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101 Cards in this Set
- Front
- Back
What does an outer membrane on bacterial cells do?
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this lipid membrane found on gram - cells prevents the passage of small molecules like antibiotics and bile salts, and allows the bacteria to survive treatment and the gut--> note that lipid enveloped viruses undergo respiratory transmission, while naked viruses are usually gut survivors, transmitted by the orofecal route
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What virus is the main cause of the common cold?
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Rhinovirus
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What 2 viruses are the main causes of the common cold?
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Rhinovirus > Coronaviruses
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What is coryza?
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nasal symptoms of the common cold
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Name a couple diseases caused by viruses that have incubation periods that last for months or more.
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AIDS
rabies |
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About how long would the incubation period be for a systemic viral infection, such as measles or mumps?
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1-3 weeks
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What medication would you use to treat Herpes?
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acyclovir
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Can Herpes cause encephalitis?
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yes
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What is the virulance factor associated with Streptococcus pyogenes?
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M protein
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What are the encapsulated bacteria?
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"Some Killers Have Pretty Nice Capsules"
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What bacteria is responsible for Scarlet fever and what is its toxin that causes most of the symptoms?
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Streptococcus pyogenes
Scarlet fever = strep throat (local infection) complicated by systemic toxemia (inflammation) as a result of pyrogenic exotoxin 25% of Strep. pyogenes are lysogenized by phage that encodes pyogenic exotoxin |
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What Penicillins have been modified to interact with gram - bacteria?
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Remember: all Penicilins end in "cilin"
"Ordinary Men Never Take 2nds": Oxacillins (Cloxacilin, Dicloxacillin, Flucloxacillin) Methicillin, Nafcillin, Temocillin -->all are part of 2nd group which means they are beta lactamase resistant Penicillin V & G are used against gram + All other Penicillins are noted for their use against gram - (particularly common are Ampicillin and Amoxicillin) |
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Would you still be able to repress a represssible operon if the repressor gene were mutated and the reporessor protein inactivated?
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Yes, because all repressible operons are also under attenuation
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What family of viruses does RSV belong to?
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Paramyxo--they form synctia
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Patient presents with cough, coryza, conjunctivitis, and bluish gray spots on buccal mucosa. What does he have?
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Measles
the 4 Cs: cough, coryza, conjunctivitis, & Koplick spots |
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What drug might you use against an Influenza flu, especially if you don't know whether it's type A or B?
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Neuraminidase inhibitors
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What is the most likely causative agent in a kid receiving Penicillin for an illness caused by beta-hemolytic bacteria?
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Streptococcus pyogenes
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What is the only membrane directed antibiotic that is specific for bacterial cells?
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Polymyxin
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If there is a mutation in the palindrome of the operator region of an inducible Operon, what will happen?
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The Operon, which would normally be repressed, would be active, since the repressor protein would not be able to bind to the operator.
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What 2 enteroviruses cause hand foot and mouth disease?
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Entero 71 and coxsackie A virus
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Are Haemophilus influenza capsulated or nonencapsulated?
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Both! Some have capsules and can travel further in the body that those that do not have capsules.
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What organism commonly causes infections in AIDS patients and might be treated with Fluconazole?
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Candida albicans
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What bacteria are acid fast?
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Mycobacteria, Nocardia, Rhodococcus
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What are you thinking when a pseudomembrane forms in the airways, obstructing airflow?
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the Strangling Angel of Death--Corynebacteria diphteria
local URT ix with systemic toxemia due to diptheria toxin (encoded by tox gene on phage genome) preventable with DTap vaccine and Tdap booster |
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What acid fast organism branches?
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Nocardia
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What are some characteristics of atypical pneumonia?
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it will be bronchial (not lobar)
little to no sputum |
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What organism is responsible for an atypical pneumonia that can be diagnosed with a cold-agglutinin serum titer?
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Mycoplasma
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What's the causative agent in a poorly immunized individual now experiencing muscle spasms?
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Clostridium tetani -- tetanus
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Patient presents with difficuty seeing, swallowing, speaking. Later has weakness in upper extremities, spreading to respiratory tract.
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Patient has symmetric descending flaccid paralysis, a symptom of food borne botulism--> caused by consumption of the botulinum neurotoxin formed by Clostridium botulinum
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IV drug abuser with wound--experiences flaccid paralysis around site of wound that is spreading away from it
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Wound botulism caused by wound contamination with the spores of Clostridium botulinum
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Infant ate honey; now can't suck, can't poop, is weak and has CN deficits. What caused this?
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kid ingested Clostridium botulinum spores which grew and produced neurotoxin in kid's intestines.
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What vaccine is particularly important for college freshmen and what does it prevent?
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Meningococcal vaccine
prevents meningitis |
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What type of hemolysis shows a zone of greening and what organism/s is it associated with?
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alpha hemolysis
caused only by normal flora streptococci exception: S. penumoniae can be normal flora or a serious pathogen |
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What type of hemolysis shows a zone of clearing and what organism would you particularly associate it with?
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beta hemolysis
bacteria with cytolytic toxins, especially Strep. pyogenes |
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What type of hemolysis do GAS, GBS, and GDS show? What is the prototypical species for each of these?
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beta
GAS = S. pyogenes GBS = S. agalactiae GDS = Enterococcus spp |
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Name a gram + diplococcus
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Strep. pneumoniae
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What is the significance of Streptococcal spp being catalase negative?
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They lack the enzyme to detoxify H2O2 and are thus anaerobes. Catalse test is used to distinguish Staph. from Strep.
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What is the major cause of neonatal meningitis?
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GBS (Strep. agalactiae) from the maternal vaginal canal
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What beta hemolytic species is never considered normal flora?
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Streptococcus pyogenes
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What is the ajor virulance factor of GAS (S. pyogenes) and how does it work?
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M protein
more than 60 serotypes functions like a capsule to inhibit complement fixation and phagocytosis |
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What 2 exotoxins does GAS possess that provide a cloud of cytotoxins (that kills WBCs) around the site of infection?
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Streptolysin O (oxygen labile--> active only in anaerobic conditions)
Streptolyisn S (think "S for oxygen Stable") |
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What is Spe and who produces it?
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Spe = pyrogenic exotoxin made by GAS (S. pyogenes) that are lysogenized by certain phages
Spe are inflammatory superantigens |
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Person with flushed cheeks and strawberry tongue. Rash spreads to extremities, trunk and causes desquamation. What's going on?
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strep throat (GAS/S. pyogenes) complicated by pyrogenic exotoxin (Spe) b/c this particular GAS happens to be lysogenized
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Person comes in with erythematous skin lesions, subcutanous nodules, and joint pain. What should you look for in history?
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a sore throat (pharyngitis) 2-3 weeks earlier--pt probably had GAS infection and now has Acute Rheumatic Fever
Need to watch heart valves |
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Pt with acute glomerulonephritis mentions that they had a skin infection a few weeks earlier. Cause?
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probably GAS--S. pyogenes infections in the pharynx or the skin can be complicated by hypersensitivity reactions and lead to AGN
Must perform serology to lab to detect anti-streptolysin O (ASO) or other |
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How do you treat a Streptococcus pyogenes infection?
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Penicillin--nearly all strains are sensitive
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Should you freak out if you find pleomorphic, club-shaped rods forming "Chinese characters" (V or L shapes) in someone's URT?
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Not necessarily.
Corynebacterium diphteriae are only pathogenic if they are lysogenized with a phage containing the tox gene for Diphtheria toxin |
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These normal flora of the mouth are known to invade the bloodstream and cause endocarditis:
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HACEK group
H= Haemophilus influenzae A = aggregati bacteria C = Cardiobacterium hominis E = Eikenella corrodeus K = Kingella |
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Moraxella catarrhalis, of the genus Neisseria, causes waht dieseases?
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otitis media in kids
chronic bronchitis in adults dz is similar to thsoe caused by unencapsulated H. influenzae |
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D factor and V factor are blood-derived products that are components of enriched chocolate agar. What grows in this special media?
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Haemophilus influenzae
It will not grow on blood agar! |
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Why must gram stains be performed on samples from sterile sits but antigen detection assays do not?
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Sterile sites don't contain normal flora. We detect specifically those antigens on pathogenic organisms.
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What is Hib?
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a vaccine against the type b capsule of Haemophilus influenzae
composed of purified type b capsular polysaccharide conjugated to protein the capsule of H. influenzae is its major virulance factor, though there are many different types and not all strains have one at all (they are non-encapsulated and thus non-typable) |
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What normal bacteria of the nasopharynx can spread locally to cause the following invasive infections?
epiglottitis cellulitis pneumonia |
H. influenzae
this is now uncommon since most such infections were caused by type b strains and most people are protected due to the Hib vaccine |
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What infections are nontypable strains of H. influenzae known for causing?
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Surface infections:
otitis media (2nd to S. penumoniae) Sinusitis Cunjunctivitis (pink eye) Chronic bronchitis, pneumonia (in debilitated adults) |
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30-yo breaks his nose. Several weeks later says he feels sick, collapses, and is taken to ED with high fever. What's going on?
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sinus trauma allowed nontypable Haemophilus influenzae to invade CNS and cause meningitis
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Bacteria with cholesterol in its membrane and no cell wall
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mycoplasma
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What bacteria will only grow slowly on special media enriched in sterols (i.e. cholesterol) and finally produces fried-egg colonies?
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mycoplasma
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22 yo comes in with walking case of bronchopneumonia. You get no growth on routine media. Likely agent? Treatment
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mycoplasma
Treat with erythromycin (targets 50S ribsosomal subunit) this atypical bacterium (no cell wall) causes atypical (walking) pneumonia and can't be treated with antibiotics that target the cell wall |
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What is the number one cause of Community acquired pneumonia?
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Strep. pneumoniae
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an organism that buds and branches
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Candida albicans--has both yeast and mold (hyphal) forms
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white patches on a newborn kid's throat
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thrush caused by candida albicans
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person with thickened, discolored fingernails and itchy rash in skin folds
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C. albicans infection
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person with lesions around mouth that are mildly disfiguring and unresponsive to medications
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Chronic Mucocutanous Candidiasis--genetically weakened immunity to Candida
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diabetic patient with urinary catheter begins to experience urgency and hematuria. what organism might you find and what's going on?
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Candida albicans ascended to kidney, causing cstitis/pyelonephritis
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A member of what genus causes whooping cough?
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Bordatella genus
(Bordatella pertussis) |
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What are agglutinogens, pertactin, PT and fimbrial hemagluttinin (F-HA)?
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components of the acellular pertussis vaccine
(PT = pertussin toxin) |
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What toxin causes increased levels of intracellular cAMP to inhibit monocyte and neutrophil activation/killing?
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Pertussis toxin, an adenylate cyclase (of Bordatella pertussis)
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What are the stages of pertussis?
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Catarrhal (mild sx but highly infectious)
Paroxysmal (whoping cough but decreasing communicability) |
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What is Tdap?
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a booster given ppl 11-64 yrs of age, mainly for tetanus but also for diphtheria and pertussis
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What might be causing ciliary paralysis in a kid with a loud, barking cough?
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tracheal cytotoxin realeased from Bordatella pertussis
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Stenotophomonas maltophilia and Burkholderia cepacia often cause what and in whom? What other organism also causes this?
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LRT (often pneumonia) in cystic fibrosis patients
Pseudomonas aeruginosa is the most common culprit |
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A teenager has a jetski accident on a lake and cuts his foot badly. Later, the wound is infected. What is the likely organism?
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Aeromonas hydophila
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A wounded soldier in Iraq gets an infection in her wound. What is the likely cause?
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Acinetobacter baumannii, found in soil and water
likely resistant to antibiotics |
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Unusal gram - organisms should be expected to display the following traits:
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affect compromised hosts (inlcuding those who have wounds)
be transmitted from the environment (soil, water, hospital, etc.) be resistant to antibiotics |
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CF patient with pneumonia--what's the cause? What's the capsule?
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Pseudomonas aeruginosa that has switched phenotypes from a slime layer capsule to a mucoid capsule.
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What is elastase?
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One of Pseudomonas aeruginosa's arsenal of exotoxins. It shifts the balance of proteolytic and anti-proteolytic enzmes in the lung to cause direct damage to lung tissue and vessels.
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wound oozing gren pus
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infected with Pseudomonas aeruginosa whose pigments lend the green color
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kid with swimmer's ear (acute otitis externa)
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dermatitis of the ear canal and skin caused by Pseudomonas aeruginosa
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How would you treat a CF patient with copious sputum production as a result of pneumonia?
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Pseudomonas aeruginosa is notoriously resistant to antibiotics and the mucoid capsules protect the organism further. USe combination (2 drug) therapy including quinalones (that target nucleic acid replication)
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What is the only atypical bacteria that can cause hospital acquired pneumonia?
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Legionella (usu. pneumophila)--> while most Legionella ix are caused by serogroup 1, nosocomial ix can be caused by others
"pneumo" (lung) + "phila" (love) = loves lungs |
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Where do Legionella grow?
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in protozoa (amoebas) in water and in macrophages within the human body
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What can you get from a cooling tower?
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Legionnaire's Dz (acute pneumonia) or Pontiac fever (mild form) caused by Legionella
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Pt with cough, fever, feels kind of lous. CXR shows pneumonia. Normal labs are negative and there's no growth on traditional media. Penicillin doesn't help.
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Legionella
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Pt with a Penicillin resistant, atypical pneumonia that won't grow on traditional agar has negative results with most labs. Urine antigen test for Legionella also negative. What's he got?
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Probably still Legionella. Urine antigen tests only detect serotype 1, which is the most common.
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Patient gets an atypical pneumonia from non-serotype 1 Legionella. What do you do?
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Treat patient with macrolides (b/c Legionella resistant to Penicillin)
Monitor and disinfect water reservoirs in hospital b/c non serotype-1 Legionella is probably nosocomial and Legionella is transmitted through contaminated water |
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What atypical mycobacteria cause pulmonary diseases in AIDS patients?
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Mycobacterium avium/intracellulare
Mycobacterium kansasii |
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AIDS patient with respiratory disease and brain abscess. agent?
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Nocardia spp
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AIDS patient with lung disease caused by acid fast bacteria. PPD and IFN gamma release assays are negative. Agent?
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Might still be Mycobacterium b/c AIDS px often give false negatives. But a related acid fast pathogen is Rhodococcus.
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Mycoplasma and Mycobacterium both have unusual structural characteristis. What are they and what diseases do these organisms cause?
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Mycoplasma have no cell wall. Causes respiratory dz of varying degrees of severity (including atypical pneumonia) but is never invasive.
Mycobacteria are acid fast. Causes TB and leprosy. |
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What are mycolic acids and what genus possesses them?
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cell wall outer glycolipids that confer a waxy quality to mycobacterium, rendering them acid fast
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What was 'Sharepoint Server 2001' and how is it different from the current iteration of Sharepoint?
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Document management and enterprise search based on MS Exchange. The current iteration is based on .NET and SQL server.
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TB patient gets meningitis and dies. What happened?
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Miliary (extrapulmonary) TB = complication where mycobacteria sprads via bloodstream to distant organs ncluding meninges
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BCG vaccine
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live attenduated strain of Mycobacteria bovis for prevention of the related TB
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MVA85A
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new TB vaccine in trials
recombinant vaccinia virus expressing antigen 85A from Mycobacterium tuberculosis |
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What causes meningitis, pneumonia, and otitis media?
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"Pneumococcus is to Parents what group B strep is to Babies"
GBS causes meningitis and pneumonia in neonates Strep. pneumoniae causes meningitis and pneumonia in adults. It also causes otitis media in kids. |
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most common cause of otitis media?
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Strep. pneumoniae/pneumococcus
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Major cause of both nosocomial and hospital acquired pneumonia. Heavy consolidation on CXR with copious "rusty" sputum?
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Strep. pneumoniae / pneumococcus
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How do you treat pneumococcal pneumonia?
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Usually Penicillin
should be prevented with a conjugate vaccine (or with the originial PPV 23 vaccine) |
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What vaccination against pneumococcus should you give to a 4 month old child?
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PCV-13 (replaced PCV-7)
purified capsule polysaccharides of the 13 most common serotypes conjugated to protein PPV (Pneumovax 23) is only given to adults |
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pt with meningitis. organism visualized by INdia Ink
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cryptococcus
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Immunosuprressed diabetics in ketoacidosis are susceptible to what mycosis?
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zygomycosis
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