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| 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 |
