Phage therapy - pdfs.semanticscholar.org · •Phage therapy trials without serious side effects or allergic reactions •Single dose would be sufficient to cure the patient •Bacteriophages

Phage therapy

Institute of Molecular Biomedicine

Comenius University, Faculty of Medicine

www.imbm.sk

tothova.lubomira@gmail.com

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 !