15/16 study MJ

What are opportunistic pathogens?

capable of causing disease in compromised persons

How are opportunistic pathogens different from true/primary pathogens?

True/primary pathogens can cause infection and disease in a healthy person, opportunistic pathogens don’t cause illness in a healthy person.

What are some examples of opportunistic pathogens

Pseudomonas, Candida albicans, Staphylococci & Streptococci

Which parts of the body are sterile?

the organs above the bladder and (uterus, bladder, liver, bronchi, lungs, kidneys, etc.)

What is the difference between infectious and non-infectious disease

infectious means the disease can be spread, non-infectious means it cannot be spread

What is the difference between endogenous vs exogenous?

endogenous: origin of microbe is from the body, it was already in or on the body. When normal flora are intoduced

exogenous: Origin of microbe is outside the body

If a person has a disease but no noticeable sign/symptom, the disease is said to be ______________

asymptomatic or subclinical

What does communicable mean?

easily spread from person to person

What does non-communicable mean?

Cannot be passed on easily

What is a nosocomial infection

infections acquired in hospital

What is a Iatrogenic Infection

developed after a medical procedure

What is a Zoonotic disease?

infectious disease transmitted from animals to humans

Is Malaria infectious? contagious? communicable?

Yes, malaria is infectious and communicable, but not contagious

What is the incubation period?

time of contact, to appearance of first symptoms

What happens in the prodromal stage?

• General symptoms like discomfort, aches, feeling tired

• Activation of immune system

What happens during the period of invasion/illness

• Specific signs and symptoms

• marked by fever

What is the period of decline

pathogen/particle number declines, signs/symptoms decline

What happens in the convalescent period?

patient returns to normal functions, damage repair

At which stage can patients be contagious?

Any

What is an acute disease?

rapid onset of disease that lasts a relatively short time (flu)

What is a chronic disease

disease that lasts over a longer time i.e. Chronic gastritis

What is a Latent disease

pathogen goes dormant for extended period of time i.e. Chicken pox

causing- Varicella Zoster Virus which causes Shingles later on.

What is the difference between virulence and pathogenicity?

Virulence is a spectrum of severity, pathogenicity is simply the ability to cause an infection.

If an organism can cause infection it is said to be ________

pathogenic

How easily an organism can cause infection depends on its ________.

virulence

If a pathogen can easily cause infection does it mean that it can cause severe disease?

No

What is Median Infectious dose (ID50)?

The minimum amount of agent needed to cause infection in 50% of inoculated animals

What is Median Lethal dose (LD50)?

The minimum amount of agent needed to kill 50% of inoculated animals

What are the stages of pathogenesis

portal of entry, adhesion, evasion/invasion, infection/damage, portals of exit and transmission

What are the portals of entry?

skin, GI tract, urogenital, respiratory, maternal/fetal

What does STORCH stand for?

Syphilis, Toxoplasmosis, Other viruses, Rubella, Cytomegalovirus, Herpes

Most pathogens enter the body via the __________ system.

Respiratory

Which is the hardest portal of entry to access?

Maternal/Fetal

What bacterial structures aid in adhesion?

fibriae, pilli, capsules, glycocalyx*

What protozoan structuctures aid in adhesion?

cillia

What viral structures aid in adhesion?

capsids or viral membranes

What is EPS? What is it associated with?

Extrapolymeric substances, associated with biofilms

What are some bacteria that survive phagocytosis?

L. monocytogenes, Shigella, H. pylori (neutrophile), and M. tuberculosis

What are the different types of infection?

local, focal, systemic, primary, secondary

What is a local infection

confined to small area around portal of entry

What is a focal infection

pathogen from a localized infections-toxins spread to secondary location

What is a systemic infection

disseminates throughout body

What is a primary infection?

initial infection caused by one pathogen

What is a secondary infection?

primary infection causes damage and become infected with secondary pathogen

Why is it important for a pathogen to leave the host?

The host is dying/dead

What are virulence factors (VFs)?

Proteins encoded by genes that determine an individual organisms degree of pathogenicity and how much damage they can do

Name the group of VFs that aid in pathogen attachment to host cells.

Adhesions

What is the correlation between the adhesion and the attachment tissue type

the adhesions are made to attach to a certain tissue type

What are exoenzymes? What do they do?

enzymes released extracellularly, they help to invade host cells and get in deeper. They also have specific targets

What is an example of a Glycohydrolase that degrades hyaluronic acid that cement cells together to promote spreading through tissue

Staphylococcus aureus

What is an example of a Nuclease that degrades DNA released by dying cells that can trap the bacteria

S. aureus

What do phospholipases do?

Degrades phospholipid bilayer of host cells, causing lysis (Bacillus anthracis)

What do proteases do?

Degrade the collagen in connective tissue (clostridium perfringens)

What are the four exoenzyme classes?

Glycohydrolases, nucleases, phospholipases, Proteases

What does collagenase do?

degrades the collagen between the endothelial cells, allowing the bacteria to enter the bloodstream

What is an exotoxin?

protein toxins released mostly by gram-positive bacteria- target specific cells

What are endotoxins?

only found in gram-negative bacteria because the LPS in their outer membrane is the endotoxin; released when the cell lyses

Which part of a lipopolysaccharide is toxic?

Lipid A

What is epidemiology?

study of how disease originates or what causes a disease (etiology) and how it transmits or spreads throughout a population

What is morbidity?

state of being diseased; expressed with the number of individuals

What is the morbidity rate?

number of diseased individuals in a population; number of individuals per 100,000 people

What is the Mortality (death) rate

can be expressed as a percentage of the population that has died from a disease or the number of deaths per 100,000 persons

Prevalence of disease

number or proportion of individuals with that illness in a given population at a given time

Incidence of disease

is the number of new cases in that period of time

Sporadic disease

diseases seen randomly on occasion like tetanus, rabies or the plague

Endemic disease

diseases that are constantly present within in particular geographic region like Malaria in some regions of Brazil or Africa

Epidemic disease

seasonal occurrence of disease in a particular geographic region such as the Flu

Pandemic disease

epidemic that occurs worldwide, across continents like HIV/AIDS and some novel flu viruses

Notifiable diseases

supposed to be reported to the CDC such as Measles, West Nile virus, HIV, etc.

What are Reservoirs?

where a pathogen persists or resides for long periods of time

What is a carrier

an individual capable of transmitting the disease

Passive carrier

– uninfected individual who can mechanically transmit the pathogen i.e. health care worker who does not wash their hands

Active carrier

infected individual who can transmit during some part of the infection cycle so they may or may not have symptoms when they do

What is vertical transmission

mother to child

Which of the following would be considered a symptom

body ache  & chillsbody ache  & chills

Which of the following is an example of a nosocomial disease

catching a Pseudomonas respiratory infection during a recent visit to the hospital

Sickle cell anemia can be classified as which type of disease?

non-infectious, non-communicable

Identify which pathogen is the least virulent on the basis of ID₅₀

pathogen A with an ID₅₀ of 1000 cells

Which pathogen cannot pass the blood–placenta barrier and infect a fetus

Salmonella typhi (Salmonellosis)

Which virulence factor, produced by Staphylococcus aureus, allows the bacterium to be coated in fibrin that protects it from phagocytes?

coagulase

What is the toxic component of endotoxin

lipid A

An enterotoxin targets which type of cell?

intestinal cells

________ are exotoxins that can trigger a cytokine storm.

Superantigens

Catheter associated skin infections are caused specifically due to ______________

S. epidermidis

Neisseria gonorrhoeae binds to cells in reproductive tract due to which external appendage?

Pili

A high concentration of this in the blood, leads to the development of Sepsis.

Endotoxins

The part of the gastrointestinal tract with the largest natural microbiota is the _________.

Large Intestine

Toxic Shock Syndrome Toxin-1 (TSST-1) is associated with

Staphyolocci

Which of the following applies to hyaluronidase?

It acts as a spreading factor to spread the infection

Which of the following would be a sign of an infection?

fever

Which of these structures aids in attachment to the host cell?

Protein coat

Which species is frequently associated with nosocomial infections transmitted via medical devices inserted into the body

Staphylococcus epidermidis

Which stage is associated with activation of the immune system?

Prodromal

During which stage does the patient show SPECIFIC signs and symptoms of the disease

Period of illness/invasion

During which stage does the patient show GENERAL signs and symptoms of the disease

prodromal stage

Which of these portals of entry of a pathogen is considered an indirect portal of exposure to the external environment

Maternal/fetal

Which of these is an exoenzyme- enzyme released extracellularly by the pathogen that targets and degrades DNA released by dying host cells

DNase