microbiology exam 3

Pathology

The study of disease

Etiology

The cause of disease

Pathogenesis

The manner in which a disease develops

Infection

Invasion or colonization of the body by pathogens

Infectious disease

Occurs when an infection results in an change in the state of health

Can an infection still exist in the absence of a detectable disease?

Yes

Is there specific location where the disease may result?

No a disease may result in there a particular type of microorganism located in part of the body that it is not normally found in

Where do you get your first microbiome from?

Your mom and how you were born

What type of microbiome do you have based on the way you were born?

If you born through the vagina or through C section is how it determines your microbiome

How does your microbiome adapt over your life?

It changes over time based on the environment, food, etc.

What is microbial antagonism?

Where the growth of one bacter prevents the growth of another bacteria

How does microbial antagonism help the host?

Preventing a pathogen from infection

How does a microbial antagonism prevent a pathogen from infection?

• compete for nutritients

• Produce bacteriocins

• Change pH/O2 levels

What is symbiosis?

A relationship b/w organisms in which at least one organism is dependent on the other

Commensalism

One organism benefits, and the other is unaffected

Mutualism

Both organisms benefit

Parasitism

One organism benefits at the expense of the other, many disease causing microorganisms are parasites

What is Koch’s first postulate?

Isolate microbe from disease host that is not normally found in the healthy host

What is the second step of Koch’s postulates?

Grow microbe in pure culture

What is the third step of Koch’s postulates?

Inoculate healthy host w/ microbe

What is the fourth step of Koch’s postulates?

Disease is reproduced

What is the fifth step of Koch’s postulates?

Isolate suspected microbe again

Symptoms

Subjective changes in the body function that are felt by a patient as a result of disease

Can symptoms be seen by an observer?

No they cannot be seen by an observer

Signs

Objective changes in a body that can be measured or observed as a result of disease

Syndrome

A specific group of sign and symptoms that accompany a disease

Communicable disease

A disease that is spread from one host to another

What are examples of communicable diseases?

COVID-19, chicken pox, measles, influenza, genital here pets, tuberculosis

Contagious diseases

Disease that are easily and rapidly spread from one host to another

Noncommunicable diseases

A disease that is not spread from one host to another

What is an example of a noncommuniable disease?

Tetanus

Incidence

Number of people who develop a disease during a particular time period

Prevalence

Number of people who have a disease at a specified time, regardless of when it first appeared

What does prevalence all take into account?

Both new and old cases

Sporadic disease

Disease that occurs only occasionally

Endemic disease

Disease constantly present in a population

Epidemic disease

Disease acquired by many people in a given area in a short time

Pandemic disease

Worldwide epidemic

What is an example of a pandemic?

COVID-19

Duration

Average time that individuals have a disease from diagnosis until they are either cured or die

Acute disease

Symptoms develop rapidly but has a short duration

Chromic disease

Symptoms develop slowly, likely to last for a long period of time

Subacute disease

Intermediate between acute and chronic

Latent disease

Causative agent is inactive for a time but then activated and produces symptoms

Herd immunity

Immunity in most of a population

Severity

The presence and extensiveness of a disease in the body and its ability to cause death

Infection fatality ratio (IFR)

Divide the number of deaths attributed to a disease by the total number of infected individuals within a specific time period

What does a lower IFR mean?

It means that there is a lower number of deaths

Case fatality ratio (CFR)

Proportion of individuals diagnosed with a disease who die from that disease within a certain period of time

Local infection

Pathogens are limited to a small area of the body

Systemic (generalized) infection

An infection spread throughout the body by the blood and lymph

Focal infection

Systemic infection that began as a local infection

Sepsis

Toxic inflammatory condition arising from the spread of microbes, especially bacteria or other toxins, from a focus of infection

Bacteremia

Bacteria in the blood

Septicemia

AKA blood poisioning

Growth of bacteria of in the blood, bacteria proliferating the blood

Toxemia

Toxins in the blood

Viremia

Viruses in the blood

Primary infection

Acute infection that causes the initial illness

Secondary infection

Opportunistic infection after a primary (predisposing) infection

Subclinical infection

No noticeable signs or symptoms (no noticeable infection, asymptomatic infection

Predisposing facts

Variables that make body more susceptible to disease or many alter the course of a disease

What are examples of predisposing factors?

• age

• Sex

• Nutrition

• Genetic inheritance

Incubation

Exposure to first symptoms

Prodromal period

Early nonspecific + mild symptoms

Period of illness

Mast severe disease

Period of decline

Signs + symptoms start improving

Period of convalescence

Return to predisposed state

Human reservoir

Continual source of pathogen

• symptomatic host

• Carriers = asymptomatic

Animal reservoir

Disease transmitted from animals to human and then human to animals

• zoonoses

What are examples of non living reservoirs?

• soil

• Water

• Food

Direct contact transmission

Requires close association b/w the infected + susceptible host

Congenital transmission

Transmission from mother to fetus or newborn at birth

Indirect contact transmission

Spreads to a host by a non living object called a fomite

Droplet transmission

Transmission via airborne droplets less than 1 meter

Nosocomial infections

Acquired while receiving treatment in a health care facility

Compromised host

An individual whose resistance to infection is impaired by disease, therapy, or burns

How are healthcare associated infections transmitted?

• microorganisms in the hospital environment

• Weakened immune status of host

• Chain of transmission in a hospital

What makes a compromised host?

• broken skin or mucous membrane

• Suppressed immune system

• Invasive procedures and devices

What percent of HAI’s are due to catheters and urinary tract infections?

11.1%

What percent of HAIs are associated with venitalators?

28.1%

What percent of HAIs are associated with central lines?

16.2%

What percent of HAIs are associated with surgical site infection?

13.9%

What percent of HAIs are due to gastrointestinal infections?

30.7%

What are some chain of transmissions?

• urinary catheters

• Intravenous catheters

• Respiratory aids

• Needles

• Surgical dressings

What is the reproductive number?

Average number of people infected by 1 individual

What does R0 < 1 mean?

Sporadic

What does an Ro ~ 1 mean?

Epidemic

What does an Ro > 1 mean?

Epidemic