Module 5

Question 1

Bacteria characteristics

Answer 1

prokaryotic cells (metabolism), large, cells walls

Question 2

Gram negative

Answer 2

Extra outer membrane than gram positive so it has 2 periplasmic spaces

Question 3

Bacillus anthracis

Answer 3

• Rod + gram positive + non-motile + spores
• Pathogenesis with pXO1 (virulence) and pXO2 (Capsule)
• Zoonotic
• Cutaneous or inhalation
• ID relies on mutation because bacteria clone

Question 4

Yersinia pestis

Answer 4

• Rod + gram negative + enteric bacteria (gastric)
• Zoonotic
• Subspecies based on ability to ferment glycerol and reduce nitrate (3 biovars)
• Causes pneumonic plague (no vector), bubonic plague (insect vectors like fleas + lymphatic system), and septicemic plague (blood)

Question 5

Francisella tularensis

Answer 5

• Rod + gram negative
• Carried by rodents and some domestic animals
• Two biovars

Question 6

Brucella sp.

Answer 6

• Gram-negative
• HIGHLY infectious (less than 10 cells)
• Most common zoonotic infection + reported lab-acquired infection
• Through unpasteurized milk/cheese

Question 7

Melioidosis and Glanders

Answer 7

• Rod + gram negative
• B. pseudomallei
• Infectious via inhalation
• High degree of recombination

Question 8

Clostridium botulinum

Answer 8

• Rod + gram positive
• Anaerobic spore-forming bacteria (most toxic)
• BOTOX

Question 9

Bacterial forensics techniques

Answer 9

• Gram-staining
• 16S rRNA gene sequences: present in all organisms unless no mitochondria, highly conserved, may not distinguish between pathogen and closely related non-pathogen
• VNTR: high precision and high resolution, identical copy numbers at several VNTR loci = related
• MLVA: organizes size dependent on number of repeats in isolate
• MLST: uses essential gene found in ALL bacteria, database searching
• WGS: Illumina, ion torrent, nanopore