intestinal microbiology, pathogens and host virulence Flashcards
describe the the types of microbes in the oral cavity
buccal surface, tongue, teeth:
- facultative and obligate aeropes (strep, pasteurellaceae, actinomyces)
- enteric bacteria (E coli)
- neisseria
- simonsiella
gingival crevice
- almost entirely obligate anaerobes
- bacteroides, fusobacterium, peptostreptococcus, porphyromonas, prevotella
describe the types of bacteria in the oesophagus
no defined flora - contaminated by organism similar to those in saliva
describe the types of bacteria in the stomach
- hostile organisms
- some pathogens are endemic in a number of populations
- problems in neonates where acid environment not fully developed
what kind of microbes are in the alimentary canal
- bacteria
- anaerobes
- enterobacteriaceae
- streptococci, enterococci
- lactobacillus
- protozoa, fungi and yeat
list species of enterobacteriaceae
- E. coli
- salmonella
- yersinia
- aeromonas hydrophila
describe qualities of enterobacteriaceae
- gram negative
- rods
- oxidase negative
- facultative anaerobes
- grow on MacConkey
- tolerate bile salts
which strains of E coli cause enteric disease
- enterotoxigenic E coli
- attaching and effacing E coli
- enteroaggregative E. col
what E coli patho types are associated with extra-intestinal disease
- avian pathogenic E coli
- septicaemic E coli
- uropathogenic E coli
- others causing local infection
list sources of salmonella infection
- contaminated water sources
- carrier animals (with low level GI carriage or subclinical GI carriage)
- faecal contaminated environment
- foodborne
what is the pathology of enteric salmonellosis
- attachment and invasion
- penetration of mucosal barrier, inflammation and fluid secretion
- neutrophils attracted to site and also into the lumen of the villi
- infection of macrophages
- transfer to systemic sites requires TTSS-2 for intracellular survival (macrophage trying to kill
discuss symptoms of enteric salmonellosis
- acute disease can effect a range of domestic and farm species
- profuse foul smelling diarrhea
- restricted to the intestine and its mucosa
- some invasion to other organs (mostly not)
- fever
- depression
- anorexia
- severely affected animals may become recumbent
- when endemic milder signs may occur due to acquired immunity
discuss septicaemic salmonellosis
- common to specific host serotype combinations
- host may vary in susceptibility with age
- sudden high fever, depression, recumbence, rapid breath
- the mucosa is a route to deeper tissues letting it spread to the blood and lympth inside macrophages
- organisms can spread to other organs (liver splee and oviduct in birds)
list common steps for most culture detection of salmonella
- sample preparation
- enrichment (optional)
- selective culture
- pick suspect colony
- may sub culture
- confirmation
discuss campylobacter
- gram negative
- flagellated
- motile
- microaerophilic
- optimum growth temp is 42 degrees (will grow 37-42)
- grown using campylobacter selective medium
- can be seen as commensals in the intestinal tracts of warm blooded animals
- contaminates meat
how do you take samples for campylobacter
- environmental samples
- fecal swabs
- boot swabs
- gut contents
- neck swabs (abbatoir)
- skin samples
- juice from meat package
- whole meat sample
