2. Phages – An Introduction Where we can find
Taxonomy Phages?
Phage characteristics Culture-commercial
production
Fates of Phages
Administration
Antibiotic Resistance-
Growing Problem Examples
Phage Therapy Enzybiotics
History Phages in other
industries
Why phage
therapy????? Future
Initial problems Challenges
Prerequisites for Phage Conclusion
therapy
3. A bacteriophage is any one of a number of viruses
that infect bacteria
They do this by injecting genetic material
Bacteriophages are among the most common and
diverse entities in the biosphere
Phages are widely distributed in locations
populated by bacterial hosts
It has been estimated that there are more than 100
different phage species and at least 10 phages for
each bacterium
4. This group established the International Committee
for the Taxonomy of Viruses whose objective, since
1971, is to continually update taxonomic guidelines.
The ICTV placed the tailed bacteriophages under
the order of the Caudovirales
Within this order there are three families: the
Myoviridae, with long, contractile tails, the
Siphoviridae with long, non-contractile tails, and
finally, the Podoviridae with short, stubbed tails and
a striking lack of features.
Each of these three families may be further broken
down into genera Using this grouping there is 1
order, 13 families and 31 genera.
5. The genome sizes of phages vary enormously, from
a few thousand base pairs up to 498 kilobases in
phage G
A bacteriophage particle or virion consists of a
single or double stranded (ss of ds) DNA or RNA
molecule, encapsulated inside a protein or
lipoprotein coat
Tail morphologies- long, flexible tails; double-
layered, contractile tails ; short, stubby tails
The size of the phage heads is correlated to the
genome size being packaged, and varies in
diameter between 45 and 100 nm.
6.
7.
8. Main reason is abusive use over the past twenty
years
The resistance phenomenon represents not only a
important healthcare issue but also an economic
problem
Penicillin fails to completely eradicate Streptococci
in up to 35 % of patients
Infections caused by Streptomyces agalactiae in
pregnant women cannot be treated with antibiotics
because they increase the risk of abortion
9. Phage therapy is the therapeutic use of
bacteriophages to treat pathogenic bacterial
infections
This method of therapy is still being tested for
treatment of a variety of bacterial and poly-microbial
biofilm infections
Has not yet been approved in countries other than
Georgia
Phage therapy has many potential applications in
human medicine as well as dentistry, veterinary
science, and agriculture.
10. Bacteriophages are much more specific than
antibiotics
Have a high therapeutic index
In the West, no therapies are currently authorized
for use on humans, although phages for killing food
poisoning bacteria (Listeria) are now in use.
11. From 1920 to 1940, phage therapy was extensively
used to treat various infectious diseases
In 1915, Félix d'Herelle observed "clear spots" on
bacteria culture.
In 1917, d'Herelle presented a note to the
"Académie des sciences de Paris‖
In 1919, there was an epidemic of "fowl typhoid" in
France
First administration of phages was given in 1921 at
the Hôpital des Enfants-Malades (Paris).
12. In Paris, "le laboratoire du bactériophage" produced
many phages directed against common infectious
diseases
In 1945, a new era appeared in Western countries
with the golden age of antibiotics
Phage therapy was abandoned in the Western
world, but maintained (it seems) on a large scale in
Poland and the USSR where infections continued
being successfully treated.
13.
14.
15. Problem 1- host range
Problem 2- bacterial debris present in phage
preparations
Problem 3- attempts to remove host bacteria from
therapeutic preparations
Problem 4- rapid clearance of phages
Problem 5- lysogeny
16. Levin and Bull 2004 suggest that phage therapy
only needs to decrease the numbers of infecting
bacteria to a level where the host defenses can
take care of the remaining bacteria.
Various prerequisites that should be met:
1. Phage therapy should not be attempted before the
biology of the therapeutic phage is well
understood.
2. Phage preparations should meet all the safety
requirements
3. Phage preparations should contain infective phage
particles
17. …
4. The phage receptor should be known.
5. The efficacy of phage therapy should be tested
in an animal model.
18. In humans and animal intestines
In running water
In the soil
Effluent outlets
Sewage from corpses .
19. D‘Herelle‘s commercial laboratory in Paris
produced at least five phage preparations against
various bacterial infections.
The preparations were called Bacte-coli-phage,
Bacte-rhinophage, Bacte-intesti-phage, Bacte-pyo-
phage, and Bacte-staphy-phage
Therapeutic phages were also produced in the
United States.
In the 1940s, the Eli Lilly Company (Indianapolis,
Ind.) produced seven phage products for human
use
20. Lyophilized phages were shown to be superior to
liquid preparations.
Repeated cycles of freezing and thawing were not
linked to activity loss
acidity below pH 3.5 decreased the phage activity
substantially
only egg yolk had some protective properties on the
phage preparation
Under dry conditions the phage preparation
resisted temperatures at least up to 55°C
21. Orally
Topically on infected wounds
Application in liquid form is possible, stored
preferably in refrigerated vials
Injection is rarely used.
22. Phage therapy reduces Campylobacter jejuni
colonization in broilers
Attempts to prevent Campylobacter colonization of
chickens by biosecurity measures have proven
extremely difficult
Probiotic treatment with lactic acid bacteria and
competitive exclusion with beneficient microflora was
only partially effective
Aprevention group was infected with C. jejuni at day 4 of
a 10-day phage treatment
Atherapeutic
group was phage treated for 6 days, starting 5 days
after C. jejuni colonization of the broilers had been
established
23. Treatment was monitored by enumerating
Campylobacter colony forming units (CFU) and
phage plaque forming units (PFU) from caecal
content
A clear log decline in C. jejuni counts in both
preventive and theraputic groups were observed
24. Killing of Mycobacterium avium and
Mycobacterium tuberculosis by a
Mycobacteriophage Delivered by a Nonvirulent
Mycobacterium
Tuberculosis is a serious public health problem that
results in millions of deaths around the world each
year
Mycobacterium smegmatis, an avirulent
mycobacterium, is used to deliver the lytic phage
TM4 where both M. avium and M. tuberculosis
reside within macrophages
25. These results showed that treatment of M. avium–
infected, as well as M. tuberculosis–infected, RAW
264.7 macrophages, with M. smegmatis transiently
infected with TM4, resulted in a significant time-
and titer-dependent reduction in the number of
viable intracellular bacilli.
26. In 1963 a total of 30,769 children (6 months to 7
years old) were enrolled in Tbilisi, Georgia, in an
oral phage prophylaxis trial against bacterial
dysentery.
The children were followed for 109 days.
Phage administration was associated with a 3-8
fold decrease in dysentery incidence
Phage exposure also decreased the incidence of
any form of diarrhea
27. The term ― enzybiotic ‖ was used for the first time in
a paper by Nelson et al 2001
Other names that are used with respect to
enzybiotics are lytic enzymes and peptidoglycan
hydrolases
Most important characteristics of enzybiotics are a
novel mode of antibacterial action
The capacity to kill antibiotic - resistant bacteria
Another feature is the low probability of developing
bacterial resistance
28.
29.
30. Lysins or endolysins are double - stranded DNA
bacteriophage – encoded enzymes that cleave covalent
bonds in peptidoglycan.
The term ― endolysin ‖ was introduced to the scientific
literature by F. Jacob and C. R. Fuerst to stress that
enzyme molecules act on peptidoglycan from within the
bacterial cell in which they are synthesized
Recombinant enzymes acting on the cell wall from
outside the cell (e.g., those used for therapeutic
purposes) were referred to as lysins rather than
endolysins
Another name proposed to designate a lysin is
‗virolysin‘.
31.
32. The majority of lysins described to date exhibit only
one kind of muralytic activity, whereas relatively few
possess two separate enzymatic domains
33.
34. In food industry:-
Bacteriophage bioprocessing is bacteriophage control
as practiced in the factory particularly as means of
reducing food bacterial loads
Phage-based control of pathogens is a non-thermal
intervention, and has been demonstrated to control the
growth of Campylobacter and Salmonella on chicken
skin, Salmonella enteritidis in cheese Listeria
monocytogenes on meat and on fresh-cut fruit
Phage application has also been studied as a method to
control the presence of biofilms in the food processing
environment, Such a treatment is potentially useful in
the control of L. monocytogenes
35. Food and drug administration concerning to use of
phage in food industry:- ―……for the safe use of
mixture of bacteriophages as an antimicrobial
agents on foods, including meat and poultry
products neither an environmental assessment nor
an environmental impact is required.”
36. In agriculture and fisheries:-
Bacteriophages have been considered, for
example, to control Salmonella infestation of cut
fruit
The most successful use of phage therapy, already
in practice, has been in the control of fish
pathogens
To avoid contamination of food products with
Listeria monocytogenes, Salmonella on cut
vegetables and fruits, or the pathogenic Escherichia
coli O157 : H7, phage therapy is now being
advocated for use in the food and livestock market
37.
38.
39. Phage typing is also known as the use of sensitivity
patterns to specific phages for precisely identifying
the microbial strains
The sensitivity of the detection would be increased
if the phages bound to bacteria are detected by
specific antibodies
The technique has most extensively been used for
the detection of Mycobacterium tuberculosis, E.coli,
Pseudomonas, Salmonella, Listeria, and
Campylobacter species
40. Novelty
Specificity of phages
Efficacy and other technical challenges
Regulatory approvals
Patent protection.
Market acceptance
41. Multidrug-resistant bacteria have opened a second
window for phage therapy.
Modern innovations, combined with careful
scientific methodology, can enhance mankind‘s
ability to make it work this time around.
Phage therapy can then serve as a stand-alone
therapy for infections that are fully resistant.
It will also then be able to serve as a co-therapeutic
agent for infections that are still susceptible to
antibiotics, by helping to prevent the emergence of
bacterial mutants against either agent
42. Borysowski J and Gorski A (2010) Enzybiotics and their
potential applications in medicine Enzybiotics: Antibiotic
Enzymes as Drugs and Therapeutics Pp 1-22. L. Hirzfeld
Institute of Immunology and experimental therapy, Wroclaw,
Poland
Broxmeyer L et al Killing of Mycobacterium avium and
Mycobacterium tuberculosis by a Mycobacteriophage
Delivered by a Nonvirulent Mycobacterium: A Model for Phage
Therapy of Intracellular Bacterial Pathogens J Infect Dis 186:
1155-60
Brussow H (2005) Phage therapy: the Escherichia coli
experience Microbiol 151:2133-40
Carlton R M (1999) Phage therapy: Past history and Future
prospects Arch Immunol Ther Exp 47: 267-74
Haq I U et al (2012) Bacteriophages and their Implications on
Future Biotechnology: A Review J Virol 9:
43. Hermoso J A et al (2007) Taking aim on bacterial
pathogens: from phage therapy to enzybiotics Curr Opin
Microbiol 10:1-12
Inal J M (2003) Phage Therapy: a Reappraisal of
Bacteriophages as Antibiotics Arch Immunol Ther Exp
51:237-44
Skurnik M and Strauch E (2006) Phage therapy:Facts
and Fiction Int J Med Microbiol 296 :5-14
Sulakvelidze A (2011) The Challenges of Bacteriophage
Therapy Eur I Pharm 10:14-18
Thiel K (2004) Old dogma, new tricks—21st Century
phage therapy Nat Biotechnol 22:31-36
Wagenaar J A (2005) Phage therapy reduces
Campylobacter jejuni colonization in broilers Vet
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