Week 12 Flashcards
what are the links in the chain of infection
- infectious microbe
- susceptible host
- reservoir
- portal of exit
- modes of transmission
- portal of entry
infective etiologies
smallest to biggest
- prions
- viruses
- bacteria
- fungi
- protozoa
- multicellular parasites
routes of transmission
- person-to-person
- common vehicle/source
- vector borne
- endogenous
mechanisms of route of transmission
- airborne
- contact with infectious material
direct person to person transmission
- sexual transmission
- perinatal mother to child transmission
- needle injection
- skin-to-skin
- human bites
indirect person to person transmission
- fomites (contaminated objects)
- air: airborne & droplets
common vehicle spread
ingested & biological products
zoonotic agents
animal bites, blood/air/food/water/vector borne
what are endogenous routes of transmission
from human flora
systemic clinical features of infection
- fever
- chills
- constitutional symptoms
local clinical features of infection
site-dependent
pathogenicity
ability to cause disease in the host
virulence
extent of disease caused by organism
walking pneumonia AKA
pneumonia from mycoplasma pneumoniae
pneumococcal pneumonia AKA
pneumonia from streptococcus pneumoniae
mechanism of virulence includes
maintaining presence & invading host
- capsules/cell wall
- toxins
- adhesins
- enzymes
what is the function of capsules/cell wall
evade host defences such as phagocytosis & white cell attachment
what is the virulence function of gram negative bacteria
mediates septic shock using lipopolysaccharide
what is the virulence function of clostridium difficile toxins
causes clostridium difficile associated diarrhea, colitis
what is the virulence function of encapsulated bacteria
capsules help prevent phagocytosis and recognition by host immune system
what are the treatment of infections
- antimicrobials
- surgical interventions
what do surgical interventions do
address structural abnormalities & reduce burden of disease
what are examples of antimicrobials
antibiotics, antifungals, antivirals
beta lactams mechanisms of action
binds to transpeptidase active site
clostridium difficile associated diarrhea is often associated with __
antibiotic use as it affects normal bowel flora
Multidrug resistant gram negative organisms
- Multidrug resistant pseudomonas
- Carbapenemase producing bacteria
what are the 5 pillars of infection control
- isolation & barrier precautions
- decontamination of equipment
- decontamination of environment
- prudent use of antibiotics
- handwashing
what is surveillance
early recognition of problems for more effective infection control
the lesser the virulence, the ___ of survival & propagation
greater success
specific symptoms of COVID-19
anosmia (loss of smell) & aguesia (loss of taste)
what are the methods of infection control
- hand hygiene
- social distancing
- extensive surveillance
- contact tracing
clinical presentations of clostridium difficile associated diarrhea
diarrhea, colitis, fever, abdominal pain
what factors involved nucleic acid synthesis
folate synthesis, DNA gyrase, RNA polymerase
what factors involved protein synthesis
50S & 30S subunit
what factors involved cell wall synthesis
Beta lactams, vancomycin bacitracin, cell membrane
what are markers of inflammation
C-reactive protein, procalcitonin, ESR, differential count
what do gram positive bacteria produce
exotoxins
what do gram negative bacteria produce after death
endotoxins
what are primitive forms of bacteria which replicate via binary fission
chlamydiae, rickettsia, mycoplasma
bacteria reproduce by __
binary fission
incubation period
Time between entry of organism into the body and
appearance of clinical signs of disease
prodromal period
early symptoms which indicate disease onset before more specific symptoms develop
Septicemia
multiplication of pathogens in blood
Bacteremia
presence of bacteria in blood
Viremia
presence of virus in blood
leukocytosis suggests __
bacterial infection
leukopenia suggests __
viral infection
what type of infleunza is most associated with severity and epidemics
Type A & B
why type of influenza is mild & common version of flu
type C
anatomical distribution of pneumonia
lobar, broncho, interstitial pneumonia
diagnostic tests for active infections
- acid-fast sputum fast
- CXR
- sputum culture & sensitivity
