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 genomes and ecosystem in/on the human body Together supraorganism New genes with advantages Mouth, skin, gut... Unique ecosystems
We are bacteria 10 13 10 14 Human cells Bacterial cells
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
10 31 members of virome 1% 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 efflux pumps 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 speciesspecific, it is necessary to precisely characterize the infectious bacterial agent prior to their application Phage defined in vitro environment as strictly lytic, could change this cycle under 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-phage interactions..., ) Safety testing!!!
Commercial products Phagobioderm Biophage-PA Routes of administration Oral Topical Intravenous
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!