Step 1 Micro Review PDF

STEP 1 REVIEW MICROBIOLOGY - BACTERIA High-Yield Clinical Presentations - Sore throat Corynebacterium - Grey pseudomembranes - Inactivation of EF-2 diptheriae - Black eschar on skin Pseudomonas - Inactivation of E...

STEP 1 REVIEW MICROBIOLOGY - BACTERIA High-Yield Clinical Presentations - Sore throat Corynebacterium - Grey pseudomembranes - Inactivation of EF-2 diptheriae - Black eschar on skin Pseudomonas - Inactivation of EF-2 aeruginosa - Travel to another country - Severe watery diarrhea Vibrio cholera - Activates Gs -> cAMP - Step on a dirty nail - Spastic paralysis - Lock jaw (trismus) - - Bent spine (opisthotonus) Toxin prevents release of Clostridium tetani GABA and glycine - Baby eats honey - Adult eats canned food - Descending flaccid Clostridium botulinum paralysis, diplopia, dyspnea - Toxin cleaves snare and inhibits NT release - Necrosis of skin - Crepitus Clostridium perfringens - Toxin degrades tissue and membranes - Diarrhea after antibiotic use or hospitalization Clostridium difficile - Recent nose surgery or young female on menses - - Fever, rash, hypotension Toxin cross links TCR to Staph aureus MHC II - Infects catheters, valves - Biofilm production Staph. epidermidis - 2nd cause of UTI (painful, frequent urination) in a Staph. saprophyticus young female - Red, bulging tympanic membrane Step. pneumoniae - Ear pain - Infection after recent Strep. viridans (S. dentist visit mutans and S. mitis)  Strep. pyogenes - Sore throat with white exudate, no cough - M protein Ab, molecular mimicry - Baby with meningitis, pneumonia or sepsis Strep. agalactiae (Group - Screen mom at 35-37 wk B Strep) pregnancy Strep. Bovis (gallolyticus) - Underlying colon cancer in pt with fever and new murmur  Bacillus cereus - N/V 1-5 hours after eating rice - - Unpasteurized dairy, deli - Tumbling motility Listeria - Grows at low temp - Branching G+ rod - Acid-fast staining Nocardia - Lung infection - Branching G+ rod - Yellow sulfur granules Actinomyces - Face infxn after dentist - Fever, night sweats, weight loss, hemoptysis Mycobacterium tuberculosis - Caseating necrosis - IFNgamma for granulomas - Acid fast - Cavitation at apex of lung - AIDS pt with CD4 < 50 MAC - Skin and nerves affected - Immigrant Mycobacterium laprae - Lion like face - Young sexually active pt - Purulent discharge Neisseria gonorrhea - Antigenic variation of pilus - - - College student or military Fever, headache, stiff neck Neisseria meningitis - Drooling - Head forward gasping for air Haemophilus influenzae - X-ray of lateral neck shows thumbprint sign  Bordetella pertussis - Persistent cough - Cough then vomit - Exposed to contaminated - AC, water tank on cruise Legionella ship or in NH - Silver stain - Low sodium - Lung and abdomen sx Shigella - Bloody, mucoid stool - Invasion of M cells  Salmonella typhi - Travel to another country - Constipation and red spots on abdomen - Animal exposure - RLQ pain that mimics Yersinia - appendicitis - Kid gets bloody diarrhea EHEC after eating a burger - Low platelets, low Hb and Hct, high BUN and cr - PBS shows schistocytes  Klebsiella - Red jelly-like mucus in an alcoholic or DM pt - Bloody diarrhea after eating chicken or contact with a dog Camplyobacter - - Can lead to ascending paralysis - Skin inflammation after sea water exposure Vibrio vulnificus - Worse in liver disease  H. pylori - Burning pain after eating - Antrum of stomach - Urease producing, high pH - Bulls eye, target lesion on skin after hiking - - Ixodes tick bite Borrelia - Can lead to unilateral facial drooping - Water with rats running around nearby Leptospira - Jaundice, kidney issues - Multiple sexual partners - Organism seen on Treponema pallidum dark-field microscopy - RPR-VDRL, FTA-ABS positive - Painless genital lesion Primary syphilis - Rash on palms and soles Secondary syphilis - - Pupils constrict with accommodation but not to light Tertiary syphilis - Loss of touch, vibration, proprioception, + romberg  Congenital syphilis - Newborn with runny nose and linear scars at edge of mouth - Child with notched teeth - Purulent vaginal discharge - No organism seen on Chlamydiae gram stain - - EB infect, RB replicate - Painless genital lesion Lymphogranuloma venereum - Painful lymph node - Ixodes tick bite Borrelia, Anaplasma, Babesia - Cat scratches pt Bartonella - HIV pt gets purple spots - on skin - Infection after rabbit bite Francisella  Rickettsia - RMSF - Hiking then get rash on palms and soles - Rash on body Ehrlichia - Infects macrophages, mononuclear, monocytes - - Rash on body Anaplasma - Infects neutrophils, PMNs, granulocytes - Young, healthy pt gets nonproductive cough and Mycoplasma pneumonia diffuse infiltrate in lungs - Lacks cell wall - Grows on eaton agar - IgM, cold agglutination - Female has thin, grey, fishy vaginal discharge Gardnerella - Bacterial vaginosis - Epithelial cells covered in - bacteria (clue cells)  STEP 1 REVIEW MICROBIOLOGY - FUNGI High-Yield Clinical Presentations - Mississippi and Ohio - Macrophages filled with Histoplasma pathogen - Exploring caves, bird and bat droppings - Eastern, central US Blastomyces - Broad based budding - California, Arizona - - Circle shaped spherules Coccidiodes filled with endospores - Itching between toes, thick nails Dermatophytes (Microsporum, Trichophyton, - Flower shaped scaly, itchy lesions on Epidermophyton) head/body/inguinal region - Hypopigmented spots on back Tinea versicolor - Spaghetti and meatball - White patches in mouth - Candida albicans that scrape off - White thick vaginal discharge - Acute angle branching - Affects pt with low Aspergillus neutrophil count - AIDs pt + fever, headache, stiff neck Cryptococcus - India ink stain shows - organism w/ thick capsule neoformans - Pt with uncontrolled Mucor and Rhizopus diabetes - Black necrotic lesion around eye, nose area - AIDS pt + pneumonia - Diffuse bilateral interstitial Pneumocystis jirovecii lung infiltrates - Silver stain - Gardening - Pustules in a line across Sporothrix the skin (follows - lymphatics)  STEP 1 REVIEW MICROBIOLOGY - PARASITES High-Yield Clinical Presentations - Fatty smelly diarrhea after hiking/camping Giardia - RUQ pain and bloody Entamoeba histolytica diarrhea - - Liver abscess - Flask shaped ulcers - AIDS pt + watery diarrhea - Acid fast staining Cryptosporidium - Cat feces or undercooked meat Toxoplasma - AIDS pt + multiple ring enhancing lesions in brain - Baby + intracranial calcifications Naegleria fowleri - Death after swimming - Pathogen gets into cribiform plate - Transmitted by Tsetse fly - - Fever, sleepy T. brucei - Trypomastigote seen in blood smear - Travel outside of US - Fever comes and goes, P. vivax/ovale anemia - Ring form in RBCs - Hypnozoite in liver - No travel outside of US - Fever, anemia Babesia - Tetrads/cross form in RBCs - Travel to South America T. cruzi - - Big heart, colon, esophagus and eyes - Trypomastigote seen in blood smear - Transmitted by sandfly - - Organ or skin lesions Amastigotes in Leishmania macrophages - Green vaginal discharge - Punctate hemorrhages on cervix (strawberry cervix) Trichomonas - Motile organisms on wet mount Enterobius vermicularis - Child with itchy bum - Eggs seen on tape test - Lung and GI - Thick, knobby coated, Ascaris lumbricoides oval shaped eggs - Lung, GI, skin - Larvae in feces Strongyloides stercoralis - Walking barefoot at the - beach - Low Hb, Hct and MCV Ancylostoma, Necator (hookworm) - Itchy foot with picture of serpiginous rash on foot  Trichinella - Eat undercooked pork - Muscle pain - Black fly - Blindness Onchocerca - - Worm invades lymph nodes Wuchereria and Brugia - Lymphedema - Eat undercooked pork - Cysts in the brain Taenia solium - Seizures - Eat raw fish - Causes B12 deficiency D. latum - Eat dog feces - Eggshell calcifications Echinococcus - and cysts in liver - Anaphylaxis can occur due to rupture of cysts - Water with snails, immigrant - Bloody urine, bladder Schistosoma squamous cell carcinoma - Terminal spine on egg - Eat raw fish - Cause gallstones and Clonorchis cholangiocarcinoma Sarcoptes scabiei - Itching between fingers and toes - Lice (Pediculus humanus) - Itchy head, body or pubic itching  STEP 1 REVIEW MICROBIOLOGY - VIRUSES High-Yield Clinical Presentations - Painful vesicles around HSV mouth, genitals or finger - Latent, recurrent - Enveloped DS DNA virus - Fleshy, cauliflower shaped genital lesions HPV 6 and 11 HPV 16 and 18 - Postcoital bleeding - Friable cervix mass - HIV pt with demyelinated - plaques + memory decline JC Virus - PML - Non-enveloped SS DNA - Newborn with hydrops fetalis - Child with red cheeks, Parvovirus look like they got slapped - Low Hb, Hct, reticulocytes in SS pt (aplastic crisis) - Young, healthy pt with meningitis HSV - Temporal lobe affected - Child with vesicles in Varicella different stages of healing - Elder pt with painful vesicles on one side of trunk that doesn’t cross Zoster midline - Teenager with sore throat, enlarged liver and spleen, EBV avoid sports - Infects B cells - Atypical T cells seen on PBS - - AIDS pt with esophagitis and retinitis CMV - Owl’s eye inclusions - Associated with EBV nasopharyngeal carcinoma and Burkitt lymphoma HHV 6/7 - Baby gets a fever 1st, then gets rash later - AIDS pt gets dark purple lesions on the body HHV 8 - - Replicates in nucleus All DNA viruses except pox and retro/influenza - Common cold - Uses ICAM-1 receptor Rhinovirus - - Mosquito bite, travel, flaccid paralysis West Nile Virus - Cough, coryza, conjunctivitis, coplik spots in mouth, fever, Measles rash - Paramyxovirus - Fever, rash, Rubella lymphadenopathy - Baby with deafness, cataracts and PDA - Togavirus - - Fever, dry cough, SOB Loss of taste and smell COVID-19 - - Child with barking, seal Parainfluenza like cough, inspiratory stridor - Steeple sign on cxr - Bit by bat - Scared to drink water, Rabies drooling, fever - Negri bodies - Enlarged parotid gland - and testes Mumps - Can cause infertility - Unvaccinated child - Rash on palms, soles and inside mouth Coxsackie - Kid gets watery diarrhea Rotavirus (reovirus) - Fever after christmas shopping - Uses hemagglutinin for Influenza entry and neuraminidase - for release HTLV-1 - Adult T cell leukemia lymphoma  Chikungunya - Aedes mosquito bite - Joint pain, rash, fever - Hemorrhagic fever Dengue - Joint and muscle pain - Rash, neutropenia, thrombocytopenia, shock - Jaundice, black vomit - - Councilman bodies Yellow Fever - Travel to tropics - Baby with enlarged ventricles and Zika calcifications - Acute, self-limiting - Eat raw shellfish Hep A (RNA - picorna) Hep B (DNA - hepadna) - Chronic - Blood, bed, birth - Chronic Hep C (RNA - flavi) - IV drug use - - Requires Hep B to infect Hep D (RNA - delta) Hep E (RNA - hepe) - High mortality in pregnant patients - - Associated with mixed cryoglobulinemia (palpable purpura and joint pain), PCT (blisters Hep C on back of hands) - Associated with membranous GN and PAN Hep B Hep B Recovery - Anti-HBs and Anti-HBe positive - - Anti-HBs positive only Hep B Vaccine - Pt with scrapable white plaques in mouth gets fever, headache, stiff neck showing pathogen HIV staining with india ink - Use gp120 for attachment and gp41 for fusion - Binds to CCR5 on HIV macrophages, CXCR4 on CD4 T cells - Affects AIDS/transplant pt - Linear ulcers in CMV esophagus, cotton wool spots, owl eye inclusions  THANK YOU! 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