[BIO 120.11] Module 4 Part 1

TRUE

T/F: Biofilms are an attached polysaccharide matrix containing embedded bacterial cells

FALSE

T/F: Biofilms are an attached lipid matrix containing embedded bacterial cells

Water or moist soil

For biofilms to form, the surface must be immersed where?

FALSE

T/F: Biofilms can either functional or dead microbial communities

TRUE

T/F: Biofilms are composed of functional and growing microbial communities

FALSE

T/F: Biofilms are made of only one species of bacteria to prevent competition from happening

TRUE

T/F: Biofilms may contain one or multiple species of bacteria

700

How many phylotypes of bacteria are found in human mouth biofilm?

Bacteria, Archaea, Yeasts

Biofilm formation can occur with what organisms

Attachment, Colonization, Development, Active Dispersal

What are the 4 stages of biofilm formation?

Attachment

Stage of Biofilm Formation: Adhesion of a few motile cells to a suitable solid surface

Pili, Fimbriae, Capsule, Flagella

What parts of a bacteria can be used for attachment?

Colonization

Stage of biofilm formation wherein EPS is produced

Colonization

Stage of Biofilm Formation: Characterized by intercellular communication, growth, and polysaccharide formation

Intercellular communication, growth, polysaccharide formation

What are 3 things we can observe in the colonization stage of biofilm formation?

Extracellular Polymeric Substances

Substances needed for biofilm formation and explains the calcified nature of biofilmsD

Development

Stage of Biofilm Formation: Characterized by more growth and polysaccharideA

Active Dispersal

Stage of Biofilm Formation wherein cells migrate outside of the biofilm to transfer biofilms or live a planktonic lifestyle

Active Dispersal

Stage of Biofilm Formation triggered by environmental factors such as nutrient availbaility

Water channels

Source of moisture in biofilms

Development

Stage of biofilm formation wherein we can observe water channels

Nutrient Availability

What is an example of an environmental factor that can trigger active dispersal in biofilm formation stage?

Protection, Trap nutrients, Allow complex microbial interactions

3 Advantages of a biofilm lifestyle

Harmful chemicals, phagocytosis, bacterial grazing by protists

Having a biofilm lifestyle can protect against what 3 things?

Implicated in difficult-to-treat infections, Dental cavities and gum disease, Fouling, plugging, and corrosion in tubes and pipes, Contamination of fuel (storage tanks)

What are 4 consequences of biofilm formation for humans?

Waste treatment (longer viability), Bioremediation

What are 2 positive benefits of biofilm formation for humans?

Pseudomonas aeruginosa, Vibrio cholerae

What are 2 model bacteria for biofilm studies?

Cystic Fibrosis

What disease is caused by P. aeruginosa?

AHL

In P. aeruginosa, what triggers the expression of the subset of biofilm-related genes?

Explosive Death

What triggers P. aeruginosa biofilm formation?

Positive regulation

What kind of QS is needed for P. aeruginosa biofilm formation

Expression of lysis protein by an inactive prophage in P. aeruginosa geneome

What causes explosive death in P. aeruginosa?

Stressful conditions, can occur occasionally as random event under normal conditions

What triggers explosive death in terms of environmental conditions?

DNA release

In P. aeruginosa, this event is critical to EPS formation

Low Cell Density

When is V. cholerae biofilm formation promoted?

VpsR, VpsT

Transcriptional regulators in V. cholerae that activate expression of matrix protein genes

c-di-GMP

This component must be bound to VpsT before transcription of biofilm genes in V. cholerae can occur

VpsT

In what transcriptional regulator must c-di-GMP be bound to before V. cholerae biofilm translation can occur?

HapR

Protein that represses VpsR and VpsT

High cell density

When is HapR among V. cholerae expressed?

Bacteria

Causal agents of infectious diseases

Disk Diffusion Assay, Minimum Inhibitory Concentration

What are 2 ways to do antimicrobial activity assays?

FALSE

T/F: Disk diffusion assay is quantitative test

TRUE

T/F: Disk diffusion assay is qualitative assay, but can be standardized

Disk Diffusion Assay

Test for antibiotic susceptibility of clinical isolates

Antimicrobial agent, Solubility, Diffusion Coefficient, Overall effectiveness

What are the 4 factors that affect the zone of inhibition?

Zone of inhibition

What is being measured in the disk diffusion assay?

Mueller Hinton Agar

What agar is recommended for Disk Diffusion Assay?

Minimum Inhibitory Concentration Assay

Smallest amount of the agent needed to inhibit the growth of a test organism

TRUE

T/F: The Minimum Inhibitory Concentration refers to the smallest amount of an antibiotic agent to inhibit growth

FALSE

T/F: The Minimum Inhibitory Concentration refers to the concentration of an antibiotic with no cells growing at all

Minimum Bactericidal Concentration

Refers to concentration of antibiotics with no cells growing at all

Microdilution or Microtiter Plate

What is the most common way of doing MIC assays?

Over-prescribing of antibiotics, Patients not finishing their treatment, Over-use of antibiotics in livestock and fish farming, Poor infection control in hospitals and clinics, Lack of hygiene and poor sanitation, Lack of new antibiotics being developed

What are the 6 causes of Antibiotic Resistance Development?

Intrinsic, Adaptive, Acquired

What are 3 types of resistance based on mechanisms?

Intrinsic

Resistance that result from the inherent characteristics of microorganisms

Efflux pumps, Reduced permeability among Gram negatives and capsulated bacteria

What are 2 examples of intrinsic resistance?

Acquired Resistance

Resistance that occurs when there is a change in the genome of a bacterium

Mutations or HGT

What is an example of acquired resistance?

Adaptive Resistance

Resistance that refers to the capacity to become resistant to antibiotics in response to environmental signals

FALSE

T/F: Acquired resistance is temporary

FALSE

T/F: Adaptive resistance is permanent

TRUE

T/F: Adaptive resistance is temporaryA

Adaptive Resistance

What type of resistance is temporary?

Biofilm formation

What is an example of adaptive resistance?

Alteration of target, Antibiotic Degrading Enzymes, Antibiotic Altering Enzymes, Efflux Pumps

What are 4 mechanisms of antibiotic resistance?

Antimicrobial Drug Resistance

The acquired ability of a microorganism to resist the effects of an antimicrobial agent to which it was formerly susceptible

MDR, XDR, PDR

What are 3 types of antimicrobial drug resistance?

Multidrug Resistance (MDR)

ADR: Nonsusceptibility to ≥1 agent in ≥3 antimicrobial categories

Multiantibiotic

Organism that is resistant to 3 drugs, but all belonging from one class

Extensively Drug Resistance (XDR)

ADR: Susceptibility limited to ≤2 categories

Pan Drug Resistance (PDR)

ADR: Nonsusceptibility to all agents in all antimicrobial categories

Molecular processes targeting antibiotics, Cell membrane and cell wall-targeting antibiotics

What are 2 types of antibiotics based on antibiotic targets?

Antibiotics

Antimicrobial agents produced by microorganisms (bacteria and fungi)

Bacteria, Fungi

What organisms produce antibiotics?

Antibiotics

Agents that have the ability to either kill or inhibit the growth of bacteria

Antimicrobial Agents

Natural or synthetic chemicals that kill or inhibit the growth of microorganisms

-cidal Agents, -static Agents, -lytic Agents

What are the 3 types of antimicrobial agents>

-cidal Agents

Agents that kill by binding tightly to their cellular targets

TRUE

T/F: In -cidal Agents, dead cells are not lysed

FALSE

T/F: In -cidal Agents, dead cells are also lysed

Formaldehyde

What is an example of a -cidal agent?

Optical Density

What is an example of a bacterial counting technique that measures both dead and living cells

Plate Count

What is an example of a bacterial counting technique that measures only living cells

-cidal Agents

What is the antimicrobial agent that will show the data in the graph?

-static Agents

Antimicrobial agents that serve as inhibitors of important biochemical processes

-static Agents

Antimicrobial agent that bind relatively weak

-static Agents

Antimicrobial agent that serve as growth inhibitors (keep a pathogenic bacterium from multiplying until the immune system can rid the body of the pathogen)

Sulfonamides

Example of a -static Agent

-lytic Agents

Antimicrobial agent that kills by cell lysis and release of cytoplasmic contents

Penicillin, Detergents

What are 2 examples of -lytic agents?

-static Agents

What is the antimicrobial agent that will show the data in the graph?

-lytic Agents

What is the antimicrobial agent that will show the data in the graph?

Food infection

FBD: Ingestion of food containing viable pathogens

Food Infection

FBD: Sufficient to cause colonization and growth of the pathogen in the host

Food Infection

FBD: With longer incubation time

Food Poisoning or Intoxication

FBD: Ingestion of foods containing preformed microbial toxins

Food Poisoning or Intoxication

FBD: Bacterial cells do not have to grow and are non-viable

Food Poisoning or Intoxication

FBD: Short incubation time

Toxin activity

What causes the illness in food poisoning or intoxication?