Boards and beyond

Question 1

Bacteria with capsules

Answer 1

• Strep pneumonia
• H. influenza
• N. meningitidis
• E. coli
• salmonella
• Klebsiella
• Group B strep (agalactiae)

Question 2

how does the body defend against encapsulated bacteria?

Answer 2

• B cells secrete capsular antibodies (IgG) - antibodies bind capsule
• Phagocytosis consumes bacteria via Fc receptors from antibodies
• Antibodies also bind complement leading to
  
  • formation of MAC -> cell death
  • Formation of C3b -> opsonizing for further phagocytosis

Question 3

Mechanism of recurrent encapsulated bacterial infections

Answer 3

• If there is a deficiency or loss of B cells, antibodies or complement
• Also asplenia (risk of sepsis from encapsulated bacteria because of loss of splenic phagocytes)

Question 4

What are capsular vaccines?

Answer 4

• many vaccines utilize bacterial capsule polysaccharides because they are often weakly immunogenic
• often conjugated to an immmune-stimulator protein such as (diphtheria toxoid, tetanus toxoid, meningococcal outer membrane protein, mutant diptheria protein

Question 5

What conjugated vaccines are available for encapsulated bacteria?

Answer 5

• Neisseria meningitides
• Streptococcus pneumonia
• Haemophilus influenzae type B

Question 6

What is a glycocalyx?

Answer 6

a “sugar coat” made of polysaccharides that is similar to a capsule

forms biofilms

often adheres to catheters

Question 7

Glycocalyx vs capsule

Answer 7

• bacteria with distinct firmly attached gelatinous layer have a capsule
• Bacteria with irregular slimy fuzz layer have a glycocalyx (biofilms)

Question 8

Bacteria with glycocalyx

Answer 8

common one is S. epidermidis

Question 9

Pili and fimbria structure

Answer 9

• structurally similar to flagella
• made of proteins
• appendages or arms of bacteria

Question 10

Functions of pili

Answer 10

• ordinary pili (allows adherence to surfaces)
• sex pili (attaches to another bacteria for conjugation)

Question 11

Bacteria that have pili and fimbriae

Answer 11

commonly

E coli ( pili allow( attachment to urinary tract) UTIs/pyelonephritis)

Neisseria Gonorrhea (pili have antigenic variation so at risk for subsequent infections) (antigenic variation) because antibodies made for previous infection may not apply to another infection

Question 12

What are plasmids?

Answer 12

• small DNA molecules in a cell that are physically separate from chromosomal DNA
• Can replicate independently
• can contain genes for things like antibiotic resistance or toxins
• They can be transferred from bacteria to bacteria

Question 13

bacterial ribosomes subunits

Answer 13

50s and 30s Syedberg units

Question 14

Tetracyclines bind

Answer 14

bacterial 30s subunit of ribosome

Question 15

aminoglycosides interferes with?

Answer 15

bacterial 30s protein synthesis

Question 16

What are spores?

Answer 16

dormant state called a spore where they become very highly resistant to starvation orenvironmental conditions

does not have metabolic activity but can later convert back to a metabollically active bacteria (like a seed)

Question 17

Spore structure

Answer 17

• outermost layer is Coat
  
  • made of “keratin-like” protein
  • impermeable to many chemicals and antibacterial agents
• Cortex/Core wall
  
  • innermost layer
  • made of peptidoglycans
• Dipicolinic acid
  
  • large amounts inside spore
  • may help with heat resistance

Question 18

spore forming bacteria to know

5 listed

Answer 18

• Bacillus anthracis
• Bacillus cereus
• Clostridium perfringens
• Clostridium tetani
• Clostridium botulinum