Micro Flashcards
What is the most sensitive and specific test for diagnosing C. difficile?
NAAT using a PCR
A combination of nicotinic and muscarinic blockade is strongly suggestive of which organism?
- Clostridium botulinum toxin
- Diplopa, Dysphagia, and Dysphonia = “3 D’s”
Small, ovoid bodies within macrophages is characteristic of which fungus?
Histoplasma capsulatum
Hepatosplenomegaly, LAD, pancytopenia and ulcerated lesions on the tongue are very characteristic of disseminated infection by which fungus?
Histoplasma capsulatum
How does Dengue Fever most commonly present?
Acute febrile illness w/ HA + retro-orbital pain + joint and muscle pain
Which viruses have the capability of undergoing reassortment due to their segmented genomes?
- Bunyaviruses
- Orthomyxoviruses
- Arenaviruses
- Reoviruses
What are the clinical manifestations of Tuberculoid Leprosy?
Mild skin plaques –> hypopigmentation, hair follicle loss, and focally decreased sensation
Hepatocytes with finely granular, diffusely homogenous, pale eosinophilic cytoplasm aka “ground-glass” is a distinct histopathologic manifestation of which infection?
Hepatitis B due to accumulation of HBsAg
Which stage of syphilis is characterized by a maculopapular, bronzing rash that covers the entire body; how is this stage diagnosed?
Secondary syphillis; order RPR which is then confirmed by FTA-ABS
A boxcar-shaped, gram-positive rod describes what?
Bacillus anthracis
Presence of leukocyte esterase and nitrites in urine are highly sensitive for a UTI caused by what 3 organisms?
Gram-negative –> E. coli, Klebsiella, and Proteus
Which infectious agent causes a maculopapular rash that begins on the face before quickly spreading to the trunk and extremities and is also associted with postauricular and occipital LAD?
Rubella (Togavirus) - positive sense ssRNA virus
List the 5 most common catalase-positive organisms,
- S. aureus
- Burkholderia cepacia
- Serratia marcescens
- Nocardia
- Aspergillus
What is the most common cause of spontaneous gas gangrene (i.e., rapid-onset pain, hemorrhagic bullae, and tissue crepitus); what is the greatest risk factor for infection?
- Clostridium septicum
- Underlying colonic malignancy is the greatest risk factor for infection
Which enzyme in prokaryotes has 5’ to 3’ exonuclease activity and functions to remove the RNA primer and replace it with DNA?
DNA polymerase I
Which endotoxin from the LPS of gram-negative bacteria is highly toxic and can lead to gram-negative sepsis and endotoxic septic shock; how does this occur?
- Lipid A
- Activates macrophages and granulocytes; causing synthesis of pyrogens such as IL-1, prostaglandins, and inflammatory mediators TNF-alpha and interferon
What is the major virulence factor of Haemophilus influenzae type b (Hib)?
Polysaccharide capsule, composed of polyribosylribitol phosphate (PRP)
Which fungus has branching at acute angle with septations?
Aspergillus fumigatus
What is the MOA of both tracheal cytotoxin and pertussis toxin from Bordetella pertussis?
- Tracheal: directly damages and destroys ciliated epithelial cells = loss of airway protection, subsequnt microaspiration and development of the hallmark paroxysmal cough
- Pertussis: enters cells, activates adenylate cyclase, leading to alterations in cellular signaling that inhibit phagocyte activity
What is the characteristic histopathologic finding in the brain of patient with HIV-associated dementia?
Microglial nodules and multinucleated giant cells
