micro Flashcards
What is deficient in ataxia telangiectasia?
IgA
What is the treatment of Di George syndrome?
Transplant of fetal thymus
How do you differentiate Scalded Skin Syndrome (Ritter’s Disease) from TEN (Lyell Disease)?
Separation occurs at STRATUM GRANULOSUM in Ritters disease vs. separation at DERMO EPIDERMAL JUNCTION at Lyell Disease
What 3 diseases present with a strawberry tongue?
Toxic shock syndrome, Kawasaki disease, Scarlet fever
What is the DOC for VRSA?
Linezolid
What is the 2nd most common cause of UTI in sexually active women?
Staph saprophyticus
Most common bacterial cause of sore throat?
Strep pyogenes (group A beta hemolytic streptococci)
What facilitates cellulitis caused by Strep pyogenes?
Hyaluronidase (spreading factor)
Rash begins in the trunk then spreads to the extremities but spares the face
Scarlet fever
What test is used to determine a patient’s susceptibility to scarlet fever?
Dick test
Most common cause of neonatal pneumonia, sepsis and meningitis
Strep agalactiae (GBS)
Differentiate Strep pyogenes from Strep agalactiae
B - BRAS: gBs Resistant, gAs Sensitive
Gram positive “lancet-shaped” cocci in pairs or short chains
Strep pneumoniae
What bacteria is sensitive to optochin and exhibits a (+) Quellung reaction?
Strep pneumoniae
Most common cause of subacute endocarditis?
viridans Streptococci (S. sanguis)
Aerobic, gram (+) box car like rods, spore forming
Bacillus anthracis
DOC for cutaneous anthrax
Ciprofloxacin
The capsule of Bacillus anthracis is unique, what is it made of?
poly-D-glutamic acid
What gram (+) bacteria causes ophthalmitis described as no light perception within 48hrs of traumatic eye injury?
Bacillus cereus
What is the DOC for Bacillus cereus?
None. Symptomatic treatment only. (Tricky!!)
What anaerobic gram (+) bacteria looks like a tennis racket?
Clostridium tetani. Due to the presence of a terminal spore
What are the most common immunologic types of C. botulinum in humans?
Types A, B and E
What makes up the triad of Botulism?
Symmetric descending paralysis, absence of fever, and intact sensorium
Anaerobic, gram (+), non motile bacteria that grows on egg yolk agar
Clostridium perfringens
What toxin is involved in Gas Gangrene?
Alpha toxin - Clostridium perfringens
Gram (+) bacteria that exhibits double hemolysis on blood agar
Clostridium perfringens
What is the most common cause of antibiotic associated diarrhea?
Clindamycin
Non-motile, gram (+) club/comma shaped rods arranged in a V or L shape that looks like chinese characters
Corynebacterium diphtheriae
What test do you use to detect toxigenicity of Corynebacterium diphtheriae?
Modified Elek test
Metachromatic granules of Corynebacterium diphtheriae
Babes-ernst granules or Volutin granules
Where do you culture Corynebacterium diphtheriae?
Tellurite plate
Gram (-), kidney bean diplococci with an insignificant capsule
Neisseria gonorrhea
Gram (-) diplococci that ferments maltose and glucose
Neisseria meningitidis
Classic medium for culture of Neisseria meningitidis
Thayer - Martin VCN media
Most severe form of meningococcemia that results to adrenal insufficiency
Waterhouse - Friderichsen Syndrome
What do you call the rash in meningococcemia?
Purpura fulminans
DOC for Neisseria gonorrhea
Ceftriaxone + Doxycycline
Perihepatitis associated with gonorrhea
Fitz - Hugh - Curtis Syndrome
What is the most common cause of epiglottitis?
H. Influenzae
Most common cause of COPD exacerbations?
H. Influenzae
2nd most common cause of otitis media
Non - typable H. Influenzae
Most common cause of septic arthritis in infants
H. Influenzae
Where do you culture Bordetella pertussis?
Bordet - Gengou agar or Regan Lowe charcoal medium
What toxin causes whooping in B. Pertussis infection?
Tracheal cytotoxin
What organism causes Pontiac Fever? Described as a mild flu-like illness
Legionella pneumoniae
What E. coli toxin causes bloody diarrhea?
Verotoxin (shiga-like)
What causes traveler’s diarrhea or Montezuma’s Revenge?
Enterotoxigenic E. Coli
What teat detects Salmonella antibodies in the patient’s serum?
Widal Tests
What causes Salmonella setpticemia?
Salmonella choleraesuid
Where does the chronic carrier state of Salmonella typhi occur?
Gallbladder - treated with Ampicillin or cholecystectomy
Where is Shigella and Salmonella cultured?
XLD (xylosine lysine deoxycholate) medium
Gram (-), non-lactose fermenting rod, non-motile. Humans are its only host.
Shigella
Most common cause of bacillary dysentery
Group D: Shigella sonnei - Duval’s bacillus
Most severe form of bacillus dysentery. Also the most common cause of epidemic dysentery.
Group A: Shigella dysenteriae type 1 - Shiga bacillus
Bacteria found in contaminated raw seafood and among shellfish handlers
V. parahaemolyticus and V. vulnificus
True or False: Shigella has a low infectious dose making it highly virulent
TRUE
What is the toxin released by cholera?
Choleragen
What is the culture medium of cholera?
TCBS (thiosulfate citrate bile salts) agar
Short term immunity with the cholera vaccine may cause?
Herd immunity
Comma shaped, gram (-) rod that grows well on Skirrow’s agar
Campylobacter jejuni
True or false: V. Cholera is the most common cause of bacterial gastroenteritis
False - most common is Campylobacter jejuni
What are the 2 disease associations of Campylobacter jejuni infection?
Guillain-Barre Syndrome and Reiter’s Syndrome
Triad of Reiter’s Syndrome
Urethritis, Uveitis, and Arthritis
H. Pylori is the most common cause of?
Duodenal ulcers
What organism is associated with “currant jelly sputum”?
Klebsiella pneumoniae - necrotizing pneumonia
What are struvite stones made of and what organism is this associated with?
Magnesium ammonium phosphate, Proteus mirabilis
What is the medium used to culture Pseudomonas aureginosa?
Cetrimide agar
Gram (-) rod, obligate aerobe, non-lactose fermenting which gives a green-blue stain on wound dressings
Pseudomonas aureginosa
Organism responsible for malignant otitis externa among diabetics
Pseudomonas aureginosa
Predominant anaerobe of the human colon
Bacteroides fragilis
Only 2nd gen cephalosporin with good anaerobic coverage. Used to treat Bacteroides fragilis infections.
Cefoxitin
What is the treatment for undulating fever?
Brucella abortus (Brucellosis) - doxycycline plus rifampicin
Gram (-) rod with bipolar (safety pin) staining
Yersenia pestis
Assay used to determine drug resistance for Mycobacterium tuberculosis
Luciferase assay
Most important virulence factor in TB
Cord factor
Radiologically detectable calcification in TB
Ranke’s complex
Differentiate primary complex TB from reactivation TB
Primary - middle or lower lobes. Reactivation - apices.
Culture medium of M. Leprae
Mouse footpads, armadillo
Most common presentation of TB in adults? In children?
Adults - cough. Children - weight loss.
DOC for acute flare-ups of Lepromatous Leprosy
Erythema nodosum leprosum - Thalidomide
Medium for the smallest free living organism
Eaton’s culture - Mycoplasma pneumoniae
Most common infectious cause of Stevens-Johnson syndrome
Mycoplasma pneumoniae (walking pneumoniae)
Gram (+), beaded, filamentous anaerobic organism that grows as normal flora in the mouth
Actinomyces israelii
Fite-Faraco stain can be used on what 2 organisms?
M. Leprae and Nocardia asteroides
Tiny gram (-) bacteria that look like corkscrews
Spirochetes
Specialized flagella of spirochetes that run sideways along the organism under the outer membrane sheath
Periplasmic flagella
Cause of death of congenital syphylis
Pulmonary hemorrhage
What is the Hutchinson Triad seen in congenital syphylis?
Hutchinson teeth, deafness, keratitis
Pupils that accommodate but do not react seen in Tertiary Syphylis
Argyll Robertson pupils or Prostitute’s Pupil
What is the screening test for syphylis?
RPR-VDRL
Confirmatory test for Syphylis
FTA-ABS
Diagnostic lesion in secondary Syphylis
Condyloma lata
Influenza-like symptoms few hours after receiving penicillin
Jarisch - Herxheimer Reaction
Organism responsible for a firm, ulcerated painless lesion with a punched out base and rolled edges
Treponema pallidum, chancre of primary syphylis
What 2 bacteria exhibit a CSF analysis with lymphocytic predominance?
Treponema pallidum, Mycobacterium tuberculosis
DOC for Treponema pallidum infection
Syphilis - Benzathine penicillin G
Largest medically important bacteria
Borrelia burgdorferi
Lyme disease is caused by a bite from?
Deer tick (Ixodes scapularis)
DOC for Borrelia burgdorferi infection
Lyme Disease - Doxycycline
Pathognomonic lesion for Borrelia burgdorferi infection
Lyme disease - erythema chronicum migrans
DOC for Relapsing Fever
Borrelia recurrentis - Doxycyline or erythromycin
Transmission of relapsing fever is through?
Human body louse - Pediculus humanus
Obligate aerobe with a Shepherd’s crook appearance. In what medium does it grow?
Leptospira interrogans - EMJH or Fletcher’s Medium
Gold standard in diagnosing Leptospirosis
Leptospire Microscopic Agglutination Test (MAT)
Pathogenesis of meningitis and glomerulonephritis in Leptospirosis
Immune complex mediated
CXR finding in Leptospirosis pulmonary involvement
Snow flake lesion
Weil’s Triad
Leptospirosis - jaundice, bleeding, uremia
Most common COD in Leptospirosis
Massive pulmonary hemorrhage
Most common STD overall. Obligate intracellular bacteria, uses host ATP
Chlamydia trachomatis
Most common cause of infectious blindness
Trachoma - Chlamydia trachomatis
Cytoplasmic inclusion bodies near the nuclei of conjunctival epithelial cells in trachoma
Halberstadter - Prowazek inclusions
Characteristic cough in neonatal pneumonia caused by Chlamydia trachomatis
Staccato cough
Organism that causes Bird Fancier’s Disease
Chlamydia psittaci
Test to confirm the diagnosis of Rickettsiae
Weil - Felix Reaction
Gram (-) rod responsible for Cat Scratch Disease
Bartonella henselae
What is the presentation of Cat Scratch Disease in immunocompetent patients? Immunocomprised?
Immunocompetent - cat scratch fever, Immunocompromised - bacillary angiomatosis
Tick that transmits Ehrlichiosis
Ehrlichia chaffeensis - Dermacentor (dog tick)
Gram (-) rod presenting as a painful genital ulcer
Haemophilus ducreyi - Chancroid
Gram (-) rod that causes Mesenteric Adenitis
Yersenia enterocolitica
Encapsulated, pleomorphic gram (-) bacillus with bipolar densities
Klebsiella granulomatis (Donovanosis) - Donovan bodies that look like closed safety pins
Clinical presentation of Granuloma inguinale
K. Granulomatis - beefy red ulcer, pseudobuboe formation
Essential sterol in fungi
Ergosterol
Toxin of Aspergillus flavia that causes Liver Ca
Aflatoxin, found in peanuts and grains
Most common agar used to diagnose fungal infections
Sabourad’s agar
Organism responsible for Tinea Versicolor or An-An. What is its appearance on KOH?
Malassezia furfur - spaghetti and meatballs appearance
Treatment for Rose Gardener’s Disease
Sporotrichosis (Sporothrix schenckii) - Itraconazole or Potassium iodide
Infection with Coccidioides immitis. What is the characteristic lesion?
Valley Fever - erythema nodosum or Desert Bumps
Infective form of Histoplasma capsulatum. Common in bird and bat droppings
Inhaled Micronidia
Fungal infection that mimics TB
Histoplasmosis - Histoplasma capsulatum
DOC for all systemic mycoses
Itraconazole or Amphotericin B
Round yeast with broad based bud. Most common cause of fungal pneumonia
Blastomycosis - Blastomycosis dermatitidis
Yeast with multiple buds in wheel configuration. Found in Central and South America
Paracoccidioides brasiliensis
Organism that causes pseudomembranous esophagitis in immunocompromised hosts
Candida albicans
Abundant in pigeon droppings, most common cause of meningoencephalitis in AIDS patients
Cryptococcus neoformans - oval yeast with a narrow base bud
Exist only as molds. Hyphae form V shaped branches in acute angles (<90)
Aspergillus fumigatus
Fungus that commonly infects patients with diabetic ketoacidosis, burn patients, leukemia
Mucormycosis - Rhizopus oryzae and Mucor spp. Rhino-orbital-cerebral infection.
DOC for PCPo
Trimethroprim-sulfamethoxazole
Diagnostic methods for PCP
Broncheoalveolar washings (toluidine blue and methenamine silver stain) - hat shaped cells. CXR - ground glass infiltrates (ARDS).
Causes spongiform encephalopathies and pathogenic as beta pleated sheets
Prions
True of False: Among viruses, purified nucleic acids of most dsDNA and (+) strand genome ssRNA viruses are infectious
TRUE
Enzyme required by (-) strand RNA virus to undergo translation in the host cell
RNA - dependent RNA polymerase
Only live attenuated vaccine that can be given to HIV (+) patients
MMR
Smallest icosahedral virus with a single strand of DNA
Parvovirus
Erythema infectiosium
Parvovirus B19 - Fifth disease
Hydrops fetalis is common among infants with what viral infection and during what trimester
Parvovirus B19 - 2nd trim
Only virus with fiber. Causes URTI symptoms and hemorrhagic cystitis
Adenovirus - Cowdry type B intranuclear inclusions on histopathology
Condition caused by JC Polyoma virus among immunocompromised patients
Progressive Multifocal Encephalopathy - affects oligodendrocytes
Inactivate tumor suppressor genes in HPV infection
Genes E6 and E7
DOC for herpes simplex virus
Acyclovir
Site of latency of HSV 1? HSV 2?
HSV 1 - trigeminal ganglia. HSV 2 - lumbosacral ganglia.
Histopathology finding in HSV
Cowdry Type A - large, pink to purple intranuclear inclusion cyts
Smear used to diagnose HSV
Tzanck smear - multinucleated giant cells
VZV affecting geniculate ganglion causing facial nerve paralysis
Ramsay Hunt Syndrome
Virus that is cultured in shell tubes with a (-) heterophil test
Cytomegalovirus
Histopathology of the virus reveals giant cells with owl’s eye nuclear inclusions
Cytomegalovirus
Virus that infects B lymphocytes
Epstein - Barr Virus
Rare complication of Infectious Mononucleosis
Splenic rupture - EBV (kissing disease)
Cancers associated with EBV
Burkitt’s lymphoma, Nasopharyngeal Ca
Malignancy of vascular endothelial cells. Lesions are dark purple, flat to nodular, and appear at multiple sites.
Human herpesvirus 8 - Kaposi’s sarcoma
Histopathology of Smallpox
Variola virus - Guarnieri bodies
DOC for CMV infections
Ganciclovir
Virus that produces papular skin lesions with an umbilicated center and Henderson - Peterson bodies on histopathology
Molluscum contagiosum
Only DNA virus that produces DNA by reverse transcription with mRNA as the template
Hepa B
Autoimmune vasculitides associated with Hepa B infection
Polyarteritis nodosa
Hepatitis virus associated with Hepatocellular Ca
Hepatitis B
Virus that replicates in motor neurons in the anterior horn of the spinal cord causing paralysis
Poliovirus
Histopathologic findings in Poliomyelitis
Cowdry type B intranuclear inclusions
Most common cause of viral myocarditis and pericarditis
Coxsackie B
Organisms responsible for the common cold
Rhinovirus, Coronaviridae
Most common cause of non bacterial diarrhea in adults
Norwalk Virus
Most common cause of childhood diarrhea
Rotavirus
Virulent spikes in Influenza virus
Hemagglutinin, Neuraminidase
Type of Influenza that does not cause outbreaks
Influenza C
The only human Influenza virus, there is no animal source
Influenza B
DOC for Influenza B and C
Oseltamivir or Zanamivir
DOC for Influenza A
Amantadine or Rimantidine
Pathognomonic histopathologic finding in Measles (Rubeola)
Multinucleated giant cells - Warthin Finkeldey Bodies
True or False: A patient with Rubeola presenting with rash is still infective
FALSE
DOC for a virus with fusion proteins as surface spikes and is the most important cause of pneumonia and bronchiolitis in infants
RSV - Ribavirin
CXR finding in Croup
Parainfluenza 1 and 2 - Steeple sign
Bullet shaped enveloped virus
Rabies virus
Histopathologic finding in Rabies Virus
Intracytoplasmic Negri Bodies
Vector of Breakbone Fever
Dengue virus - Aedes aegypti
Most prevalent blood borne pathogen
Hepatitis C virus
Most common indication for liver transplantation
Cirrhosis secondary to Hepa C infection
Group specific antigen that serves as an important serologic marker of infection
p24
Reason behind the numerous antigenic variants of HIV
gp120
HIV regulatory gene that decreases CD4 and class I MHC proteins
nef
Main immune response against HIV
Cytotoxic CD8+ lymphocytes
Definitive diagnostic test for HIV
Western blot
Laboratory exam in HIV patients that is used for prognostication
PCR - can determine viral load
Define HAART
2 nucleoside inhibitors (zidovudine and lamivudine) and 1 protease inhibitor (indinavir)
Histopathology finding of malignant T cells with flower shaped nucleus
Human T Cell Lymphocytic Virus
Thread-like viruses with 100% mortality rate due to profound capillary leak and hemorrhage
Ebola Virus
Flavivirus with a bird-mosquito-man cycle. May progress to neuroinvasive disease
West Nile Virus
Most common cause of epidemic encephalitis, transmitted by Culex mosquitoes
Japanese B Virus
CT scan findings on Japanese B Encephalitis
Thalamic infarcts
Free living organism that passes through the digestive tract without infecting the host
Spurious parasite
True or False: The definitive host harbors the larval/asexual stage
False - the definitive host is where the parasite attains sexual maturity, the intermediate host is where the you can find the larval/asexual stage of the parasite
Protozoa that exhibits Brownian movement
Entamoeba histolytica
Characteristic lesion in Amebic colitis
Flask shaped colon ulcers
DOC for E. histolytica cyst carrier state? Amebic colitis?
Cyst - Filoxanide furoate, Colitis - Metronidazole
Protozoa with a falling leaf motility, adheres to the SI and causes malabsorption
Giardia lamblia - diarrhea and flatus that smells like rotten eggs
Acid fast protozoa that causes diarrhea in immunocompromised patients, with thick walled oocysts. . Treatment?
Cryptosporidium parvum, treat with Nitazoxanide
Sexually transmitted protozoa that exists only as a pear shaped, flagellated trophozoite
Trichomonas vaginalis
Most important parasitic disease in man
V. Plasmodium
True or false: Individuals with RBC defects are immune to malaria
TRUE
Which malarial vector has the worst clinical scenario
P. falciparum
What malarial species causes Recrudescence?
P. falciparum and malariae - recurrence of symptoms after 2 to 4 weeks
Diagnostic exam for Malaria
Thin and thick smears with Giemsa stain
What malarial dots are seen in the different species?
Schuffner - ovale and vivax, Maurer - falciparum, Ziemann - malariae
Organism that causes hemolytic anemia, Durck granulas, blackwater fever, and septic shock (algid)
Malaria - cerebral
Vector of Trypanosa cruzi
Reduviid bug
Infective stage of Trypanosoma cruzi
Trypomastigotes
Diagnosis and treatment for Chagas Disease
Trypanosoma cruzi - Xenodiagnosis, treat with Nifurtimox
Organism responsible for African Sleeping Sickness
Trypanosoma brucei gambiense and rhodesiense
Posterior cervical lymph node enlargement seen in African Sleeping Sickness
Winterbottom Sign
Plasma cells with cytoplasmic immunoglobulin globules seen in encephalitis caused by African Sleeping Sickness
Mott Cells
Most common cause of red tide in the Phil
Pyrodinium bahamense var compressum
Transmission of red tide
Dinoflagellates in bivalve mollusks
Only ciliated protozoan to cause human disease
Balantidium coli
Classic maltese cross on blood smear. Vector?
Babesia microti. Ixodes rick, can have a co-infection with Lyme disease
Vector of Leishmaniasis
Sandfly (Phlebotomus)
DOC for Leishmaniasis infections
Antimony compounds - Stinogluconate
Treatment for all cestodes
Praziquantel - except E. granulosus (Albendazole)
Which tapeworm can cause neurocysticercosis and worms in vitreous humor?
Taenia solium (pork tapeworm)
Cestode infection that causes megaloblastic anemia due to Vit B12 deficiency
Diphyllobothrium latum (fish tapeworm)
Organism that causes Hydatid cysts in the liver which may lead to an anaphylactic reaction if ruptured
Echinococcus granulosus
Treatment for hydatid cysts
Albendazole, PAIR procedure
Most common tapeworm in developed countries. Contain polar filaments and six hooked larva
Hymenolepsis nana
DOC for all trematodes
Praziquantel
Intermediate host of Schistosoma japonicum
Snail - Oncomelania hupensis quadrasi
Diagnosis of Schistosoma
Circumoval precipitin test - demonstrates ovoid egg with small hook
Illness caused by Schistosoma that presents with fever, hives, headache, weight loss, cough
Katayama Fever
Trematode with melon-like ridges on Potassium permanganate stain (KMnO4)
Clonirchis sinensis
Ca associated with Clonorchis sinensis chronic disease
Cholangiocarcinoma (Klatskin’s Tumor)
Sheep liver fluke presenting with objstructive jaundice and painful pharyngitis
Fasciola hepatica - Halzoun (from eating watercress)
Intestinal fluke that mimics peptic ulcer disease
Heterophyes heterophyes
Hypersensitivity pneumonitis seen in ascaris infection
Loeffler’s syndrome
Nematodes that causes microcytic hypochromic anemia and cutaneous larva migrans
Necator and Ancylostoma
Kato katz reveals barrel shaped eggs with bipolar plugs
Trichuris trichiura
Whipworm infection results to this disease from increased peristalsis to expel the worms
Trichuris trichiura - rectal prolapse
Pinworm that causes pruritus ani. What is the appearance of the eggs on Graham’s scotch tape technique?
Enterobius vermicularis - D shaped eggs
DOC for pinworm
Enterobius vermicularis - Pyrantel pamoate
Medium for the diagnosis of Strongyloides stercoralis
Harada - Mori Culture
DOC for Strongyloides stercoralis infection
Ivermectin
Only nematode whose life cycle involves a migratory bird
Capillaria philippinensis
Diagnostic findings of Capillaria philippinensis in Kato katz
Peanut shaped eggs with flattened bipolar plugs
Clinical presentation of Wuchereria and Brugia
Wuchereria - hydrocoele, Brugia - elephantiasis
Most debilitating nematode infection, common among abaca farmers
Wuchereria and Brugia
Infective stage of hydrocoele and elephantiasis
Wuchereria and Brugia - 3rd stage larvae
Small epithelioid granulomas in Wuchereria and and Brugia
Meyers - Kouvenaar Bodies
Nematode that invades striated skeletal muscle and is encysted within a host derived cell
Trichinella spiralis - Nurse cell
DOC for Trichinella spiralis
Thiabendazole
Vector of Onchocerca volvulus
Female blackfly (Simulium) - river blindness
DOC of Onchocerca volvulus and SE of lysis of worms
Ivermectin - Mazzotti Reaction
Transmitted by deer or mango fly (Chrysops)
Loa Loa - worm crawling across conjuctiva and Calabar swellings (subcutaneous edema)
Guinea fir worm, live worm in skin ulcer
Dracunculus medinensis - ingestion of copepods in water
Visceral larva migrans, dog ascaris
Toxocara canis
Most common cause of parasitic eosinophilic meningitis
Angiostrongylus cantonensis
Etiology of eosinophilic gastroenteritis
Anisakis simplex
