Infectious Disease Flashcards
What are the 3 types of microorganisms?
1) bacteria
2) viruses
3) fungi
What is the broad name/category for most bacteria in the body? What does this mean?
commensal bacteria
It lives symbiotically with you and causes no harm, its your own natural flora in gut, skin, vagina, etc.
Specifically, what type of bacteria is in our flora?
lactobacillus “good” bacteria
What do commensal bacteria secrete?
commensal bacteria secretes toll-like receptor (TLR) ligands which bind to TLR on the surface of normal intestinal tissue
Where does commensal bacteria bind to and what does this allow?
binds to the epithelium of the gut and allows signaling for repair, protection of injury, etc.
What does it mean for the body if TLR signaling is intact?
TLR ligands will bind to TLR and cause basal signaling
this leads to homeostasis of the intestinal surface and robust repair in response to injury
Describe what happens if TLR signaling is disrupted
TLR ligands will bind to TLR, but no signaling will occur/no activation of signaling
this will cause enhanced sensitivity to injury and diminished capacity to induce repair
What does it mean if there is no TLR signaling in the gut?
There are no ligands binding to TLR, so basal signaling is inactive and does not occur
this will lead to enhanced sensitivity to injury and diminished capacity to induce repair
What does basal signaling do in simplest terms?
protects against cellular injury
What is an example that may disrupt TLR signaling?
antibiotics can eradicate commensal bacteria which results in compromised ability of the intestinal epithelium to withstand injury and repair cell damage
What happens to the body if antibiotics disrupt your natural flora?
body will be more susceptible to bacterial infections, such as C. diff
What does C. diff cause?
Hint: think in terms of when the natural flora is disrupted through antibiotics
pseudomembranous colitis and candida overgrowth
Where in the body is it sterile (no commensal bacteria)?
blood, CSF, kidneys, bladder, female fallopian tubes/ovaries
How is infection typically transmitted?
through direct contact, such as touch or sex
or through fomites (inanimate objects such as medical instruments, bed linens, etc.
List at least 3 ways infections are spread
in no specific order:
1) needle or injury (direct access to blood)
2) bites, stings or worms (direct access to blood)
3) animals (vector-borne)
4) sexual intercourse
5) ingestion (contaminated soil/water, poultry, eggs, oral/nasal secretions, etc)
6) inhalation (oral/nasal secretions)
What is an example of infection that inhales microbes through nasal/oral secretions?
TB
What is an example of infection that uses a vector, or in other words animal/insect intermediate?
malaria
What is an example of a microorganism that can cross the placenta? What infection does it cause?
Treponema pallidum causes Syphilis
this can really infect the fetus and cause neuro damage or fetus can even die in utero
What are nosocomial infections?
any infection acquired within a hospital or medical facility
What is the most common nosocomial infection? What are the secondary infections that are also fairly common?
most common= staph causes UTIs
secondary= wound infections, pneumonia, or diarrhea
What is the most common serious nosocomial infection? Secondary infection?
most common= MRSA (Methicillin-resistant staphylococcus aureus)
second most common= C. diff
How easy is it for C. diff to enter the body? What happens once a pt has C. diff?
once the bacteria gets in the body, it’s very easy to get through the stomach (entrance is easy if pt is susceptible to infection)
C. diff causes pseudomembranous colitis, which results in diarrhea, abdominal pain, and high fever
What are the 3 ways bacteria can infect you?
1) secrete toxins
2) secrete enzymes
3) become spores
some bacteria can do more than 1 of these options
What are the toxins that bacteria secrete?
exotoxins or endotoxins