MICROBIO FINAL

bacteriostatic

stops or slows down the growth of certain microbes

bactericidal

kills microbes

resident bacteria

Microorganism that colonizes an area from months to years

resident bacteria functions

- aid in immune system development
- maintenance of homeostases of organism

transient microbes

1. Organisms present for temporary time period
2. Do not usually multiply in the skin
3. Typically acquired via direct contact
4. Transfer depends on
• Number of bacteria
• Species of bacteria

What determines the effectiveness of cleansing agents?

Active ingredients

At what level does a cleaning agent interact with the microbe?

based on the cellular component that they interact. could interact with enzyme or the entire cytoplasmic membrane.

microbiota

the community of microorganisms that live in and on our bodies
- personalized
-Number and type of organism can vary depending on location
-May play an essential role in development

factors affecting microbiota

environment and foods we eat

pathogenic

bacteria that cause disease

Non-pathogenic

bacteria that are not harmful, normal

opportunistic pathogens

viral infection, no cure
(ex. ammonia, e. coli)

commensal microbes

microbe that doesnt cause harm to host

symbiotic microbes

host has good relationship with microbe ; tthey both benefit from eachother

parasitic microbe

the host is harmed, only microbe benefits

ubiquitous

present or existing everywhere.
- bacteria are ubiquitous ( unless place sterile)

what is the goal for lab (2-1): ubiquity of microorganisms

to see if we have bacteria everywhere

what is the goal for lab (1-2): comparison of hand cleaning agents

to find out which hand cleanser was the most effective on killing bacteria

reservoir

can serve as a source of infection

what is the goal for lab (1-4): aseptic transfer

to learn how to properly transfer bacteria from one media to another while being sterile to help prevent contamination from pathogens.

Pathogen

An organism that causes disease

sterility

aseptic technique

agar

a gel-like texture full of nutrients used to grow bacteria.

broth

liquid media used for bacteria

slant

solid media in a test tube set at an angle

culture medium (media)

Sterile (nothing growing yet) nutrient food source for growth of microorganisms

pure culture

grow a single kind of bacteria

mix culture

grows more than one type of bacteria

pure colony

one bacteria grow on solid media as colones

mix colony

2 or more bacteria grow on solid media as colony

contamination

when you intend to grow a single bacteria in a medium, and expect to see one type of colony growing. however, you see several types of colonies growing.

negative control

no bacteria in the medium

aseptic technique

(sterile) are practices and procedures to prevent contamination from pathogens.

rules for loop

Metallic loops and needles need to always be sterile. For that we use flame to sterilize them before and after we take bacteria. ALLOW THEM TO COOL PRIOR TO ADDING BACTERIA

rules for agar

(made of plastic) cannot be sterilized with flame, so only open their lids at 45º angle while removing or introducing bacteria!

rules for test tubes

(made of glass) need to also be sterile before we take bacteria and after we introduce bacteria into test tubes.

How can you tell whether you have bacterial growth in a medium agar plate, in a slant, in a medium broth

presence of colonies, turbidity or cloudiness

Why plates are inverted when left in the incubator

so the lids dont fall from the medium

bacterial transfer (subculture)

Bacteria which grow in a medium, need to be eventually transferred to another fresh medium since bacteria will eventually run out of nutrients.

2 techniques to get isolated pure colonies from a mixed culture

4 quadrant streak and spread plate method

what is the goal of lab (1-5): streak plate method

to identify the pathogenic bacteria from a mix culture of bacteria

streak plate method

used to isolate pure cultures

the use of the streak plate method in medical field

to analyze urine sample for possible e.coli infection (UTI).

the goal of lab (1-6): spread plate method

isolation of bacterial species and could also be used to quantify bacteria.

use of spread plate method in medical field

to identify a pathogen

streak plate method

a method of isolating a culture by spreading microorganisms over the surface of a solid culture medium

the goal of lab (2-5): evaluation of media

know what kind of media autotrophs and heterotrophs grow better in. ????

autotroph

An organism that makes its own food

heterotroph

An organism that cannot make its own food.

fastidious bacteria

Depend largely on the environment to obtain organic material. (Heterotrophs are the most fastidious.)

non-fastidious bacteria

Less dependent on the environment for organic material.

undefined (complex media)

exact composition not known. It's rich in nutrients where a variety of microbes can grow on.
- Example: Brain heart infusion (BHI)

Defined (simple media made of specific chemicals)

Chemical amount and identity known. This medium supports a narrower or more specific range of microbes• - Example: Glucose Salt Media (GSA)

general purpose media

where many microbes will grow since they have enough nutrients.
- Example: TSA/TSB

enriched medium

where even more microbes will grow because they have additional nutrients.
- Example: BHI

differential media

where you will be able to differentiate microbes.

selective medium

where only selected microbes will grow, and growth of others is prevented or inhibited.

obligate aerobes

Require oxygen for survival

Microaerophiles

cannot tolerate atmospheric oxygen, only a little.

Capnophiles

are some of the microaerophiles that can live only if CO2 levels are elevated

faculative aerobes

organisms that don't require oxygen to survive but if they have oxygen, they can generate more ATP and therefore will grow better. In case they don't have access to oxygen, they can still survive. ; can use oxygen or not

aerotolerant anaerobes

Can live equally with or without oxygen

obligate anaerobes

Organisms that die in the presence of oxygen.

What is FTM tube good for?

multipurpose, enriched, and differential medium used primarily to determine the oxygen requirements of microorganisms. Fastidious and non-fastidious will grow here.

What are the components and function of FTM

• L.cysteine: reducing agent
• Marble chip: buffering agent
• Sodium thioglycollate: reducing agent
• Resazurin: oxygen indicator (turns pink in the presence of oxygen, remain unchanged if there is no oxygen)
• 0.4% agar: localize organism in favorable conditions. This is a small amount of agar to slow down the diffusion of oxygen

what is the goal of lab (2-6):

Organisms can survive a wide range of oxygen concentrations

cardinal temperatures

the minimum, maximum, and optimum growth temperatures for a given organism

Psychrophiles

cold-loving microbes ; microbes that thrive below 19 degree celcius

Mesophiles

microbes that thrive between 20-39 degree celsius; moderate temperature loving microbes (human pathogens here)

Thermophiles

microbes that thrive between 40 degree celsius ; heat loving microbes

extreme thermophiles

microbes that thrive between 65-110 degree celsius; thrive in very hot environments

what is the goal for lab (2-8) : bacterial optimum pH

what is the purpose of lab (2-9): bacterial optimum pH

Acidophiles

microbes that grow in acidic environments (pH below 7)

neutrophiles

microbes that thrive in neutral environments (pHh around 7) ; bacteria are in general neutrophiles

Alkaliphiles

microbe that thrive in alkaline or basic environments (pH above 7)

osmosis

waer diffuses from areas of low solute to areas of high solute, or high water volume to low water volume.

hyperosmotic

greater solute concentration outside the cell ; water moves out (cell shrinks)

isosmotic

solute concentration is the same ; no net water movement (cell stays the same)

hyposmotic

greater solute concentration inside the cell ; water moves in (cell swells or burst)

extreme halophiles

like high levels of salt (15-25%)

halophile

like high salt more than 3%

Osmotolerant

less than 3% ; likes sugar

240-280nm

the most detrimental wavelength of UV damaging bacterial DNA: UV-C
\---\> Therefore, mutations in DNA damages proteins structures, and potential cell death

goal of lab (2-12): ultraviolet light

UV

ultraviolet can be blocked by plastic, cloth, paper, fabric

why do we use paper for the UV light experiment?

we used paper to block the UV light to the control group of the experiment from killing the bacteria

why do we remove the lids in UV experiment?

we remove the lid so it doesn't inhibit to kill the bacteria in its full effect.

goal of lab (2-13): antiseptics and disinfectants

disinfectants

such as bleach, lysol, hydrogen peroxide are chemicals ONLY USED ON OBJECTS

antiseptics

such as alcohol, soap, mouthwash, fruit/vegetable wash, betadine, iodine are SAFE FOR HUMAN TISSUE.
- 70% alcohol prevents the introduction of skin bacteria, especially pathogens, into tissue where they could cause disease

% bacterial reduction for interpretation of efficiancy

percent reduction\= (colony count 1st press) - ( colony count 2nd press) /(colony count 1st press) x 100

control side of antiseptic experiment

had colony of bacteria

experiment side of antiseptic

side C had colony of bacteria. However on side D, after putting on the antiseptic, there were only seperated bactera.

brightfield microscope

let the light rays pass directly to our eyes without being deflected

total magnification

(ocular lenses) x (objective lens)

how to clean objectives

use lens paper

3 different lenses of microscope

- eye piece (ocular)
- objectives ( 10x- low power ; 40x- high dry ; 100x- oil immersion)
- condenser

Arm and Base (Microscope)

used to carry the microscope

stage of microscope

where the slide containing the microbe is placed