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Z - Micro 05
Micro 05
Question | Answer |
---|---|
Pertussis toxin | A and B subunits; G protein --> andenylate cyclase --> inc cAMP --> inhibits macrophage and neutrophil phagocytosis |
When is patient with whooping cough contagious? | 1. catarrhal stage - regular cold like sx's, most contagious; 2. paroxysmal stage - big cough; 3. convalescent - recovering, no longer contagious |
What to collect whooping cough specimens with? Why? | Calcium alginate swab because B. Pertussis won't grow on cotton. |
Bordet-Gengou medium | potato blood,and glycerol agar; B. pertussis. |
Patient over 50 yo, smoker, with pneumonia | Legionella pneumophila |
Water-loving bacteria | Pseudomonas and Legionella |
Mists - grocery stores, restaurants | Legionella pneumophila |
atypical pneumonia with kidney problem (hypoNa, hyperK, metabolic acidosis | Legionella pneumophila |
How can a patient with Legionella atypical pneumonia get hyponatremia? | Legionella pneumophila affects kidneys --> interstitial nephritis --> knocks off juxtaglomerular apparatus --> low renin, low aldosterone --> lose salt in urine --> hyponatremia |
How to treat Legionella atypical pneumonia? | Erythromycin |
Bipolar staining pattern | Yersinia pestis |
Patient with red hot painful lymph nodes, esp inguinal LNs, blackish discoloration from hemmorrhaging under skin | Yersinia pestis, bubonic plague |
well demarcated hole in skin with black base, red hot painful lymph nodes | Tularemia; Francisella tularensis |
Handling rabbits --> pneumonia | Tularemia; Francisella tularensis |
What is the vector for tularemia? | tick; Francisella tularensis |
drinking unpasteurized milk, worker in meat packing industry | Brucella |
aborted animal placenta | Brucella |
camping in Arizona or Mexico, swollen LNs | Yersinia pestis, bubonic plague |
Camping in Western U.S., rustic mountain cabin, fever that relapses | Borrelia recurrentis (relapsing fever). This bug is a master at changing its antigens --> cause of the relapses. Must get blood samples during fever episodes only. |
Consuming cow or goat products in Mexico | Brucella |
Illness with rise in temp during the day, declining at night | Undulant fever --> Brucellosis, Brucella |
Cat bite | Pasteurella multocida (don't close the wound! --> anaerobic environment good for P multocida) |
Cat bite --> low grade fever and malaise | Bartonella henselae, cat scratch disease. Causes a mixed T and T cell hyperplasia in the lymph nodes --> granulomatous microabscesses. See with silver stain. Can also cause bacillary angiomatosis. |
Stellate granulomas with central necrosis | Bartonella henselae, cat scratch disease. Causes a mixed T and T cell hyperplasia in the lymph nodes --> granulomatous microabscesses. See with silver stain. Can also cause bacillary angiomatosis. |
Why are Chlamydia and Rickettsia not considered viruses? | They have both DNA and RNA while viruses have either or |
Diagnosis of conjunctivitis in babies born to moms with Chlamydia infection | inclusion bodies in the cytoplasm of conjunctival cells (initial bodies -- the ones that inhibit phagocytosis and reproduces itself) |
Organisms that cause atypical pneumonia | viruses, Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia pneumoniae |
What is atypical pneumonia vs. regular pneumonia | Regular (Strep pneumoniae): appears very sick, coughs up lots of pus, lungs have infiltrate, rales; Atypical: fever, headache, dry cough, no pus, normal lung exam, streaky infiltrate on lung X-ray. |
Typical pneumonia in elderly | Moraxella catarrhalis (G-diplococcus) |
Where do Rickettsia replicate vs. Chlamydia? | Rickettsia: cytoplasm of ENDOthelial cells. Chlamydia: endosomes of columnar EPIthelial cells. |
Rickettsia - ticks (arthropod) | Rocky Mountain Spotted Fever, Rickettsia rickettsii |
Rickettsia - louse | Epidemic typhus |
Rickettsia - flea | Endemic typhus |
Patient from SouthEastern US (Appalachian range) comes in with fever, conjunctival redness, headache and rash on wrists, palms, ankles, soles. | Rocky Mountain Spotted Fever, Rickettsia rickettsii |
Why would removing a tick early lead to prevention of Rocky Mountain Spotted Fever? | Tick transmits the Rickettsia within its first 6 to 10 hours of feeding, so if you remove before the transmission, you can prevent the disease |
Exposure to flying squirrel in Texas --> abrupt fever 2 weeks later, small pink macules on trunk, palms and soles spared | Epidemic typhus |
Soldier in the trenches, febrile episodes every 5 days | Bartonella quintana |
Work with cow hides, pneumonia, no rash | Q Fever, Coxiella burnetti, has endospore, must use host's ATP |
Name the three genera of spirochetes | 1. Treponema, 2. Borrelia, 3. Leptospira |
Painless chancre with nontender LN swelling, rash on palms and soles and mouth | Treponema pallidum (syphilis) |
T or F: Antimicrobial therapy can make gummatous syphilis in bones resolve. | TRUE |
T or F: Antimicrobial therapy can make cardiovascular syphilis (aortic aneurysm and aortic valve insufficiency) resolve. | FALSE |
CSF analysis yeilds: high neutrophil count, high protein, low glucose | Acute bacterial meningitis |
CSF analysis yeilds: high lumphocyte count, high protein, low glucose | Subacute meningitis: Mycobacterium TB and Treponema pallidum (neurosyphilis) |
Hx of syphilis, loss of reflexes and loss of pain and T sensation | Tabes dorsalis, damage to posterior columns and dorsal roots of the spinal cord |
Pupil constructs during accommodation (near vision) but does not react to light | Argyll-Robertson pupils, midbrain lesion, suggests syphilitic Tabes dorsalis or general paresis |
In mom that has syphilis, can congenital syphilis be prevented? | Treponema pallidum infxn doesn't damage fetus until 4th month, so treating the mother before then can prevent congenital syphilis. |
VDRL/RPR | Nonspecific tests for Treponema pallidum. Infection --> cellular damage --> release lipids including cardiolipin and lecithin --> measure the abs that bind to these lipids (in blood and CSF). May have false + |
FTA-ABS | Specific tests for Treponema pallidum --> soak up all abs against non-pathogenic Treponema strains, then use killed pathogenic Treponema as antigen and see if patient serum has the abs to bind to these antigens |
Why would patients with syphilis seem to get worse with abx treatment? | killed Treponema releases pyrogen. Sx's should resolve. |
Condyloma latum | painless wartlike lesion, vulva or scrotum, packed with spirochetes that ulcerates --> extremely contagious |