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77 Cards in this Set
- Front
- Back
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What are the meaning of these words?
Abscess Cellulitis Emesis Folliculitis Desquamation Hemotogenous Nosocomial |
Localized collection of pus
Inflammation of connective tissue Vomiting Inflammation of hair follicles Inanimate objects that can transfer a diseae Shedding of skin Blood produced/transmitted Resulting from Hospital stay |
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Give 8 traits of staphylococcus?
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Faculative anaerobe
Non-motile Gram possitive Cocci Number one reason for noncomial infection Salt tollerant Common component of normal human skin flora Catalase positive Coagulase positive |
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What does Coagulase do?
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Cause blood to clot by allowing fibrogen convert to fibrin
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What does catalase do?
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functions to catalyze the decomposition of hydrogen peroxide to water and oxygen
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What are the two clinical relevant staph?
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S.aureus and S.epidermidis
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What is the Coagulase test?
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If place staph in test tube the fibrogen(soluble) will convert to fibrin(insoluble)
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If you leave S.aureus to long in coagulase test, you will see a false positive, why?
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S.aureus has staphylokinase and dissolves fibrin
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What is the most common staph that is coagulase positive?
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S. aureus
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What three surface proteins are prevelant on Staph?
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Coagulase
Protein A- binds constant region of many antibodies MSCRAMM-microbial surface components recognizing adhesive matrix molecules |
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What helps adhesion in staph?
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Teichoic acid
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What provides protection from phagocytosis and along with teichoic acids aid in adhesion?
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Capsule/slime layer
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What toxins come from S.auerus?
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Alpha
Gamma and Panton-Valentine Beta Superantigens |
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What is a result of the S. aureus toxin superantigen?
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The superantigen produces TSST
The superantigen is also Mildly heat stable, protease resistant – may cause food poisoning, strong emetic |
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What forms calcium channels in cell membrane?
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Gamma and Panton-Vaentine
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What toxin from S.auerus forms a hexameric structure in cell membrane, can induce apoptosis?
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The alpha toxin (ionophore)
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What are the requirements for TSST-1?
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Seems to require high O2 and neutral pH for expression
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What does the beta toxin do in S.auerus?
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Beta toxin is a Sphingomyelinase
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What gives Staph there penicillin resistance?
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Beta lactamase
Transpeptidase, mecA gene produces transpeptidase protein which is highly tolerant to beta lactams -mecA confers resistance to methicillin/oxacillin |
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What are some enzymes found s.aureus?
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Catalase
Coagulase Fibrinolysin Lipases Nucleases Hyaluronidase |
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Staph aureus grows on _______ and produce _______ and _____ stable toxin
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Food
Heat and protease |
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Define these terms:
Impetigo Folliculitis Furuncles Carbuncles |
superficial infection, starts as red spot, develops into pus filled vesicle
infected hair follicle, some pus bigger, more puss-filled folliculitis bigger deeper furuncles, reaches subcutaneous tissue – may spread to blood from this stage. |
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What toxin is linked to give TSST, seen heavy in menstrating women?
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TSST-1
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What are the symptoms of TSST?
How do you treat TSST? |
severe fever (over 102), myalgia, malaise, vomiting, diarrhea, sore throat, hypotension, diffuse rash, lightheadedness and other mental signs. Hyptotension and Rash which will lead to desquamation are very indictative of TSST.
Treated by removing/debriding source of infection and, IV fluid and antibiotic administration. This replaces fluids lost by vomiting/diarrhea and helps raise blood pressure. Hypertensives (epinephrine, etc) may also be given. |
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What are these terms:
Endoccarditis Osteomyelitis Septic arthritis |
Infection of heart
Infection of long bones Joint infections |
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What inhibits Necrotizing fasciitis
and what bacteria causes the disease? |
Oxygen inhibits
caused by Streptococcus pyogenes, but mixed infection of S. pyogenes and S. aureus are often found, and S. aureus alone may cause as well. --Usually from a predisposing condition such as diabetes |
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What are some characteristics of streptoccoucs?
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Gram positive cocci
Catalase negative Faculative anaerobe Doesn't grow in clusters like STAPH!!!, grows in chains or pairs |
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What are the three strep groups?
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pyogene Group A
agalactiae pneumoniae |
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Pyogene is a strepcoccus in what group?
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Group A Strepptoccocus
GAS |
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Give some general descriptions of GAS?
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It is beta hemolytic
It has many was to avoid immune defense Most common strepcoccus Frequently encapsulated |
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What are the four ways that GAS can avoid the immune system?
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C5a peptidase
M proteins M like proteins Capsules composed of hyaluronic acid |
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What is the purpose have having Capsules composed of hyaluronic acid for an immune defense for strep?
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They prevent phagocytosis
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What type kind of infections can strep cause?
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Pharyngitis
Necrotizing fasciitis Bacteremia Pyoderma/impetigo Erysipelas Cellulitis |
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What are the toxins and enzymes produced via strep?
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Streptokinases
-Thrombolytic – cleaves plasminogen, releasing plasmin. Plasmid cleaves fibrin, causing clots to dissolve Streptolysin O-oxygen liable --Immunogenic – presence of Anti-streptolysin O antibodies is diagnostic Streptolysin S-oxygen stable --Responsible for β hemolysis |
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What are two GAS sequelae (an aftereffect of disease, condition, or injury)
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Rheumatic fever and Glomerulonephritis
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What is Rheumatic fever?
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An immune reaction against heart tissues, associated with pharyngitis
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What is glomerulonephritis?
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Deposition of immune complexes in kidney, associated with pharyngitis and skin infections
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What streptoccous is fastidious growth, colonies will show a distinct dimpled shape, grows in pairs and is USUally,can be beta, alpha hemolytic?
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Pneumoniae
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What disease can be given by Step. pneumoniae?
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Pneumonia, meningitis and bacteremia
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What is Erysipelas?
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A type of skin infection
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What are the types of pathogenic mechanism with S.pneumoniae?
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Pneumolysin
-binds cholesterol in cell membrane and forms pores -Activates complement -Degrades hemoglobin (alpha hemolytic) Secretory IgA protease -prevents trapping of bacteria in mucus Hydrogen peroxide production -Toxic to Staph aureus Capsule -Prevents phagocytosis - |
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Staphollococcus is resistant to many mechanisms, describe some of its tools it uses to fight eradication?
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Modified transpeptidases (resistant to beta lactams)
Efflux pumps Beta Lactamases |
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What is MRSA and how is it treated?
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MRSA is Methicillin Resistant Staph Aureus and it is treated by using Vancomycin. This is done because the gene that provides resitance to methiclin also provides resistance to numerous other beta lactams (gene PBP2a)
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How do beta lactams work?
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inhibit the growth of sensitive bacteria by inactivating enzymes located in the bacterial cell membrane, which are involved in the third stage of cell wall synthesis.
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Is PBP2a a transpeptidase or a beta lactamase?
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A transpeptidase
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Besides the Vancomycin providing treatment against MRSA, what else can be used?
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Zyvox
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What is more virulent strain, the CA or HA of MRSA?
ca-community acquired HA-Hospital acquired |
Ca
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What are some similarities the Strep agalactiae group B has in common with group A?
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They grow in chains BUT!! they are longer
ALSO THEY ARE LESS HEMOLYTIC |
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Who are succeptible to group b strep?
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Elderly immune compromised-result in bacteremia, pneumonia, bone and joint, soft tissue
Acquired at birth-result in bactermia, pneumonia, meningitis |
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Fill in:
Strep Hemolysis Pyogene____ Agalactiae ___ ___ Pneumoniae ____ |
Beta
Weak beta Alpha |
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What is Coagulase and Catalase positive?
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Staph
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What is coagulase and catalase negative?
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Strep
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What does coagulase do?
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Reacts with prothrombin in the blood. The resulting complex is called staphylothrombin, which causes blood to clot by converting fibrinogen to fibrin.
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What is catalase?
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Turns hydrgoen peroxide into water and oxygen
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What is:
Grapelike clusters in culture Yellow/gold colored in colonies Coagulase and catalase positives Beta hemolytic |
S.aureus
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What is:
weak beta or Alpha hemolysis Culture shows pairs diplococci, capsule Dimple colonies Sensitve to optochin, resistant to bacitracin |
S.pneumoniae
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What is:
Strong beta hemolysis Sensitive to bacitracin, resistant to optochin Cultures in long chains Serological test for group A antigen |
S.pyogenes
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What are spore forming gram positive rods, faculative anaerobe?
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Bacilli
The two common are Anthracis Cereus |
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Anthrax is neutral on alkaline soil and is usually found in area with what?
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Found in areas of floods, Found in lower Mississippi valley in U.S
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When does sporulation occur in anthrax?
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When exposed to atmosphere, less CO2 and more 02
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B. Anthracis have these characteristics:
NON _____ Catalase _____ CO2 induces expression of capsule and toxins = ___ host O2/low CO2 induces germination= ____ host Capsule is made of poly D _____ long, thin gram positive ____ |
hemolytic
Positive In Out Glutamate Rods |
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Describe how one gets anthrax through inhalation?
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Inhale
Goes to alveolar Phagocytosis in alveolar macrophages Macrophage moves to lymph Germination of Anthrax Anthrax leaves macrophage and infect lungs and other what nots |
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Describe the two stages of Anthrax infection?
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Non specific symptoms – fever, chills, headache, nausea, malaise, abdominal and chest pain. May be followed by transient improvement.
‘Fulminant’ stage: Sudden fever, shortness of breath, sweating, shock, dementia (can spread to nervous system), ~50% develop bleeding in brain – aka hemorrhagic meningitis |
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What are the two locations of Anthrax disases?
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Cutaneous
GI |
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What Bacilli is:
Ubiquitous IN SOIL Weakly beta hemolytic in sheep agar Non fastidious growth requirements Only rarely causes infections, usually in immune compromised |
Cereus
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In B.cereus, there are Two forms of food poisoning
enemitic and diahreha, describe? |
Diarrheal form – ingestion of spores and germination in GI tract, production of heat-labile enterotoxin
Emetic – caused by germination on food and production of heat stable enterotoxin Intoxication - short duration (~10 hours), abrupt onset Starchy foods – rice, potato flakes Meats and vegetables Infection (not an intoxication) ~24 hour course |
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What does lable mean?
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Open to change; adaptable
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How does one treat anthrax?
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Use ciproflaxin
Also passive immunization is good |
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What is the most deadliest way to obtain anthrax?
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Inhalation
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How could someone die from anthrax infection even if antibiotic is effective against the bacteria?
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Toxins can build to lethal levels quickly, patient can die even if antibiotic treatment is effective against bacteria.
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What makes survivors of anthrax resilliant to a later infection?
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Protection gained through antibodies specific for toxins (particularly PA) as well as poly D glutamate
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What is used for the vacination of anthrax?
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The sterne strain (missing plasmid for capsule formation)
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What is the target for the sterne strain and what process is used to make the vaccine?
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PA is antigenic target, but will also include other soluble bacterial proteins, including other toxin factors
Cell-free filtrate of Sterne strain i.e. cells are grown, the culture is then filtered and denatured. Gives a heterogenous and largely undefined mix of proteins, but should contain significant amount of toxoid. |
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What are the toxins in anthrax?
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B subunit(used for cell binding)
A subunit (Two different kinds, two names) -----Three proteins, two toxins |
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What does the PA (Protective Antigen) do?
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Binds host cellular receptor, undergoes cleavage, inserts into membrane as a heptamer. Allows Edema Factor or Lethal Factor into cell
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What does the LF(Lethal factor) accomplish?
-protease, cleaves MAP kinases |
Lethal factor seems to account for much of the impaired immune response to Anthrax. Cleavage of MAP kinases interferes with signalling pathway of TLRs. Dendritic cells fail in fully activating T cells. Activation of Macrophages through TLRs leads to apoptosis, dormant macrophages survive unless activated later. There are likely many other effects in different cells from Lethal Factor.
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What does edema factor (EF) accomplish?
--adenylate cyclase activity (increases cAMP) |
Increase of membrane permeability
Inhibition of phagocytosis by macrophages and neutrophils |
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Finish
PA + EF= PA +LF= |
PA + EF = Edema Toxin
PA + LF = Lethal Toxin |
