Micro Flashcards

Question

Staph

Answer 1

S. aureus - b-hemolytic, protein A - inflammatory disease - skin infections, abscesses, etc. - TSS - toxin binds to MCH and T cell receptor, shock, desquamation, elevated liver enzymes - scalded skin syndrome (exfoliative toxin) - rapid-onset food poisoning (heat stable) - MRSA - altered PBP S. epi - ...urease pos, doesnt ferment mannitol (unlike S aureus)

Answer 2

disease of skin and nerves (Schwann cells)- why? - because leprae grows at core body temperature transmitted in unhygienic conditions - through respiratory route, armadillo presentation depends on strength of cell-mediated immune response - tuberculoid leprosy - occurs in pts with Th1 mediated response --> hypopigmented skin plaques, hair follicle loss, focally decreased sensation - lerpromatous leprosy - occurs in pts who have a weak Th1 response, and respond with Th2 instead - macrophage killing is limited --> mycobacteria disseminate --> tuberculoid presentation + leonine facies, testicular destruction, blindness, etc. ddx by - skin biopsy, PCR treat with dapsone, rifampin (+ clofazamine)

Answer 3

g- rod, fimbriae (UTIs), K capsule (pneumonia, meningitis) - green on EMB agar EIEC - invasive, dysentery, similar to Shigella ETEC - heat labile and heat stable enterotoxins = 2 toxins - does NOT invade, travellers diarrhea EPEC - Pediatric - no toxin - adheres --> flattens vili EHEC O157:H7 - only one that does NOT ferment sorbitol or have glucuronidase - dysentery - toxin causes necrosis and inflammation - HUS

Answer 4

very mucoid colonies

Answer 5

CAMPY g-, comma shaped with polar flagella (looks like a swirly macaroni), oxidase positive - grows at 42degC - (hot Camp fire) - fecal-oral transmission, undercooked meat, contact with infected animals - bloody diarrhea (esp in kids) VIBRIO comma shaped, also oxidase pos, grows in alkaline media, *acid labile* - acquired through shellfish - enterotoxin activates Gs

Answer 6

g-, non-lactose fermenters, oxidase negative, invade GI tract via M cells (of Peyers patches), endotoxin (S typhi also has Vi capsule, Shigella has shiga toxin) SALMONELLA general - H2S production, motile, requires high innoculum - antibiotics prolong fecal excretion Salmonella typhi - carried in gallbladder - monocyte response - constipation - vaccine against Vi capsule - typhoid fever - treat with ceftriaxone, FQ Salmonella other - human and animal reservoirs (other have only human reservoirs) - neutrophil response - diarrhea - no antibiotics needed Shigella - low innoculum (fingers, flies, food, feces) - *cell-to-cell spread* (Salmonella moves hematogenously) - bloody diarrhea - neutrophil response

Answer 7

g- rod, dog feces/pork, *daycares* pseudoappendicitis or acute diarrhea

Answer 8

curved, flagellated, g- rod triple - catalase positive, oxidase positive, urease positive - colonizes antrum of stomach (base, closest to the pylorus) risk factor for: peptic ulcer disease, gastric adenocarcinoma, MALT lymphoma treat with amoxicillin (or metro), clarithro, and PPR

Answer 9

Leptospira interrogans - found in water contaminated with animal urine - leptospirosis - flu-like, calf myalgias, jaundice, photophobia is conjunctiva erythema, surfer in Hawaii - Weil disease, icterohemorrhagic leptospirosis - severe jaundice and azotemia, fever, hemorrhage, anemia Lyme disease - ixodes tick - natural reservoir is the mouse, common in NE US 1) erythema migrans + flu-like symptoms 2) early disseminated - bilateral Bells palsy (unilateral bells palsy is due to HSV), *AV block*, migratory arthritis 3) late disseminated - encephalopathy, chronic arthritis - doxy, amoxicillin (or cef for erythema migrans?) note- Babesia (blood protozoa) is also transmitted by this tick - fever and hemolytic anemia - asplenia increases risk of severe disease - ring form and maltese cross in RBCs - PCR to ddx - treat with atovaquone and azithro Syphillis 1) chancre - use dark field microscopy to visualize fluid from chancre - side note - chancROID is painful! 2) disseminated disease - rash (on palms and soles), condylomata lata (warty, white growth on butt), patchy hair loss - confirm ddx with FTA-ABS 3) gummas (chronic granulomas on face), aortitis, neurosyph (positive Romberg, test spinal fluid), Argyll Robertson pupil - stroke without HTN congenital syphilis - linear scars at angle of mouth, snuffles, saddle nose, notched teeth and mulberry molars, short maxilla, saber shins (shin that juts anteriorly), CN8 deafness - treat mom early - transmission can occur even in first trimester - often results in stillbirth, hydrops fetalis why would VRDL be falsely positive - viral infection (EBV, hep), drugs, rheumatic fever, lupus, leprosy Jarisch-Herxheimer reaction

Answer 10

Gardnerella - elevated pH - gray vaginal discharge with fishy odor, nonpainful (vaginitis would be painful) - Whiff test (KOH enhances odor) - clue cells - metro of clinda Trichomonas - only exists in humans, elevated pH - green discharge - itching and burning, strawberry cervix - metro for pt AND partner Candida - normal pH, treat with an azole

Answer 11

doxy Rocky Mountain spotted fever - South atlantic states, dermacentor tick - triad: headache, fever, rash (vasculitis) (rash on palms and soles - RMSF, Coxsackie, Syphilis) Typhus - fleas (endemic), epidemic (louse) - rash starts centrally and spreads out, spares palms and soles Ehrlichiosis - tick - monocytes with mulberry-like inclusions in cytoplasm Analplasmosis - tick - granulocytes with morulae in cytoplasm Q fever - Coxiella, spores are inhaled from cattle, sheep - pneumonia, common cause of culture negative endocarditis

Answer 12

Chlamydia - most common bacterial STI in US - cant make its own ATP - elementary (dense) body is enfectious --> reticulate body replicates by fission - C. Trachomatis - reactive arthritis, follicular conjuntivitis, urethritis, PID - C. pneumo, C. psittaci (parrots) - atypical pneumonia, transmitted by aerosol - ddx with PCR, NA amplification test - treat with azithro or doxy (+ cef, targets the gonorrhea) - note chlamydia has no cell wall C trach serotypes - ABC - africa, blindness, chronic infection - D-K - urethritis/PID/ectopic, neonatal pneumonia (staccato cough) with eos, neonatal conjunctivitis (1-2 weeks after birth) - L1-3 - lymphogranuloma venereum - painless ulcers --> swollen, painful LNs, give doxy Gonorrhea - creamy purulent discharge - intracellular with neutrophils - no maltose metabolized - condoms decrease sexual transmission, erythromycin eye ointments prevent neonatal blindness - treat with cef PID - CMT, Fitz-Hugh-Curtis syndrome

Answer 13

grown on Eaton agar, bacterial membrane contains sterols (requires cholesterol for growth) atypical pneumo < 30 yo, in close quarters high titer of cold agglutinins - IgM treat with macrolides, doxy, FQ (no cell wall)

Answer 14

Histo < RBC = Blasto < Coccidio, Paracocidio - cause pneumonia and can disseminate, can form granulomas - mold in the cold, yeast in the heat Histo - midwest (MI, OH), bird/bat droppings - many inside macrophages - palatal/tongue ulcers, splenomegaly Blasto - eastern and central US, broad-based budding - inflammatory lung disease --> skin and bone - verrucous skin lesions ~SCC Coccidio- SW US, *spherule* - disseminates to skin/bone - erythema nodosum or multiforme, arthralgias - meningitis Paracoccidio - Latin Am, males - captain's wheel formation fluconazole, itra- for local infection, ampho B for systemic to summarize - it is spectrum 1) histo - lungs, mouth ulcers 2) blasto - moves to skin and bone, lesions that look like SS 3) coccidio - moves to brain (meningitis)

Answer 15

extremely heat stable macrophage activation (TLR4) - IL1, IL6, TNFa, NO complement activation --> C3a leads to histamine release, C5a attracts neutrophils and tissue factor activation --> DIC VS exotoxin - plasmid/bacteriophage - worse than endotoxin - less heat stable

Answer 16

tinea (dermatophytes) - branching septate hyphae, pruritis - corporis - ring worm, can be acquired from cat/dog - unguium - onychomycosis (ragged nails), nails tinea (pityriasis) versicolor - Malassezia species, a yeast-like fungus (spaghetti and meatballs appearance) - degradation of lipids --> acids --> damage to melanocytes --> patches of variable pigment - can occur anytime - more common in summer - treat with selenium sulfide, topical antifungals

Answer 17

Giardia - transmitted by cysts in the water - fatty stools - trophozoites/cysts in stool, stool antigen - metro Entamoeba histolytica - only one in this group that causes *bloody* diarrhea - flask shaped ulcers - transmitted by cysts in water - trophozoites with 4 nuclei or engulfed RBCs, stool antigen - anchovy paste liver abscess, RUQ pain - metro, parmomycin or iodoquinol for asymptomatic cyst passers Cryptosporidium - AIDs diarrhea - transmitted by oocysts in water - can see oocysts on acid-fast stain, stool antigen - prevent by water filtration - treat with nitazoxanide in immunocompetent hosts

Answer 18

Toxo - cysts in meat, oocysts in cat feces (preggos should avoid cats), tachyzoite (banana-shaped) - congenital - chorioretinitis, hydrocephalus, *intracranial calcifications* - AIDs - ring-enhancing lesions - sulfadiazine and pyrimethamine Naegleria fowleri - fatal meningoencephalitis - Nalgene - swimming in fresh water lakes --> enters cribiform plate - amoebas in spinal fluid - ampho B Trypanosoma brucei - Tsetse fly, painful bite - enlarged lymph nodes, recurring fever (due to antigenic variation) - will see trypomastigote in blood smear - suramin for blood-borne, melarsoprol for CNS penetration (I sur am mel-low

Answer 19

T. cruzi - dilated (cardiomyopathy, megacolon, megaesophagus) - unilateral periorbital swelling characteristic of acute stage - Reduviid bug - *feces* - benznidazole, nifurtimox Leismania - sandly, macrophages will contain amastigotes - visceral - spiking fevers, HSM, *pancytopenia* - cutaneous - ampho B, stibogluconate

Answer 20

sarcoptes scabiei - common in kids, crowded pops, transmitted by skin-to-skin or via fomites - mite burrows into stratum corneum - itching is worse at night, lines in webbing - treat with permetrin cream, clean bedding pediculus humanus/phtirus pubis = lice - can transmit rickettsial typhus, relapsing fever (Borrelia recurrentis), or trench fever (Bartonella quintana) - treat with pyrethroids, malathion, or ivermetin lotion - kids can be treat at home without interrupting school attendance

Answer 21

like HBD and HBV

Answer 22

BOAR - segmented viruses Bunya Flu (orthomyxoviruses) - vaccine is usually killed, live-attenuated is intranasal (temp sensitive mutant that replicates in the nose) - antigenic SHIFT - pandemics - orthomyxovirus - enveloped, -ssRNA, 8 segment genome - HG binds sialic acid --> viral entry - NA - promotes progeny virion release - post viral - S pneumo, S aureus, H flu Arena Reo

Answer 23

Ebola = bloody mess - filovirus, incubates for 21 days --> abrupt onset flu - can progress to DIC, diffuse hemorrhage, shock - targets endothelial cells, phagocytes, hepatocytes - transmission through body fluids, infected bats/monkeys - ddx with RT-PCR, supportive care and isolation precautions Zika - flavivirus, Aedes mosquito - conjunctivitus, low-grade fever, itchy rash - congenital microceph, miscarriages - RT-PCR, serology

Answer 24

bullet shaped virus, Negri bodies in Purkinje cells and hippocampus skunk/raccoon bite - long incubation period - postexposure - clean wound + immunize with killed vaccine and rabies Ig binds to NAch receptors --> travels to CNS by migrating retrograde fever, malaise --> agitation, photo and hydrophobia, hypersalivation --> paralysis, coma, death

Answer 25

pencillin G resistant, catalase negative, PYR pos

Answer 26

transformation - S pneumo, H Flu, Neisseria - these are also the encapsulated orgs! (use polysaccharide + protein conjugate) - sickle cell pts - also have IgA protease type 3 secretion system - Pseudomonas, Salmonella, Shigella, E coli

Answer 27

S. aureus (always) or something else cat and dog bites - Pasteurella IVDA - Pseudomonas, Candida, S. aureus MRI!!!

Answer 28

rash begins at head and moves down - Measles rash coalesces, Rubella doesnt Measles - paramyxovirus - fever, cough, coryza, conjunctivitus, Koplik spots - rash 1-2 days later - lymphadenitis with giant cells (fused lymphocytes) - *paracortical hyperplasia* - subacute sclerosing panencephalitis, giant cell pneumonia - vitamin A supplementation can help Rubella - postaurical LAD - togavirus - congenital - blueberry muffin appearance due to dermal extramedullary hematopoiesis, deafness, and cataracts (mom will have rash, ALD, arthritis)

Answer 29

rabies, flu, Salk, HAV

Answer 30

MMR, Chickenpox, Smallpox Yellow fever, rotavirus

Answer 31

gram negative rod, use silver stain (it is part of atypicals along with Chlamydia and Mycoplasma) grow on charcoal yeast + Fe + cysteine aerosol transmission from a water source - air conditioning, hot water tanks, does NOT transmit person-to-person treat with macrolide or quinolone Legionnaries - common in smokers and COPD-ers, severe pneumonia, GI, CNS symptoms Pontiac fever - mild flu

Answer 32

S aureus, S pyogenes, S agalactiae

Answer 33

cause illness in kids - parainflu, measles, mumps, RSV, human metapneumovirus - all contain F protein --> epithelial cells fuse - palivizumab is anti-F - prevents pneumonia cause by RSV in premies croup - HG, NA - stepple sign on XR, pulsus paradoxus secondary to upper airway obstruction

Answer 34

flagella - protein, pilus - glycoprotein spore - keratin-like coat, dipicolinic acid center, gram pos only - the only way to kill spores is by autoclaving * cytoplasmic* membrane - PBPs - lipoteichoic acids - induce TNFa and IL1 giemsa - chlamydia,rickettsia, trypanosomes, plasmodium PAS - Whipple disease intracellular orgs - legionella, rickettsia/anaplasma/ehrlichia, chlamydia, salmonella, listeria, francisella, yersina, mycobac, brucella, coxiella, neisseria - rickettsia, chlamydia, coxiella are obligate = need host ATP anaerobes - foul smelling due to short-chain fatty acids) - gram pos bac - generally facultative anaerobes

Answer 35

nocardia, aspergillus, candidia listeria, pseudomonas, h pylori e coli, staph, serratia (red pigment), b cepacia

Answer 36

kleb, proteus (swarming motility on agar), crytococcus, nocardia, s epi and sapro

Answer 37

adenovirus - linear - pharyngitis, acute hemorrhagic cystitis, pneumonia, conjunctivitis papillomavirus - circular polyomavirus - circular - JC virus, BK (kidneys, transplant pts) parvo - ssDNA, linear

Answer 38

ss RNA, nonenveloped polio (can cause meningitis in unvaccinated kids), echo, rhino, coxsackie (A - hand-foot-mouth disease) - *proteases* - viral meningitis Rhino - binds to ICAM1, 100 serotypes, acid labile

Answer 39

S epi, Viridans group, P aeruginosa (respiratory tree, contact lens), unencapsulated H flu (otitis media)

Answer 40

group A strep erythrogenic toxin, Botulism, Cholera, Diphtheria, Shiga toxin

Answer 41

B. anthrax - only bacteria with a polypeptide capsule (D-glutamate), halo of projections (medusa head) - cutaneous - painless papule surrounded by vesicles --> black eschar (painless) - pulmonary anthrax - inhaled spores --> pulmonary hemorrhage, mediastinitis (woolsorters disease) C. tentani - both tetanus and botulism toxins cleave SNARE proteins - tetanus toxin blocks release of GABA and glycine from Renshaw cells in SC - prevent with vaccine, antitoxin, diazepam C. botulinum - heat labile toxin that inhibits Ach release at NMJ (floppy baby syndrome) - diplopia, dysarthria, dysphagia, dyspnea C. perfringens - a toxin - lecithinase aka phospholipase --> gas gangrene, hemolysis - heat stable enterotoxin C. diff - toxin A - enterotoxin that binds gut brush border, alters fluid excretion - toxin B - cytotoxin that disrupts cytoskeleton via actin depol - treat with metro, vanc, or fidaxomicin

Answer 42

g+ rod diphtheria via exotoxin encoded by b-prophage - *inhibits protein synthesis via ADP-ribosylation of EF2 pseudomembranous pharyngitis with LAD, myocarditis, arrhythmias black colonies on cysteine-tellurite, metachromatic granules on gram stain, Elek test for toxin

Answer 43

facultative intracellular - rocket tails (actin) that allows cell-to-cell spread dairy, deli meats amnionitis, septicemia, spont abort, granulomatosis infantiseptica, neonatal meningitis and in immunocompromise mild self-limiting gastroenteritis in healthy

Answer 44

gram pos, filamentous rods Nocardia - aerobe, weakly acid fast, found in soil - pulmonary infections in immunocompromised (can mimic TB), cutaneous infections in immunocompetent, can spread to CNS - bactrim Actinomyces - anaerobe, not acid fast, normal GI flora - oral/facial abscesses (lumpy jaw) that drain through sinus tracts - often associated with dental caries/tooth extraction - yellow "sulfur" granules - treat with penicillin

Answer 45

e coli, kleb, enterobac, serratia e coli also produces b-galactosidase

Answer 46

gram neg coccobacilli, aerosol transmission, can give Hib before the age of 2 nontypable are the most common cause of mucosal infections and invasive infections culture on chocolate agar with NAD and hematin MOPS, epiglottitis (thumb sign on xray) amoxicillin and clavulanate, cef for meningitis, rifampin for prophylax close contacts

Answer 47

polysaccharide capsule, maltose and glucose fermentation meningococcemia with petechial hemorrhages and gangrene of toes, Waterhouse-Friderichens, meningitis prophylax with rifampin, cipro, cef treat with cef or penicillin G

Answer 48

g-, aerobic coccobacillus pertussis toxin disables Gi tracheal cytotoxin catarrhal - low grade fevers, coryza paroxysmal - whooping cough convalescent - gradual recovery of chronic cough elicits lymphocytic leukocytosis

Answer 49

motile, oxidase pos, grape-odor, mucoid capsule endotoxin exotoxin A - inactivates EF2 phospholipase C ecthyma grangrenosum (seen in immunocompromised, rapidly progressive), osteomyelitis, otitis externa

Answer 50

pos ssRNA - i went to a RETRO TOGA party where i drank FLAVored CORONA and ate HEPE CALI PICkles - corona - common cold, SARS, MERS - calcivirus - norovirus - viral gastroenteritis - flavi - yellow fever - Aedes mosquito, human or monkey reservoir - high fever, black vomitus, jaundice, Councilman bodies in liver - reovirus = rotavirus - most common cause of infantile gastroenteritis, daycares, villous destruction with atrophy (decreased Na in, increased K loss) only reovirus is dsRNA flu and retroviruses replicate outside cytoplasm

Answer 51

2 RNA molecules - env - gp120 attaches to host cells (CD4 or macrophages), gp41 mediates fusion and entry - gag - capside, matrix - pol - RT, aspartate protease, integrase ELISA (high false pos rate, rule out test), Western blot (rule in), viral lode (esp in neonates, where anti-gp120 crosses placenta and can give false pos) - high false NEG in first 2 months - neonates with HIV - chronic diarrhea AIDs < 200 1) window period (flu like) - acute HIV infection, viral dissemination and seeding of lymphoid organs 2) latent - virus replicates in LNs 3) skin and mucosal infections - less than 500 - candida, EBV Bartonella, HHV8, HPV 4) systemic and AIDS defining illnesses - less than 200 - histo (oval cells within macrophages), HIV dementia, JV virus, pneumocystis - less than 100 - aspergillus, candida, CMV (owl eye inclusions, cotoon wool spots), cryptococcus and sporidium, EBV lymphoma, MycoAC, toxo DRUGS: HAART - 2 NRTIs and an integrase inhibitor NRTIs (lamivudine, tenofovir, AZT aka zidovudine) - tenofovir is a nucleoTide, all others are nucleosides - need to phosphorylated to be active - AZT prophylaxis during pregnancy - abacavir contraindicated in HLA-B5701 - bone marrow suppression (give G-CSF and EPO), peripheral neuropathy, lactic acidosis, anemia (ZDV), pancreatitis (didanosine) NNRTIs - dont require phosphorylation - rash and hepatotox, vivid dreams with efavirenz Protease inhibitors - navir - ritonavir is a CYP inhibitor - hyperglycemia, GI intolerance, lipodystrophy - indinavir has renal effects - use rifabutin instead of rifampin Integrase inhbitors - increased CK fusion inhibitors - enfuvirtide (binds gp41), maraviroc (binds CCR5 on T cells, prevents docking)

Answer 52

staph aureus, viridans group multiple abscesses from bacteremia single lesions are from neighboring sites - otitis media, mastoiditis, sinusitis

Answer 53

D-ala-D-ala structural analog amox, amp, aminopenicillins - b-lactam sensitive - use for enterococci, gut bacteria, and H flu - ADRs - HSR, rash, pseudomembranous colitis penicillinase-resistant - diclo, naf, ox have bulky R group - interstitial nephritis pip and tic are anti-pseudomonal cephalosporins - bind PBPs, bactericidal 1) UTI bugs and gram pos - cefazolin (used to prevent postsurg staph a infection), cephalexin 2) fake fox fur - H flu, enterobacter, Neisseria, Serratia, UTI bugs 3) can cross BBB - meningitis, gonorrhea, lyme disease, pseudomonas 4) cefipime = g+ and g-, pseudomonas 5) ceftaroline - covers LAME bugs - listeria, atypicals, MRSA, enterococcus - ADRs - HSR, hemolytic anemia, disulfiram-like reaction, vitamin K def, increases nephrotox of AGs vanc binds D-ala-D-ala of cell wall, usu bacteriocidal (except with C. diff) - nephro and ototox, thrombophlebitis, red man syndrome (prevent by slow infusion) carbapenems + cilastin (inhibitor of renal dehydropeptidase 1) - b-lactamase resistant - broad spectrum, last resort - ADRs - GI distress, rash, seizures monobactam - binds to PBP3, no cross-allergy with penicillins - gram negative rods - non toxic - use in renal insufficiency pts

Micro Flashcards

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