Lecture 12

Question 1

What bacteria are emerging threats

Answer 1

Yersinia pestis - Plague

Legionella pneumophila

Campylobacter spp

Question 2

Yersinia pestis

Answer 2

• Wild rodents
• Pneumonic, Bubonic, and Septicemic plague
• 2000-3000 p.a. with 182 deaths

Plague: Bioterrorism

Question 3

Biofilms as emerging threats

Answer 3

Implant, catheter contamination

Gum disease

Question 4

Bacteriophages

Answer 4

Bacteriophages infect bacteria

Common, widely distributed

Ubiquitous, found in all reservoirs

Question 5

Natural sources for phages

Answer 5

Dense natural sources (9x10^8 virions ml-1)

70% of marine bacteria may be infected by phages

Question 6

Phage structure

Answer 6

Collar, core, helical shealth, tail spikes

Head and tail

Question 7

Phage therapy

Answer 7

• Therapeutic use of lytic bacteriophage to treat pathogenic bacterial infections
• Does not replace antibiotics as first line, general antibacterial therapy in major western countries

Question 8

Phage therapy - propogation of bacteriophage

Answer 8

• Collecting local water samples to isolate
• High quantities of bacteria and bacteriophages
• Lytic phage amplified on cultures of target bacteria - passed through filter to remove all but phage and centrigugation

Question 9

Advantages over antibiotics

Answer 9

• Can be effective
• Super phage attacks super bacterium when it appears - Isolate from same environment
• Phage is localised use
• Phage stops reproducing after bacteria are destroyed
• Bacteria can become resistant to antibiotics - ‘inexhaustable’ supply of phages

Question 10

Disadvantages over antibiotics

Answer 10

• Phages need to be refrigerated
• Doctors need special training
• Difficulty treating multiple infection - Several different phages needed
• Particular phages can only be used once in intravenous treatment
• Different cocktails required for treatment of same infection
• Mixture of phage often applied for efficiency
• No lytic phage has been discovered for Clostridium difficile
• Viruses can’t reach same places as antibiotics
• Reluctance from public to embrace phage therapy due to negative perception of viruses

Question 11

Phage delivery routes

Answer 11

• Parental - Intramuscular, Subcutaneous, or IP
• Oral for gastro-intestinal infections
• Local delivery e.g. Topical, chronic otitis, Dental phages, Inhalation by nebuliser

Question 12

Phages have been found to eliminate pathogens from:

Answer 12

Raw food: Campylobacter

Fresh food - Listeria

Reduce food spoilage bacteria

Question 13

Phages in argiculture

Answer 13

Farm animals - Campylobacter, Escherichia and Salmonella species
Fish - Lactococcus and Vibrio
Plants: Erwinia and Xanthomonas

Question 14

Manuka honey

Answer 14

Effective against 80 microorganisms

Affects osmolarity

Peroxide action

Targets stress and membrane proteins

Decreases QS, siderophores, and surface adhesion

Inhibits biofilm formation, adhesion to epithelial cells, and binding to human cells

Question 15

What is Teixobactin effective against

Answer 15

S. aureus, C. difficile, M. tuberculosis, Bacillius anthracis

Question 16

What is Teixobactin ineffective against

Answer 16

Majority of gram negative bacteria