Bacterial Pathogenesis Flashcards
(35 cards)
Pathogenicity
ability to cause disease
Infection
Host response - inflammation: Pain, Red, Immobility, Swelling, Heat
Endogenous infection
infection by member of NF
Exogenous infection
Infection not by a member of NF
Local infection
infection restricted to an area
Focal infection
localised infection but the pathogen releases by-products that can spread to other parts of body e.g. tetanus
Systemic infection
Infection spread throughout the body by organism and their by-product
Primary infection
initial infection caused by one pathogen
Secondary infection
infection that follows primary infection e.g. may contract another infection because immune sys. is weak from 1º infection: cold -> flu
Latent infection
Infection that one may have but symptoms arise at a later date
Acute infection
rapid @ start & more severe e.g. measles
Chronic infection
Slow progressive disease e.g. TB
Commensals (refer to microbes)
rarely cause disease
Define Pathogen and list 3 types
may cause disease in normal host.
3 O’s: Opportunistic; Obligate; Overt
Opportunistic pathogens
a microbe that can become pathogenic under circumstances like if body is immunocompromised (weak immune sys)
Obligate pathogen
Always cause disease => transferred from one host to another = survive
Overt pathogen
organism that is ALWAYS regarded as pathogenic by clinical labs
What is ID50 and what does it measure?
Infectious dose 50: measure # of bacteria to infect 50% of population of animals exposed (NOTE: Lo val. = more virulent)
What is LD50 and what does it measure?
Lethal dose 50: measure # of bacteria to kill 50% of population of animals exposed (NOTE: Lo val. = more virulent)
Which virulence factors in pathogens aids in attachment to body surfaces?
Glycocalyx (Capsule and slime layer); pili and fimbrae
Explain the emergence of Haemophilius influenzae as a secondary pathogen?
H. influnzae becomes a secondary pathogen if the host’s immune defences are weak due to the response to a primary pathogen: cold-> flu
What is glycocalyx and how can this contribute to the virulence of a pathogen?
capsule/slime layer made up of glycoproteins and /or polysaccharides.»_space; sticky = adherence= resist cough reflex; resist phagocytosis (too big for macrophages)
How may collagenase act as a virulent factor?
Break down collagen in connective tissue = allow pathogen to spread to neighbouring tissues
What is the basis of vaccine for tetanus?
Exotoxin from clostridium tetani converted into toxoids for vaccine: heat treated or formalin treated (= to stimulate primary immune resp.)
