococcus withstand?
high salt concentrations (7.5-10%), extremes in pH, drying, and relatively high temperature (60 °C for 60 mins)
What is the most important human pathogen of staphylococcus?
S. aureus
What are virulence factors?
enzymes and toxins that allow cells to invade tissues and cause disease
What are some virulence factors of S. aureus?
coagulase, staphylokinase, hyaluronidase, nucleases, lipase, penicillinase, hemolysisns, leukocidin, enterotoxins, exfoliative toxin, protein A, and TSS (toxic shock syndrome) toxin
What is the function of coagulase?
cause the coagulation of blood plasma to put a layer of fibrin around cells
What is the function of a layer of fibrin around cells caused by coagulase?
may protect cells from phagocytosis in body
What pathogens can produce coagulase?
S. aureus and S. intermedius
S. intermedius is a pathogen found in ___.
dogs
What is the function of staphylokinase?
activates a blood plasma protein (plasminogen) to protease (plasmin) that digests fibrin in clots
What is the function of hyalurondiase?
digests hyaluronic acid that binds together connective tissue to allow invasion of tissues
What is the function of nucleases?
digest DNA and RNA
What is the function of lipase?
allows staphylococci to colonize oil skin surfaces
What is the function of pencillinase?
destroy pencillins
What is the function of hemolysisns?
lyse RBCs (red blood cells)
What is the function of leukocidin?
lyse WBCs (white blood cells)
What is the function of enterotoxins?
damage intestinal epitherial cells causing water and electroyte loss (secretory diarrhea)
What is the function of exfoliative toxin?
cause loss of epidermal layer of skin
What is the function of protein A?
a cell wall-associated protein that binds antibody molecules (IgG) nonspecifically and incapacitates them
What is TSS (toxic shock syndrome) toxin?
enters blood and causes fever, rash, vomitting, liver damage, renal failure, etc.
Organisms that produce TSS toxin can be growing in ___ in men, women, or children.
nasal passages
TSS toxin is usually due to a ___ in women.
vaginal infection
Why are women at a greater risk for TSS toxin?
ultra-absorbent tampons absorb large amounts of Magnesium irons leads to heavy colonization by S. aureus
Staphylococcus can cause ___ and ___ infections as well as food poisioning.
cutaneous and systemic
What are cutaneous infections associated with?
skin, hair, or nails
What are cutaneous infections?
infections of hair follicles, sweat glands, and/or sebaceous galnd
Cutaneous infections can cause ___ if follicle or gland abscesses.
boils (furuncles)
What are clusters of furuncles (larger, deeper boils) called?
carbuncles
Superfical skin infections (staphyloccal impetigo) may results in ___.
scalded skin syndrome
Scalded skin syndrome is due to production of ___.
exfoliative toxin
What is a systemic infection?
infection spreads from skin infections to other sites
An infection in bone is called?
osteomyelitis
An infection in the lining of the heart is called?
endocarditis
An infection in lungs is called?
pneumonia
An infection in CNS is called?
meningitis
Organisms common on skin and in nasal passages can easily contaminate ___ leading to ___.
foods; food poisioning
Foods must be ___ to prevent growth of organisms.
refrigerated
Some strains of staphylococcus produce ___ that is heat resistant.
potent enterotoxins
Potent enterotoxins act on ___ to cause cramping, diarrhea, nausea, and committing.
intestinal tract
How long and at what temperature does it take to inactivate potent entrotoxins?
100 °C for 30 min (therefore reheating food probably will not deactivate toxin)
How many cells does it take to produce enough enterotoxins to cause symptoms?
10^6 cells/gm
Symptoms of food poisioning appear within ___ and can least ___.
2-6 hrs and last 24 hrs
Are immunizations available for staphylococcus?
no; however there has been a recent breakthrough that may lead to one
What chemotherapy can be used for staphylococcus?
penicillin, methicillin, vancomycin (important one)
Why are most staphylococcus resistant to pencillin 95% of the time?
due to pencillinase production
Methicillin is resistant to ___ was the drug of choice against staphylococcus but ___ is now a major problem.
pencillinases; MRSA (methicillin-resistant S. aureus)
What is the current chemotherapy drug that works against staphylococcus?
vancomycin
What are species of coagulase negative staphylococci?
S. epidermidis, S. capitis, S hominis, S. aprophyticus
Coagulase negative staphylococci can cause infections like ___ but can also cause ___.
S. aureus; urinary tract infections (UTI)
How are coagulase negative staphylocci usually introduced to the body?
breaks in skin especially in immunocompromised individuals
Note
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