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129 Cards in this Set
- Front
- Back
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Portal of Entry
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site where a pathogen must enter to cause disease / infection to host
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What are the 2 types of mode of transmission?
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indirect / direct
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What is direct transmission?
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direct contact and respiratory droplets
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What is indirect transmission?
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this form of transmission requires a vehicle (fomites / vectors)
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Fomite vs Vector
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fomite = non-living object used to transmit pathogen
Vector = living organism used to transmit pathogen |
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What are virulence factor
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molecules expressed and secreted by pathogens that enable them to: attach, colonize, evade, damage
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What is the pathway a pathogen takes?
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entry > attach > evade/depress immune > produce toxin
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How does a pathogen attach?
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attachment protein / cilia / flagella
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What does Treponema pallidum cause?
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spyhilis
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What is the latent phase of Treponema pallidum?
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2ndary
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What does chlamydia trachomatis responsible for?
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nongonococcal urethritis; NGU
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How does syphilis move?
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axial filaments; between inner & outer membrane
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What causes Rocky Mt. spotted fever?
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Rickettsia rikettsiae
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What is a hallmark symptom of spotted mt. fever?
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Rash on extremidies (feet / palms of hands) ; severe headaches
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What's the smallest organism we have covered so far?
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Chlamydia > rikettsia
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What disease is not an acute but chronic?
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syphillis
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What is the organism responsible for the plague (black death)?
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Yersinia pestis
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When & where was the last pandemic of plague?
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Hong Kong 1894
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What is the reservoir & vector for the plague?
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Reservoir - rats
Vector - rat fleas |
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How does one get primary pneumonic plague?
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From a person with 2ndary pneumonic plague
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What is 2ndary pneumonic plague?
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Someone who origially had bacteria in buboes that migrated to lungs
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Of the 2 types of plague which is passed from man-man?
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pneumonic plague; super contageous; main cause for epidemics
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What is the name of the plague in the Southwest region of the US? Also the reservoir?
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Sylvatic plague; on parie dogs (desert rodent)
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Where is the hot zone for R. rickettsiae?
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NC, SC and some middle states
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What is the #1 std in US?
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C. trachomatis ; nongonococcal urethritis (NGU)
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How is Vibrio cholerare treated?
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Replinish with water ASAP
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What is the tell-tell sign of V. cholerae?
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Rice-water stool
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How much water can a person loose in a day with V. cholerae?
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2.5-4 gallons
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What toxin does V. cholerae produce?
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only virus infected V. cholerae are capable of producing cholera toxin
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How is Helicobacter pylori able to survive in the stomach?
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has urease which breaks down urea > CO2 + NH4
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What is the treatment for H. pylori?
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Antibiotic + pepto-bismol
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List all food infection pathogenic bacteria.
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Salmonella ; Campylobacter jeuni ; E. coli
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What's the organism the cause the #1 direaheal disease in USA?
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C. Jeuni
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What's the reservoir for C. jeuni?
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Farm animals (sheep, goat, pigs)
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Who produce transferrin?
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human in liver; binds Fe;
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what is the function of siderophores?
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bacteria produce to steal Fe off from human transferrin
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What type of bacteria produce endotoxin?
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only gram negatives (-)
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what is the chemical nature of endotoxin vs exotoxin?
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Endotoxin= LPS
Exotoxin= proteins / often enzymes |
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T/F: Endotoxin are secreted from bacteria.
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F: only exotoxin; for endotoxin to be released the bacteria must have been lysed
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Which type of toxin are heat stable?
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endotoxin
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which type of toxin can be used to produce toxoid?
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exotoxin
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Between endotoxin & exotoxin which is more antigenic, so much that neutralizing antibodies may form?
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exotoxin
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Which is more toxic of the 2 (endo vs exo)
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exotoxin
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What's the 3 line of defense?
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1. human body / bacterial flora
2. phagocytosis 3. acquired immunity |
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Quorum sensing
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method for bacteria to talk to one another through the gradient changes
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2 types of quorum sensing
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AI-1= very specific to species; tell # of species members
AI-2= less specific to tell the location of others; all bacteria understand this |
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Where can resistance genes be found?
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on plasmid since they are not house keeping genes
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Who created antibiotics?
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Alexander Fleming 1928; penicillium
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What does antibiotic target and what type of immunity is it considered to be?
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target cross-linking / some may interferes against metabolism; artificial
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Briefly describe the cell mediated pathway.
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T-cell get stimulated by antigen > lymphokines + macrophages > activated macrophages
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Function of precipitin?
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target toxin protein by binding to toxin at its active site to neutralize toxin
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what does bacterial lysins do
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activate by o-antigen to start up complement system; already exist in blood; pre-made
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selective vs differential media
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selective= select for a specific group
differential= both grows but can be differentiated on this media |
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What is the pathogen that causes common food poisoning in the USA?
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S. Aureus
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What the incubation period for S. aureus?
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1-6 hours
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What is the duration of S. aureus poisoning?
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24 hours
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Which Staphylococcus is part of the normal flora?
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S. epidermidis
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Describe the 3 different types of hemolysins
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alpha: partially lyse cells, not complete; may produce H2O2 to see green tint in medium
beta: completely lyse cells gama: do not have hemolysins |
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How can Streptococcus pyogenes spread?
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Direct , indirect and respiratory droplets
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What is an important disease that is cause by S. pyogenes?
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scarlet fever; rheumatic fever
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What is the key symptom of scarlet fever?
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strawberry tongue; rash all over body; fever of 104+
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what is rheumatic fever?
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damage to heart valves by antibodies due to similarity to protein M from S. pyogenes
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What is the key symptom of rheumatic fever?
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heart mummer
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what must have happen for scarlet/ rheumatic fever to occur?
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must have Strep. throat first
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What's another requirement that the pathogen must need to cause scarlet fever?
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bacteria must have been infected with virus and had its DNA inserted into the bacterial chromosome to make erythrogenic toxin
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What bacteria is responsible for causing the most common cases of pneumonia in the USA?
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S. pneumoniae
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What type of organism is S. pneumoniae?
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opportunistic pathogen
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If S. pneumoniae is an opportunistic pathogen then what tends to help it invades a host?
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influenza
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S. mutans ferments sucrose into what substance?
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lactic acid which will then degrade enamel
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List all endospore forming rods.
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Bacillus anthracis / Bacillus cereus / Clostridium botulinum / Clostridium tetnai
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Between Bacillus and Clostridium, which is obligate anaerobic?
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Clostridum
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Who is the main target of B. anthracis?
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Animals; humans is just an accidental host
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What are the different portal of entry for B. anthracis?
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wound / ingestion / inhalation
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How long does it take to kill a person after anthrax symptom show?
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1-3 days
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what is the incubation period for B. cereus?
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1-6 hours
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Is C. botulinum food infection or food poisoning?
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most of time it is food poisoning
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What does C. botulinum toxin do?
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prevent the release of acetylcholine at neuromuscular junction
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What is a key symptom of botulism?
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flaccid paralysis; double vision; death due to respiratory failure
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What is the incubation period of botulism? How long does it last?
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18-36 hours; duration = depends
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How can botulism be prevented?
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heat food for ten minutes because the botulinum toxin is teat liable
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What is infant botulism considered as?
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food infection since the spores are occupying the underdeveloped intestinal tract of the newborn
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What is the portal of entry for tetani?
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wound; must be deep enough to reduce amount O2 for toxin to begin forming
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What does tetanospasmin toxin cause?
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rapid release of acetalcholine; and may move through axon towards cns
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What are some hallmark symptoms of tetnus?
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lock-jaw / muscle contractions that does not break = trismus / Risus sardonicus = strained facial muscle
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Opisthotonus
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arching body from tetnus toxin making back bend
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How long to death with tetnus?
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1-4 days after symptoms due to cardiac arrest
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What is the treatment for tetnus?
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antibiotics + anti-toxins + surgical debridement
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How is Corynebacterium diptheriae transmitted?
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respiratory droplet / direct contact
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palisades
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diptheria cell arrangements that make it look like chinese characters ; pleomorphic ( no specific form)
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Who is the reservoir for C. diptheria?
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Human
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What is a key symptom for diptheria?
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formation of a pseudomembrane
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What type of food can you find Listeria monocytogenes?
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soft cheese & processed meats
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What is the symptoms for Neisseria Meningitidis?
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neck rigidity / severe headaches / skin eruption
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What is the distinctive shape of Neisseria?
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2 coffee bean squished together
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What does nosocomial mean?
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hospital acquired
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how to treat N. gonorrhea if resistance to penicillin G?
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increase dose
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N. gonorrohea: target / transmission /
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human pathogen ; direct contact
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Which sexually transmitted pathogen is the #1 cause of preventable blindness?
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Chlamydia Trachomatis
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what is the incubation period for Salmonella?
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12-72 hours
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What is the symptoms of salmonella?
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fever & chills = classic endotoxin (heat stable)
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What is the duration of salmonella?
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4-7 days
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which strain of E. coli is dangerous?
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EHEC
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When is the 1st case of EHEC?
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1993 at jack in the box
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What is the incubation of E. coli?
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12-60 hours
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What is HUS caused by?
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hemolytic uremic syndrome cause by the EHEC strain; blood clot in kidneys due to toxin
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Where did E. coli get toxin from?
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toxin was conjugated from shigella
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What pathogen is responsible for causing the #! pediatric kidney failure?
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E. coli EHEC
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What is the pathogen that is responsible for #1 diarrhea in USA?
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Campylobacter jejuni
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What is a distinctive symptom of C. Jejuni?
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bloody diarrhea
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C. jejuni incubation? duration?
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incubation = 2-5 days
duration = 7-10 days |
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What pathogen can target both animals and plant?
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Pseudomonas aeruginosa
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What must have happened 1st for P. aeruginosa infection to occur?
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opportunistic pathogen; vics tends to have burns or cystic fibrosis
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What type of toxin does Pseudomonas aeruginosa have?
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exotoxin A: most powerful protein inhibitor
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why is Helicobacter pylori capable of surviving in stomach with low pH?
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has urease which breaks down urea into NH4
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what is treatment for H. pylori?
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pepto bismol and antibiotics
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what is the 3 methods used to diagnose TB?
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x-ray , PPD (purified protein derivative) , acid fast test
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of the 3 methods used to diagnose TB which gives the definitive answer?
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acid fast
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how is the acid fast done?
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carbol fuchsin > acid alchohol (decolorize except TB) > methylene blue; red = positive even if 1 organism
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what is the treatment for tb?
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isoniazid + antibiotic up to a year
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List all obligate intracellular pathogen.
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chlamydia, rickettsia NOT mycobacterium tuberculosis
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what vector carries the pathogen that causes rocky mt. spotted fever?
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tick-borne typhus
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what vector cause epidemic typhus?
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body louse
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what cause endemic typhus?
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rat fleas
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what cause scrub typhus?
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chiggers / mites
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which stage of syphilis does the chanre disappear?
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2ndary stage
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what's a chancre?
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painless pimple
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what is typically seen in the 1st stage of syphilis?
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local multiplication and a SINGLE chancre
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what's the symptoms in the 2nd stage of syphilis?
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rash, patches of hair loss, painful mouth lesions
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what is the most deadly bacterial std?
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syphilis
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