Bacterial Diseases Pt. 1 (Gram + Cocci)

Strep 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