Phage therapy Institute of Molecular Biomedicine Comenius University, Faculty of Medicine www.imbm.sk [email protected]
Phage therapy
Institute of Molecular Biomedicine
Comenius University, Faculty of Medicine
www.imbm.sk
Outline
• Introduction
• Taxonomy
• Cycles of phages
• Bacterial resistance
• Phage therapy
• Conditions for phage therapy
• Enzybiotics
• Phages in other industries
• Phage typing
• Phage display
• Bacterial sensing
• Future outlook
Microbiome
• Total microorganisms, their genomesand ecosystem in/on the human body
• Together „supraorganism“
• New genes with advantages
• Mouth, skin, gut...
• Unique ecosystems
Human cellsBacterial
cells
We are bacteria
10 13 10 14
• „core microbiome“
• „variable microbiome“
• Personalized medicine
• Host´s physiology
• Health status
HUMAN MICROBIOME
PROJECT 2007
Mammalian virome
• Viruses of eukaryotic cells (e.virome)
• Bacteriophages infecting bacterial cells (b.virome)
• Viruses of archea (a.virome)
• Virus-derived genetic elements in host chromosomes
1031 members of virome1% explored
Bacteriophages
• Most abundant entities in biosphere
• Viruses specific for bacterial cells
• Distribution according to their hosts
Where can we find phages ?
• Everyday life
• Soil
• Sewage
• Food
• Water
....
• Everywhere where bacteria are present
Taxonomy• ICTV (not CVTI ) International Committee for Taxonomy of Viruses
• Up-to-date taxanomic guidelines
Tailed bacteriophages order CAUDOVIRALES
Three families Myoviridae
Siphoviridae
Podoviridae
Different genera
13 families and 31 genera
• Diverse genome size
• ss DNA, ds DNA or ss RNA, ds RNA
• Phage particles (VIRIONS) lipoprotein
or protein coat
• Tails
• ~ 200 nm
Life cycles of phages
• Lytic
• Lysogenic
• Pseudolysogenic
Phage therapy• Therapeutical usage of bacteriophages for treating bacterial infections
• Long history (1915/1917)
• Some approvals
• Georgia, Russia and Poland
Frederick Twort Félix d´Herelle
• Medicine, dentistry, veterinary science and agriculture
Mechanisms of antibiotics
• Cell wall synthesis
• Protein synthesis
• Nucleic acid synthesis
• Cell membrane functions
• Metabolism
• Others
Resistance of bacteria
• Antibiotics vs. multidrug resistant bacterial strains
• Biofilm
Resistance of bacteria
• Absence of a susceptible target
• Multidrug resistance effluxpumps
• Mutations
• Transformation
• Modification of target site
• Direct antibiotic inactivation
Lack of new antibiotics or effective treatment !!!
Phage therapy renaissance
Pros and cons of bacteriophage therapy
• Bacteriophages infect only bacterial cells
• Bacteriophages are capable
of self-replication and self-elimination
• Bacteriophages with narrow host range
• Phage therapy trials without serious side effects or allergic reactions
• Single dose would be sufficient to cure the patient
• Bacteriophages in combination with antibiotic therapy may lower the occurrence of bacterial resistance
• Bacteriophages are highly species-specific, it is necessary to precisely characterize the infectious bacterial agent prior to their application
• Phage defined in vitro environment asstrictly lytic, could change this cycleunder the physiological conditions of the human body
• Possibility of toxic shock after the bacterial lysis and subsequent amplification of neutralizing antibodies during the re-treatment of the patient
Prerequisites for phage therapy
• Host range
• Purity of phage preparations
• Clearance of phage therapeuthics
• Lysogeny in vivo
• Complete phage characterization (genes, receptors ... host-phageinteractions ..., )
• Safety testing !!!
Commercial products
PhagobiodermBiophage-PA
Routes of administration
OralTopicalIntravenous
Phages in agriculture
• Intralytix, Inc. (http://www.intralytix.com)
• EBI Food Safety (http://www.ebifoodsafety.com)
• Omnilytics, Inc. (http://www.omnilytics.com)
• Sevapharma, a.s.(http://www.sevapharma.cz)
Enzybiotics
• Hybrid name lytic enzymes + antimicrobial potential
• Enzymes able to cause microbial cell death
Endolysins (from phages)
Bacteriocins (from bacteria)
Autolysins (from bacteria)
Lysozymes (various organisms)
How endolysins work?
• Enzymatic cleavage of bacterial cell wall peptidoglycans (cell lysis)
• ds DNA phages
• end of the lytic cycle
(1) N-acetylmuramoyl-L-alanine amidases;
(2) endopeptidases;
(3) N-acetyl-β-D-glucosaminidase;
(4) N-acetyl-β-D-muramidases (lysozymes)
(5) lytic transglycosylases
Methods: Vectors in MB
Methods: Phage typing
• Used for identification and differentiating of bacterial pathogens
• Lysis due to viral infection is specific
• Bacteriopage-based diagnostics
Methods : Bacteria sensing
Biosensors advantages
• Sensitive, rapid and selective detection
• Cost-effective and portable
• Lower limit of detection
• Minimum sample preparation
Methods : Phage display
More information by J.B.
Future outlook
• Large range appplication of phages in molecular biology,
biotechnology and medicine ! ! ! ! !
• Safety and efficacy issues
• Unexplored entities
Thanks for Your attention !