Microbe Human interactions Flashcards
microbes that engage in mutual or commensal associations with humans belong to the?
normal resident microbiota
A condition in which pathogenic microbes penetrate hosts defenses, enter tissue, and multiply
infection
microbe acting as infection that causes damage or disruption to tissues and organs.
pathogen
an infection that causes damage or disruption to tissues and organs
infectious disease
colonization of the body involves a constant.
“give and take”
microbes that occupy the body for only short periods
transients
microbes that become established
residents
In many cases, microbiota benefits host by preventing overgrowth of harmful microbes.
microbial antagonism
what is the largest and most accessible organ?
skin
what cling to the surface but do not grow there; influenced by hygiene.
transients
stable, predictable, less influenced by hygiene, primarily bacteria and yeasts
residents
variations in flora distribution due to shifting conditions in
pH, oxygen tension, anatomy
what is the most diverse and unique flora of the body?
microbiota of the mouth
intestinal environment favors
anaerobic bacteria
what are the sites of the genitourinary tract?
females- vagina and outer opening of urethra
male- anterior urethra
major factors in development of infection finding a portal of entry.
skin
GI tract
respiratory tract
urogenital tract
endogenous biota
attaching firmly
fimbriae
capsules
surface proteins
viral spikes
hooks
existing hosts: portals of exit
respiratory tract, salivary glands
skin cells
fecal matter
urogenital tract
blood
introducing known microbes back into the body
probiotics
what are factors that weaken hosts defenses and increase susceptibility to infection?
old age, extreme youth
genetic defects
surgery organ transplants
capable of causing disease in healthy persons with normal immune defenses
true pathogens
cause disease when the hosts defenses are compromised or when they grow in part of the body that is not natural to them.
opportunistic pathogens
characteristic route a microbe follows to enter the tissues of the body.
portals of entry
originate from source outside the body ex. Flu
exogenous
already exist on or in the body (normal flora)
endogenous
characteristic or structure that contributes to the ability of a microbe to cause disease
virulence factor
portals of skin
skin
gastrointestinal tract
respiratory tract
urogenital tract
transplacental
pathogens that infect during pregnancy STORCH
syphilis
toxoplasmosis
other diseases
rubella
cytomegalovirus
herpes simplex virus
minimum number of microbes require for infection to proceed
infectious dose (ID)
microbes with a small IDs have a
greater virulence ex. measles
what are the 3 phases of an infection
phase 1 becoming established
phase 2 attaching to the host
phase 3 invading and becoming established
microbes gain a stable foothold at the portal of entry; dependent on binding between specific molecules on hosts and pathogens.
adhesion
how are microbes attach to the host
fimbrae
flagella
glycocalyx
cilia
suckers
hooks
barbs
bacteria produced extracellular enzymes that dissolve barriers and penetrate through or between cells to invade underlining tissues
exoenzymes
toxins secreted by bacteria damage target cells which die and begin to slough off
toxins
specific chemical product of microbes plants and some animals that has poisonous effects on other organ
toxinoses
not secreted but released after the host cell is damaged
endotoxin
secreted by a living bacterial cell into the infected tissue
exotoxin
four distinct stages of clinical infections
incubation period
prodromal stage
period of invasion
convalescent period
time from initial contact with the infection agent to the appearance of first symptoms agent is multiplying but damage is insufficient to cause symptoms serval hours years
incubation period
vague feelings of discomfort
prodromal stage
multiplies at high levels becomes well-established more specific signs and symptoms.
period of invasion
as a person begins to respond the infection symptoms decline
convalescent period
what is the pattern of infection?
localized infection
systemic infection
focal infection
mixed infection
microbes enter the body and remains confined to a specific tissue
localized infection
infection spreads to several sites and tissue fluids usually in the bloodstream
systemic infection
when infectious agent breaks loose from a local infection and is carried to other tissues
focal infection
several microbes grow simultaneously at the infection site
mixed infection
objective evidence of disease as noted by an observer
sign
subjective evidence of disease as sensed by the patient
symptom
initial infection
primary infection
subsequent infection by a different microbe
secondary infection
comes on rapidly severe but short-lived effects ex stomach bug
acute infection
progress and persists over long period of time ex HIV Herpes
chronic infections
what are the earliest signs of a disease
fever pain soreness swelling edema granulomas abscesses lymphadenitis
although infected the host doesn’t show any signs of disease
asymptomatic
what are the signs of infection in the blood
changes in the number of circulating white blood cells
increase in white blood cells
leukocytosis
decrease in white blood cells
leukopenia
microorganisms are multiplying in the blood and present in large numbers
septicemia
small numbers of bacteria present in blood not necessarily multiplying
bacteremia
small number or viruses present not necessarily multiplying
viremia
portals of exit
respiratory and salivary portals
epithelial cells
fecal exit
urogenital tract
removal of blood or bleeding
after the initial symptoms in certain chronic diseases the microbe can periodically become active and produce a recurrent diseases person may or may not shed it during the latent stage
latency
person with a latent infection who sheds the infectious agent
chronic carrier
long-term or permanent damage to tissues or organs
sequelae
study of the frequency and distribution of the disease and other health-related factors in defined human populations
epidemiology
individual who inconspicuously shelters a pathogen and spreads it to others
carrier
shows no symptoms
asymptomatic carrier
contained healthcare provider transfers them to other patients
passive carrier
primary habitat of pathogen in the natural world
reservoir
individual or object from which an infection is actually acquired
source
spread the infectious agent during the incubation period
incubation carriers
recuperating without symptoms
convalescent carriers
individual who shelters the infectious agent for a long period
chronic carrier
a live animal that transmits an infectious agent from one host to another
vector
infection indigenous to animals naturally transmissible to humans
zoonosis
when an infected host can transmit the infections agent to another host and established infection in that host
communicable disease
infectious diseases does not arise through transmission from host to host
non-communicable
physical contact or fine aerosol droplets
direct contact
passes from infected host to intermediate conveyor and then to another host ex doorknob cell phone
indirect contact
inanimate material, food, water, biological products, fomites
vehicle
droplet nuclei, aerosols
airborn
total number of existing cases with respect to entire population usually represented by a percentage of the population
prevalence
measures the number of new cases over a certain time period as compared with the general healthy population
incidence
the total number of deaths in a population due to a certain disease
mortality rate
number of people afflicted with a certain disease
morbidity rate
disease that exhibits a relatively steady frequency over a long period of time in a particular geographic locale
endemic occurrence
when occasional cases are reported at irregular intervals
sporadic occurrence
what does epidemiologists consider?
virulence, portals of entry and exit and the course of disease
colleting analyzing and reporting data on rates of occurrence mortality morbidity and transmission of infection
surveillance
what is the CDC?
centers of disease control and prevention principal government agency responsible for keeping track of infectious diseases nationwide
who is the WHO?
world health organization for worldwide tabulation and control
when prevalence of a disease is increasing beyond what is expected
epidemic occurrence
epidemic across continents
pandemic occurrence
what are (HAIs)
nosocomial infections also called healthcare associated infections are diseases that are acquired or developed during a hospital stay.
what are nosocomial infections
the most common involve surgical incisions and the respiratory tract, GI tract, skin, urinary tract, and blood sepsis
stringent measures to prevent the spared of nosocomial infections from patient to patient from patient to worker and from worker to patient
universal precautions
