Bacterial control through dispersion of bacteriophage powders.

A method of eliminating, reducing or preventing bacterial contamination of a surface, the method comprising dispersing a bacteriophage containing composition in air in proximity to the surface. In some embodiments, the bacteriophage containing composition is a powder dispersed by pressurizing a load chamber containing the powder so that the powder is expelled through an outlet. Also, devices for performing the method and a powder used in the method.

FIELD OF THE INVENTION

The present invention relates to the general field of bacteriophages and is more particularly concerned with bacterial control through dispersion of bacteriophage powders.

BACKGROUND

Prevention and elimination of bacterial contamination is important in many contexts, for example in hospital settings. Current methods of reducing or eliminating bacterial content in hospital rooms typically involve spraying surfaces with a bactericide solution and wiping the thus sprayed surface manually. As such, they are time consuming, labour intensive, and costly. It is also difficult to achieve a desired degree of decontamination using such methods. In addition, many bactericides have a relatively small effective duration as they are rapidly degraded and may lead to bacterial resistance, both to the specific bactericide used, and to other useful bactericides, such as antibiotics.

It has been proposed to use fogging, a wet process, to disperse bacteriophages in a room. However, fogging may require multiple hours or days depending on the square footage of the facility. This means that patients would need to be removed from the rooms while fogging takes place during that period. Also, many fogging methods are not compatible with bacteriophage viability. The use of fogging chemicals such as H2O2is known to impact bacteriophage activity.

Therefore, there is a need to provide novel and improved methods and devices for reducing or preventing bacterial contamination.

An object of the present invention is to provide such methods and devices.

SUMMARY OF THE INVENTION

In a broad aspect, there is provided a method using bacteriophages for at least partially disinfecting a surface exposed to air, the method comprising: providing a powder, the powder including bacteriophages; and dispersing the powder in the air in proximity of the surface to apply at least part of the powder on the surface, wherein the powder is dispersed nonpyrogenically using a dry dispersion mechanism.

There may also be provided a method wherein providing the powder includes providing the powder in a load chamber; and dispersing the powder includes pressurizing the load chamber to a dispersion pressure larger than atmospheric pressure to expel the powder out of the load chamber.

There may also be provided a method wherein pressurizing the load chamber includes introducing a pressurized gas having a gas pressure larger than atmospheric pressure in the load chamber.

There may also be provided a method wherein the load chamber is at least in part destroyed when the pressurized gas is introduced in the load chamber.

There may also be provided a method wherein the powder is expelled out of the load chamber through at least one nozzle in fluid communication with the load chamber.

There may also be provided a method wherein the powder consists essentially of bacteriophages.

There may also be provided a method wherein the bacteriophages are in the form of lyophilized bacteriophage particles.

There may also be provided a method wherein the powder further includes auxiliary particles.

There may also be provided a method wherein the powder includes lyophilized bacteriophage particles dispersed in the auxiliary particles.

There may also be provided a method wherein the lyophilized bacteriophage particles make up from about 1 percent to about 50 percent in mass of the powder.

There may also be provided a method wherein at least part of the bacteriophages are immobilized on the auxiliary particles.

There may also be provided a method wherein at least 95 percent of the lyophilized bacteriophage particles in particle number has less than about 180 μm in size.

There may also be provided a method wherein at least 95 percent in mass of the lyophilized bacteriophage particles has less than about 180 μm in size.

There may also be provided a method wherein at least 95 percent of the lyophilized bacteriophage particles in particle number has less than about 45 μm in size.

There may also be provided a method wherein at least 95 percent in mass of the lyophilized bacteriophage particles has less than about 45 μm in size.

There may also be provided a method wherein at least 95 percent of the lyophilized bacteriophage particles in number have more than about 10 μm in size.

There may also be provided a method wherein at least 95 percent of the lyophilized bacteriophage particles in mass has more than about 10 μm in size.

There may also be provided a method wherein the load chamber is pressurized to between about 4 MPa and about 7 MPa.

There may also be provided a method wherein dispersing the powder includes aerosolizing the powder.

There may also be provided a method wherein the surface include one of a room surface inside a room, a vehicle surface inside a vehicle, an exposed wound surface, a conduit surface inside a conduit, an outdoors surface in the environment or combinations thereof.

There may also be provided a method further comprising lysing bacteria present on the surface with the bacteriophages.

There may also be provided a method wherein the surface is a surface inside a lung, the method further comprising leading part of the powder inside the lungs through inhalation of the part of the powder after dispersion of the powder.

In another broad aspect, there is provided a device for at least partially disinfecting a surface exposed to air using bacteriophages, the device comprising: a pressurized gas source for providing a pressurized gas at a pressure larger than atmospheric pressure; a load chamber containing a powder, the powder including the bacteriophages; a valve provided between the pressurized gas source and the load chamber, the valve being configurable between a closed configuration in which the pressurized gas is prevented from entering the load chamber and an open configuration in which the pressurized gas is allowed to enter the load chamber to pressurize the latter; and an actuator for selectively moving the valve from the closed to the open configuration; wherein, when the valve is configured from the closed configuration to the open configuration, the pressurized gas enters the chamber and expels the powder therefrom and into the air through an outlet.

There may also be provided a device wherein the outlet is formed by a dispersion head defining at least one nozzle in fluid communication with the chamber.

There may also be provided a device wherein the dispersion head defines a plurality of nozzles configured to cause an omnilateral dispersion of the powder upon pressurization of the load chamber.

There may also be provided a device wherein the dispersion head defines a plurality of nozzles dispersed around a segment of a cylindrical surface covering between about 60 and about 180 degrees.

There may also be provided a device wherein the dispersion head defines a plurality of nozzles dispersed around a segment of a cylindrical surface covering between about 60 and about 120 degrees.

There may also be provided a device further comprising a diaphragm between the load chamber and the dispersion head, the diaphragm being weak enough to burst under pressurization of the load chamber with the pressurized gas when the valve is opened.

There may also be provided a device further comprising a mesh diaphragm between the load chamber and the dispersion head.

There may also be provided a device wherein the load chamber is structurally unable to withstand the pressure of the pressurized gas so that the load chamber is at least partially destroyed when the valve is opened to create the outlet allowing dispersion of the powder in the air.

There may also be provided a device wherein the pressurized gas source includes a compressed gas cartridge.

There may also be provided a device wherein the compressed gas cartridge contains compressed CO2.

There may also be provided a device wherein the actuator is remote controlled.

There may also be provided a device wherein the actuator includes a timer and is operative for moving the valve from the closed configuration to the open configuration after a predetermined delay after activation of the timer.

There may also be provided a device wherein the actuator is operative for repeatedly dispersing a predetermined quantity of the powder at predetermined time intervals by repeatedly opening the valve for a predetermined duration, closing the valve immediately after the predetermined duration and repeating opening and closing of the valve after the predetermined time intervals.

There may also be provided a device wherein the valve is a poppet valve.

There may also be provided a device wherein the powder has one or more characteristics similar to those mentioned with respect to powder of the method described hereinabove.

In yet another broad aspect, there is provided a powder comprising: lyophilized bacteriophage particles; and biologically inactive auxiliary particles; wherein the powder includes between 1% and 50% in mass of the lyophilized bacteriophage particles. The powder may have one or more characteristics similar to those as mentioned with respect to the method described hereinabove.

There may also be provided a powder wherein auxiliary particles are selected from the group consisting of MgSO4particles, MgCO3particles, CaCO3particles and talc particles.

There may also be provided a method There may also be provided a method using bacteriophages for at least partially disinfecting a surface exposed to air, the method comprising: providing a powder, the powder including bacteriophages; and dispersing the powder in the air in proximity of the surface to apply at least part of the powder on the surface, wherein the powder is dispersed nonpyrogenically.

There may also be provided a method of treating a pulmonary bacterial infection in a mammal having lungs, the method comprising: providing a powder, the powder including bacteriophages infectious for bacteria causing the bacterial infection; dispersing the powder in the air, wherein the powder is dispersed nonpyrogenically using a dry dispersion mechanism; and having the mammal inhale the powder to deliver the bacteriophages to the lungs.

The powder and the device described hereinabove may be used to perform this latter method.

Advantageously, the proposed method is rapidly executed and does not depend unduly on the skills of the operator of the proposed device. In opposition to fogging, the proposed method releases the fine particles of the powder almost instantaneously. In some embodiments, it may take as little as a few seconds to disperse the bacteriophages. The proposed method also doesn't require the use of phage-toxic gases.

Furthermore, the use of a solid preparation is advantageous when compared to liquid preparations as liquid bacteriophages or dispersion of liquid particles of phages, are susceptible to quick inactivation at room temperature or at high temperature in developing country settings. Stability of the proposed powdery suspensions including fine particles is typically much greater, in some embodiments over 600 days stability at room temperature. Accordingly, in some embodiments, there is no need for cold-chain and storage at 4° C. Room temperature stability alleviates the need for cold chain packaging, shipping and storage, which significantly decreases price, footprint, and the necessity of having cold rooms, and dependability on electricity in third world settings.

The proposed method differs markedly from, for example, fogging of particles including bacteriophages through faster and more effective deployment. Fogging may require multiple hours or days depending on the square footage of the facility. This means that patients would need to be removed from the rooms while fogging takes place during that period. The proposed method releases the fine particles almost instantaneously. Also, many fogging methods are not compatible with bacteriophage viability. The use of fogging chemicals such as H2O2is known to impact bacteriophage activity. The proposed method doesn't require the use of phage-toxic gases.

In addition, fogging requires a control of temperature and humidity to create the aerosol droplets. The proposed method does not require stringent temperature or humidity control and works in a very diverse set of environments. When using fogging, ventilation is required to disperse the droplets in all parts of the room, or a person is required to direct the fog in different spaces and areas. In some embodiments, the proposed method is self-dispersing and doesn't need ventilation. The proposed fine particles can, in some embodiments, be commercialized as disposable units or refill cartridges, which is relatively easy to distribute and use.

DETAILED DESCRIPTION

It is proposed to treat a surface exposed to air to at least partially disinfect the surface, for example by eliminating, reducing or preventing bacterial contamination of the surface using a powder, the powder including bacteriophages. The powder including bacteriophages is referred to herein as “the powder”. The bacteriophages may be in the form of lyophilized bacteriophage fine particles, either purely such particles or in the presence of auxiliary particles, or include bacteriophages that are immobilized on fine particles. The fine particles, also referred to simply as “particles” have a dimension small enough to remain suspended in air for a duration long enough that when suspended, the particles can diffuse or move through convection adjacent the surface to treat to eventually contact the surface.

In some embodiments, the powder includes lyophilized bacteriophage particles, or consists essentially of such lyophilized bacteriophage particles, and at least 95 percent in mass or in particle numbers of the lyophilized bacteriophage particles have less than about 180 μm in size or less than about 45 μm in size. In some embodiments, at least 95 percent in mass or in particle numbers of the of the lyophilized bacteriophage particles includes particles having more than about 10 μm in size. If other particles are present in the powder, such as auxiliary particles detailed hereinbelow, the size distribution for the other particles can meet the same limits as the ones mentioned for the lyophilized bacteriophage particles, or the size distribution for the other particles can differ from these limits. For example, having the other particles that are larger than the lyophilized bacteriophage particles may be acceptable or even desirable in some embodiments. For example, larger particles may settle faster and travel less than the bacteriophage particles, but help in the initial dispersion or during manufacturing of the powder.

In some embodiments, the surface to treat is in a room or any other enclosed or mostly enclosed space and most or all of the surfaces present in the room may be treated. Example of such spaces include hospital patient rooms, operating rooms, intensive care units, and other medical treatment facilities. Temporary structures, such as tents, and vehicles, such as ambulances and military vehicles, could also benefit from the proposed treatment method. In other embodiments, the surface to treat is the internal surface of a water or air conduit. In yet other embodiments, the surface to treat is an exposed surface of a wound. In other embodiments, the particles are dispersed outside, in the environment, for example to decontaminate agricultural fields or outdoor surfaces contaminated by biological weapons. The proposed method may also be used to provide respiratory therapy to a patient, a human or a non-human mammal, suffering from a bacterial infection, by dispersing the powder as above and having the patient inhale the powder suspended or aerosolized in the air. In such cases, bacteriophages intended to treat the pulmonary infection are provided.

When auxiliary particles are present, they may include one or more of inorganic salt particles, hydrophobic polymer particles, such as the polymers described in US patent application publication US20160375139A1 published Dec. 29, 2016, the contents of which is hereby incorporated by reference in its entirety, silica, polyvinylpyrrolidone, cellulose ethers, polyethylene glycol, polyvinyl alcohol or poloxamers. Other examples of auxiliary particles include particles of inorganic salts, such as MgSO4, MgCO3, CaCO3and talc. Yet other example of suitable auxiliary particles include surfactants, ionic or non-ionic. Yet other example of suitable auxiliary particles include magnesium aluminometasilicate, cyclodextrins, talc, magnesium stearate, and starch, and bactericide particles, such as detergents, antibiotics or other bactericides, such as nanoparticles, metallic powders, for example AG, Cu, AGCU alloys, bimetallic nanoparticles, could also be contained in the composition, if compatible with bacteriophage viability. In yet other embodiments, the auxiliary particles include FeO4, FeO3, FeO, superparamagnetic particles, and combinations thereof. In some embodiments, the bacteriophages are adsorbed on the surface of solid particles, lyophilized, spray-dried or dispersed in degradable particles that will experience relatively quick degradation upon contact with the atmosphere or the surface. In some embodiments, the composition replaces the bacteriophages with phage-related products, or includes such phage-related products in addition to the bacteriophages. Examples of such phage-related products include endolysins, phage proteins, phage enzymatic formulations, and combinations thereof.

The particles may be discharged in air in any suitable manner. An advantageous way of performing this discharge is to use a sudden increase in pressure in a container using a compressed gas. In some embodiments, the container is destroyed when the pressure increase is created. In other embodiments, the container includes an exhaust having a shape suitable to allow dispersion of the particles through the exhaust when the pressure is increased in the container. The exhaust may be used to control or influence the direction in which the particles are spread and the speed at which they are ejected.

Referring toFIGS.1and2, there is shown a first embodiment of device10for disinfecting a surface11(only schematically represented inFIGS.1and2) exposed to air using bacteriophages. The bacteriophages are present in a powder15containing the bacteriophages, as detailed hereinabove, and schematically represented inFIG.2. The device10includes a pressurized gas source12providing a pressurized gas at a pressure larger than atmospheric pressure a load chamber14adjacent the compressed pressurized gas source12and a dispersion head16in fluid communication with the load chamber14and providing an outlet for the powder15. A valve18is provided between the pressurized gas source12and the load chamber14, the valve18being configurable between a closed configuration in which the pressurized gas is prevented from entering the load chamber14and an open configuration in which the pressurized gas is allowed to enter the load chamber14to pressurize the latter. The valve18is operated by an actuator20that can selectively allow an intended user to move the valve18from the closed to the open configuration. When the valve18is configured from the closed configuration to the open configuration, the pressurized gas enters the load chamber14and expels the powder15therefrom and into the air through the dispersion head16. For example, the load chamber is pressurized at between about 4 MPa to about 7 MPa, for example about 6 MPa, but lower or larger pressures may be used in some embodiments.

The pressurized gas source12is of any type that may provide enough gas at enough pressure to cause dispersion of the powder in the air. For example, referring toFIG.2, the pressurized gas source12includes a receptacle30defining a gas source chamber32thereinto. The gas source chamber32is provided with a conventional cartridge opener34extending thereacross for opening a conventional compressed gas cartridge36, such as a CO2cartridge, contained in the gas source chamber32. The gas source chamber32for example defines an axial aperture38allowing insertion of the compressed gas cartridge36thereinto and may be closed with a screwable cap40inserted in the axial aperture. Screwing the cap40pushes the compressed gas cartridge36towards the cartridge opener34, which breaks the conventional seal on the compressed gas cartridge36and pressurized the whole gas source chamber32.

In some embodiments, the compressed gas cartridge36is replaced after each use or after a predetermined number of uses of the device10. The compressed gas cartridge36is therefore provided filled with a compressed gas and discarded or sent for refilling when the pressure in the compressed gas cartridge36is too low.

In other embodiments (not shown in the drawings), the pressurized gas source12includes a chamber that can be pressurized using a compressed gas, for example through a commercial compressed gas cylinder. Other manners of providing the compressed gas are also within the scope of the appended claims.

As seen inFIGS.1and2, in some embodiments, the pressurized gas source12, load chamber14and dispersion head16have a generally cylindrical shape and are screwed to each other to allow easy disassembly and assembly of the device10. In other embodiments, most of the components of the device10are permanently attached to each other, and only the end cap40and one junction of the load chamber14, either in the load chamber14itself, or at one end thereof, can be unscrewed to respectively allow insertion of the gas cartridge36in the gas source chamber32and insertion of the powder15in the load chamber14.

Referring toFIG.1, in some embodiments, the actuator20is of the type including a controller28operative for allowing a power source29, such as a battery, to power electro-mechanical valve18, to open the valve18to allow the pressurized gas to reach the powder15for dispersion. The controller28may be a simple push button connected through wires27to the power source29, that, when activated, transmits an electrical signal, through another wire26, to an electro-mechanical valve18that release the pressure from the compressed gas source12into the load chamber14when the electrical signal is received. However, the actuator20may be also wireless, and responsive to opening the valve18when a predetermined wireless signal is received, or mechanical. In some embodiments, the controller28includes circuitry providing a timer characteristics allowing to activate the device10and then leave so that the user of the device10is not exposed to a large concentration of powder15and does not affect the dispersion of the powder15.

In yet other embodiments, the controller28is operative for periodically dispersing a predetermined quantity of the powder15at predetermined time intervals. For example, the controller28includes a microcontroller running software operative for periodically opening the valve18for a predetermined duration and immediately after closing the valve18. These periodic dispersals of the powder15may for example be performed many times before there is a need to reload the load chamber14, or the device10may then be provided with a powder dispenser that refills the load chamber14after each powder15dispersal. For example the powder dispenser includes a container containing the powder15and is provided with an access door leading into the load chamber14, so that the access door may be opened to reload the load chamber14each time the device10has dispersed the powder15. Other suitable mechanisms for refilling the load chamber14automatically may also be used. Periodic dispersal may be performed in “burst” mode, wherein pressurization of the load chamber14is performed at intervals of a few seconds to a few minutes from each other, or over a more extended time period, wherein the pressurization of the load chamber14is performed at intervals of more than a few minutes to weekly or monthly intervals.

An example of a purely mechanical controller is shown for device100ofFIG.4, in which a push button122mounted to the compressed gas chamber112is used to activate a poppet valve118mounted through a wall113separating the compressed gas chamber112and the load chamber114. The push button122may be used to move a piston142mounted on a bearing140. The piston142operates the poppet valve118. The poppet valve118includes a head117which, when pushed in the load chamber114allows the compressed gas to flow out of the compressed gas chamber112into the load chamber114. The push button122may be spring biased so that a predetermined pressure exerted thereon is required to activate the poppet valve118. The compressed gas chamber112may be refilled using a pressurized gas source through a gas inlet22, for example provided with a one-way valve allowing to easily refill the compressed gas chamber112. Any other suitable valve and actuator may also be used in alternative embodiments of the invention.

The load chambers14and114contain the powder15to be dispersed.

Reference will be made below to the load chamber14for simplicity, but the load chamber114operates similarly to the load chamber14. These powders15could be provided directly into a load chamber14strong enough to withstand the relatively large pressures required for dispersion of the powder15. In such cases, a diaphragm33or132, seen inFIGS.2and4respectively, may extend between the powder15and the dispersion head16, but in some embodiments, the diaphragm33or132is omitted. When present, the diaphragm33or132is made of material that is strong enough to confine the powder15in the load chamber14before the valve18is moved to the open configuration, but weak enough to be damaged or destroyed when the relatively large gas pressure of the compressed gas present in the pressurized gas source12is released in the load chamber14. The diaphragm33or132may for example be made of relatively thin polymer or paper. In other examples, the diaphragm33or132is not destroyed in use and is a relatively sturdy mesh of a size small enough to prevent the powder from significantly exiting the load chamber14when the latter is not pressurized, but large enough to allow the powder to relatively easily be expelled from the load chamber14when the latter is pressurized.

In other embodiments, the diaphragm132is part of a capsule including the powder15. Indeed, to facilitate handling of the fine particle loads, the powder15may come packaged in a capsule including an outer shell, made of a material similar to that from which the diaphragm132may be made, containing the powder15. For example, the outer shell may be fragile enough to allow relatively easy penetration of the poppet valve head117thereinto when the valve is opened, which leads to sudden pressurization of the outer shell and release of the fine particles as the diaphragm132is damaged or destroyed.

The powder15may substantially entirely fill the load chamber14, either relatively loosely or compressed. Alternatively, only a fraction of the load chamber14may be filled with the powder15.

Returning toFIG.2, the dispersion head16is for example of the type including a hollow internal chamber19from which a plurality of outlets17, or nozzles, extend, leading to the atmosphere. The outlets17are dispersed on the outer surface of the dispersion head16, for example in a substantially cylindrical or spherical configuration, among others. In some embodiments, the outlets17are dispersed around a segment of a cylindrical surface covering between about 60 and 180 degrees, so that the fine particles are projected generally upwardly when the surface of the dispersion head16opposed to the outlets17is facing the ground or a generally horizontal support surface. In other embodiments, the outlets17are configured to cause an omnilateral dispersion of the powder upon pressurization of the load chamber, for example by being dispersed along a cylindrical surface. In yet other embodiments, outlets are dispersed around a segment of a cylindrical surface covering between about 60 and about 180 degrees or between about 60 and 120 degrees, among others. Other outlet configurations are also within the scope of the appended claims. The internal chamber19is in fluid communication with the load chamber14(once the diaphragm33has burst, if needed for dispersion) so that when the latter is filled with compressed gas, the powder15are projected into the internal chamber and through the outlets17.

In other embodiments, the load chamber14is filled with a liquid including bacteriophages, or with a liquid suspension of particles with bacteriophages adsorbed or dispersed in the particles and/or dispersed in the liquid. In some embodiments, the quantity of bacteriophages contained in each load of the load chamber14is sufficient to provide between about 104and 108PFU/m2on the surfaces to treat, but higher and lower quantities of bacteriophages are also within the scope of the invention.

In yet other embodiments, a device similar to the devices10and100is single-use. In yet other embodiments, a device200, seen inFIG.5A, includes a load chamber214having at least part thereof that is too weak to withstand a high gas pressure separated from a compressed gas chamber212by a valve218. The valve218may be a single use valve that allows the gas contained in the compressed gas chamber212to exit through the valve218when activated. This gas enters the load chamber214and damages, bursts, destroys or pulverizes at least part of the compressed gas chamber212, which results in dispersion of the fine particles contained therein, as seen inFIG.5B.

For example the valve218is simply a pin or other similar structure that obstructs an aperture extending between the load chamber214and compressed gas chamber212and which, when slid perpendicularly to the aperture, releases the gas. Other suitable valves218are usable.

The above-described devices10,100and200, along with any alternative suitable devices, may be used to perform a method300using bacteriophages for at least partially disinfecting a surface exposed to air and illustrated inFIG.6. The method starts at step305. Then, at step310, the method includes providing the powder15, the powder15including bacteriophages. Subsequently, at step315, the method includes dispersing the powder15in the air in proximity of the surface to apply at least part of the powder15on the surface. The powder is dispersed at a distance from the surface such that a significant portion of the powder will be able to reach the surface to disinfect. For example, the powder is dispersed adjacent the surface or up to many meters, 10 meters, or a few decameters away from the surface or even further away from the surface. The exact distance from the surface depends on the quantity of powder released, the release pattern and the speed at which the powder particles are released. The powder15is dispersed nonpyrogenically. In some embodiments, the powder is dispersed using a dry dispersion mechanism, that is in the absence of liquid, using only a gas. For example, the method300uses a sudden pressurization to a dispersion pressure larger than atmospheric pressure of a load chamber containing the powder15to expel the powder15from the chamber and form a cloud of powder suspended in the air, for example in the form of an aerosol.

Once in the air, part of the powder15may settle on the surface to treat. It should be noted that due to the small size of the particles, this surface may be at a relatively large distance from the powder release site, such as many meters or even more from the powder release site.

In some embodiments, the powder15may only include a small fraction of its mass in bacteriophages particles, for example between 1% and 50%, the remainder being in the form of auxiliary particles, and nevertheless remain effective. This is detailed in example 1.

An SPK bacteriophage cocktail (active againstStaphylococcus aureus, Pseudomonas aeruginosaandKlebsiella pneumoniaebacteria, 1.4×109PFU/ml) was diluted 1/10 in Trehalose 0.5M and lyophilized using the following cycle and stored at 4° C.

As a control of phage activity, 1 vial of lyophilized SPK cocktail (mean weight of 100 mg) was resuspended in 1 mL of sterile water and tittered SMQ-121 (SaX), ATCC15442 (PsA-159) and KP27 forS. aureus, P. aeruginosaandK. pneumoniaephages, respectively. The table below presents phage titer per mL and g of lyophilized phage powder.

Lyophilized phage pellets were delicately broken with a sterile spatula and homogenized with high homogenizer to make a uniform fine powder, which had a final density of 0.33 g/cm3.

After mixing, activity testing was performed on 10 mg of lyophilized phage+additive mixture by pouring the powder on a layer of bacteria (1004 of bacterial culture at exponential phase in 2.5 mL of top agar). The bacteria used were SMQ-121 (SaX), ATCC15442 (PsA-159) and KP27 forS. aureus, P. aeruginosaandK. pneumoniaephages, respectively. Plates were incubated overnight at 37° C. before taking pictures with a gel doc system. In addition, negative controls of 10 mg of each additive and positive controls: of 10 mg of lyophilized SPK cocktail were used.

FIG.7A to7Drepresents the results of control experiments. Lysis is clearly visible on the positive control (FIG.7A) and absent on the negative controls (FIGS.7B to7D).FIGS.8A to8D,9A to9D and10A to10Drepresent the results of phage activity in respectively 1:1, 1:10 and 1:100 dilution (w/w) of lyophylized phages in auxiliary powder (A: MgSO4, B: MgCO3, C: CaCO3, D: talc). In all cases significant phage activity was detected. Lyophilized phages mixed with different additives were able to lyse bacterial lawns even at 1:100 ratio equivalent to 2.4E2, 2.3E3 and 2.1E3 pfu ofS. aureus, P. aeruginosaandK. pneumoniaephages (each image includes one plate for each bacteria). Tested additives do not have any effect on phage activity but help spreading lyophilized phage powder more efficiently on the bacterial lawn.

Although the present invention has been described hereinabove by way of exemplary embodiments thereof, it will be readily appreciated that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, the scope of the claims should not be limited by the exemplary embodiments, but should be given the broadest interpretation consistent with the description as a whole. The present invention can thus be modified without departing from the spirit and nature of the subject invention as defined in the appended claims.