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53 Cards in this Set
- Front
- Back
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How is corynebacterium diptheria transmitted? And in what situations?
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C. Diptheria is transmitted through droplets, direct contact w/ cutaneous infections & occasionally fomites.
More frequent in developing countries w/ poor public health infrastructure |
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What is the local effect of DT?
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Causes pseudomembrane - which is a gray fibrous exudate composed of bacteria, WBCs, & necrotic mucosa.
This may lead to airway obstruction |
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Why is the pathology of DT called pseudomembrane?
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Because no epithelial cells are present, rather it is all fibrin & PMNs that make up the "membrane"
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What is the local effect of DT?
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Causes pseudomembrane - which is a gray fibrous exudate composed of bacteria, WBCs, & necrotic mucosa.
This may lead to airway obstruction |
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What toxins does Corneybacterium Diptheria secrete? What are the MOA?
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it is an AB toxin
Secreted -> binds cell and enters via endocytosis into vacoule -> A (of AB) portion released into cytoplasma -> A portion ADPR the EF2 making it inactive -> tRNAs cannot be brought together to form proteins. (Protein synthesis inhibitor) |
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What are the pathogenic steps in DT pseudomembrane formation?
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DT is endocytosed into a vacoule which releases DT into cytoplasma to cause mucosal cell death which recruits PMNs & fibrin that form the pseudomembrane layer. DT may then enter the blood to causes distant issues.
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How does Listeria Monocytogenes invade and spread? Which pathogen is it similar to?
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Internalin stimulates reorganization of host cytoskeleton -> endocytosed in a vacoule -> LLO lyses vacoule to release Listeria into cytosol -> takes charge/disrupts host cytoskeleton -> protrude into adjacent cells (spread)
Similar to shigella movement |
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What is the Bacillus Anthracis morphology?
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Large gram (+) rod in chains
Aerobic non-motile protein capsule Spore-forming |
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What are the virulence factors of Bacillus Anthracis?
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Spores germinate -> protein capsule antiphagocytic -> secretes potent exotoxin (3protein complex) -> enters, converts ATP to cAMP -> edema & inhibits PMN -> cell death
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How can a bacterium produce a toxin as potent as diptheria toxin without self destructing?
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DT acts on host EF2 and host ribosomes. Host ribosome machinery is different from bacterial.
Recall Ribosomal Subunits 30s & 50s = bacteria 40s & 60s = human |
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How does the ability of Bacillus Anthracis to produce spores relate to its potential for biological warfare?
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DMARKS
spores have Dipicolinic acid & Keratin Metabolically quiescent Autoclave to kill (121c for 15min) Resistant to chemicals Stable for long periods of time |
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How is the listeria monocytogenes infection acquired? In adults? In neonates?
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Adults - Food causes inoculaton (unpasteurized milk, ready to eat foods, cured sausages, Nacho cheese, cole slaw, cantaloupe) of the human resovoir in intestines.
Neonates - infection may cross placenta, contamination from vaginal canal during birth |
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How does corynebacterium diptheriae produce disease without invading host tissues? What is the clinical manifestation of this?
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Bacteria does not invade rather it secretes DT which is an AB toxin that binds to and inhibits the synthesis of proteins in the cell through the EF2 ADPR MOA.
This creates a gray fibrous exudate (pseudomembrane) which may block the airway elaborate on tropism and disease |
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How does a corneybacterium diptheriae infection clinically present?
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Local disease - pseudomembrane formation -> airway obstruction
Systemic - Myocarditis, polyneuritis |
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How is the Corneybacteria diptheria vaccine created? How is it prophylactically used?
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The vaccine is a Ab against the DT. It utilizes a diptheria toxoid that is produced from Formalin treatment that damages the B portion of the AB toxin.
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What are the steps used by listeria monocytogenes to invade & disrupt adults cells?
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Listeria monocytogenes is ingested -> penetrates GI mucosa -> Invades phagocytes -> grows/replicates intracellularly -> becomes bacteremic -> tropism for neural = meningitis
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What are the steps used by listeria monocytogenes to invade & disrupt fetal/neonate cells?
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Travel through placenta results in disease presenting earlier then if puerperal (during pregnancy). Invades cells via internalin then LLO releases microbe to take over cytoskeleton to invade adjacent cells.
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What bacterial features of Listeria monocytogenes enhance its ability to be transmitted to humans?
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Internalin protein that allows rearrangement host cytoskelton to endocytose
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What are the steps of Bacillus Anthracis causing antrax in a bioterrorism manner?
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Spores are stable and can produce "clouds" that cause the respiratory form of disease. Recall fever, dyspnea, dry cough & 100% mortality
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What is a unique property of Listeria Monocytogenes?
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It is the only gram (+) bacteria WITH endotoxin
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What are the symptoms of listeriosis?
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Meningitis & sepsis in neonates or immunocompromised
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How is neonatal listeria monocytogenes infection acquired?
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generally during childbirth from an infected vagina.
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What is unique about the bacillus anthracis capsule?
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it is composed of protein rather than polysaccharide. This is the only medically important bacteria to do this.
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Pneumonic for all of the bacteria that produce cAMP:
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"CAMP"
Cholera Anthrax E (which is really a sideways M). Coli Pertussis |
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What is the species of corynebacteria that are on the skin flora? Do they cause disease?
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Diptheroids are a normal part of skin flora.
Only DT+ corynebacterium cause disease |
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What is the shape of corneybacterium diptheria?
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pleomorphic, club shaped gram (+) rods
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Why is it only carnebacteria diptheria that causes disease? How is it controlled?
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Bacteriophage brought the DT producing genes. Ony bacteria that are lysogenic for these Beta prophages produce disease.
Expression of DT is controlled by DtxR (repressor) |
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How does Corynebacteria Diptheria have systemic effects? What are they?
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C. Diptheria does NOT invade. Rather it causes local damage and may secrete the DT toxin into the blood.
Systemically DT B unit may bind heart/nervous tissue to cause: Cardiac - arrhythmia & myocarditis Nervous - cranial & peripheral nerve palsy |
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Which lab tests are useful to confirm a clinical suspicion of corneybacterium diptheria?
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Diagnosis is mostly clinical, no labs routinely
Able to do throat culture using SPECIAL media Stain might show Gram + rod, aerobic, that is "Chinese" letter shaped |
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How is pseudomembrane and systemic DT treated?
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Antitoxin - may prevent any systemic hear/neuro sequelae. Would probably have little effect on the local damage.
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Do we see Diptheria in AZ?
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Yes, generally with unimmunized groups: immigrants/migrants/religious groups (select)
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Should we scrape the Pseudomembrane produced in corynebacteria diptheria to remove the toxin secreting microbes?
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No, it may cause bleeding & further toxin spread.
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How does neonatal Listeriosis compare to GBS?
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????????????
1 slide on .pdf comparing it somewhat |
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What unique aspect makes Listeria dangerous? What makes listeria monocytogenes appear in sausages and ready to eat foods?
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Ready to eat foods because it can grow at refrigerator temperatures
Sausage is packaged in animal intestine... (unpasteurized milk, ready to eat foods, cured sausages, Nacho cheese, cole slaw, cantaloupe) |
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What are the spore forming microbes we have learned?
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Bacillus Anthracis
Clostridium Perfringes Clostridium Tetani B Cereus Clostridium Botulinum Coxiella burnetti All are GPR but NOT all GPR form spores |
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What is the purpose of LLO in listeria?
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Listerolysin O - pore forming complex
It releases microbe from the vacoule after it is endocytosed via the internalin protein. |
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How is listeria monocytogenes diagnosed? and prevented?
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1. Diagnosis is made by stain that is Gram + rod, with tumbling motility. &
2. Culture on routine blood culture. 3. Prevention is through public health measures?? |
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How does Bacillus Anthracis enter the body and what disease does each cause?
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1. Cutaneous abrasion - 2-5days malignant pustule -> hemorrhage/necrosis/pustules = black eschar
2. Ingestion - lesions resulting in dysentery 3. Inhalation - 1-5days. Spores germinate in nasopharynx, bacteremia then toxin secreted respiratory distress & cyanosis (fever, dyspnea, dry cough)then 100% mortality |
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How is anthrax spread? What populations are at risk?
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"humans get in the way of this animal disease"
Spores are found in animals (goat/cow/herbivore) -story about goat skin w/ dormant spores -Eradicated developed nations -Not spread human2human Another spread is via bioterrorism spread of spores. |
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What is woolsorters disease?
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bacillus anthracis caused by spores on sheep hide and the small quarters they are located in.
Anthrax is associated w/ natural imported animal hides |
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How is b. anthracis diagnosed?
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based on bacteriology:
Gram (+) rods found in sputum or CSF Routine culture (but difficult to dx because uncommon) - Gram (+) rod in chains, with protein capsule, aerobic & nonmotile serology |
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Can B. Anthracis be prevented?
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Prophylactic tx is w/ Ciproflaxcin
Military & russia have vaccines - either Inactivated toxin or live attenuated respectively |
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What is common between C Diptheria, L. Monocytogenes, B. Anthracis?
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all gram (+) rods
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Corynebacterium Diptheria mnemonic
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ABCDEFG
Adp ribosylation Beta-prophage Corynebacterium Diptheria Elongation Factor 2 Granules |
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What are some clinical manifestations of C. Diptheria?
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"bullneck" - cervical adenitis & edema
Paralysis - soft palate, occulomotor... |
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Where does pseudomembrane in DT appear?
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pharyngitis, tonsilitis.
gray exudate patches on uvula, tonsils, sof palate, pharyngeal wall |
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Which form of anthrax would I want?
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?
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Are gram + rods a common cause of disease?
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No
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What are symptoms of 1y infection by listeria monocytogenes?
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Often occult, possible gastroenteritis.
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What is the at risk populations for Listeria Monocytogenes?
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Elderly, Newborns, Immunocompromised
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What is the cardiac complication caused by C. Diptheria?
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Diphtheritic myocarditis. Necrosis and inflammation are present in this section of myocardium from a fatal case of diphtheria.
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What is the overview of Listeriosis?
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Listeriosis overview. Listeria monocytogenes is ingested in dairy and meat products. It invades through the intestinal mucosa producing a bacteremia. The organisms may seed elsewhere particularly the brain (meningitis) or the fetus in pregnancy.
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What is the actin Tail? What pathogen is it found in?
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Listeria monocytogenes. This cell is propelled through and soon beyond the cell by the actin tails formed behind it
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