BACTE LEC HOST PATHO Flashcards
cycle of host pathogen interaction
Pathogens > Host susceptibility > Modes of pathogen shedding > reservoir host > routes of entry > modes of transmission> (repeat)
necessary for establishing methods to isolate microorganisms from patient specimens and for developing effective treatment strategies
host pathogen interaction
a person who harbors the etiologic agent but shows no apparent signs or symptoms of infection or disease
Carrier
a single source or reservoir from which an etiologic agent responsible for an epidemic or outbreak originates
Common Source
Infection acquired in an activity or group that is not in a health care setting or environment
Community- associated infection
the number of new diseases or infected persons in a population
Disease Incidence
the percentage of diseased persons in a given population at a a particular time
Disease prevalence
a disease constantly present at some rate of occurrence in a particular location
Endemic
a larger than normal number of diseased or infected individuals in a particular location
Epidemic
a microorganism responsible for causing infection or infectious disease
Etiologic Agent
Infections acquired as a result of a short or long term admission into a health care facility
health care- associated infection
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
Mode of transmission
the state of disease and its associated effects on the host
morbidity
the incidence of a particular disease state
Morbidity 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 long-term health care center or facility
Nosocomial infection
a larger than normal number of diseased or infected individuals that occurs over a relatively short period
Outbreak
an epidemic that spans the world
Pandemic
the origin of the etiologic agent or location from which it disseminates
reservoir
how to prevent Nosocomial infection
Handwashing
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 that transmits the etiologic agent
Vector
a non living entity that is contaminated with the etiologic agent and as such is the mode transmission for that agent
Vehicle
transmitted by direct contact between reservoir and host
direct transmission
transmitted to host via intervening agents
indirect transmission
particles that are 5-500um in size and cannot travel more than 3 feet
Respiratory Droplet
particles that are <5 um in size and can travel more than 3 feet
Aerosol particles
a human infection when microorganisms primarily infect animal populations and on occasion accidentally encounter and infect humans
zoonotic infection
a specific type of infection from regular interaction with animals for food production
Livestock-associated infection
microorganisms that are able to survive on the skin of the host without gaining access to internal tissues
Ectoparasties
infection caused by ectoparasites are called __________________
infestation
is the growth of microbiota in or a body site without the production of damage or notable symptoms
Colonization
defined as the associated of two organisms living together
Symbiosis
a symbiotic relationship in which both organisms benefit from each other
Mutualism
a relationship in which one organism benefits while there is no beneficial or harmful to the other organisms
Commensalism
is a relationship in which one organisms benefits at the expense of the host
Parasitism
microorganisms that colonize an area for months or years
Resident Microbiota
microorganisms that are present at a site temporarily
Transient Microbiota
an infection that does not normally cause disease or damage in a host but under specific conditions or opportunities causes pathology or disease
Opportunistic Infection
inhibit the growth of closely related bacteria
Bacteriocins
microenvironment hostile to potential pathogen
metabolic by-products
the ability of a microorganism to produce disease in an individual
PATHOGENICITY
the relative ability of a microorganism to cause disease or the degree of pathogenicity
VIRULENCE
organisms that can establish infection with a relatively low infective dose are considered ____________ than organisms that require high numbers for infection
more virulent
usually measured by the numbers of microorganisms necessary to cause infection int he host
VIRULENCE
are substances produce by pathogenic microorganisms causing tissue and cellular damage
Toxic Factors
enzymes produced by bacteria that aid in the spread of infection disease
Enzymatic factors
also known as spreading factor
hyalurodinase
provides an additional protection to the bacteria
Cellular structure
genomic regions found in pathogenic microorganisms where virulence factors are encoded
Pathogenicity Islands
first step of infection and disease development
ADHERENCE
microbial surface structures that mediate attachment are called __________________
Adhesins
main adhesins in bacteria
Fimbriae/ pili and surface polysaccharides
a pathogen must multiply, following its attachment to host cells in order to establish and case a disease
Proliferation
produced by the host as a way to protect against infection
secretory antibody, lactoferrin and lysozyme
uses lactoferrin as a source of iron
Neisseria meninggitidis
a result of either preformed toxin or the disruption of the normal functioning of the intestinal cells
Tissue Damage
process of penetrating and growing in tissues
Invasion
spread of microorganisms to distant body sites
Dissemination
source of exotoxin
Gram positive mostly/ gram negative
source of endotoxin
gram negative
Toxin release of exotoxin
a metabolic product released by living cell
Toxin release of endotoxin
upon lysis of the cell
Genetics of Exotoxin
carried by plasmids or bacteriophages
Genetics of endotoxin
synthesized by bacterial chromosome
Chemistry of exotoxin
Simple proteins, peptides
Chemistry of Endotoxin
Lipid A
Heat Stability of Exotoxin
Destroyed rapidly at 60 deg C (except Staphylococcal enterotoxin)
Heat Stability of Endotoxin
Heat stable at 100 deg C for 1 hour
Antigenicity of exotoxin
Highly immunogenic- converted to toxoids for vaccines
Antigenicity of endotoxin
poorly antigenic
Signs and symptoms of exotoxin
Specific, cytotoxic, neurotoxic, enterotoxic
Signs and symptoms of endotoxin
general/ non -specific (fever, shock)
mode of action for exotoxin
Various
mode of action for endotoxin
includes TNF, IL-1, IL-6
toxicity of exotoxin
high
toxicity of endotoxin
low
lethal dose of exotoxin
low (1 microgram)
lethal dose of endotoxin
high
examples of exotoxin
Tetanus/ lock jaw, Botulism/ floppy baby syndrome
examples of endotoxin
UTI, meningococcemia sepsis
test to detect endotoxin in body fluids and surgical instruments
Limulus Lysate Test
detects gram negative endotoxin
Limulus Lysate test
Limulus Lysate test reagents
Blood of horseshoe crab and Limulus polyphemus
Limulus Lysate test principle
endotoxin make amoebocytes release lysate, causing clumping
a group or community of microorganisms capable of adhering to each other or to other surfaces
BIOFILM FORMATION
an accumulation of microorganisms embedded in a complex matrix composed of proteins, polysaccharides, extracellular DNA, and other molecules
BIOFILM FORMATION
involves the growth and multiplication of microorganisms that cause damage to their host
INFECTION
Bodily invasion of pathogenic microorganisms that reproduce, multiply, and cause disease
INFECTION
a specific disorder that is characterized by a recognizable set of signs and symptoms which are attributable to heredity, infection, diet or environment
DISEASE
results when the infection produces notable changes in human physiology, specifically that cause damage to the organ system
DISEASE
means signs and symptoms are confined in one area
local infection
starts as local infection before spreading to the other parts of the body
Focal infection
microorganisms spread throughout the body causing infection via blood or lymph
Systemic/ Generalized infection
presence of bacteria int he blood (no active multiplication)
Bacteremia
active multiplication of the invading bacteria in the blood
Septicemia
a condition wherein pus-producing organisms repeatedly invade the bloodstream and localized at different parts of the body
Pyemia
presence of toxins in the blood
Toxemia
develops rapidly and usually with a short duration
acute infection
clinically silent inside the body and causes no noticeable illness in the host
Latent Infection (silent Phase)
an infection which progresses slowly from weeks to a period of years
Chronic infection
measurable indications or physical observations
objective
Signs
indicators as described by the patient
Subjective
Symptoms
a group of signs and symptoms that are associated with disease
Syndrome
time between the exposure to a pathogenic organism and the onset of symptoms
incubation period
appearance of signs and symptoms
Prodromal Period
peak of characteristic signs and symptoms of an infection or a disease
Clinical or Illness Period
signs and symptoms begin to subside as the host’s condition improves or deteriorates possible to death
Decline period
period in which the surviving host is recuperating towards full recovery or chronic infection or death
Convalescent Period
