M4 Sources of Microorganisms Flashcards
what s the sequence of events for pathogenesis
adhere/colonise and invade
evade host defence
multiply/compete its life cycle
exit host
what are some common bacteria use humans as reservoir
TB Diphtheria Hep A & B Influenza Measles
what are some common bacteria use animals as reservoir
Zoonoses
accidental infection of man
may involve vector
plague
what are some sources of environment for bacteria
soil nd water
contaminated sewage
opportunistic pathogens
what are some bacteria that use the environment as a resveoir
clostridium tetani
legionella
what is an animate nd inanimate source
animate - animal
inanimate - environment
what is human period of infectivity
casual hours
acute days
transient weeks
chronic months +
what are the carrier states
active
convalescent
healthy
incubator
what is the active state
overt clinical presentation
what is the convalescent state
recovering bit still carrier
what is a healthy state
no overt signs of illness
what is the incubator state
maintaining large numbers of pathogens prior to illness
what are the means exiting a host
natural or artificial
what is the natural exit way
sneezing, shedding
what sit he artificial exit way
blood, saliva, aerosols (drill)
what are some means of spreading to new host
direct/indircet contact
air bourne
vector bourne
what are the types of direct contact spread
vertical - child to mum
horizontal - cough
what are the types of indirect contact speed
format
what is an air bourne spread
droplets
aerosols
what is vector bourne spread
insects
how can microbes escape body
tears nasal sec saliva blood resp fluid contact with skin breast milk faeces semen urine
what are some routes of microbial entry
ingestion inhalation injection across mucous mem into ear transplacental
what kind of bac can be ingested
salmonella
what kind of bac can be inhaled
myco TB
what kind of bac can be injected
Hep b
can reservoirs change
can vary during the course of a disease
what is an exogenous bac
infective material derived from outside patients body
what is endogenous
bac/fungi part of natural microbiota commensal
change in natural flora
what are some infections from exogenous bac
TB - myco - humans
Pneumonia - legionella - soil/water
Tetanus - clostridium tetani - soil
what bac present when burns or wounds
s aureus
p aeruginosa
what bac present when bowel rupture
bacteriodes fraigils
when is there a normal presence of foreign body
prosthesis
catheters
absence of shedding surface an form of biofilms
what are some key points on biofilms
multi cellular community 3D interfaces water channels resistant to antimicrobial agents and host defences
what si the way a bacteria can go to the incorrect site
heatogenuos spread
what can suppress immune system
cancer therapy
immune suppression
reduced Abs
what are some exogenous infections pathogens
influenza - destroy line of resp tract
AIDS immune suppression
antibiotics can disrupt what microflora
natural flora
c albicans
c difficile
what are the factors in establishing disease
dose of infectious agent
virulence of organisms
seusceptitbitly/ resistance of host
give a summary of pathogenesis
source microbe escape form source spread to new host entry into host infection of host damage to host
what is primary sources of dental practice
resp trat and muht
secretions saliva and blood
what is the secondary source of dental practise
surgery equipment
drill mirror
what are some challenges faced by pathogenic bac in water
low temp low nutrient pH neutral oxygen available resp metab free iron available adhesins stick to rocks
what re some challenges faced by pathogenic bac in humans
higher temp 37C energy higher low pH then higher low or no oxygen fermentative metab iron bound to harm adhesions stick to cells expo to bile salts
what do endogenous microbes do to survive
adapt to host and adhered more likely to poise a threat
