Bacteriophages

1. Isolation from Environmental Samples
   1. Soil
   2. Sewage
   3. Feces
   4. Water
   5. Retail Foods

1. Host Range
2. Host Specificity
   1. Genera
3. Immune Response
   1. To enzymes?
      1. Not in mice
4. USSR Research
5. Testing for residual phages
   1. Sample contamination issues?

1. Pre-Biotic
   1. Control of Salmonella in Chickens
      1. If this works, why aren't we using it?
   2. EPECs
      1. Calves
      2. Piglets
      3. Lambs
   3. E. coli O157:H7 Shedding
      1. Beef Cattle
2. Tail Spike Proteins (Tsps)
   1. Podoviridae P22 bacteriophage
      1. Targets lipopolysaccharides
         1. Salmonella Typhimurium in live chickens

1. Overwhelm Pathogenic Cells During Primary Infection
   1. Phage Resistance Not Relevant
   2. Cell Lysis without Phage Replication
      1. Membrane Electric Potential Disrupted
      2. Cell Wall Degradation Enzymes

1. Phage Replication and Subsequent Cell Lysis
   1. Transmission to Neighboring Target Cells

1. Works with lysins to lyse cells from within
   1. Export lysins through inner membrane to gain access to peptidoglycan layer

Nota:

• http://journal.frontiersin.org/article/10.3389/fmicb.2014.00542/full

1. Lysin/Endolysin
   1. Chimeolysins
      1. Cell Wall Binding Domains (CBDs)
      2. Catalytic Domains
   2. Artificial lysins (artilysins)
      1. Whole or partial lysin plus a peptide or protein
         1. Gram positive and negative bacteria simultaneously
            1. Gram negative bacteria may be less susceptible to lysins due to outer membrane differences?
         2. Improved activity
   3. Six categories
2. Lethal 'from without'
   1. Digest cell walls
      1. MDR gram positive baceria
         1. Restriction enzymes not a problem?
         2. Treatment of systematic infections
            1. MRSA
            2. E. faecium
            3. Streptococcus pneumoniae
   2. Is activity lost over time?
      1. Removal of CBD
         1. Retains specificity
      2. Phages neutralized by sanitizers?
3. Do not affect normal microflora
4. Effective on mucosal surfaces

1. Enzymatic Targeting of Biofilms
   1. Hydrolysis of exopolysaccharides

1. Biofilm Genes

1. Abortive Infection

1. CRISPR/cas Systems
2. Restriction Endonucleases
   1. Phage Resistance!

1. Lytic Infection

1. Temperate Phase
2. Lysogenic Infection
   1. Gene Expression
      1. Prophage Lamda
      2. Antimicrobial Resistance
      3. Is it possible to encode a gene sequence into a pathogen genome, through use of a phage, to impede virulence or enhance a desirable trait?
         1. Insertion of lethal gene to kill cells without lysis
            1. Prevent release of endotoxins in cells
         2. Genes to increase sensitivity to antibiotics
         3. Insert genes for bacteriocins into probiotic cells