Bacte, USMLE Flashcards
What does Candida albicans do that distinguishes it from other fungi?
It forms a germinal tube at 37°C.
What protozoal parasite results in dysentery with blood and pus in the stool, is transmitted via fecal-oral route, is diagnosed by cysts or trophozoites in the stool, and forms liver abscesses and inverted flask-shaped lesions in the large intestine?
Entamoeba histolytica (treat with metronidazole)
What is the most likely causative organism for a patient with folliculitis after spending time in a Hot Tub?
Pseudomonas aeruginosa
What two viruses get their envelope not from budding but from coding?
HIV and poxvirus
Which type of hepatitis can cause hepatocellular carcinoma?
Hepatitis B
Gas gangrene is associated with which Clostridium species?
Clostridium perfringens
Which dimorphic fungus is found as hyphae with nondescript conidia in rotting wood in the Upper Great Lakes, Ohio, MIssissippi, eastern seaboard of the United States, and southern Canada?
Blastomyces dermatitidis
Which parasitic organism, when it crosses the placenta, results in intracerebral calcifications, chorioretinitis, microcephaly, hydrocephaly, and convulsions?
Toxoplasma gondii
What staphylococcal species is positive for b-hemolysis and coagulase?
Staphylococcus aureus
What vector is associated with malaria?
Anopheles mosquito
What is the term for hyphae with constrictions at each septum that are commonly seen in Candida albicans?
Pseudohyphae
Which cestode infection results in alveolar hydatid cyst disease?
Echinococcus multilocularis
Which hepatitis virus is in the Flaviviridae family?
Hepatitis C
What nonmotile gram-netative, non-lactose-fermenting facultative anaerobic rod uses the human colon as its only reservior and is transmitted by fecal-oral spread?
Shigella
What is the only Rickettsia that is stable in the environment?
Coxiella burnetii
Regarding the viral growth curve, is the internal virus present before or after the eclipse period?
After the eclipse period
What Ab is an indication of recurrent disease for hepatitis?
HBcAb
What small gram-positive, non-spore-forming rod is a facultative intracellular parasite that grows in the cold and is associated with unpasteurized milk products?
Listeria monocytogenes
What is the only DNA virus that is not icosahedral?
Poxvirus
Which organism causes trench mouth?
Fusobacterium
True or false? All of the following are inactivated vaccines available in the United States: influenza, Vibrio cholera, hepatitis A, rabies, and adenovirus.
False, Adnovirus vaccine is a live pathogenic virus in an enteric coated capsule. All of the others are inactivated vaccines.
No persistent liver stage or relapse; blood smear shows multiple ring forms and crescent-shaped gametes; irregular febrile pattern; associated with cerebral malaria
Plasmodium falciparum
No persistent liver stage or replapse; blood smear shows rosette schizonts; 72-hour fever spike pattern
Plasmodium malariae
Persistent hypnozoite liver stage with relapses; blood smear shows amoeboid trophozoites with oval, jagged infected RBCs; 48-hour fever spike pattern
Plasmodium ovale
Persistent hypnozoite liver stage with relapses; blood smear shows amoeboid trophozoites; 48-hour fever spike pattern; the most prevalent form worldwide
Plasmodium vivax
True or false? A positive PPD skin test indicates the patient has active pulmonary disease.
False. The PPD tests exposure to TB.
What Viral infection is known to cause intracerebral calcifications?
CMV; Toxoplasma also causes intracerebral calcifications but it is a parasite.
What viruses are associated with cervical carcinoma?
HPVs 16 and 18
What motile, gram-negative spiral bacillus with flagella is oxidase positive, urease positive, and associated with gastritis, peptic ulcer disease, and stomach cancer?
Helicobacter pylori
What glycoprotein in the HIV virus is used for fusion?
GP41
What Ag is needed to diagnose an infectious patient with hepatitis B?
HBeAg
Which organism causes multiple infections by antigen switching?
Borrelia recurrentis
What is the first Ag seen in an individual with hepatitis?
HBsAg (incubation period)
With which DNA virus are guanieri bodies associated?
Variola (smallpox)
What nematode is known as Pinworms? What is the treatment?
Enterobius vernicularis; the treatment is albendazole.
What protein allows Mycoplasma to attach to the respiratory epithelium?
P1 protein
Day care-associated diarrhea in infants
Rotavirus
Watery diarrhea from beef, poultry, or gravies
Clostridium perfringens
Rice water stools
Vibrio cholera
Diarrhea associated with raw or undercooked shellfish
Vibrio parahaemolyticus
Bloody diarrhea associated with hamburger ingestion
Enterotoxigenic Escherichia coli
Which fungus is found worldwide on plants, is a cigar-shaped yeast in tissue form, and results in rose gardner’s disease?
Sporothrix schenckii
Which type of hepatitis is a picornavirus?
Hepatitis A (infectious)
What gram-positive rod is distinguished by its tumbling motility?
Listeria
What is the vector for Leishmania infections?
Sandfly
What organism causes Q fever?
Coxiella burnetii
What are the three naked RNA viruses
1) Picornavirus
2) Calicivirus
3) Reovirus
HIV’s capsid, core nucleocapsid, and matrix proteins are products of what structual gene?
gag gene
What facultative intracellular fungus is associated with hepatosplenomegaly?
Histoplasma capsulatum infects the cells of the RES and can result in hepatosplenomegaly.
What type of hepatitis has the highest mortality rate among pregnant women?
Hepatitis E
Which gram-netative diplococcus ferments maltose?
Meningoccus (Gonococcus does not)
Are antibiotics helpful in treating a disease caused by a prion?
No. Prions are infectious proteins, so antibiotics are useless.
What bacterium is associated with hand-foot-and-mouth disease?
Coxsackie A
What is the only trematode that is not hermaphroditic?
Schistosoma have separate males and females.
What water-associated organism is a weakly stained gram-negative rod that requires cysteine and iron for growth?
Legionella (think air conditioners)
With what virus are Downey type II cells associated?
EBV
True or false? Interferons are eukaryotic proteins that inhibit viral replication by being virus specific.
False. Interferons are produced by virally infected cells to Inhibit viral replication via RNA endonucleases. They Do Not act directly on the virus, nor are they virus specific.
What is the vector for yellow fever?
Aedes mosquito
What small, facultative gram-negative intracellular rod’s transmission is associated with unpasteurized dairy products and undulant fever?
Brucella
True or false? All Proteus species are urease positive.
TRUE
Nails and skin only
Epidermophyton
Hair and skin only
Microsporum
Skin, hair, and nails
Trichophyton
What protein of the HIV virus does ELISA detect to determine whether a patient is HIV positive?
P24
What genus of bacteria is described by catalase-positive, gram-positive cocci in clusters?
Staphylococcus
True or false? Vibrio parahaemolyticus require NaCl in its growth medium.
True. Staphylococcus aureus and group D enterococci also grow in high-salt media.
What virus causes small pink benign wartlike tumors and is associated with HIV-positive patients?
Molluscum contagiosum
What two bacteria are associated with drinking unpasteurized milk?
Brucella and Listeria (has tumbling motility)
What cestode causes Cysticercosis?
Taenia solium
What DNA virus is associated with exanthem subitum (roseola)?
HHV 6
Which acid-fast rod is an obligate intracellular parasite?
Mycobacterium leprae
What form of the Plasmodium species is ingested by mosquitoes?
Gametocytes
What small gram-negative aerobic rod requires Regan-Lowe or Bordet-Gengou medium for growth?
Bordetella pertussis
True or false? Streptococci have catalase.
False. Staphylococci have catalase; Streptococci do not.
What 3 bacteria are positive to Quellung reactive test
1) Neisseria meningitidis
2) Hemophilus influenzae
3) Streptococcus pneumoniae
A patient goes to the ER with abdominal cramps, vomiting, diarrhea, and sweating less than 24 hours after eating potato salad at a picnic; what is the most likely responsible organism?
Staphylococcus aureus
True or false? All spore formers are gram positive.
TRUE
What is the only DNA virus that has the reverse transcriptase enzyme?
Hepadnavirus
What enzyme does HIV use to integrate the proviral dsDNA into the host?
Integrase
What are the two hepatitis viruses that can be chronic and can lead eventually to hepatocellular carcinoma?
Hepatitis B and hepatitis C
What gram-positive spore-forming anaerobic rod blocks the release of Ach at the NMJ, resulting in reversible flaccid paralysis?
Clostridium botulinum
Name at least two products of HIV’s pol gene.
Protease, integrase, and reverse transcriptase
What form of Plasmodium species affects the liver?
Hypnozoite
What small coagulase-positive, gram-negative rod with bipolar staining is a facultative intracellular parasite resulting in buboes?
Yersinia pestis
What hemoflagellate species is the cause of Chagas disease?
Trypanosoma cruzi
To what host cell receptor does the rabies virus attach?
ACh receptor
Which hepatitis virus is in the Picornaviridae family?
Hepatitis A
Abs to what hepatitis B Ag provide immunity?
Abs to HBsAg
What type of spore is defined as an asexual budding daughter yeast cell?
Blastoconidia
Eukaryotic cell, 15 to 25 microns, 80S ribosomes, no cell walls, replicates via cytokinesis with mitosis and meiosis
Parasites
Small prokaryotic cells; no histones; 70S ribosomes; no sterols in cell membrane; peptidoglycans in cell wall; replicate by binary fission
Bacteria
Eukaryotic cell; 3 to 10 microns; 80S ribosomes; chitinous cell wall; ergosterol in cell membrane; replicate via cytokinesis with mitosis and meiosis
Fungi
Acellular; some are enveloped; replicate within the host cell; no cell walls
Viruses
What mosquito is the vector for dengue fever?
Aedes (the same for yellow fever)
True or false? Gonococcus is encapsulated.
False. Meningococcus is encapsulated; Gonococcus is not.
What virus is associated with Guarnieri bodies?
Variola virus
Regarding the viral growth curve, is the external virus present before or after the latent period?
After the Latent period
What aerobic branching rod that is gram positive and partially acid-fast is associated with cavitary bronchopulmonary disease in immunosuppressed patients?
Nocardia asteroides
What obligate extracellular fungus is silver stain-positive and is associated with pneumonia in patients with AIDS?
Pneumocystis carinii
What Vi-encapsulated gram-negative motile anaerobic rod that produces H2S is associated with enteric fever, gastroenteritis, and septicemia?
Salmonella typhi
What is the most likely organism causing cellulitis in a patient who was cut by an Oyster Shell?
Vibrio vulnificus
What virus is associated with the Norwalk agent?
Calicivirus
b-Hemolytic Streptococcus; positive cAMP test; hydrolyzes hippurate
Streptococcus agalactiae
a-Hemolytis Streptococcus; lysed by bile; sensitive to Optochin
Pneumococcus (Streptococcus pneumoniae)
a-Hemolytic Streptococcus; not lysed by bile; not sensitive to Optochin
Streptococcus viridans
b-Hemolytic Streptococcus sensitive to bacitracin
Streptococcus pyogenes
What is the only nonmotile pathogenic Clostridium species?
Clostridium perfringens
If a virus has positive sense RNA, can it be used as mRNA or is a template needed?
Positive sense RNA Can be used as mRNA. Negative sense RNA CanNot be used as mRNA; it requires special RNA-dependent RNA polymerases.
Where do adult tapeworms develop, in the intermediate or definitive host?
Adult tapeworms develop in the Definitive host, whereas Cysticerci or Larvae develop in the Intermediate host.
Which streptococcal species is characterized by being catalase negative, turning bile esculin agar black, producing a positive PYR test, and resulting in biliary and urinary tract infections?
Enterococcus (Streptococcus faecalis)
What 3 carcinomas are associated with EBV
1) Burkitt lymphoma
2) NPCA
3) Thymic carcinoma
Which organism causes trench fever?
Rochalinaea quintana
Based on the onset of the symptoms, how are bacterial conjunctivitis from Neisseria and Chlamydia differentiated?
The onset of symptoms for Neisseria gonorrhea conjunctivitis is 2 to 5 days, whereas onset of symptoms for Chlamydia trachomatis is 5 to 10 days.
