micro review #2 Flashcards
is there a toxin associated with B. burdorferi?
no
what are Stx-1 and Stx-2 encoded by?
bacteriophages
H pylori spread: mechanism for host damage:
spread: fecal-oral mechanism for host damage: grows in the mucosa of stomach, releases ureases which converts urea into ammonia—> increases the pH of the stomach, which increases the survival of H pylori It also injects CagA into epithelaial cells which increases inflammation —> erosion of tissue —> peptic ulcers
B. bacilliformis reservoir: vector: diseases:
B. bacilliformis reservoir: ? vector: Lutzomyia verrucarum (sandfly) diseases: carrion’s disease, acute oroya fever, chronic verruga peruana
EHEC spread: mechanism of damage: local impact: systemic impact:
EHEC spread: zoonotic (from GI flora that gets into meat/is used in fertilizer/ gets on vegetables) mechanism of damage: Systemic toxin release EHEC adheres to cells in the colon —> shigatoxins (stx) 1 and 2 which depurinates rRNA, blocking protein synthesis in host cells. Locally: GI inflamation and hemorrage Systemically: endothelial damage, hemolytic uremic syndrome (lysis of RBCs/damage to kidneys)
Tularemia and Francisella tularensis source: spread: 3 manifestations:
source: tick deerfly (which can bite humans directly, or bite rabbits– lawnmower!) spread: local replication (skin) —> drain into a lymph node 3 manifestations: 1. ulceroglandula tularemia (painful ulcer, lymphadenopathy) 2. Typhoidal tularemia (sepsis, hepatosplenomegally) 3. pneumonic tularemia (pneumonia associated with inhalation of org– lawn mowers)
three different tests for Syphilis and when are they used
- Darkfield– over 95% effective for primary syphilis. not used for others 2. Non-Treponemal- good for secondary and latent syphilis, but it wanes over time 3. Treponemal– ok for primary, better for secondary, latent and tertiary, but once positive, always positive!
aschoff bodies, what are they and what disease are they associated with?
aschoff bodies (little foci of inflammatory cells in tissue with rheumatic fever that don’t include bacteria) this is associated with rheumatic fever (S. pyogenes)
Adult foodborne botulism entry: manifestations: prevention:
Adult foodborne botulism entry: toxin ingested manifestations: flacid paralysis prevention:propper canning, proper reheating food (boiling for more than 10 minutes)
anthrax shape: gram stain: spores?
shape: bacillus Gram stain: positive Spores: present and seen as empty vacules withing the bacillis
why aren’t Abx recommended for people with EHEC?
beause damage to the bacteria (caused by Abx) leads to lytic virus and toxin production
pneumonic plague manifestation
fulminant hemorrhagic pneumonia
C. difficile, EHEC, Salmonella, Shigella, C jejuni and Y enterocolitica all cause diarrhea via ________? whereas ETEC and v. cholerae causes what type of diarrhea?
the big group causes diarrhea via tissue damage, whereas ETEC and v cholerae are non-invasive secretory diarrheas
pneumococcal pneumonia who does it affect: spread: manifestations: bacteria description:
pneumococcal pneumonia who does it affect: older adult with risk factors (lung disease, smoking, respiratory virus) spread: droplets from person to person manifestations: acute onset, fever, pleuritic pain, cough, “rust” colored sputum with bacteria description: GPC in pairs
B. quintana reservoir: vector: diseases:
B. quintana reservoir: ? vector: pediculus humanas (body louse) for trench fever diseases: trench fever, bacillary angiomatosis, endocarditis
manifestations of cutaneous anthrax
papule —> eschar —> resolution
where is S pyogenes and s. pneumoniae normally found in the body
pharynx
scarlet fever results from which bacteria? manifestations: etiology:
results from: S. pyogenes etiology: erythrogenic exotoxin
what tests are available to diagnose TB by looking for immune response?
- purified protein derivative (PPD) skin test, IFN-y release assays (IGRA)
path of Yersinia pestis/plague
xenopsylla cheopsis (flea) bites human (or rat does) —-> bacteria spread to lymph node —> MASSIVE inflammation —> either bubonic plague, septicemic plague or pneumonic plague
treatment for diptheria?
antitoxin and antibiotics
localized stage of lyme’s disease timing: site: manifestation: test:
- localized timing:Days site: skin manifestation: erythema migrans test: clinical diagnosis
where is S. aureus normally found in the body?
nose and skin
infant botulism entry: manifestations: prevention:
infant botulism entry: bacterium in the GI manifestations: flacid paralysis – think of the baby slouched on the mother with eyes closed because he can’t keep his eyelids open! prevention: avoid honey < 1yo
tetanus entry: manifestation: prevention:
tetanus entry: bacterium in wound manifestation: rigid paralysis (characteristic “sardonic smile”– bottom lip is curled upward, but top lip is still pulled straight) and autonomic dysfunction (HR is irregular and BP is unregulatable) prevention: vaccination (which includes the toxoid) and wound care
adult wound botulism entry: manifestations: prevention:
entry: bacterium in wound manifestations: flacid paralysis prevention: wound care
treponemal test for syphilis tests for…
the specific Ab against treponemal pallidum
which 4 bacteria cause infectious diarrhea through invasive mechanisms?
- salmonella 2. shigella 3. c. jejuni 4. y. enterocolitica
Bubonic plague mnifestations
fever, massive lymph node (bubo) which can break through the skin, +/- skin lesion at site of infection
Bartonella gram stain: shape: slow or fast growing: pathogenesis (2) diagnosis by:
Bartonella gram stain: positive shape: bacilli slow or fast growing: slow pathogenesis (2): granuloma w/cat scratch disease (occurs in kids), vascular endothelial proliferation —> angiogenesis in bacillary angiomatosis (in people who are immunocompromised) diagnosis by: serology or PCR of tissue. culture is insensitive and slow
Pseudomona aeruginosa: who does it affect: what bacteria does inside the host: bacteria description:
Pseudomona aeruginosa who does it affect: compromised hosts (people w/CF, hospitalized or ventilator pt) bacteria in the host: forms biofilms, aggregates of bacteria in EC matrix bacteria description: non-enteric gram positive bacillus, resistant to Abx and host defenses
ETEC and v cholerae mechanism: fever: leukocytosis: PMN in stool: Blood in stool:
ETEC and v cholerae mechanism: toxins cause ion and water secretion fever: NO leukocytosis: NO PMN in stool: NO Blood in stool: NO
4 mechanisms of tissue damage for S aureus
- alterations in coagulation due to coagulase 2. enzymatic digestion of tissue via hyaluronidase, fibrinolysin, Lipases, DNAase 3. Cytolysins 4. Pyogenic inflammation
how does B. burgdorferi cause damage?
it spreads and recruits damaging immune/inflammatory response
Diptheria description of the organism from a culture: manifestations: how is the damage caused:
organism: irregular club shaped organism– scattered like a torn down picket fence manifestations: fever, malaise, gray membrane, cardiac and neurological manifestations damage: the organism stays in one place, but the A-B toxin spreads, causes ADP ribosylation of EF-2 and blocks protein synthesis
3 bartonella infections
- B hensalae 2. B quintana 3. B bacilliformis
C difficile: mechanism of tissue damage: fever? leukocytosis? PMN in stool? Blood in stool?
C difficile: mechanism of tissue damage: local toxin causes cell death (cytotoxic) fever: yes leukocytosis: yes PMN in stool: yes Blood in stool: yes
3 Infections that affect the soles of hands and feet
- secondary syphilis– scaly rash 2. RMSF 3. TSS—> desquamation of the hands and feet
list the 4 skin and soft tissue infections caused by S. pyogenes
- impetigo 2. erysipelas 3. cellulitis 4. necrotizing fasciitis
describe the immune response to MTB (mycobacterium tb) in someone who has reactivation
- initially MTB proliferates unchecked within phagosomes of macrophages (the immune system has to ramp up to stop it) 2. the TH1 response makes macrophages competent to kill TB (via IFN-y), leading to latency and granuloma formation the failure of the TH1 response leads to reactivation TB
How do you distinguish between Enterococcus and Group D strep given that they’re both GPC, catalase negative, and gamma hemolytic?
bile esculin and high salt test: Enteroccocus has positive growth on both, Group D. Strep can grow on bile esculin, but not in high salt
B burgdorferi is associated with which disease?
Lymes disease
which bacteria(s) cause infectious diarrhea via the following mechanisms: secretory diarrhea because of toxins (2): tissue damage from systemic toxins (1): tissue damage from local toxins (1): tissue damage from invasive pathogens (4):
which bacteria(s) cause infectious diarrhea via the following mechanisms: secretory diarrhea because of toxins (2): ETEC and V. cholerae tissue damage from systemic toxins (1): EHEC/STEC tissue damage from local toxins (1): C diff tissue damage from invasive pathogens (4): shigella, salmonella, C. jejuni, Y enterocolitica
Tuberculosis how is it spread? what are the two pathways it can take and symptoms of each
tuberculosis spread: airborn from person to person 1) if you have a strong immune response, then the TB will be asymptomatic, and the MTB will persist in a latent phase. If you are ever immunocompromised there can be reactivation of TB leading to fever, night sweats, weight loss, cavitation and cough and extrapulmonary problems 2) if you hae a weak immune response, you can get progressive primary TB which is confined the the lungs and looks like typical lobar pneumonia 2) If you have a weak immune response, the it will progress to primary TB and
Rocky Mountain Spotted Fever (RMSF) vector: pathogen: mode of infection: damage:
Rocky Mountain Spotted Fever (RMSF) vector: Dermacentor tick pathogen: R. rickettsii mode of infection: R. rickettsii infects vascular endothelial cells and then spread directly to new cells via their actin polymerization (like Lysteria monocytogenes) damage: inflammation and endothelial damage —-> increased permeability and coagulation —> thrombosis, hemorrhage and edema —> organ damage/shock which can be legal
how do you distinguish between GPC in chains that are catalase negative and alpha hemolytic (s. pneumoniae vs viridans strep
Optochin susceptibility: S. pneumoniae is sensitive, and viridans are resistant
mechanism of anthrax toxin
the anthrax toxin hasone B and two A groups 1. B binds to cell 2. A portion leaves 3. the b portion multimerizes 4. the A portions (edema factor or lethal factor) binds 5. the multimer toxin is endocytosed 6. Edema factor leads to more cAMP, causing H20 efflux/edema, lethal factor inhibits MAPK kinase which leads to cell death
source/spread of plague and yersinia pestis
xenopsylla cheopsis (a flea) that can bite humans directly or spread it to rat that then bite humans