Micro Flashcards
what bug is this
Neisseria gonorrhea
How does the presentation and epidemiology of pneumonia from mycoplasma pneumoniae differ from that of legionella pneumophila?
In common, they both do not show up well or at all on Gram stain.
Mycoplasma pneumoniae infection causes tracheobronchitis or walking pneumonia. However, symptoms of infection are typically subacute and mild. The presence of high fever and confusion makes an alternate diagnosis far more likely.
Legionella pneumophila infection is typically marked by high fever and fatigue followed by significant gastrointestinal, pulmonary, and constitutional symptoms.
T/F: B cell deficiencies result in recurrent Bacterial infections whereas deficient T cells result in recurrent viral and fungal infections
TRUE
what is cholera toxin
Cholera toxin stimulates adenylate cyclase via activation of Gs → increased cyclic AMP → increased ion (mainly chloride) and water secretion into the intestinal lumen → profuse liquid stools
what is shiga toxin
A toxin produced by Shigella spp., which inhibits the 60S subunit of ribosomes by cleavage of adenine in rRNA (ribosomal RNA). Causes enterocyte damage and bloody diarrhea. Similar to the Shiga-like toxin produced by EHEC (enterohemorrhagic E. coli)
what is an endotoxin
A lipopolysaccharide found in the outer cell membrane of several gram-negative bacteria. Consists of O antigen, a core polysaccharide, and lipid A. Released by living bacteria through membrane blebbing and upon bacterial cell death, inducing host release of IL-1, IL-6, and TNF-α, which cause fever and hypotension leading to septic shock. Can also trigger the coagulation cascade, leading to disseminated intravascular coagulation (DIC).
pertussis toxin
pertussis toxin binds to and activates adenylate cyclase by permanently inhibiting Gi
impairs phagocytosis, allowing the bacteria to survive
Pertussis toxin is responsible for most of the systemic manifestations associated with whooping cough (e.g. hypoglycemia, lymphocytosis, modulation of host immune response).
in what population does Group B strep mostly occur
babies (pneumonia, meningitis, sepsis) mn: B for Babies
it is otherwise a common bacteria of the vagina, so pregnant pts are screened at 35-37 weeks gestation to make sure they don’t have it.
anthrax toxin
an exotoxin consisting of protective antigen,lethal factor,and edema factor
lethal factor mechanism: inactivation of protein kinase signals macrophages to release TNF-alpha –>
tetanus toxin vs botulinum toxin
both tetanus and botulinum toxins (both from clostridium spp) are proteases that cleave the SNARE proteins, a component of the N-ethylmaleimide-sensitive factor attachment protein receptor complex, —> impairs vesicular fusion –> no neurotransmitter released
Tetanospasmin spreads by retrograde axonal transport CNS and blocks release of GABA and glycine in spinal cord –> tetanic paralysis
botulinum toxin inibits ACh release at NMJ
what toxin does C perfringens produce
α-toxin, which is a phospholipase
what’s the pathogen and what infections does it cause
Listeria monocytogenes
Amnionitis, septicemia, and spontaneous abortion in pregnant patients;granulomatosis infantiseptica;meningitis immunocompromised patients,neonates,and older adults;mild,self-limiting gastroenteritis in healthy individuals.
what’s the pathogen and what infections does it cause
Nocardia
pulmonary infections in immunecompromised (pulmonary nocardiosis), cutaneous infections, can spread to CNS causing cerebral abscess
what’s the pathogen and what infections does it cause
actinomyces
oral facial abscesses (a/w cavities or oromaxillary trauma), and PID with IUD use
what’s the pathogen and what infections does it cause
mycobacteria
causes TB
induces release of TNF-alpha and produces sulfatides (prevent phagolysosome fusion)
young pt with fever, severe sore throat, lymphadenopathy, and purulent tonsillar exudates.
what’s the dx?
streptococcal pharyngitis
note the LACK of cough
M protein is found on the surface of what pathogen
Group A Streptococci such as S pyogenes
diptheria toxin
what is the pathogen and what infection(s) does it cause
diphtheria (club shaped gram positive rods)
Diphtheria presents with pharyngitis, cervical adenopathy, low-grade fever, and a characteristic gray-white pseudomembrane. Cardiac involvement can be seen 1 to 2 weeks after the onset of symptoms and can result in potentially life-threatening myocarditis and cardiomyopathy
mn: “i’m gonna dip into the club”
Immunosuppressed patient with ring-enhancing brain lesion and the attached histopath, what’s the dx
Toxoplasma gondii
Toxoplasma is an intracellular protozoan parasite in humans.
Approximately 70% of the population of the United States is seropositive, so reactivation of cysts held in latency by a normal immune response becomes commonplace as the immune response declines.
Cats act as the definitive host of the parasite and shed infectious forms in their feces.
Epstein-Barr virus (EBV). It is characterized by
a positive heterophile test (monospot), fever, pharyngitis, and lymphadenopathy.
Importantly, a monospot would be negative in a patient with CMV infectious mononucleosis. EBV serology can be assessed with tests for the viral capsid antigen (VCA),
which pathogens exhibit Retroviral infection of T cells what what dzs are assoc.
HIV and human T-cell leukemia-lymphoma virus (HTLV), which are associated with non-Hodgkin lymphoma and adult T-cell leukemia/lymphoma, respectively.