Step 1 - Micro (STDs, UTIs, Diarrhea, Meningitis, Arthropod)

denniskwinn's version from 2015-04-26 02:22


Question Answer
Opportunistic infections and neoplasmsHIV/AIDS
Koilocytotic cells and possible progression to
- Squamous cell carcinoama (types 16, 18)
-Condylomata acuminata (types 6, 11)
HPV ,Anogenital warts
Painful ulcers on external genitaliaChancroid, Haemophilus ducreyi
Painful ulcerative lesions on genitalia,Fever and swelling of regional lymph nodes Genital herpes, Herpes simplex virus 2
- Multiple ulcerating granulomatous lesions in inguinal region and genitalia.
- Donovan bodies (intracellular bacteria) seen in biopsy or smear
Granuloma inguinale,
Calymma-to-bacterium granulomatis
Acute jaundice, rash, arthritis, nausea, RUQ painHepatitis, Hepatitis virus (types B, C)
-Painful genital lesions
-Draining lymph nodes
-Rectal strictures in women
Lymphogranuloma venereum, Chlamydia trachomatis (types L1 to L3)
(Leaky Lymphs, Lines)
Hard, painless chancres on genitalia (primary) Gray wart-like, painless lesions (condylomata lata), fever, lymphadenopathy, skin rash (secondary), gummas, neurologic manifestations (tabes dorsalis, dementia), ascending aortic aneurysm (tertiary)Syphilis, Treponema pallidum
Vulvovaginitis with frothy discharge; usually asymptomatic in menTrichomoniasis, Trichomonas vaginalis
Coinfection common Acute PID,Urethritis, cervicitis.
C. trachomatis (types D to K),Neisseria gonorrhoeae
Coinfection common Acute PID with Conjunctivitis and Reiter syndrome(chlamydia)
Coinfection common Acute PID with Arthritis and pharyngitis(gonorrhea)


Question Answer
E coliGram negative, no capsule, metallic-green colonies on EMB agar, MC cause of UTIs (50% to 80%)
Staphylococcus saprophyticusGram positive, coagulase negative, resistant to novobiocin, 2nd MC cause of UTIs in young women (10% to 30%)
Proteus mirabilis
Gram negative, urease positive, swarming growth on agar, Associated with struvite urinary stones
Klebsiella pneumoniae
-Gram negative, nonmotile, prominent capsule, large mucoid colonies

-Usually in catheterized patients
Enterobacter speciesGram negative, motile, capsule, grey-moist colonies, often drug resistant, Usually in immunocompromised patients
Pseudomonas aeruginosaGram negative, oxidase positive, fruity odor, blue-green pigment, Usually in patients with kidney stones, chronic prostatitis, or a catheter
Enterococcus faecalisGram positive, variable hemolysis, salt tolerant (6.5% NaCl), Usually in immunocompromised or catheterized patients
(lower UTI)
1. Most commonly caused by E. coli.
2. Higher incidence in women
3. Dysuria, frequency, urgency, suprapubic pain
4. Not accompanied by bacteremia
(upper UTI):
1.flank pain, fever, chills, dysuria
2. Results from ascension of bacteria from infected bladder
3. May be accompanied by bacteremia

Diarrheas=type,toxin?,factoid (BOTH)pt1

Question Answer
Vibrio cholerae1.Watery (NI)
2. toxin (↑ cAMP)
3. Rice-water stools, vomiting, dehydration
Bacillus cereus1. Watery (NI)
2. Enterotoxins (preformed)
3. Reheated rice and beans, rapid onset
Campylobacter jejuni1. Watery or bloody (I)
2. Undercooked meats and poultry, unpasteurized milk; fever, cramps;
-May last 3 to 4 weeks
Clostridium difficile1. Watery or bloody (I)
2. Toxin A (cholera-like); toxin B (cytotoxic)
3. Antibiotic use; pseudomembrane
Clostridium perfringens(type A)1. Watery (NI)
2. Heat-labile enterotoxin (disrupts ion transport)
3. Leftover meat and poultry dishes
Escherichia coli (EHEC)1.Bloody (I-I)
2. Shigatoxin (Vero-toxin)
3. Undercooked hamburger; hemorrhagic colitis, hemolytic uremic syndrome (strain O157:H7)
Escherichia coli (ETEC)1. Watery (NI)
2. Cholera-like enterotoxin
3. Heat-labile (↑ cAMP); heat-stable enterotoxin (↑ cGMP)
4. Traveler's diarrhea; fever and vomiting sometimes
Salmonella species1. Watery or bloody (I and I-I)
2. No toxin
3.Often food-borne (eggs or poultry); typhoid fever (invasive Salmonella typhi)


Question Answer
Shigella species1. Watery, then bloody (I)
2. Shiga toxin inhibits protein synthesis
3. Mild disease (Shigella sonnei) common in day care centers; severe invasive disease (Shigella flexneri, Shigella dysenteriae)
Staphylococcus aureus1. Watery (NI)
2. Enterotoxins (preformed)
3. Picnic foods (cold cuts, potato salad), custards; nausea, vomiting; rapid onset
Vibrio parahaemolyticus1. Watery (I and I-I)
2. No toxin
3. Shellfish
Yersinia enterocolitica1. Watery (I-I)
2. N toxin
3. Cabbage, other raw vegetables, cheese
Norovirus1. Watery (NI)
2. No toxin
3. Often in outbreaks (schools, ships); nausea, vomiting, fever sometimes
Rotavirus1. Watery (NI)
2. No toxin
3. Infants, winter months; fever, vomiting, dehydration
Cryptosporidium species1. Watery (NI)
2. No toxin
3. Large fluid loss; most common in immunocompromised patients
Entamoeba histolytica1. Bloody (I)
2. No toxin
3. Amebic dysentery; lower abdominal pain, mucus and blood in stools
Giardia lamblia1. Watery (NI)
2. No toxin
3. Contaminated stream water (campers, hikers);fatty, foul-smelling stools

Diarrhea A/W

Question Answer
Poultry bugSalmonella enteritidis, Campylobacter species
Raw eggs bugSalmonella enteritidis
Dairy products bugListeria monocytogenes, Brucella species, Mycobacterium bovis
Shellfish bugVibrio species
Reheated rice bugBacillus cereus
Undercooked beef bugEscherichia coli O157:H7, B. cereus, Brucella species, C. perfringens
Picnic foods (mayonnaise, custard, salted meats) bugS. aureus toxin mediated
1 to 6 hours onsetS. aureus and Bacillus cereus (preformed toxin)
8 to 16 hours onsetClostridium perfringens and B. cereus (toxin produced after infection)
24 to 48 hours onsetNorwalk virus and rotavirus
48 hours onsetE. coli (ETEC) and Vibrio cholerae (toxin produced after infection)
More than 24 hours onsetE. coli (EHEC); Shigella, Salmonella, and Campylobacter species; Yersinia enterocolitica, Entamoeba histolytica, and Giardia lamblia (adherence, growth, invasion)



Question Answer
Bacterial meningitis1)Neisseria meningitidis* (Accompanied by petechiae, capsule) , 2)Streptococcus pneumoniae* (Capsule)
3) H influenzae (Capsule)
4)Listeria monocytogenes
5)Mycobacterium tuberculosis
Neonatal meningitis1)Group B streptococci*
2) E coli*
3)Listeria monocytogenes*
Fungal meningitisCryptococcus neoformans (India ink test, capsule)
Viral (aseptic) meningitisEnteroviruses: Coxsackie, echo, polio, Lymphocytic choriomeningitis (LCMV), Mumps, Arboviruses, HSV (especially HSV-2)
Encephalitis-HSV*( Frontal lobe, nonseasonal, sequelae)
-Arboviruses: flavivirus (Japanese, West Nile, St. Louis)
-Togavirus (equine encephalitis)
-Bunyavirus (California)*(Seasonal, minimal sequelae)
-Measles, Mumps, Rabies (Treatable after infection)
Tropical spastic paraparesisHTLV-1
SSPE(Subacute sclerosing panencephalitis)Defective measles virus (Vaccine preventable)
Sx-seizures, myoclonus, photosensitivity
PML(Progressive multifocal leukoencephalopathy)JC polyoma virus=type of papovirus (In immunocompromised (e.g., AIDS))
Cerebral malariaMalaria+encephalopathy
-Caused by Plasmodium falciparum
 Neurologic syphilisTreponema pallidum
 Lyme diseaseBorrelia burgdorferi
Brain abscess-Various bacteria
-Toxoplasma gondii (especially neonates and AIDS)
Cysticercosistissue infection after exposure to eggs of Taenia solium, the pork tapeworm
 Spongiform encephalopathiesPrions: Creutzfeldt-Jakob disease agent
CSF findings in Bacterial meningitis↑pressure, ↑protein, ↓↓sugar, Normal lymphocytes, ↑PMNS
CSF findings in Viral meningitisNormal pressure, N or ↑ protein, Normal sugar, ↑ lymphocytes, Normal PMNs
CSF findings in Fungal meningitis, TB↑↑ pressure,↑protein,↓sugar,↑lymphocytes, Normal PMNs

Arthropod associated diseases (Cause, Vector, Location)

Question Answer
Lyme disease1. Borrelia burgdorferi
2. Tick (Ixodes species)
3. New England, West Coast
Epidemic relapsing fever1. Borrelia recurrentis
2. Louse
3. Europe, North Africa, India
Endemic relapsing fever1. Borrelia species
2. Tick
3. North and South America, Africa, Asia
Tularemia1. Francisella tularensis
2. Tick
3. Worldwide
RMSF1. Rickettsia rickettsii
2. Deer tick
3. Southeastern and (Dermacentor species) south-central United States
Epidemic typhus1. Rickettsia prowazekii
2. Louse
3. Worldwide
Murine typhus1. Rickettsia typhi
2. Flea
3. Southeastern United States, near Gulf of Mexico
Ehrlichia1. Ehrlichia species
2. Tick
3. Southeastern and south-central United States
Anaplasmosis1. Anaplasma phagocytophilum
2. Tick
3. Worldwide
Plague1. Yersinia pestis
2. Flea
3. Asia, Africa
Visceral leishmaniasis1. Leishmania donovani
2. Sandfly (Phlebotomus species)
3. Tropical and subtropical areas
Malaria1. Plasmodium species
2. Mosquito (Anopheles species)
3. Worldwide
African sleeping sickness1. Trypanosoma brucei
2. Tsetse fly
3. Africa
Chagas disease1. Trypanosoma cruzi
2. Reduviid bug
3. Latin America
Equine encephalitis (Eastern, Western, and Venezuelan)1. Alphavirus (togavirus)
2. Mosquito (different species)
3. North and South America
California encephalitis1. Bunyavirus
2. Mosquito (Culex species)
3. North America
Yellow fever1. Flavivirus
2. Mosquito (Aedes species)
3. South America, Africa
Dengue fever1. Flavivirus
2. Mosquito (Aedes species)
3. Tropics
St. Louis encephalitis1. Flavivirus
2. Mosquito (Culex species)
3. North America
West Nile encephalitis1. Flavivirus
2. Mosquito
3. Eastern United States, Africa, Asia
Colorado tick fever1. Reovirus
2. Wood tick
3. North America


Question Answer
Acute Endocarditis1. Rapid onset; usually involves previously normal valves
2. S. aureus (MC cause) and Strep pneumoniae
Subacute endocarditis1. Slow onset over months; usually involves diseased, abnormal, or prosthetic valves
2. Viridans streptococci (MC) and Enterococcus species
3. Staphylococcus epidermidis and S. aureus (particularly involving prosthetic valves)
4. HACEK organisms-Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella(Aseptic blood findings)
Toxic shock is caused1.By superantigen activation of T cells and massive cytokine release.
2. S. aureus TSST, Streptococcus pyogenes erythrogenic toxin A or C
Sepsis induces1. systemic release of acute phase cytokines
2. Toll-like receptor-mediated response of leukocytes to presence of bacterial cell wall components in blood
3. Usually gram-negative bacteria
Ear infections1. Otitis media, sinusitis in children
2. Strep pneumoniae, H. influenzae, Moraxella catarrhalis, anaerobes
3. Otitis externa (swimmer's ear)-P. aeruginosa
Osteomyelitis1. S. aureus in most individuals (especially children)
2. Salmonella in individuals with sickle cell disease
Congenital, neonatal complicationsTORCHES-TOxoplasma, Rubella virus, CMV, HSV, Syphilis