BACTEE - INFECTION AND IMMUNITY
Infection acquired as a result of a medical procedure
Iatrogenic
an individual's microbiologic environment, present in or on the human host (normal flora)
Microbiome
the means by which etiologic agents are brought in contact with the human host (example: infected blood contaminated water insect bite)
mode of transmission
the state of disease and its associated effect on the host
Morbidity
the incidence of a particular disease state
morbidity rate
rate death resulting from disease
Mortality
the incidence in which a disease results in death
mortality rate
infection for which the etiologic agent was acquired in a hospital or a long term health care center or facility
Nosocomial infection
a larger the normal number of deceased or infected individuals that occurs over a relative short period
Outbreak
an epidemic that spans the world
pandemic
the origin of the etiologic agent or location from which it disseminates example water food insects animals other humans
reservoir
laboratory based characterization of etiologic agents designed to establish their relatedness to one another during a particular outbreak or epidemic
strain typing
any type of epidemiologic investigation that involves data collection for characterizing circumstances surrounding the incidence or prevalence of a particular disease or infection
surveillance
a living entity (animal, insects, or plant) that transmit the etiologic agent
Vector
a specific type of infection resulted from regular interaction with animals for food production
livestock-associated
a human infection when microorganisms primarily infect animal populations and on occasion– accidentally encounter and infect humans
zoonotic infection
infectious agents from animal reservoirs are transmissible directly to humans through an animal bite or indirectly through the bite of insects vectors that feeds on both animals and vectors
Animals as microbial reservoirs
intervening agents
vectors and vehicles
modes of transmission
direct and indirect
Humans, animals, food (from plants and animal sources), water, air, soil.
Microorganism sources or reservoir
a living entity that is contaminated with the etiologic agent and such is the mode of transmission for that agent
vehicle
direct is transmitted by direct contact between reservoir and host
direct MOT
transmitted to host via intervening agents
indirect MOT
Factors that determine the composition of the usual microbial biota (mahon)
- amount and types of nutrients available in the environment
- ph
- oxidation-reduction potential
- resistance to antibacterial substance
microorganisms that are present at a site temporarily
transient microbiota
microorganisms that colonize an area for months and years
Resident microbiota
are commonly found on or in body sites of healthy persons
Normal flora
is a relationship in which one organism (parasite) benefits at the expense of its host
parasitism
A relationship in which one organism benefits while there is no beneficial or harmful to the other organism
Commensalism
a symbiotic relationship in which both organisms benefit from each other
mutualism
defined as the association of two organisms living together
symbiosis
is the growth of microbiota in or a body site without the production of damage or notable symptoms
Colonization
infection ectoparasites cause
infestation
microorganism that are able to survive on the skin of the host without gaining access to intestinal tissues
ectoparasites
the most common role of insects (arthropods) in the transmission of infectious disease is as vectors rather than as reservoirs
insects as vectors
role of the microbial biota in the host defense against infectious disease
- develop immunologic competence
- blocks colonization
- produce bacteriocins
- metabolic by-products
Causes of opportunistic infection
- alteration of habitat
- host immune system is compromised
- overuse and misuse of antibiotics
Cause opportunistic infection (an infection that does not normally cause disease or damage in a host but under specific conditions or opportunities causes pathology or disease)
Opportunist
Certain members of the normal flora are ___
opportunist
microbiota____ since the immune system is constantly primed by contact with microorganisms
develop immunologic competence
microbiota produces a___ that blocks colonization by extraneous pathogens (competition for space and nutrients)
micro environment
some microbiota produce___inhibits the growth of closely related bacteria
bacteriocins
some microbiota produce___that results in a micro environment–hostile to potential pathogen
metabolic by-products
enzyme produced by bacteria that aid in the spread of infection and disease (hyaluronidase, coagulase, collagenase, hemolysin)
enzymatic factors
toxins are substances produced by pathogenic microorganisms causing tissue and cellular damage
toxic factors
toxic factors
endotoxin and exotoxin
enzymatic factors
- hyaluronidase
- coagulase
- collagenase
- hemolysin
Toxic virulence factors
toxic factors
enzymatic factors
cellular structure
> organisms that can establish infection with a ___ are considered more virulent than organisms that require high numbers for infection
relatively low effective dose
usually measured by the numbers of microorganisms necessary to cause infections in the host
Virulence
The relative ability of a microorganism to cause disease or the degree of pathogenicity
Virulence
the ability of a microorganism to produce disease in an individual
Pathogenicity
Pathogenicity
>true pathogens
>opportunistic pathogens
first step of infection and disease development
Adherence
Factors that influences violence
factors
adherence
proliferation
tissue damage
production of toxins
invasion
dissemination
provides an additional protection to the bacteria (example: capsule - resist phagocytosis)
cellular structure
comprise one or more virulence associated genes and mobility genes (example: integrases and transposases) that mediate movement between various genetic elements (example: plasmids and chromosomes) and among different bacterial strains
Pathogenicity islands
mobile genetic elements that contribute to the change and spread of virulence factors among bacterial population of a variety of species
Pathogenicity islands
genomic region found in pathogenic microorganisms where virulence factors are encoded
Pathogenicity islands
spread of Microorganisms to distant body sites
dissemination
process of penetrating and growing in tissues
invasion
noticeable manifestation of disease or infections occurs
Tissue damage
a result of either performed toxin or the disruption of the normal functioning of the intestinal cells
Tissue damage
have IgA protease
H. influenzae, N. gonnorhoeae
degrades the IgA at mucosal surfaces
IgA protease
uses lactoferrin as a source of iron (not inhibited by the presence of lactoferrin)
Neisseria meningitidis
Neisseria meningitidis uses ___ as a source of iron
lactoferrin
produced by the host as a way to protect against infection
secretory antibody lactoferrin and lysozyme
a pathogen must multiply following its attachment to host cells in order to establish and cause a disease
Proliferation
adhere to host cell surfaces increasing pathogens colonizing ability
fimbriae/pili and surface polysaccharides
main adhesins in bacteria
fimbriae/pili and surface polysaccharides
must possess the necessary receptors for the adhesins
host cells
microbial surface structures that mediate attachment are called
Adhesins
factor that influence virulence factors in which the source is gram positive/negative
exotoxin
factor that influence virulence factors in which metabolic producut is released by living cell
exotoxin
factor that influence virulence factors in which the genetics is carried by plasmids or bacteriophages
exotoxin
factor that influence virulence factors in which the chemistry are simple proteins and peptides
exotoxin
factor that influence virulence factors in which is destroyed rapidly at 60 degC except ___
exotoxin , staphylococcal enterotoxin
factor that influence virulence factors in which it is highly immunogenic--converted to toxoids for vaccines
exotoxin
factor that influence virulence factors in which the signs and symptoms are specific. give 3 examples
exotoxin. cytotoxic, neurotoxic, enterotoxin
factor that influence virulence factors in which it has various mode of action
exotoxin
factor that influence virulence factors in which it has high toxicity
exotoxin
factor that influence virulence factors in which it has low lethal dose. how much dose?
exotoxin, 1 mg
give examples of exotoxin
tetanus/lock jaw; botullism
factor that influence virulence factors in which its source is gram negative
endotoxin
factor that influence virulence factors in which its release is upon the lysis of the cell
endotoxin
factor that influence virulence factors in which its genetics is synthesized by bacterial chromosome
endotoxin
factor that influence virulence factors in which its chemistry is lipid A
endotoxin
factor that influence virulence factors in which its stable at 100 degC for 1 hour
endotoxin
factor that influence virulence factors in which it's poorly antigenic
endotoxin
factor that influence virulence factors in which its signs and symptoms is general/non-specific. give 3 examples.
endotoxin. fever, shock, hypotension
factor that influence virulence factors in which its mode of action includes TNF, IL-1, IL-6
endotoxin
factor that influence virulence factors in which it has low toxicity
endotoxin
factor that influence virulence factors in which it has high lethal dose
endotoxin
provide examples for endotoxin
UTI, Meningococcemia sepsis
results when the infection produces notable changes in human physiology specifically that cause damage to the organ system
disease
a specific disorder that is characterized by a recognizable set of signs and symptoms which are attributable to heredity, infection, diet, or environment
disease
bodily invasion of pathogenic microorganism that reproduce multiply and cause disease
Infection
Involves the growth and multiplication of microorganisms that cause damage to their host
Infection
may form from monomicrobic irrigation or polymicrobic aggregation
biofilm formation