USMLE First Aid Microbiology – Flashcards
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gram positive cocci
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Staphylococcus, Streptococcus
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gram neg cocci
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Neisseria
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gram positive bacilli
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Clostridium, Corynebacterium, Bacillus, Listeria, Mycobacterium (acid fast)
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gram positive branching filaments
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Actinomyces, Nocardia (weakly acid fast)
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Spiral
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spirochetes: Leptospira, Borrelia (Giemsa), Treponema
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bacteria with unusual cell membranes/walls
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Mycoplasma - sterols, no cell wall Mycobacteria - mycolic acid. High lipid content
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Bugs that do not gram stain well
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TRMMLC - These Rascals May Microscopically Lack Color Treponema (too thin, dark field, fluorescent Ab), Rickettsia (intracellular) Mycobacteria (acid fast), Mycoplasma (no cell wall), Legionella pneumophilia (intracellular, silver stain), Chlamydia (intracellular, no muramic acid)
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Giemsa Stain
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Gee These Bad Puns are Cheesy Giemsa, Trypanosomes, Borrelia, Plasmodium, Chlamydia
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PAS stain
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PASs the whipped cream & sugar glycogen, mucopolysaccharides, diagnose Whipple's
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Ziehl-Neelsen stain
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Acid-fast
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India Ink stain
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Cryptococcus neoformans
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Silver stain
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Fungi, Legionella
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Obligate aerobes
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Nagging Pests Must Breathe Nocardia Pseudomonas Aeruginosa Mycobacterium Tuberculosis Bacillus
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Obligate Anaerobes
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Anaerobes Can't Breathe Air Clostridium, Bacteroides, Actinomyces
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Obligate intracellular
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Really Cold Rickettsia Chlamydia
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Facultative Intracellular
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Some Nasty Bugs May Live FacultativeLY Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia Pestis
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Catalase positive orgs
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SSPACE for your Cats S. aureus, Serratia, Pseudomonas, Actinomyces, Candida, E. coli, Catalase
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Urease positive orgs
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PUNCH-K Proteus, Ureaplasma, Nocardia, Cryptococcus, H. pylori, Klebsiella
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Pigment-producing bacteria
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Actinomyces israelii - Israel has yellow sand S. aureus - yellow pigment "golden" Pseudomonas AERUGinosa- blue-green AERUGula is green Serratia marcescens - red pigment - Red maraschino cherries
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IgA protease orgs
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Enzyme that cleaves IgA SHiN - S. pneumoniae, H. influenza type B, Neisseria
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Endotoxin features
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Outer cell membrane of gram negs Lipopolysaccharide - structural part of bacteria, released when lysed Bacterial chromosome Fever, Shock Induces TNF and IL-1 Meningococcemia, sepsis by gram neg
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Endotoxin efx
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Endotoxin (esp Lipid A) 1)Activates Macrophages: IL-1->fever TNF->fever, hemorrhagic tissue necrosis Nitric Oxide->Hypotension (shock) 2)Activates complement (alt. pathway): C3a->hypotension, edema C5a->neutrophil, chemotaxis 3)Act. Hageman factor: Coagulation cascade->DIC
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Identification gram pos cocci
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on the STAPH retreat, there was NO StRESs Staphylococci NOvobiocin- Saprophyticus is Resistant; Epidermidis is Sensitive Streptococci OVeRPaSs Optochin-Viridans is Resistant; Pneumoniae is Sensitive size B-BRAS Bacitracin- group B strep are Resistant; group A strep are Sensitive
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Alpha hemolytic
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green apple Strep pneumoniae - op sens; quellung pos Strep viridans - op res; bile growth Optochin- OVeRPaSs
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Beta hemolytic
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Because we need space -clear space Staph aureus - cat and coag pos Strep pyogenes - grpA - bacitracin sens Strep agalactiae- grpB - bacitracin res Listeria monocytogenes (tumbling, newborn meningitis, unpast. milk)
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Strep pneumoniae
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S. pneumoniae MOPS are Most OPtochin Sensitive Meningitis, Otitis media, Pneumonia, Sinusitis Lancet shaped, gram pos diplococci, encapsulated IgA protease "rusty" sputum, sepsis in sickle cell anemia and splenectomy
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Staph aureus
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Gram pos cocci in clusters Protein A (vir) bind Fc-IgG, inhibits complement fixation and phagocytosis TSST superantigen that binds MHC II T cell receptor, T cell activation Causes acute bacterial endocarditis, osteomyelitis
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Strep viridans
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alpha hemolytic dental caries (S. mutans) and endocarditis (S. sanguis)
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Strep pyogenes (groups A strep)
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PHaryngitis can result in rheumatic PHever and glomerulonePHritis No "rheum" for SPECCulation: Subcutaneous plaques, Polyarthritis, Erythema marginatum, Chorea, Carditis Bacitracin sens, Abs to M protein, ASO titer
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Strep agalactiae (group B streptococci)
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B for Babies Bacitracin res; Beta hemolytic; CAMP factor pneumonia, meningitis, sepsis in babies Penicillin prophylaxis in Pregnancy
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Enterococci (group D strep)
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UTI and subacute endocarditis Grow in salt and bile VRE Vancomycin Resistant Enterococci
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Corynebacterium diphtheriae
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Pseudomembranous pharyngitis w/ lympahenopathy ABCDEFG ADP ribosylation (inh protein synth), Beta-prophage (exotoxin), Corynebacterium, Diptheria, Elongation Factor 2, Granules (blue & red)
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Clostridia
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gram pos, spores, obligate anaerobe rods TETanus is TETanic paralysis (Tetanospasmin blocks glycine & GABA release) from Renshaw cells in spinal cord BOTulinium from BOTtles of food & honey (flaccid paralysis heat-labile toxin inh ACh at nm junc) PERFringens PERForates a gangrenous leg (myonecrosis and hemolysis) DIfficile DIarrhea. (enterotoxin & cytotoxin) metronidazole or oral Vancomycin.
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Anthrax
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Bacillus antracis, gram pos, spores, capsule of D-glutamate Cutaneous- black painless ulcer bacteremia and death Pulmonary- inhale spores flulike fever, pulm hemorrhage, mediastinitis, shock Woolsorter's dz
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Listeria monocytogenes
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Facultative intracellular, milk/cheese, vaginal, tumbling motility Amnionitis, septicemia, abortion in preg Meningitis: neonate & immunocomp Gastroenteritis rx: Ampicillin
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Actinomyces vs Nocardia
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SNAP: Sulfa for Nocardia; Actinomyces use Penicillin Actinomyces israelii- oral/facial abscess Nocardia asteroides- soil, pulm infxn
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Mycobacteria
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Acid Fast; fever, night sweats, wt loss, hemoptysis M. tuberculosis: TB, M. kansasii: TB-like sx M. avium-intracellulare: AIDS prophyl: Azithromycin
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Leprosy
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Mycobacterium leprae, acid-fast, cool temp Hansen's Dz: 1. Lepromatous- diffuse, cell mediated, Th2 response 2. Tuberculoid- few plaques, cell mediated, Th1 resp Treat: long-term oral Dapsone; toxicity hemolysis and methemoglobinemia Other: Rifampin w/Clofazimine & Dapsone
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Lactose Fermenting Enterics
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pink colonies on MacConkey's agar Lactose is KEE test w/ MacConKEE'S Citrobacter, Klebsiella, E. coli, Enterobacter, Serratia
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Neisseria
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MeninGococci ferment Maltose & Glucose Gonococci ferment Glucose gram neg diplococci, make IgA proteases N. Gonorrhoeae- dx: Ceftriaxone N.Meningitidis- vaccine (no B) dx: Ceftri or Penicillin G; Rifampin prophylaxis
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Haemophilus Influenzae
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haEMOPhilus Epiglottitis, Meningitis, Otitis media, Pneumonia Go to the five (factor V NAD+) and dime (X hematin) to buy Chocolate (agar) small gram neg rod, IgA protease Dx meningitis w/ Ceftriaxone. Rifampin prophylaxis
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Legionella pneumophila
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Legionnaire's dz- severe pneumonia & fvr Pontiac fvr- flu-like, mild French legionnaire w/silver helmet at campfire (charcoal) w/iron dagger- he's no sissy (cysteine) Silver stain, charcoal yeast w/Fe & cysteine Dx: Erythromycin
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Pseudomonas aeruginosa
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PSEUDOmonas - wound and burn infxn Pneumonia (CF), Sepsis (black lesions), External otitis (swimmer's ear), UTI, Drug use, Diabetic Osteomyelitis, hot tub folliculitis AERuginosis-AERobic aerobic, gram+ rod, non-lactose, oxidase positive, Pyocyanin(blue-green) pigment, grape odor, water source Endotoxin and Exotoxin A (inact. EF2) Dx: Aminoglycoside+ super penicillin (piperacillin, ticarcillin)
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Escherichia Coli
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Fimbriae- cystitis and pyelonephritis K capsule- pneumonia, neonatal meningi LPS- septic shock EIEC - Invasive; dysentary ETEC- Traveler's diarrhea (watery) EPEC- children (Peds) EHEC- O157:H7 shiga-like toxin (dysentary) & Hemolytic-uremic syndrome (anemia, thrombocytopenia, renal failure) *Does not ferment SORBITOL (distinguish)
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Klebsiella
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4 A's: Aspiration pneumonia, Abscess in lungs and liver, Alcoholics, di-A-betics red currant jelly sputum polysaccharide capsule
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Spirochetes
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BLT. B is Big Borrelia (big), Leptospira, Treponema Treponema dark-field microscopy
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Lyme disease
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BAKE a key Lyme pie: Bell's palsy (bilateral), Arthritis, Kardiac block, Erythema migrans ("bull's eye rash") Borrelia burgdorferi, tick IXODES, rx: Doxycycline, Ceftriaxone
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Syphilis
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Spirochete Treponema pallidum rx: Penicillin G Primary: painless chancre Second: Secondary syphilis = Systemic disseminated, maculopapular rash, condylomata lata Third: Gummas, aortitis, neurosyphilis, Argyll Robertson Congenital: Saber shins, saddle nose, CN VIII deafness
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Gardnerella vaginalis
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I don't have a CLUE what I smell FISH in the VAGINA GARDEN Vaginosis; gray discharge, fishy smell clue cell: covered w/ bacteria rx: Metronidazole
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Rickettsial
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Rickettsia on the wRists, Typhus on the Trunk; Triad: headache, fever, rash R. Rickettsii RMSF (tick); obligate intracellular orgs need CoA & NAD+ Typhus: Endemic (fleas)- R. typhi; Epidemic (human body louse) R. prowazekii (central rash spreads out) rx: Doxycycline
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Rash on palm and sole
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you drive CARS using PALMS & SOLES PALM and SOLE rash is seen in Coxsackievirus A infection Rocky Mtn spotted fever, Syphilis
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Chlamydiae
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1. Elementary body is Enfectious and Enters cells via Endocytosis 2. Reticulate body Replicates in cell; fission Giemsa or fluorescent antibody dx: Azithromycin or Doxycycline C. trachomatis: arthritis, conjunctivitis, urethritis, PID C pneumoniae & C psittaci: atypical pneu
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Histoplasmosis
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Histo Hides (within macs) & Flys Midwest Pneumonia Mississippi and Ohio river valleys Bird or Bat droppings rx: Fluconazole/ Ketoconazole or Amphotericin B
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Blastomycosis
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Blasto Buds (Broadly) Broad based budding East US and C. America Inflammatory lung dz - diss. to skin and bone - Granulomatous nodules rx: Fluconazole/ Ketoconazole or Amphotericin B
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Coccidioidomycosis
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Coccidio Crowds, Confuses, Coughs, Quakes. Inc after earthquakes San Joaquin Valley "valley fever", SW US, CA Pneumonia & Meningitis->bone, skin Spherule filled with endospores rx: Fluconazole/ Ketoconazole or Amphotericin B
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Paracoccidioidomycosis
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Paracoccidio Parasails (budding yeast) with the CAPTAIN'S WHEEL (appearance) to Latin America rx: Fluconazole/ Ketoconazole or Amphotericin B
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Systemic mycoses
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Mycosis twins cough conazole and (amp) B all over you Pneumonia and disseminate. Dimorphic fungi rx: Fluconozole or Ketoconazole (local) Amphotericin B (systemic)
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Tinea versicolor
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Malassezia furfur hyper-, hypopigmented patches Hot and humid weather "spaghetti and meatballs" on KOH prep dx: Topical miconazole, selenium sulfide
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Encapsulated bacteria
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Qulleng rx: capsular swellung SHiN SKiS (B): Sterptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Salmonella, Klebsiella pneumoniae, group B Strep
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gram pos rods
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Clostridium (anaerobe), Corynebacterium, Listeria (beta hemolytic), Bacillus (aerobe)
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branching filaments
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Actinomyces, Nocardia
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Lysogeny, specialized transduction
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ABCDE shigA-like toxin, Botulinum, Cholera toxin, Diphtheria toxin, Erythrogenic toxin of S. pyogenes
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gamma hemolytic gram pos cocci
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Enterococcus (bile & NaCl) S. bovis (in bile, not NaCl) cows like bile, but not salt
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Spore forming
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Soil: Bacillus anthracis, Clostridium perfringens, C. tetani other: B. cereus, C botulinum, Coxiella burnetii
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Salmonella
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bloody diarrhea, flagella, hematogenous, produce H2S, monocytic resp rx: antibiotics prolong illness
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Salmonella typhi
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Typhoid fever Rose spots on abdomen, fever, headache, diarrhea Gallbladder carrier state
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Shigella
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non-lactose fermenting, bloody diarrhea
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Campylobacter jejuni
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Bloody diarrhea (esp kids) Fecal-oral, poultry, meat, milk Comma or S shaped, grows at 42 deg, oxidase pos Guillain-Barre
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Vibrio cholerae
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rice-water diarrhea via toxin> Act Gs> Inc cAMP; Comma-shape, oxidase pos, alkaline media
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Yersinia enterocolitica
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pet feces, milk, pork diarrhea in daycare Mesenteric Adenitis (mimic IBD)
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Helicobacter Pylori
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Triple Therapy 1 PPI 2 Clarithromycin 3 Amoxicillin or Metronidazole gastritis & 90% duodenal ulcers gastric adenocarcinoma & lymphoma Gram neg rod, urease pos, alkaline env
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Leptospira interrogans
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question-mark shaped, water (animal urine), surfers Flulike, jaundice, photophobia w/conjunctivitis Weil's dz: severe form jaundice & azotemia liver & kidney dysfunction, fever, anemia, hemorrhage
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Rickettsial w/ no rash
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Ehrlichiosis (tick): Granulocytes w/ berry cluster orgs Q fever Coxsiella brunetii; Pneumonia; (aerosol, tick feces & cow placenta) Q fever is Queer cuz no rash rx: Doxycycline
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Mycoplasma pneumoniae
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atypical pneumonia gold aglutinins; Eaton's agar, no cell wall, *Only bacteria w/ cholesterol military & prison rx: Tetracycline or Erythromycin
