Microbiology Test 2

psychrophiles

psychrophiles

cold-loving microbes, deep-ocean, 15 degree Celsius

psychtrophs

grow between 0 and 20-30 degrees Celsius cause food spoilage

thermoduric

can survive in elevated temps. for a short period of time

facultative halophiles

osmotolerant grow in hypertonic/isotonic, up to 15% of salt

neutrophiles

5.5-8 pH level

acidophiles

1-4.5 pH level

alkalophilic

greater than 8 pH level

enzymes that deoxify

superoxide free radicals and peroxide

superoxide dismutase

turns into hydrogen peroxide

catalase

hydrogen peroxide turns to water/gas

obligate aerobes

require oxygen

facultative anaerobes

can live with or without oxygen

physical requirements for growth

temperature, pH, osmotic pressure

chemical requirements for growth

oxygen, carbon, trace elements

mesophiles

moderate temperature loving microbes (20-40C) medical

thermophiles

heat loving microbes (40-80 C) hot springs

hyperthermophiles

survive in high temperatures 95 degrees Celius

osmophiles

survive in hypertonic conditions

extreme halophiles

live in highly saline environments, dead sea

obligate anaerobes

organisms that cannot live where molecular oxygen is present

aerotolerant anaerobes

do not utilize oxygen but can survive and grow in its presence

microaerophiles

require oxygen concentration lower than air

CO2

.03% of the atmosphere

capnophiles

grows best in 3-10% concentration of CO2

lag period

bacteria getting used to new environment, adjustment period

biofilms

aggregation of bacteria of many species embedded in gel-like matrixes

advantages of biofilms

-maintaining position in environment -protection from chemical control -increased resistance to immune system -cross feeding -quorum sensing

cross feeding

product oof one bacteria of metabolic process feed other bacteria

quorum sensing

enables microbes to detect cell density within a biofilm

autoinducer

molecule released by bacteria in biofilm, cause change in genetic expression

microbial growth

increase in number of cells, not cell size

binary fission

form of asexual reproduction, most common, DNA replication then cell division

generation time (doubling time)

time it takes to complete a fission cycle, depends on bacterial species and environmental conditions

lag phase

"flat" period of adjustment, enlargement; little growth

log phase

begin replication, ideal conditions and characteristics

stationary phase

growth rate=death rate, growth rate=0

death (decline) phase

growth rate<death rate, reduces population to zero if incubation continues

direct bacteria counting

quick, cells counted under light microscope , known quantity, cheap

plate counts

only counts viable cells, common way for bacteria are counted

serial dilution

samples can have very high bacteria concentration, must dilute to bring down total colonies

indirect bacteria counting

most probable number, useful in dilute samples, uses color change to detect microbial growth

pathology

study of disease

etiology

study of the cause of disease

pathogenesis

development of disease

infection

colonization of the body by pathogens

disease

an abnormal state in which the body is not functioning normally

Koch's Postulates

1. bacteria must be present in diseased but not in healthy individuals 2. bacteria must be isolated + grown on artificial media 3. test organism must replicate signs and symptoms of disease 4. bacteria must be reisolated + grown on artificial media

symptom

a change in a body function that is felt

sign

a change in a body function that can be observed

syndrome

a specific group of signs + symptoms that accompanies a disease

communicable

a disease that is spread from one host to another

contagious

disease that easily spread from one to another

noncommunicable

a disease that is not transmitted from one host to another

incidence

fraction of a population that contracts a disease during a specific time

prevalence

fraction of a population having a specific disease at a given time

endemic disease

established within geographical region (flu)

sporadic disease

disease doesn't naturally occur in location, new cases are random (ebola in the US)

epidemic disease

endemic disease that exceeds the number of cases for that time period, outbreak at a lower scale (ebola in Africa)

pandemic

epidemic at a global level (COVID)

herd immunity

number of individuals in a population which must acquire immunity to a disease in order to slow or stop spread

R(0)

number of individuals likely to be infected by a transmitting case

acute

symptoms develop rapidly

chronic

disease develops slowly

latent

disease within a period with no symptoms when causative agent is inactive

local infection

pathogens are limited to a small area of the body

systemic infection

an infection throughout the body

focal infection

systemic infection that began as a local infection

sepsis

toxic inflammatory condition arising from the spread of microbes

bacteremia

bacteria in the blood

septicemia

growth of bacteria in 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

human reservoirs

main reservoir, transmits actively or passively, s+s or latent infections

animal reservoirs

zoonoses, direct contact, airborne, consuming infected animal product

nonliving reservoirs

environmental sources, soil, water, environment

contact transmission

direct contact- vertical vs. horizontal, droplet, indirect-nonliving fomite

vehicle transmission

transmission by an inanimate reservoir, waterborne, airborne, foodborne

nosocomial infections

acquired in hospital, nursing home, or prison, 8th leading cause of death, compromised host through skin +mucous membrane and suppressed immune system

resident microbiota

microbes that are always there

transient microbes

microbes who colonize the body + may be present for days, weeks, or months

factors affecting distribution + composition

- nutrients, bodily fluids, diet, dead cells - physical + chemical factors - defenses of host - mechanical factors

microbial antagonism

when one microorganism kills, injures, or inhibits the growth of another microorganism

virulence factors

mechanisms that pathogens us to invade the immune system and cause infection

skin

most easily colonized area of body due to size + location, diverse environment, oily areas

gastrointestinal tract

bacteria reside in the lumen or attached to mucus epithelium, nutritional availability high

mouth

most diverse collection of microbes, aerobic bacteria survive within gumline and plaque build up

dysbiosis

an alteration of species composition in of microbiota, environmental changes responsible for change from mostly symbiotic bacteria

large intestine

highest density, contains most complex + important microbial interaction with host

genitourinary tract

sexual organs kept sterile through physical barriers, estrogen stimulates release of glycogen which encourages lactobacillus bacteria

probiotics

live culture microbes beneficial to developing human microbiota

prebiotics

a substrate that is selectively utilized by host microorganisms

portal of entry

the way a pathogen gets into your body

direct portal of entry

-gain access + adhere -avoid or penetrate host defense -damage tissue

indirect portal of entry

build up of waste/toxin

pathogenicity

the ability to cause disease

virulence

the extent of pathogenicity

stages of pathogenicity

1. exposure to host

2. adhesion

3. invasion

4. infection