Deck 31: Biofilms: Architects of Disease

Question 1

How do microorganisms that live in close proximity exchange DNA?

A) Frame-shift mutations and plasmid uptake
B) Transformation and conjugation
C) Conjugation and frame-shift mutations
D) All of the above

Answer 1

B
The biofilm is an optimal environment for the horizontal transfer for DNA.The microorganisms live in close proximity,which facilitates the uptake of DNA by transformation and conjugation.

Question 2

What are the metabolically inert microorganisms present in a biofilm called?

A) Spores
B) Pheromone cells
C) Quorum sensing cells
D) Persister cells

Answer 2

D
Persister cells,essentially metabolically inert microorganisms analogous to bacterial spores,are present in all biofilms and bacterial populations.Persister cells are hypothesized to have disabled programmed cell death or apoptosis.These cells have the greatest potential for maintenance of the gene pool and resistance to environmental stress including antimicrobial agents.

Question 3

Cobiofilms of what two organisms are associated with serious lung infections in cystic fibrosis patients?

A) Pseudomonas aeruginosa and Moraxella
B) Pseudomonas aeruginosa and Burkholderia cepacia
C) Pseudomonas aeruginosa and Mycobacterium tuberculosis
D) Pseudomonas aeruginosa and Streptococcus pneumoniae

Answer 3

B
Cobiofilms of Pseudomonas aeruginosa and Burkholderia cepacia are associated with serious lung infections in patients with cystic fibrosis.

Question 4

What is a sessile-type biofilm?

A) A biofilm made up of free-floating microorganisms
B) A multiple-species biofilm
C) A biofilm that is attached and made up of multiple species
D) A biofilm that is present in an aquatic environment

Question 5

Biofilms can protect its members from all of the following EXCEPT:

A) Antibodies
B) Oxygen-reactive molecules
C) Antimicrobial drugs
D) Phagocytosis

Question 6

What is stage IV of biofilm development?

A) Multiplication phase
B) Thickening phase
C) Cell dispersion
D) Planktonic stage

Question 7

What do biofilms allow members of the microbial community to do?

A) Withstand the shear forces of blood and urine
B) Remain in a nutrient rich environment
C) Survive
D) All of the above

Question 8

In which step of the infectious process could biofilms help bacteria when it comes to indwelling medical devices?

A) Downregulation
B) Phenotypic variation
C) Genotypic variation
D) Attachment

Question 9

What is stage II of biofilm development?

A) Irreversible binding phase
B) Multiplication phase
C) Attachment phase
D) Layering phase

Question 10

In this level of the biofilm,the organisms downregulate very efficiently and are the least metabolically active.

A) Outer
B) Intermediate
C) Inner
D) Substrata

Question 11

Biofilms are a universal strategy for:

A) Planktonic free-floating organisms
B) To increase plasmid transfer for antibiotic resistance
C) To battle sheer forces
D) Survival, horizontal gene transfer and growth

Question 12

What is stage V of biofilm development?

A) Spreading phase
B) Multiplication phase
C) Cell dispersion
D) Layering phase

Question 13

What process allows the bacteria of the biofilm to spread to other body sites?

A) Conjugation
B) Metastasis
C) Disaggregation
D) Planktonization

Question 14

What is stage I of biofilm development?

A) Multiplication phase
B) Irreversible binding phase
C) Layering phase
D) Attachment phase

Question 15

All of the following are considered some of the most efficient and upregulated prone microbes when stress hits EXCEPT:

A) Coagulase-negative staphylococci
B) Pseudomonas aeruginosa
C) Micrococcus luteus
D) Candida albicans

Question 16

What is stage III of biofilm development?

A) Irreversible binding phase
B) Layering phase
C) Attachment phase
D) Multiplication phase

Question 17

What is a biofilm?

A) Communities of organisms attached to a solid surface
B) The resulting thick, slimy mucous produced in cystic fibrosis
C) A slime factor that can be found in your gastrointestinal tract
D) The resulting film that is produced by necrotic tissue, bacteria, and immune cells

Question 18

In this level of the biofilm,the organisms downregulate somewhat their metabolic activity,but they can still use nutrients and exchange genes.

A) Outer
B) Intermediate
C) Inner
D) Substrata

Question 19

All of the following environmental and key cultural characteristics affect biofilms EXCEPT:

A) Movement of host
B) Genotypic factors
C) Nutritional resources
D) Mechanical factors and sheer forces

Question 20

This layer of a biofilm is exposed to the highest concentration of nutrients and oxygen,containing the most active organisms.What layer is this?

A) Outer
B) Inner
C) Middle
D) Substrata

Question 21

All the following are laboratory-associated problems related to identifying biofilm-associated diseases EXCEPT:

A) False-positive cultures
B) False-negative cultures
C) Viable but noncultural organisms
D) Loss of or decreased antimicrobial susceptibility

Question 22

Treating infectious diseases has shifted from planktonic susceptibility profiles to:

A) Therapeutic modalities
B) Creative treatments
C) Multiple interventions
D) Degrading enzymes

Question 23

What is the common name for a dental biofilm?

A) Cavity
B) Gingivitis
C) Periodontitis
D) Plaque

Question 24

The late colonizers in the dental biofilm include all the following EXCEPT:

A) Capnocytophaga
B) Streptococcus salivarius
C) Selenomonas flueggei
D) Prevotella

Question 25

What happens to dental plaque if it is allowed to remain undisturbed for several days?

A) The biofilm disaggregates.
B) The persister cells predominate the biofilm.
C) Pathogenic bacteria become the main bacterial constituents of the biofilm.
D) Nonpathogenic bacteria become the main bacterial constituents of the biofilm.

Question 26

What disease,caused by biofilms,consumes more resources in the intensive care unit (ICU)than any other infectious disease?

A) Blood cultures positive with coagulase-negative staphylococci
B) Urinary tract infections due to gram-negative rods
C) Surgical site infections
D) Ventilator-associated pneumonia

Question 27

What types of cells in a biofilm are viable but nonculturable?

A) Phagocytes
B) Persister
C) Attachment cells
D) Layering cells