Chapter 11 Flashcards
Symbiosis
Means to live together
Mutualism
Commensalism
Amensalism
Parasitism
Mutualism - organism one and two benefit, an example is bacteria in the human colon
Commensalism - benefits organism one and organisms two is neither benefited or harmed, example is mites in the human hair follicles
Amensalism - organism one is harmed and organisms two is neither benefited or harmed. Example is fungus secreting an antibiotic,
inhibiting nearby bacteria
Parasitism - benefits organism one and organism two is harmed. Example is tuberculosis or bacteria in the human lung
Symbiotic relationships between microbes and their hosts
Microbiome of humans
- organisms that colonize the body’s surfaces without normally causing disease
- also termed normal microbiota, normal flora, and indigenous microbiota
- two types are:
- resident microbiota
- transient microbiota
What do microbiomes do for us?
- metabolic/nutritional/energy utilization
- competitive exclusion of pathogens
- block pathogens from growing in our bodies - help our immune systems develop properly
- inflammatory response
- T-cell regulation
What are ways that organisms can change and grow in the body
Generally the environment, but more exclusively:
- pH
- temperature
- oxygen
- diet
- our mother
- exposure to radiation
- moisture levels
Commensal microorganisms do what in the body
Commensal microorganisms assist the gut in digesting food and maintaining health
Major physiological processes - pH
- Secretion of acid (HCl) - digestion of macromolecules -> pH of 2
- continues digestion. Absorption of monosaccharides, amino acids, fatty acids, water -> pH of 4-5
- absorption of bile acids, vitamin B12 -> pH 7
What plays a huge role to our microbiome situation of our body
Our mother
- out mother changes the microbiome, the temperature, the foods and many other things
Critical timeframe for intervention
Placental transfer - - - - - —————> 1000 days
Breast - milk -> Bifidobacterium spp & lactobacillus spp
Before:
Formula -> Enterococci & enterobacteria
What do microbiomes do for us?
- bacteria in out gut microbiome use enzymes that can help break down our ingested food more completely than our bodies can on their own
- SCFAs give us 5-15% of energy requirements
- food is broken down better, and more nutrients and energy are extracted
What can microbiomes do for us in regards to pathogens?
- microbiomes can block pathogens from growing in our bodies
- pathogens that make it past our other barriers to infection will need nutrients once inside our bodies
- if our microbiome bacteria are using up those nutrients, then pathogens have a harder time surviving
What causes our microbiomes to change?
- what do we think happens
- list examples of the benefits of the microbiome.
- antibiotics especially the broad-spectrum ones
- our diet, if we change what we eat then our microbiome can change (going from high to low fat can cause a disregulation in the microbiome
- when the body gets sick, the microbiome starts to change a break down. Infections by other microorganisms can start to change the body
- changes in the environment: increased stress, or changed diet, lack of sleep
What the microbiome does for us
- Helps to break down the metabolism and can help to teach the immune system. Can break down molecules so that the body can better use them in the metabolic processes.
- it is in a block so that it can work as a defense mechanism to block bad things like pathogens. Acts as a physical barrier.
- helps digestion by breaking down ingested food (Ie: fiber) so that the body can actually use it as energy.
- Helps the immune system to determine what is good and bad. It trains the immune system
Reservoirs of infectious diseases in humans
- most pathogens cannot survive for long outside their host
- reservoirs of infections
- sites where pathogens are maintained as a source of infection - three types of reservoirs
- animal reservoirs
- human carriers
- nonliving reservoirs
Reservoirs of infectious diseases in humans
- animal reservoirs
- zoonoses
- diseases that naturally spread from animal host to humans
Can acquire zoonoses through various routes:- direct contact with animals or its waste
- eating animals
- bloodsucking methods
- diseases that naturally spread from animal host to humans
- humans are usually dead-end host to zoonotic pathogens (we don’t typically pass it back to animals but rather to other humans)
- difficult to eradicate
What are some common zoonoses
- bubonic plague
- Ebola
- Zika virus
- lice
- Mad Cow disease
- lime disease
- tick fever
- Rabies
- COVID
- Malaria
Reservoirs of infectious diseases of humans
- nonliving reservoirs
- soil, water, and food can be reservoirs of infection
- the presence of microorganisms often due to contamination by feces or urine
Reservoirs of infectious diseases of humans
- human carriers
- asymptomatic infected individuals can be infective to others
- some individuals eventually develop illness, while others never get sick
- healthy carriers may have defensive systems that can protect them
The invasion and establishment of microbes in hosts: infection
- exposure to microbes: contamination and infection
- contamination
- the mere presence of microbes in or on the body
- infection
- when an organism evades body’s external defenses, multiplies, and becomes established in the body
The invasion and establishment of microbes in hosts: infection
- the role of adhesion in infection
- adhesion
- process by which microorganisms attach themselves to cells
- required to establish colonies successfully within the host
- uses adhesion factors
- specializes structures
- attachment molecules
The nature of infectious disease
- infection is the invasion of the host by a pathogen
- disease results if the invading pathogen alters normal body functions
- disease is also referred to as morbidity
That nature of infectious disease:
- causation of disease: etiology
- the study of the cause of the disease
- disease that have various causes
Where does adhesion come in with infectious material
- if there is no point of attachment there is no place for the microbe to attach to
- if the microbe can attach somewhere it is more likely to be able to adhere to the host cell and infect it
What does the microbe attach to
The microbe attaches to the receptor. The microbe has what is called a ligand which is the adhesion factor that connects the microbe to the receptor (glycoprotein) which adheres to the cell
manifestations of disease
Symptoms, signs, and syndromes
- symptoms
- subjective characteristics of disease felt only by the patient
- signs
- objective manifestations of disease observed or measured by others
- syndromes
- symptoms and signs that characterize a disease or an abnormal condition
- asymptomatic, or subclinical, infections that lack symptoms but may still have signs of infection
the nature of infectious disease: etiology
Causation of disease: etiology
- etiology
- study of the cause of the disease
- disease have various causes
The stages of infectious disease
- the disease process occurs following infection. Many of the infectious diseases have five stages following interaction
- incubation period -> onset of infection no signs or symptoms
- prodromal period -> experience vague, general symptoms
- illness -> where the most severe signs and symptoms occur
- decline -> when symptoms and signs start to decline
- convalescence -> no signs or symptoms left
modes of infectious disease transmission:
- transmission is from a reservoir or a portal of exit to another host’s portal of entry
- there are three groups of transmission
- contact transmission
- vehicle transmission
- vector transmission
contact transmission
- direct contact transmission
- usually involves body contact between hosts
- transmission within a single individual can also occur - indirect contact transmission
- pathogens are spread form host to host by fomites
- droplet contact transmission
- spread of pathogens in droplets of mucus by exhaling, coughing, and sneezing
vehicle transmission
– Airborne transmission
▪ When pathogens travel more than 1 m via an
aerosol
▪ Aerosols can occur from various activities
– Waterborne transmission
▪ Important in the spread of many gastrointestinal
diseases
▪ Fecal-oral infection
– Foodborne transmission
– Bodily fluid transmission
epidemiology
- The study of where and when diseases occur and how they are transmitted in populations
- Epidemiologists:
–Determine etiology of a disease
–Identify other important factors concerning the spread of disease
–Develop methods for controlling a disease
–Assemble data and graphs to outline incidence of disease
epidemiology of infectious diseases
- Frequency of Disease
– Disease occurrence tracked using two measures
▪ Incidence
– Number of new cases of a disease in a given
area during a given period of time
▪ Prevalence
– Number of total cases of a disease in a given area during a given period of time
– Occurrence also evaluated in terms of frequency and geographic distribution
tracking disease in the population
Reportable or notifiable diseases:
* Certain diseases must be reported to authorities
* Other diseases are reported on a voluntary basis
* A network of individuals and agencies at the local, district, state, national, and international levels keeps track of infectious diseases
Epidemiological studies
– Descriptive epidemiology
▪ Careful tabulation of data concerning a disease
– Record location and time of the cases of
disease
– Collect patient information
▪ Try to identify the index
case of the disease
healthcare-associated infections (HAIs)
- Acquired while receiving treatment in a health care facility
– Also known as nosocomial infections - Affect 1 in 25 hospital patients
- 2 million per year infected;
20,000 deaths
Circumstances make HAIs unavoidable
Factors tied to healthcare-associated infections:
*Compromised patients
*Collection point for pathogens
*Lowered defenses permit normal biota to enter the body.
*Infections acquired directly or indirectly from fomites, medical equipment, other patients, medical personnel, visitors, air, and water
healthcare can increase the likelihood of infectious agent transfer
Healthcare processes that lead to healthcare-associated infections:
* Treatments using reusable instruments such as respirators and thermometers
* Indwelling devices such as catheters, prosthetic heart valves, grafts, drainage tubes, and tracheostomy tubes form ready
portals of entry
* High proportion of the hospital population receives antimicrobial therapy, so drug-resistant microbes are selected
for at a much higher rate
most common HAIs
Most common HAIs include pneumonia, gastrointestinal illness, urinary
tract infections, bloodstream infections, and surgical site infections
Five common hospital pathogens:
* Clostridioides difficile: GI infections
* Staphylococcus aureus: pneumonia, surgical site infections, bloodstream infections
* Klebsiella species: surgical site infections, urinary tract infections, pneumonia
* Escherichia coli: urinary tract infections, surgical site infections, bloodstream infections
* Enterococcus species: surgical site infections, urinary tract infections, bloodstream infections
epidemiology of infectious disease
- Hospital Epidemiology: Healthcare-Associated (Nosocomial)Infections
– Control of healthcare associated infections
▪ Requires aggressive control measures
▪ Handwashing is the most effective way to reduce healthcare-associated infections
What is an example of trying to avoid contact transmission
- during COVID when all surfaces were disinfected with an alcohol spray between classes
- not being able to pass things from hand to hand curing pandemics because it could pass the disease
Outbreak
Sudden increases in occurrences of a diseases in a particular time and place
Endemic
- constant maintained increase in occurrences of a disease in a geographic area
Epidemic
- a rapid spread of disease to a large number of people in a given population within a short period of time
Pandemic
- spread across a large region, for instance multiple continents, or worldwide
The Centers for Disease Control and Prevention (CDC)
- collects and analyzes epidemiological information in the United States
- Publishes Morbidity and Mortality weekly report (MMWR)
Define the following:
Morbidity
Mortality
Morbidity: incidence of a specific notifiable disease
Mortality: deaths from notifiable diseases
