2450 wk 3 Flashcards
infection
invader overwhelms the body’s defenses; may not be clinically apparent
colonization
overgrowth of organisms in a body site: sometimes used interchangeably with infection, but not overwhelming to body
describe and name 3 opportunistic pathogens
normally found in host or environement, do not normally cause dz, exploit break in host defenses (candida, staph, pseudomonas)
6 links in chain of infx
- infx agent
- reservoir
- portal of exit
- transmission
- portal of entry
- host
define vertical transmission & name 3 types & effects
mother to baby
tranplacental, transcervical, breastfeeding
mental retardation, blindness, deafness
vertical transmission (TORCH)
Toxoplasmosis Other (HIV syphilis gonorrhea) rubella cytomegalovirus herpex simplex
3 methods of infx diagnosis
1 clinical evidence (systematic complaints, vital signs)
- labs
- urinanalysis
5 lab values that indicate infx
- wbc
- esr
- crp
- culture
- serology (used for titers, to ID antigens, and when culture is not possible)
purpose of U/A
screening for infx, renal funx, fluid balance
U/A test results that indicate UTI
visual: cloudy, amber
chemical: nitrite, leukocyte esterase
5 factors that determine virulence
- toxins
- adhesion factors
- evasive factors
- invasive factors
- mutations (change antigenic profile)
define toxins & toxoids
- poisonous substance released by invaders maybe modified to toxoid for immunization
- virulence factors removed, but retain antigen for T & B cells given as vaccine
define toxoids endotoxins and exotoxins
exo: released during bacterial cell growth
endo: within the cell wall of gram (-) bacteria, small amounts are harmful
describe systematic inflam response syndrome and give aka
cytokine storm that happens due to to many infectious agents
- potent response causing vasc. collapse and organ failure
- sepsis
- cytokines destroyed and trigger cascades (kinins and coagulation)
describe adhesion factors & 3 types and examples
pathogen’s ability to attach and maybe a site or cell
- hemagglutinins-viral glycoproteins that attach to cells in the respiratory tract (flu a/b, measles)
- slime- adheres to the host and also protects itself from host’ defenses (pseudomonas, strep on teeth, staph on plastic; urinary cath)
- pili fimbriae- hairlike/fringe projections that anchor bacteria to cells (like velcro) (gonorrhea )
define evasive factors and 4 examples
evading or avoiding host’s immune sys
- coagulase: envelopes invader (staph. aureus)
- protease: digests IgA (flu & gonorrhea)
- capsules: resist phagocytosis (strep, cryptococcus)
- leukocidin: kill by punching holes in membranes of neutrophil and macrophage (staph aureus MRSA)
define invasive factors
enzymes that allow penetration of tissues
define change antigenic profile and two types & two examples
are mutations in antigen that are antigenic drift (minor) & antigenic shift (major) HIV & FLU
what are the H and N in H1N1 flu virus
Hemagglutinins: glycoproteins that attach to cells in resp tract
Neuraminidase: surface enzyme of flu virus allows release of virus’ progeny from infected cells
characteristics of viruses
- small
- obligate must replicate inside cell (has only DNA or RNA (never both))
- protein coat (capsid)
- some enveloped
- may be latent
- may be oncogenic
6 steps of virus reprodux
- adsorption (attachment to target cell membrane)
- penetration (enzyme release to weaken CM and allow for penetration)
- uncoating (virus’ DNA or RNA takes off protective protein coat to go to nucleus)
- replication of genetic material
- assembly (assembly of genetic material to make new viruses)
- release (budding)
3 ways virus severity varies
- self-limiting
- cell death (herpes)
- immune complexes (HBV antigen-antibody complex cause damage)