1 - Bacterial Structure, Classification, Growth, and Survival

Taxonomy

This is the science of naming, describing, and classifying organisms

Identification

This is the process of determining what organism an isolate could be

Classification

This is the process of grouping organisms based on shared characteristics

Kingdom, Phylum, Class, Order, Family, Genus, Species

Enumerate the taxonomic heirarchy from broad to specific

Nonselective media

This type of media can support the growth of all bacteria and microorganisms

Selective media

This type of media contains substances that inhibits some organisms and permit other organisms to grow

Sodium Azide

What medium selects for Gram (+) bacteria

Bile Salts and Macconkey agar

What 2 media selects for gram (-) enteric organisms

Colistin + Nalidixic Acid

What medium inhibits many Gram (-) bacteria

CNA Blood Agar

What medium selects for Gram (+) cocci

Blood Agar

This is one of the most common different media used in laboratory settings

F; Gram (-) = Pink/Red while Gram (+) = Purple

T/F: Gram (+) bacteria presents with a pink color after staining while Gram (-) bacteria presents with a purple color after staining

Oxidase Test

This specific biochemical test can distinguish organisms based on the presence or absence of cytochrome C

Serotype

This is a group defined by a particular antigenic profile

Serogroup

These are organisms sharing important antigenic characteristics

Subtyping

This process differentiates organisms below the species level

T

T/F: Gram (-) bacteria are characterized with a thin peptidoglycan layer

Binary fission and budding

2 ways Gram (-) bacteria can reproduce

F; Thick

T/F: Gram (+) bacteria are characterized with a thin peptidoglycan layer

T

T/F: Gram (+) Eubacteria lacks an outer membrane in contrast to Gram (+) Bacteria

Binary Fission

What is the main way of reproduction for Gram (+) Eubacteria

B

QC: LPS (1) Gram (+) (2) Gram (-)

B

QC: Periplasm (1) Gram (+) (2) Gram (-)

A

QC: Techoic Acid (1) Gram (+) (2) Gram (-)

Mycoplasma

These are members of mollicutes that lack cell walls and peptidoglycan

Cholesterol

Mycoplasma require what substance for its cell membrane?

Binary Fission, Budding, and Fragmentation

3 mechanisms for mycoplasma reproduction

Halophiles

These are archaebacteria that survive in high salt environements

B

QC: Porin Proteins (1) Gram (+) (2) Gram (-)

Microbial growth

This is the orderly increase in the total components of an organism

Number of VIABLE CELLS per unit of volume of culture

What exactly is being measured when you measure cell concentration?

DRY WEIGHT of cells per unit of volume of culture

What exactly is being measured when you measure biomass concentration

F; Population of cells

T/F: The growth curve is a reflection of events in individual cells

Lag Phase

This is a period when cells adapt to their new environment, depleted of metabolites and enzymes

Log Phase

This period is characterized by the exponential increase in biomass

1 × 10^7/mL

In the case of bacteria, at what cell concentration does growth rate start decreasing

4-5 × 10^9/mL

The rate of oxygen diffusion cannot be met when bacterial concentration reaches?

Stationary Phase

This is the period when cell growth ceases leading to increasing total cell count but constant viable count

Death Phase

This is the period where cell death overtakes cell growth leading to population decline

Biofilms

This is a community of microorganisms attached to a surface and embedded in a protective glycocalyx/extracellular matrix

Quorum sensing

This is an important characteristic of biofilms where different bacteria communicate which allows for better survivability

Biocide

This is a broad spectrum chemical or physical agent that inactivates microorganisms

Bacteriostatic

This agent can only inhibit bacterial multiplication which can be restored upon removal of the agent

Bactericidal

This agent kills bacteria causing cell lysis or remaining intact

Sterilization

This is the process of eliminating all forms of microbial life, including spores

Disinfectants

This agent reduces the number of viable microorganisms on a product or surface

Septic

This is defined as the presence of pathogenic microorganisms in living tissues or associated fluids

Aseptic

This is defined as the absence of microorganisms in living tissues or associated fluids

Antispetic

These are agents that destroy or inhibit the growth of microorganisms in or on living tissue or biological fluids

Antibiotics

Organic compounds that inhibit or destroy selective bacteria, generally at low concentrations.

Preservation

This process prevents multiplication of microorganisms in formulated products such as pharmaceutical and foods

Pasteurization

This is the use of heat treatment to only reduce pathogens but not completely sterilize

Sanitization

This is the process of reducing microorganisms to an acceptable level

160-270 C for 1 hour or more

What temperature and duration is needed to sterilize dry materials

160-270 C for 1 hour or more

What temperature and duration is needed to sterilize dry materials

Biguanides

This type of chemical agents release is widely used in hand washing and oral products

Halogen-Releasing Agents

This chemical agents release chlorine to destroy the cellular activity of proteins

Organic Acids

Examples of this type of chemical agents are benzoic acid and proprionic acid

Peroxygen

The most common example of this chemical agents is hydrogen peroxide

Alcohol

This chemical agent exhibit rapid, broad spectrum antimicrobial activity

Vapor-Phase Sterilants

This type of chemical agents release is used to sterilize heat-sensitive medical devices and surgical supplies

Aldehydes

This chemical agent allows for low-temp disinfection and sterilization