Unit 3 Study guide

Infection

pathogens that establish themselves in tissues

they can multiply and invade the body

inflammation may be a response

Disease

any change from general state of good health

(damage, dysfunction, compromised or weak immune system)

Parasitism

form of symbiosis in which pathogen benefits and damages host

this can lead to disease

Pathogenicity

liklihood an infection will cause and lead to disease

Sign

body abnormality that can be detected by an observer ex: heart rate, blood pressure, temperature, test results, RBC count

Symptom

changes in body function sensed by patient ex: aches, nausea, malaise, pain

Syndrome

set of signs and symptoms that point to a specific disease

Virulence

pathogen’s ability to do harm to the host after infection

a pathogen’s degree of pathogenicity

Virulence Factors

structural or chemical components of pathogens that make it easier for them to cause disease

Opportunistic pathogens

usually commensal (already in host) that take advantage of an organism’s state of dysbiosis

primary pathogen

can cause disease in healthy individuals

antivirulent

not regarded as infectious disease agent, lacks virulence factors

infectious dose

minimal number of pathogens needed to trigger signs and symptoms of disease

diagnosis

evaluation of patient signs and symptoms based on physical exam and medical history

primary infection

infection that occurs in an otherwise healthy individual

first disease

secondary infection

additional infection that develops when someone is already weakened by primary infection

second infection ex: you have flu, now you are susceptible and are weakened, an opportunistic bacteria in respiratory tract can cause damage now.

local infection

an infection that is restricted to a single area of the body

systemic infection

infection that spreads via blood to other tissues or organs

focus of infection

the beginning/origin of a systemic infection

bacteremia

bacteria transiently (temporarily) existing in blood stream

Septicemia

blood poisoning from bacteria multiplying in blood stream

can cause sepsis and organ failure

Fungemia

spread of fungi through blood stream

Viremia

spread of viruses through blood stream

parasitemia

spread of protists/worms through blood stream

functions of bacterial capsule (2)

a thick outer layer of carbs that allows 1) pathogen to stick to cell surface and 2) pathogen to evade immune defense

function of pilli

function of virus spike

allows virus to attach to host cells with corresponding receptors

function of coagulase

proteins that surround bacteria and clot around it to protect it from immune response

what common bacteria uses coagulase

staph aureus

what undoes the clot from coagulase?

streptokinase

what is R₀ ?

measure of transmissibility, number of people in a fully susceptible population that will be infected by a single contagious person

basic reproduction number

what is R₀ > 1 and what does it mean for the spread

infection causes more than one new illness, disease will spread

what is R₀ < 1 and what does it mean for the spread

infection causes less than one new illness, disease declines

what is R₀ = 1 and what does it mean for the spread

disease will stay active but no outbreak will occur

What is a holobiont?

considered a unit of evolution, a host and all of its symbionts

2 examples of homobiont

1. The human body and all of your microbes

2. Coral

How does infectious dose affect transmission?

low infectious dose → usually more transmissible because less pathogens are required to trigger symptoms

high infectious dose → usually less transmissible because more pathogens are required to trigger symptoms

Give an example of why a microbe needs a larger or smaller infectious dose

Campylobacter cells have a small infectious dose of a few hundred to cause food poisoning. Salmonella Bacilli have a larger infectious dose of about 100,000 to cause food poisoning. This is because Campylobacter cells are more resistant to the acidic conditions of the stomach, and Salmonella are not.

Define Antigen

Foreign material or piece of pathogen recognized by the immune system

structure associated with O antigen

LPS/cell wall

Structure associated with K antigen

capsule

structure associated with H antigen

flagellum

why are antigens important for naming bacteria

they let us differetiate strains ex: E.Coli O157H7

What essential procedures do you need to follow for proper sample selection, collection, and transport?

• aseptic technique

• label specimens

• select fresh sample

• store in proper temperature

• choose high quality samples

PCR meaning

Polymerase Chain Reaction

PCR test procedure

nucleic acid sequences that are unique to pathogen are separated, Polymerase Chain reaction creates millions of copies of the DNA and adds fluorescent markers

Why do you need to use reverse transcriptase to perform a PCR sample to test for SARS- CoV2?

Covid is an RNA virus and has no DNA. PCR only amplifies DNA.

antigen test

less accurate, on the spot results, less expensive

synthetic antibodies test for specific antigens

show a positive test only for active antigens

serological test

track antigen antibody interactions

positive if infected in the past

can help identify bacteria serotypes

early bacterial colonizers in tooth decay

Staphylococcus sobrinus/mutans, Lactobacillus and Corynebacterium

What is the role of Corynebacterium in tooth decay

is the framework and foundation for future bacterial growth

What are the roles of streptococcus and Lactobacillus in tooth decay?

demineralize enamel

late bacterial colonizers in tooth decay

porphyromonas gingivalis, leptotrichia, haemophilus, and aggregatibacter

What is the role of prophyromonas gingivalis in tooth decay?

secrete enzymes and toxins that injure surrounding tissues

demineralization

cavity created from early colonizing bacteria fermenting sugars and releasing acids

Gingivitis

inflammation and bleeding of gingiva

early stage periodontal disease

develops when plaque builds up in between teeth and gums

Periodontal Disease

ulcers, degradation of ligaments, loose and lost teeth (bone resporption)

p gingivalis induces dysbiosis and some bacteria release tissue desctructing products

Non-inflammatory Gastroenteritis

very short lasting 1-6 hours. quick onset and resolution

signs vary depending on case: vomiting, cramps, diarrhea (no blood) feeling weak

infectious agents of non inflammatory gastroenteritis

most commonly staph aureus

also clostridium botulinum, clostridium perfringens, bacillus cereus

Inflammatory Gastroenteritis

acute and non-invasive 1-3 days

watery diarrhea, vomiting, fever

Invasive Gastroenteritis

longer lasting and does more damage to mucosal lining

diarrhea and abdominal pain and dysentery

vomiting uncommon

dysentery

bloody mucus in stool

Enterotoxigenic (ETEC)

traveler’s diarrhea, acute watery diarrhea, afebrile

Enteroaggregative (EAEC)

prolonged in children, watery diarrhea with mucus or blood

Enteropathogenic (EPEC)

severe acute watery diarrhea, common cause of infant illness in developing world

Enteroinvasive (EIEC)

fever, watery diarrhea can progress to bloody diarrhea