Microbiology Flashcards
What cancers is EBV associated with?
nasopharyngeal carcinoma
Burkitt lymphoma
B cell lymphoma (Hodgkin’s) in the immunocompromised
What are the four common diseases that cause rashes in infants? What viruses/bacteria/fungi cause these diseases?
Measles/rubeola - measles virus (in paramyxoviridae family)
rubella - rubella virus (a togavirus)
erythema infectiosum/slapped cheek syndrome - parvovirus B19
roseola infantum/exanthema subitum - HHV-6 and HHV-7
scarlet fever - strep pyogenes
What are the eight herpes viruses?
Herpes simplex 1&2 Varicella-Zoster virus Cytomegalovirus Epstein-Barr virus HHV-6 HHV-7 HHV-8
What organism is associated with yellow/sulfur granules?
actinomyces
How does parvovirus B19 present in children? in adults? In patients with sickle cell disease?
children - “slapped cheek” syndrome/erythema infectiosum.
adults - symmetrical arthralgias and arthritis
In sickle cell patients - aplastic crisis
What organisms can cause pelvic inflammatory disease? How do you treat PID?
chlamydia and gonorrhea
Always treat patients for both: ceftriaxone for gonorrhea and doxycycline for chlamydia
What are the common ways to transmit listeria monocytogenes?
deli meats, soft cheeses, unpasteurized dairy products
across the placenta, causing spontaneous abortion
How does clostridium botulinum cause disease in adults? in infants? What are the common sources in adults? In infants? How does it present in adults? in infants?
adults - preformed toxin ingested in contaminated food. Source = home canned foods and preserved fish. Presents as a descending, flaccid paralysis with intact cognitive function
infants - ingest spores which turn into germinating bacteria in the intestines because the digestive tract is not yet mature enough to kill the spores. Source = honey. Presents as floppy baby syndrome
What is the shape of all DNA viruses? Where do all DNA viruses replicate? What is the exception to these characteristics?
All DNA viruses are icosahedral shaped and replicate in the nucleus except Poxviridae which are brick-shaped and replicate in the cytoplasm
What are the histological changes from an HPV infection?
koilocytes - hyperchromatic, enlarged nucleus and perinuclear halo
What organism causes the intracytoplasmic inclusions called guarnieri bodies?
poxviruses (molluscum contagiosum)
What does a positive leukocyte esterase test indicate?
Neutrophils in the urine, suggesting a bacterial infection.
What family of organisms can turn nitrate into nitrite?
Enterobacteriaceae
What organism is associated with infections in burn patients?
Pseudomonas
How is toxoplasma gondii transmitted?
cat feces or undercooked pork
What infection is characterized by cutaneous hemorrhages, deafness and periventricular calcifications, microcephaly and hepatosplenomegaly in neonates?
CMV infection
the cutaneous hemorrhages are the “blueberry muffin baby” syndrome
How does CMV present in adults?
influenza-like symptoms with mild fever and generalized lymphadenopathy = mononucleosis (heterophile negative)
What is a common cause of pediatric diarrhea mini-epidemics? What are the characteristics of this type of diarrhea?
yersinia enterocolitica
Dysentery with blood, mucus and leukocytes
What are the symptoms of typhoid fever?
fever, abdominal rash and splenomegaly
What organisms are associated with aspiration pneumonia in alcoholics? Aspiration pneumonia in genera?
alcoholics - klebsiella
regular aspiration pneumonia - gram negative rods, anaerobes (peptostreptococcus, fusobacterium, bacteroides), staph aureus
What disease(s) does the dermacentor tick transmit?
rocky mountain spotted fever
tularemia
What is the process of transduction? What is the difference between specialized and generalized transduction?
transduction is the transfer of genetic material among bacteria by a virus vector (bacteriophage)
Generalized transduction - error of a lytic virus
specialized transduction - error of a lysogenic virus
What fungus is characterized as an encapsulated yeast? Broad based budding yeast? Budding yeast with spokes resembling a wheel? Spherules?
encapsulated yeast = cryptococcus neoformans
broad based budding = blastomyces
Budding yeast with spokes resembling a wheel - paracoccidiodes brasiliensis
spherules = coccidioides imitis
What are the symptoms of primary syphilis? secondary syphilis? tertiary syphilis? What diagnostic tests are appropriate for each stage?
primary - painless chancre (darkfield or fluorescent microscopy of biopsy)
secondary - bronzing rash that covers the entire body including palms and soles, condyloma lata, (first use VDRL, if negative then do FTA-ABS or microhemagglutinin)
Tertiary - gummas (syphilitic granulomas) in CNS and vasculature, tabes dorsalis, argyll-robertson pupil (FTA-ABS or microhemmaglutinin)
What organism is characterized by berry-like clusters within granulocytes? How is this organism transmitted? What disease does this organism cause?
anaplasma phagocytophilum
transmitted by the bite of the ixodes tick
Human granulocytic anaplasmosis
What organism is associated with hairy oral leukoplakia?
EBV
What are the negative sense RNA viruses?
xxx
What are the clinical manifestations of bronchiolitis?
wheezing, tachypnea, tachycardia, fever and labored breathing and rhinorrhea
What is the most common cause of bronchiolitis in infants?
respiratory syncytial virus
What are the double stranded RNA viruses?
reoviridae
What infection classically presents with symmetric arthritis, especially in the tendon sheaths, and a petechial rash?
neisseria gonorrhoeae
What bacteria have capsules that are not immunogenic?
Strep pyogenes and neisseria meningitidis
Which bacteria can’t synthesize ATP?
chlamydia - this is why it is an obligate intracellular organism
What bacteria can’t synthesize cysteine?
legionella, brucella, francisella, pasteurella
What are the common causes of diarrhea in AIDS patients? Which ones stain positive on the acid-fast stain?
cryptosporidium, adenovirus, mycobacterium avium complex, salmonella
acid fast: cryptosporidium (oocysts in the stool) and mycobacterium avium (intracellular)
What is the developmental cycle of chlamydia trachomatis?
infectious, metabolically inactive form = elementary bodies
noninfectious, metabolically active form = reticular bodies
What organism is associated with Cowdry type A inclusions?
Herpes simplex type 1
