Gapcom 4/3 Host-Microbe Relationships (X)

Front 1

what are the different types of microbial relationships?

Back 1

pathogens +/-
commensals +/0
opportunists, usually +/0 but can shift to +/-

Front 2

pathogenesis of microbial dx

Back 2

1. tissue damage (cell death through microbial replication, elaboration of toxins, mechanical blockage by large parasites)
2. aggressive IR to pathogens
3. oncogenesis

Front 3

what are the stages in infectious process?

Back 3

1. transmission-person to person, fomites, spores in soil, animals, food, water
2. entry into body - mouth, respiratory tract, thru skin/mucous membranes, urogenital tract, conjuctiva
3. avoidance of host defense mechanisms- hide within the cells, change ag, try to appear like host
4. replication and spread - local spread by degradative enzymes and fusion inducing proteins. sytemic spread by lymphatic spread, blood, nerves, tissues
5. clinical outcome - asymptomatic (mild), symptomatic, non-lifethreatnening (severe infection), life-threatening
6. shedding
7. recovery

Front 4

what are bacterial virulence factors that effect the outcome of infections?

Back 4

1. colonization factors - adhesins, biofilm
2. resist host defense factors - anti-phagocytic capsules, proteases that degrade Ab and other factors
3. enhance invasiveness factors - enzymes that break down c.t.
4. toxins

Front 5

what are adaptations to assist entry into host?

Back 5

survival for long periods outside of host, colonization of skin, attachment structures, survival in stomach acid, proteolytic enzymes, bile, and use of vectors.

Front 6

what are the stages of infection?

Back 6

incubation period - no symptoms. organism replicating and spreading (locally or systemically). variable in length depending on pathogen/infectious dose
2. illness - due to microbe and host response
3. recovery - may be complete with clearance of pathogen, or incomplete-recovery of initial symptoms, but persistence of pathogen
4. immunity - innate defenses act while adaptive defenses are being activated. adaptive defenses are stronger, more targeted, more effective than innate.
5. shedding can occur before, during, and after clinical dx. can be shed in respiratory secretions, feces, blood and tissues, urine, sexual secretions, milk, saliva (anti-pathogen Ab is detectable in higher conc in recovery vs. during acute dx)

Front 7

factors affecting the outcome of infection

Back 7

1. host factors - too weak (immunosupressed), too strong (immune aggression, balanced response to eliminate pathogen and repair damaged tissues, age, sex, nutrition, genetics, immune status
2. pathogen factors - virulence factors, site of replication, infecting dose, anti-microbial resistance, antigenic variants, emerging pathogen

Front 8

what are the types of infection

Back 8

acute and persistent (chronic and latent)