U.S. patent application number 10/953827 was filed with the patent office on 2008-09-25 for use of exogenous gaseous nitric oxide in the treatment and disinfection of biofilms.
Invention is credited to Ali Ardakani, Abdi Ghaffari, Doug Hole, Chris Miller, Bruce Murray.
Application Number | 20080233212 10/953827 |
Document ID | / |
Family ID | 36099455 |
Filed Date | 2008-09-25 |
United States Patent
Application |
20080233212 |
Kind Code |
A9 |
Miller; Chris ; et
al. |
September 25, 2008 |
Use of exogenous gaseous nitric oxide in the treatment and
disinfection of biofilms
Abstract
The administration of gaseous nitric oxide as a biocidal moiety
is proffered as a de novo treatment in the control and eradication
of biofilms. The present invention relates to the use or methods of
application of exogenous nitric oxide gas (gNO) as a stand alone
biocidal agent or in cohort with any or all adjunct vehicles in the
control of biofilms generated by microbial organisms, i.e.,
bacteria, protozoa, amoeba, fungi etc. Further, the present
invention introduces the concept of utilization and methods of
application of gaseous nitric oxide in control and eradication of
biofilm forming microorganisms. Noteworthy areas of application are
offered as examples. They include, and are not limited to, air
and/or water heating/cooling distribution systems in facilities
such as hospitals and laboratories, surfaces of medical devices,
household surfaces, dental plaque, dental and/or medical water
treatment lines, industrial pipelines, water treatment and
distribution facilities and fluids sterilization. Various
specialized delivery apparatus will be designed to facilitate
nitric oxide gas administration to each specific unique
application.
Inventors: |
Miller; Chris; (North
Vancouver, CA) ; Ghaffari; Abdi; (Edmonton, CA)
; Ardakani; Ali; (Edmonton, CA) ; Murray;
Bruce; (Tofield, CA) ; Hole; Doug; (Edmonton,
CA) |
Correspondence
Address: |
Sidley Austin LLP
555 West 5th Street
Suite 4000
Los Angeles
CA
91723
US
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20060068031 A1 |
March 30, 2006 |
|
|
Family ID: |
36099455 |
Appl. No.: |
10/953827 |
Filed: |
September 29, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60506807 |
Sep 29, 2003 |
|
|
|
Current U.S.
Class: |
424/718 |
Current CPC
Class: |
A61K 33/00 20130101 |
Class at
Publication: |
424/718 |
International
Class: |
A61K 33/00 20060101
A61K033/00 |
Claims
1. A method of preventing biofilm formation, comprising the steps
of: applying gaseous nitric oxide to a target interface where a
biofilm can be formed; providing an ambient concentration of
gaseous nitric oxide of greater than about 150 ppm; maintaining at
least about 150 ppm concentration for a finite time beyond a
minimum of 30 minutes exposure.
2. The method of claim 1 further comprising regulating the
concentration of gaseous nitric oxide delivered to the target
interface.
3. The method of claim 1 further comprising regulating the
concentration of the gaseous nitric oxide to a closed environmental
system.
4. The method of claim 1 further comprising providing gaseous
nitric oxide resulting in a concentration level equivalent to
ambient gaseous nitric oxide greater than 200 ppm.
5. A method for using nitric oxide gas (gNO) as a stand alone
biocidal agent or in combination with any or all adjunct vehicles
in the control of biofilms generated by microbial organisms:
applying gaseous nitric oxide to a targeted interface; providing an
optimum ambient concentration of gaseous nitric oxide of greater
than about 100 ppm; maintaining at least about 100 ppm
concentration for a finite time beyond a minimum of 30 minutes
exposure.
6. The method of claim 5 wherein the microbial organisms are
selected from the group consisting of bacteria, protozoa, amoeba,
and fungi.
7. The method of claim 5 further comprising the step of eradicating
biofilm forming microorganisms.
8. The method of claim 5 further comprising the treatment of air
and/or water heating/cooling distribution systems.
9. The method of claim 8 wherein the systems are located at
facilities selected from the group consisting of hospitals,
laboratories, surfaces of medical devices, household surfaces,
dental plaque, dental and/or medical water treatment lines,
industrial pipelines, water treatment facilities, water
distribution facilities and fluid sterilization products.
10. A nitric gas dispenser for mammals, comprising: a housing
containing a valve mechanism that is interconnected between a
nitric oxide gas composition dispersal unit that provides nitric
gas at a desired pressure and a gas delivery system that provides
the nitric oxide gas composition at the desired pressure and at an
ambient concentration of greater than 150 ppm to the mammal; the
valve mechanism controls the flow of the nitric oxide gas
composition between the nitric oxide gas dispersal component and
the gas delivery system to the mammal's breathing orifice so the
mammal's targeted interface receives the predetermined amount and
concentration of nitric oxide.
11. The dispenser of claim 10 wherein the nitric oxide is delivered
to the target interface at a concentration of at least 150 ppm for
a finite time beyond a minimum of 12 hours exposure.
12. The dispenser of claim 10 wherein the dispenser provides an
efficacious management of biofilm-forming microorganisms.
13. The dispenser of claim 12 wherein the microorganisms are
antibiotic resistant bacteria.
14. The dispenser of the claim 10 is any device that can deliver
the nitric oxide gas composition to a targeted interface.
15. A method for using nitric oxide gas (gNO) as a stand alone
biocidal agent or in combination with any or all adjunct vehicles
in the control of biofilms generated by microbial organisms:
applying gaseous nitric oxide to a targeted interface; providing an
ambient concentration of gaseous nitric oxide of less than 100 ppm
and equal to or greater than 1 ppm; maintaining the concentration
of the gaseous nitric oxide for a finite time beyond a minimum of
30 minutes exposure.
16. The method of claim 1 wherein the exposure finite time is 12
hours.
17. The method of claim 5 wherein the exposure finite time is 12
hours.
18. The method of claim 15 wherein the exposure finite time is 12
hours.
19. The dispenser of claim 10 wherein the dispenser is applied to
any object that can contain a biofilm, the object being selected
from a group consisting of a medical device, a conduit for
industrial, home, office space, municipal, or medical purposes, and
an animal, on the condition that the nitric oxide does not become
modified when the nitric oxide binds to another agent contained
within the animal, for internal and/or external applications.
20. The dispenser of claim 19 wherein the another agent is
blood.
21. The method of claim 1 wherein the nitric oxide is applied to
any object that can contain a biofilm, the object being selected
from a group consisting of a medical device, a conduit for
industrial, home, office space, municipal, or medical purposes, and
an animal, on the condition that the nitric oxide does not become
modified when the nitric oxide binds to another agent contained
within the animal, for internal and/or external applications.
22. The dispenser of claim 21 wherein the another agent is blood.
Description
CLAIM OF PRIORITY
[0001] This application claims priority to U.S. provisional patent
application Ser. No. 60/506,807, which was filed on Sep. 29,
2003.
FIELD OF THE INVENTION
[0002] The present invention generally relates to a methodology for
obtunding biofilms.
BACKGROUND OF INVENTION
[0003] Microbial organisms are capable of adhering to a surface
aggregate in a polymer-like matrix. This is referred to as a
biofilm and is synthesized endogenously by the microbe(s). Biofilms
are ubiquitous in nature and are commonly found in a wide range of
environments including domestic and industrial water systems.
Biofilms are also etiologic agents for a number of disease states
in mammals. Otitis media, dental plaque, bacterial endocarditis,
cystic fibrosis and Legionnair's disease along with a broad array
of hospital acquired, dental and medical clinic infections are
examples of its pathology. Bacteria growing in biofilms display
increased resistance to antibiotics. Commonly surveyed microbial
organisms that form biofilms are Burkholderia cenocepacia,
Staphlococcus, Steptococccus, Pseudomonas, and Legionnella and
their subtypes.
[0004] In U.S. Pat. No. 5,957,880, Igo taught that adding nitric
oxide to blood within an extracorporeal system is known to inhibit
platelet activation. Our summary of Igo's '880 reference is based
on Igo's teaching which is as follows (bracketed material is added
and underlining was added for emphasis):
[0005] Referring to FIG. 1, a typical CPB circuit is indicated
generally by reference numeral 10. The patient is shown by numeral
12. A venous cannula 13 inserted into the patient is connected into
a fluid inlet tube 14 that directs blood from the patient to a
venous reservoir 18. Another cannula 15 inserted in the patient is
connected to another fluid inlet 16 that also leads from the
patient to venous reservoir 18. Reservoir 18 may be a pole mounted
unit or may be located on the heart-lung machine table, but in
either case normally is the first fixed point in the circuit, lines
14 and 16 normally being flexible and long enough to allow surgeon
and surgical assistants room to maneuver around the surgical table.
The purpose of venous reservoir 18 is to accumulate the admitted
blood for feeding the balance of the CPB circuit. The accumulator
eliminates pump starvation and cessation of pump prime by providing
a buffer from ebb and flow of blood from the patient.
[0006] From the venous reservoir, plastic tubing 20 leads to the
inlet side of a roller pump 22. Roller pump 22 has a hub 24 from
which protrude two arms 26. These arms impinge on the tubing 20
collapsing it. Rotation of the pump hub 24 in the direction
indicated by reference numeral 28 provides the desired flow
direction and flow rate. The blood leaves the roller pump 22
through tubing 30 to the inlet of the oxygenator 32. The blood can
be thermally adjusted by passing it from the oxygenator 32 through
tubing 34 into a heat exchanger 36 for heating or cooling before
returning to the oxygenator 32 by tubing 38. Upon oxygenation, the
blood exits the oxygenator in two ways. The first way is through
tubing 40 to another roller pump 42, from there pumped through
tubing 44 to a cardioplegia system 46, then to the patient 12
through outlet tubing 47 and a cannula 48. The other mechanism with
which the blood leaves the oxygenator 32 is through tubing 50. A
filter 52 is located on a side branch of this portion of the
circuit. When it is desired to use the filter 52, tubing 50 is
clamped in the area noted by numeral 54 and the blood travels
through the filter 52 before returning to the patient through
outlet tubing 57 and a cannula 56. The venous return reservoir 18
is the juncture of all blood removed from the patient. It is at
this location where the improvement according to this invention
suitably may be added to the CPB circuit, prior to the pump 22 and
the blood treatment oxygenator 32.
[0007] FIG. 2 depicts an extracorporeal blood treatment circuit in
general, designated by reference numeral 11, and in which reference
numerals are the same for the like elements found in the specific
CPB circuit shown in FIG. 1. Reference numeral 41 represents a
blood treatment component. In the case of a CPB apparatus as in
FIG. 1, blood treatment component 41 comprises at least oxygenator
32 and optionally also heat exchanger 36 with connecting tubing 34,
38 and either or both of (1) the cardioplegia system 46 with
associated second pump 42 and connecting tubing 40, 44, 47 and (2)
the filter 52 with associated tubing 50. Numeral 17 indicates a
blood fluid inlet generally and numeral 49 indicates a fluid outlet
for blood return generally to the patient in FIG. 2. In accordance
with this invention, blood treatment component 41 of the fluid
circuit of the apparatus 11, instead of being an oxygenation system
as in FIG. 1, suitably may be a heat exchange system 36, a renal
dialysis component for exchange of urea and other blood chemicals
with a dialysate solution across an exchange membrane, or an organ
perfusion component such as an ex vivo liver and perfusion support
system tying into circuit interconnects 30 and 49.
[0008] In accordance with this invention, one of more feeds of
nitric oxide are employed, as necessary in the particular circuit,
to maintain the concentration of nitric oxide in the circulating
extracorporeal blood at a dosage effective to produce the desired
inhibition of platelet activation over a period of time sufficient
for the journey through the extracorporeal circulation apparatus
yet insufficient to sustain the inhibition after the blood is
returned to the patient and desired dosages. FIG. 3 depicts one
such feed at the initial (venous inlet) portion of the circuit
illustrated in FIG. 1. In this preferred embodiment of the
invention, a gas permeable membrane 60 is located within a conduit
62 of the blood circuit located immediately downstream from the
reservoir 18. The gas permeable membrane 60 is elongated and
tubular in form and is disposed longitudinally within conduit 62
adapted to come into contact with blood flowing through conduit 62.
A gaseous source, a mixture of nitric oxide and a carrier gas such
as nitrogen, is housed in container 68 under high pressure.
Regulator 66 controls the output gas pressure to periodic driver
69. The purpose of the periodic driver 69 is to induce a sinusoidal
shaped pressure curve to the gas much like a "pulse". The gas
leaves the driver through tubing 64 and flows into the interior of
gas permeable membrane 60. Due to the permeability of this membrane
60 to nitric oxide gas, the gas will diffuse through the membrane
and dissolve in the blood plasma where it will come into contact
with platelets. The membrane is selected to be impermeable to
nitrogen and the nitrogen carrier gas will not diffuse through the
membrane. Coupled to the outlet of the membrane 60 is outlet tubing
61, which is connected to valve 63. Valve 63 adjusts the back
pressure of the system. From the valve 63 the carrier gas and any
residual nitric oxide gas is carried through tube 65 into container
67, which is filled with a scavenger liquid such as methylene blue.
The gas mixture is allowed to bubble up through the container
containing the scavenger liquid. The scavenger liquid absorbs any
residual nitric oxide so that the only gas that escapes into the
atmosphere is the carrier gas.
[0009] Blood guarded by dissolved nitric oxide exits conduit 62 and
into tubing 20 where is passes by a conventional blood flow
measuring device 90. Signals from blood flow measuring device 90
are transferred by line 92 to controller feedback logic component
94 which outputs a signal through line 96 to controller driver
component 98 for controlling pressure and flow from regulator 66.
The controller system comprising units 90, 94 and 98 with
connecting lines 92 and 96 controls the flow of gas into membrane
60 in relation to the flow of blood through tubing 20. In this
manner, when the flow rate of the blood is low, the nitric oxide
introduction is correspondingly and automatically reduced.
Conversely, in cases of high flow the nitric oxide introduction is
correspondingly and automatically raised.
[0010] The gas permeable membrane 62 has a gas permeable rate K
which is dependent on the material of construction and the
molecular characteristics of the gas. For nitric oxide, the gaseous
release rate from membrane 60 is proportional to K, the exposed
surface of the membrane to the blood, the internal gaseous pressure
within the membrane and the hydraulic pressure of and gas tension
of nitric oxide (if any) in the blood flowing by it. Delivered
molecular concentrations to the blood is [sic] calculated knowing
the above plus the absorption coefficient of the blood to the
nitric oxide. Thus the controller controls the gas flow and at a
level which, for the characteristics of membrane 60 and the
absorption coefficient of nitric oxide gas at the temperature of
the blood in the apparatus (before thermal adjustment, if any), is
sufficient to provide an actual concentration of nitric oxide in
solution effective in the presence of venous red blood cell blood
hemoglobin to inhibit platelet activation.
[0011] FIG. 4 illustrates a longitudinal sectional view of the
conduit 62, the gas permeable membrane 60 and the tubing 64. Nitric
oxide gas flows into the membrane 60 at location 70. As the gas
pressure inside the gas permeable membrane 60 exceeds the pressure
of the blood within conduit 62, nitric oxide gas will diffuse from
the membrane into the blood stream as indicated by arrows 74. The
nitric oxide will be absorbed by the blood cellular components
which will mediate the inflammatory response as described
earlier.
[0012] Referring to FIG. 5, which illustrates a cross section of
FIG. 3 along the line A-A, the relationship between the geometry's
of the conduit 62 and gas permeable membrane 60 is as follows. The
cross sectional area of the inside of conduit 62 minus the
sectional area of the gas permeable membrane 60 (such difference
being referenced by numeral 76) is approximately equivalent to the
cross section of the tubing elsewhere in the CPB circuit, (i.e. the
cross section of tubing element 20). With this relationship the
blood is not subjected to an adverse pressure gradient in conduit
62. Longitudinally, the shape of the gas permeable membrane 60
follows that of the conduit 62, again so that adverse pressure
gradients are not imparted into the circuit.
[0013] FIG. 6 illustrates another preferred embodiment of the
invention. In this embodiment a carrier gas is not used so that
container 68 holds a 100% concentration of nitric oxide. A pulse
drive generator 69 is not shown but may be present. In this
embodiment, there is no outlet conduit of membrane 60. As pressure
builds up in conduit 60, the nitric oxide diffuses into the
bloodstream as previously described. Because there are no residual
carrier gas molecules, there is no need for a return. Simply
stated, components 61, 63, 65, and 67 of the embodiment depicted in
FIG. 2 are absent at the distal end of membrane 60 and the tube 62
in this configuration. As in the embodiment depicted in FIG. 3, a
controller comprising components 90, 94 and 98 with connections 92
and 96 controls the concentration of nitric oxide in solution in
the blood. FIG. 8 illustrates a cross sectional view B-B of FIG. 7
with the same numbers used in the same way as in FIG. 5.
[0014] The above embodiments illustrate an optimal configuration of
the invention in which the blood flows around the external portion
of a gas permeable membrane 60. While it is within the scope of
this invention that the system can be configured so that the gas is
on the external portion of the membrane and blood is flowed within
the membrane, in low gas pressure conditions some membranes dilate,
increasing the cross sectional area of the membrane and lowering
blood flow through that portion of the apparatus, and in high gas
pressure conditions, some membranes might collapse, reducing blood
flow. In the preferred embodiments, if gas flow is zero, the
membrane might collapse but it would not occlude or preclude blood
flow.
[0015] FIG. 9 depicts another embodiment of the [Igo] invention. In
this embodiment the nitric oxide feed is to reservoir 18. The feed
comprises a diffuser 100 for diffusing nitric oxide gas into the
reservoir, and comprises a regulator 66 for controlling gas
pressure and rate of flow into the reservoir and a driver 69 for
delivering the nitric oxide gas into reservoir 18 through inlet 64
in a pulsatile manner. Suitably diffuser 100 comprises a membrane
or filter 80 that is not permeable to blood and is permeable to
nitric oxide gas through which nitric oxide gas is introduced into
the reservoir. As in the embodiment depicted in FIGS. 3 and 6, a
controller comprising components 90, 94 and 98 with connections 92
and 96 controls the concentration of nitric oxide in solution in
the blood.
[0016] It is important that the location of the nitric oxide feed
be close to the patient cannulation point as possible in the
extracorporeal circuit to reduce so much as practicable the period
of exposure of platelets to non-endothelial surfaces. At least one
feed location is described generally as upstream of the pump that
is needed to circulate the blood extracorporeally through the
system and back to the patient. With reference to the FIG. 2, that
point is anywhere in line 15. In FIGS. 3-9, which involve a CPB
circuit where blood from two inlets 14 and 16 is pooled in
reservoir 18, either the reservoir or the tubing immediately past
the reservoir is selected for initial introduction of the nitric
oxide, for the practical reason that these are the closest
stationary locations in the system to the patient source of blood
and also because control of nitric oxide introduction is most
readily accomplished in the reservoir or in the blood filled lines
in the immediately downstream tubing under the influence of a pump
as opposed to in the blood inlet lines where lines are mobile to
allow access to the surgical field, and especially in the case of
blood suctioned from the operative field where intermittent blood
and air flow occurs. The closest stationary location will vary
according to the blood treatment component 41 involved in the use
of this invention. Because of the very short half life of nitric
oxide in the blood, additional feeds may be used further downstream
to maintain the desired nitric oxide concentration in the blood
without overdosing the blood in but one location.
[0017] In other words, Igo teaches away from adding nitric oxide to
blood to combat pathogens.
[0018] In U.S. Pat. No. 6,432,077, Stenzler teaches that topical
application of nitric oxide to wounds and/or skin of mammals is
beneficial to wound healing because it decreases further infection.
No where does Stenzler teach, disclose or suggest exposing nitric
oxide to blood to combat pathogens. Our summary of Stenzler is
based on his disclosure, which reads as follows:
[0019] The treatment of infected surface or subsurface lesions in
patients has typically involved the topical or systemic
administration of anti-infective agents to a patient. Antibiotics
are one such class of anti-infective agents that are commonly used
to treat an infected abscess, lesion, wound, or the like.
Unfortunately, an increasingly number of infective agents such as
bacteria have become resistant to conventional antibiotic therapy.
Indeed, the increased use of antibiotics by the medical community
has led to a commensurate increase in resistant strains of bacteria
that do not respond to traditional or even newly developed
anti-bacterial agents. Even when new anti-infective agents are
developed, these agents are extremely expensive and available only
to a limited patient population.
[0020] Another problem with conventional anti-infective agents is
that some patients are allergic to the very compounds necessary to
their treat their infection. For these patients, only few drugs
might be available to treat the infection. If the patient is
infected with a strain of bacteria that does not respond well to
substitute therapies, the patient's life can be in danger.
[0021] A separate problem related to conventional treatment of
surface or subsurface infections is that the infective agent
interferes with the circulation of blood within the infected
region. It is sometimes the case that the infective agent causes
constriction of the capillaries or other small blood vessels in the
infected region which reduces bloodflow. When bloodflow is reduced,
a lower level of anti-infective agent can be delivered to the
infected region. In addition, the infection can take a much longer
time to heal when bloodflow is restricted to the infected area.
[0022] This increases the total amount of drug that must be
administered to the patient, thereby increasing the cost of using
such drugs. Topical agents may sometimes be applied over the
infected region. However, topical anti-infective agents do not
penetrate deep within the skin where a significant portion of the
bacteria often reside. Topical treatments of anti-infective agents
are often less effective at eliminating infection than systemic
administration (i.e., oral administration) of an anti-infective
pharmaceutical.
[0023] In the 1980's, it was discovered by researchers that the
endothelium tissue of the human body produced nitric oxide (NO),
and that NO is an endogenous vasodilator, namely, and agent that
widens the internal diameter of blood vessels. NO is most commonly
known as an environmental pollutant that is produced as a byproduct
of combustion. At high concentrations, NO is toxic to humans. At
low concentrations, researchers have discovered that inhaled NO can
be used to treat various pulmonary diseases in patients. For
example, NO has been investigated for the treatment of patients
with increased airway resistance as a result of emphysema, chronic
bronchitis, asthma, adult respiratory distress syndrome (ARDS), and
chronic obstructive pulmonary disease (COPD).
[0024] NO has also been investigated for its use as a sterilizing
agent. It has been discovered that NO will interfere with or kill
the growth of bacteria grown in vitro. PCT International
Application No. PCT/CA99/01123 published Jun. 2, 2000 discloses a
method and apparatus for the treatment of respiratory infections by
NO inhalation. NO has been found to have either an inhibitory
and/or a cidal effect on pathogenic cells.
[0025] While NO has shown promise with respect to certain medical
applications, delivery methods and devices must cope with certain
problems inherent with gaseous NO delivery. First, exposure to high
concentrations of NO is toxic, especially exposure to NO in
concentrations over 1000 ppm. Even lower levels of NO, however, can
be harmful if the time of exposure is relatively high.
[0026] For example, the Occupational Safety and Health
Administration (OSHA) has set exposure limits for NO in the
workplace at 25 ppm time-weighted averaged for eight (8) hours. It
is extremely important that any device or system for delivering NO
include features that prevent the leaking of NO into the
surrounding environment. If the device is used within a closed
space, such as a hospital room or at home, dangerously high levels
of NO can build up in a short period of time.
[0027] Another problem with the delivery of NO is that NO rapidly
oxidizes in the presence of oxygen to form NO.sub.2, which is
highly toxic, even at low levels. If the delivery device contains a
leak, unacceptably high levels NO.sub.2 of can develop. In
addition, to the extent that NO oxides to form NO.sub.2, there is
less NO available for the desired therapeutic effect. The rate of
oxidation of NO to NO.sub.2 is dependent on numerous factors,
including the concentration of NO, the concentration of O.sub.2,
and the time available for reaction. Since NO will react with the
oxygen in the air to convert to NO.sub.2, it is desirable to have
minimal contact between the NO gas and the outside environment.
[0028] Accordingly, there is a need for a device and method for the
treatment of surface and subsurface infections by the topical
application of NO. The device is preferably leak proof to the
largest extent possible to avoid a dangerous build up of NO and
NO.sub.2 concentrations. In addition, the device should deliver NO
to the infected region of the patient without allowing the
introduction of air that would otherwise react with NO to produce
NO.sub.2. The application of NO to the infected region preferably
decreases the time required to heal the infected area by reducing
pathogen levels. The device preferably includes a NO and NO.sub.2
absorber or scrubber that will remove or chemically alter NO and
NO.sub.2 prior to discharge of the air from the delivery
device.
[0029] In a first aspect of the [Stenzler] invention, a device for
the topical delivery of nitric oxide gas to an infected area of
skin includes a source of nitric oxide gas, a bathing unit, a flow
control valve, and a vacuum unit. The bathing unit is in fluid
communication with the source of nitric oxide gas and is adapted
for surrounding the area of infected skin and forming a
substantially air-tight seal with the skin surface. The flow
control valve is positioned downstream of the source of nitric
oxide and upstream of the bathing unit for controlling the amount
of nitric oxide gas that is delivered to the bathing unit.
[0030] The vacuum unit is positioned downstream of the bathing unit
for withdrawing gas from the bathing unit.
[0031] In a second aspect of the [Stenzler] invention, the device
according to the first aspect of the invention includes a
controller for controlling the operation of the flow control valve
and the vacuum unit.
[0032] In a third aspect of the [Stenzler] invention, the device
according to the first aspect of the invention further includes a
source of dilutent gas and a gas blender. The dilutent gas and the
nitric oxide gas are mixed by the gas blender. The device also
includes a nitric oxide gas absorber unit that is positioned
upstream of the vacuum unit. The device also includes a controller
for controlling the operation of the flow control valve and the
vacuum unit.
[0033] In a fourth aspect of the [Stenzler] invention, a method of
delivering an effective amount of nitric oxide to an infected area
of skin includes the steps of providing a bathing unit around the
infected area of skin, the bathing unit forming a substantially
air-tight seal with the skin. Gas containing nitric oxide is then
transported to the bathing unit so as to bathe the infected area of
skin with gaseous nitric oxide.
[0034] Finally, at least a portion of the nitric oxide gas is
evacuated from the bathing unit.
[0035] It is an object of the [Stenzler] invention to provide a
delivery device for the topical delivery of a NO-containing gas to
an infected area of skin. It is a further object of the device to
prevent the NO-containing gas from leaking from the delivery
device. The method of delivering an effective amount of nitric
oxide gas to the infected area of skin kills bacteria and other
pathogens and promotes the healing process.
[0036] As clearly illustrated, Stenzler never taught, suggested,
nor disclosed exposing blood to NO to destroy pathogens.
[0037] In 1989 it was discovered that nitric oxide was produced by
the endothelium tissue of mammals. It has since been demonstrated
that endogenous nitric oxide is a potent modulator for a number of
systemic functions in mammals including selective pulmonary
vasodilatation, neurotransmission and cytoxic activity over a wide
range of microorganisms including bacteria and viruses. Nitric
oxide has been known for years as an environmental pollutant and is
toxic to mammals at high doses. At minimal concentrations however
exogenously supplied (eg. <100 ppm) nitric oxide has selectively
been used to treat human patients with a wide range of pulmonary
diseases including, but not limited to, chronic bronchitis, asthma,
ARDS (Acute Respiratory Disease Syndrome) etc. Nitric oxide has
also found utility in its application as both a sterilizing agent
and as a bactericidal agent for pathogenic organisms.
[0038] Septicemia is a serious, rapidly progressive,
life-threatening infection that can arise from infections
throughout the body, including infections in the lungs, abdomen,
and urinary tract. It may precede or coincide with infections of
the bone (osteomyelitis), central nervous system (meningitis), or
other tissues. Septicemia can rapidly lead to septic shock and
death. Septicemia associated with some organisms such as
meningococci can lead to shock, adrenal collapse and disseminated
intravascular coagulopathy.
[0039] In all examples referenced there is a dosage range of nitric
oxide application that needs to be maintained in order to establish
efficacy. Accordingly the employment of nitric oxide as a dissolved
gas or through selective nitric oxide donors in an extracorporeal
circuit allows for the titration of exogenously administered nitric
oxide levels required to optimize the therapeutic antimicrobial and
bactericidal benefits.
[0040] The impact from lost industrial productivity along with its
significant impact on the public health sector makes the
eradication of biofilms a major goal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIGS. 1-8 are prior art.
[0042] FIG. 9 is a schematic of the present invention.
[0043] FIG. 10 is an alternative embodiment of the present
invention.
SUMMARY OF INVENTION
[0044] The antimicrobial properties of nitric oxide as a molecule
have been well documented. The administration of gaseous nitric
oxide as a biocidal moiety is proffered as a de novo treatment in
the control and eradication of biofilms. The present invention
relates to the use or methods of application of exogenous nitric
oxide gas (gNO) as a stand alone biocidal agent or in cohort with
any or all adjunct vehicles in the control of biofilms generated by
microbial organisms i.e. bacteria, protozoa, amoeba, fungi etc.
Further, the present invention introduces the concept of
utilization and methods of application of gaseous nitric oxide in
control and eradication of biofilm forming microorganisms.
Noteworthy areas of application are offered as examples. They
include, and are not limited to, air and/or water heating/cooling
distribution systems in facilities such as hospitals and
laboratories, surfaces of medical devices, household surfaces,
dental plaque, dental and/or medical water treatment lines,
industrial pipelines, water treatment and distribution facilities
and fluids sterilization. Various specialized delivery apparatus
will be designed to facilitate nitric oxide gas administration to
each specific unique application.
[0045] The foregoing and additional advantages and characterizing
features of the present invention will become clearly apparent upon
reading of the ensuing detailed description together with the
included experimental model wherein:
DETAILED DESCRIPTION OF THE INVENTION
[0046] The administration of gaseous nitric oxide is viewed as a
novel biocidal agent in the efficacious management of numerous
biofilm-forming microorganisms with particular emphasis on
antibiotic resistant bacteria. The gNO can be administered through
a variety of mechanisms. Examples of said administration of gNO are
set forth in commonly assigned U.S. patent application Ser. No.
10/658,665. In that application, it was reported the examples are
as follows:
[0047] Referring now to FIG. 9, a gaseous nitric oxide (NO)
delivery device 1 is shown connected to a source of infected blood
from either a patient 2 or a stored blood source 3, and a pumping
system 4, through lines 5, 6.
[0048] The nitric oxide (NO) source 7, can be a pressurized
cylinder containing nitric oxide (NO) gas, and a nitric oxide flow
control valve/pressure regulator 8, delivering nitric oxide (NO) to
the gaseous nitric oxide delivery device 1 through supply tubing 9
and an optional gas blender 15. The infected blood is then exposed
to a controlled amount of nitric oxide (NO) by the gaseous nitric
oxide (NO) delivery device 1, and the treated blood is then
returned to either a patient 2 or a stored blood source 3, through
line 100. The treated blood can still carry the nitric oxide when
it returns to the patient or the stored blood source. By carrying a
sufficient quantity of nitric oxide into the patient, which is
completely contrary to the teaching of Igo, the nitric oxide can
reduce the pathogens throughout the whole body of the patient.
[0049] In FIG. 9, the nitric oxide (NO) gas source 7 is a
pressurized cylinder containing nitric oxide (NO) gas. While the
use of a pressurized cylinder is the preferable method of storing
the nitric oxide (NO) containing gas source 7, other storage and
delivery means, such as a dedicated feed line can also be used.
Typically the nitric oxide (NO) gas source 7 is a mixture of
N.sub.2 and NO. While N.sub.2 is typically used to dilute the
concentration of NO within the pressurized cylinder, any inert gas
can also be used.
[0050] When the NO gas source 7 is stored in a pressurized
cylinder, it is preferable that the concentration of NO in the
pressurized cylinder fall within the range of about 800 ppm to
about 1200 ppm. Commercial nitric oxide manufacturers typically
produce nitric oxide mixtures for medical use at around the 1000
ppm range. Extremely high concentrations of NO are undesirable
because accidental leakage of NO gas is more hazardous, and high
partial pressures of NO tends to cause the spontaneous degradation
of NO into nitrogen. Pressurized cylinders containing low
concentrations of NO (i.e., less than 100 ppm NO) can also be used
in accordance the device and method disclosed herein. Of course,
the lower the concentration of NO used, the more often the
pressurized cylinders will need replacement.
[0051] FIG. 9 also shows source of diluent gas 11 as part of the NO
delivery device 1 that is used to dilute the concentration of
nitric oxide (NO) for delivery to the gaseous nitric oxide (NO)
delivery device 1 through line 13. The source of diluent gas 11 can
contain N.sub.2, O.sub.2, air, an inert gas, or a mixture of these
gases. It is preferable to use a gas such as N.sub.2 or an inert
gas to dilute the NO concentration since these gases will not
oxidize the nitric oxide (NO) into NO.sub.2, as would O.sub.2 or
air. The source of diluent gas 11 is shown as being stored within a
pressurized cylinder. While the use of a pressurized cylinder is
shown in FIG. 9 as the means for storing the source of diluent gas
11, other storage and delivery means, such as a dedicated feed line
can also be used. The nitric oxide (NO) gas from the nitric oxide
(NO) gas source 7 and the diluent gas from the diluent gas source
11 preferably pass through flow control valve/pressure regulators
8, 120, to reduce the pressure of gas that is admitted to the
gaseous nitric oxide (NO) delivery device 1.
[0052] The respective gas streams pass via tubing 9, 13, to an
optional gas blender 15. The gas blender 15 mixes the nitric oxide
(NO) gas and the diluent gas to produce a nitric oxide
(NO)-containing gas that has a reduced concentration of nitric
oxide (NO). Preferably, the nitric oxide (NO)-containing gas that
is output from the gas blender 15 has a concentration that is less
than about 200 ppm. Even more preferably, the concentration of
nitric oxide (NO)-containing gas that is output from the gas
blender 15 is less than about 100 ppm. The nitric oxide
(NO)-containing gas that is output from the gas blender 15 travels
via tubing 160 to a flow control valve 17. The flow control valve
17 can include, for example, a proportional control valve that
opens (or closes) in a progressively increasing (or decreasing if
closing) manner. As another example, the flow control valve 17 can
include a mass flow controller. The flow control valve 17 controls
the flow rate of the nitric oxide (NO)-containing gas that is input
to the gaseous nitric oxide (NO) delivery device 1. The nitric
oxide (NO)-containing gas leaves the flow control valve 17 via
flexible tubing 180. The flexible tubing 180 attaches to an inlet
of the gaseous nitric oxide (NO) delivery device 1. The inlet for 1
might include an optional one-way valve that prevents the backflow
of gas.
[0053] In one preferred embodiment of the invention, the gaseous
nitric oxide (NO) delivery device unit 1 includes an NO sensor 140
that measures the concentration of nitric oxide (NO) in the treated
blood or fluid stream. The nitric oxide (NO) sensor 140 and nitric
dioxide sensor (15) preferably report the concentrations of NO and
NO.sub.2 to a controller within the gaseous nitric oxide (NO)
delivery device 1, for source gas flow control and alarm. The
sensors, 140, 15, can be chemilluminesence-type, electrochemical
cell-type, or spectrophotomentric type sensors.
[0054] In a similar embodiment, the present invention takes the
nitric oxide gas composition in line 18 and directs the nitric
oxide gas composition into a patient's breathing orifice, like a
nose and/or mouth. The delivery device can be a conventional gas
mask or plastic tubing.
[0055] FIG. 10 illustrates a block diagram representation of the
device 220, which can be an alternative version of item 17. The
device 220 has a power source 220 that provides sufficient voltage
and charge to properly operate the device 220. The device 220 also
has a main microprocessor 240 that controls the operation of a
solenoid valve 260, also within the device 220. The solenoid valve
260 operates in conjunction with operating parameters that are
entered via a data entry keypad 201 and the input from a pressure
sensor 280.
[0056] The operating parameters and the operating status of the
device 220 are displayed on an LCD display 210.
[0057] The device 220 has a pressure regulator 266. The pressure
regulator 266 reduces the pressure of the nitric oxide to less than
100 psi so it can be administered to the patient 2 without damaging
the patient's organs, in particular the lungs, from too much
pressure.
[0058] Calibrating the flow through the solenoid valve 264 is
obtained by selecting the pressure of the pressure regulator 266
and controlling the time that the solenoid valve 264 is open.
Thereby, the valve 264 allows a precise amount of nitric oxide gas
composition to be delivered through the gas delivery line 18, which
delivers the nitric oxide to the patient's breathing orifice(s).
The pressure sensor 280 is designed to detect a drop in pressure in
the gas delivery line 18, when the patient initiates a breath. This
pressure drop signals the main processor 240 to open the solenoid
valve 264 for a pre-programmed period of time. Among the parameters
that are programmed into the device are: Total Breaths, Start
Delay, Pulse Time, Pulse Delay, and Re-trigger Lock.
[0059] The programmable parameters are defined as follows:
[0060] Total Breaths: This parameter is the number of breaths
programmed into a run of the device 220. Each time a breath is
detected as identified above, a pulse of nitric oxide gas
composition is injected into the breath of patient 2. Breaths that
occur during a locked out time of the predetermined time frame are
not counted as breaths. After the programmed number of breaths are
counted, the program stops automatically and nitric oxide gas
composition is no longer injected into any breaths of the patient.
This number can be set anywhere from 0 to unlimited number of
breaths. If the number is set at 0 then the auto shutoff is
disabled and breaths will be injected with nitric oxide until the
user stops the device.
[0061] Start Delay: This parameter is the programmed delay time in
minutes that the user can set. The injection of nitric oxide gas
composition into each breath will begin automatically after "Start
Delay" minutes. It will then continue for the number of Total
Breaths and then the device 12 stops automatically.
[0062] Pulse Time: This parameter is the length of time that the
solenoid valve 264 will open for delivery of nitric oxide gas
composition. The resolution is 0.1 seconds and the range is 0.1 sec
to 0.9 seconds. If the regulator is set at 50 psi then each second
of the solenoid valve 264 opening 31 cc of nitric oxide gas
composition. If the regulator pressure is set at 30 psi then each
0.1 sec solenoid valve 264 opening represents 21 cc of nitric oxide
gas composition. For example, if the regulator is set at 50 psi and
the pulse time is set at 0.3 seconds then each detected breath will
be injected with a pulse of 0.3 seconds or about 90 cc of nitric
oxide gas composition.
[0063] Pulse delay: This parameter is the length of time that the
machine waits after detecting the beginning of a breath before
opening the solenoid valve 264 to inject a pulse of nitric oxide
gas composition. This allows the user to control the position of
the bolus of nitric oxide gas composition in the breath. For
example, if the user sets the solenoid valve 264 at 0.4 seconds,
then 0.4 seconds after the beginning of the breath is detected the
solenoid valve 264 will open to inject the nitric oxide gas
composition pulse.
[0064] Retrigger Lock: This parameter is the total time that the
machine will ignore new breaths beginning at the detection of a new
breath. If this parameter is set at 4.5 seconds then the device 220
will wait, after detecting a breath, for 4.5 seconds before
recognizing a new breath. Full or half breaths that are initiated
by the patient during this lockout time will not be counted and no
nitric oxide gas composition will be injected. If the breath is
initiated before the lockout expires and the patient is still
inhaling when the lockout expires then it will be recognized as a
new breath and it will be counted and injected with nitric oxide
gas composition.
[0065] The data entry keypad 202 contains five active button
switches defined as follows:
[0066] START/PULSE KEY: This key is used to start a run. The user
is required to confirm the start by pressing an UP key or to cancel
by pressing a DOWN key. When a run is in progress, pressing this
key will cause the run to pause. The run is then resumed by
pressing the UP key or stopping the run by pressing the DOWN
key.
[0067] UP key: This key is used to confirm the start of the run, to
resume a paused run and also to increment valve changes.
[0068] DOWN key: This key is used to cancel a started run, end a
paused run and also to decrement valve changes.
[0069] NEXT key: This key is used to switch screen pages on the LCD
display.
[0070] PURGE key: This key is used to open the solenoid valve 264
for two seconds to purge the line. This key is not active during a
run. The LCD display can display at least four screen pages,
defined as follows:
[0071] Each screen page displays a status line. The status
variations include NOT RUNNING, WAITING, RUNNING, PAUSED, PURGING
and START Pressed.
[0072] The main screen page has a row of asterisks on the top line.
This is the only screen available when the KEY switch is in the
locked position. This screen displays the total breaths detected
and also the total breaths that will cause the run to stop.
[0073] The second page shows two valves. The first is the START
DELAY valve. When the screen first appears the blinking cursor
shows the value, which can be changed by pressing either the UP or
DOWN key. By pressing the NEXT key switch the cursor to the second
value on the screen is TOTAL BREATHS.
[0074] The third page allows the user to change the PULSE DELAY and
the PULSE TIME.
[0075] The fourth page allows the user to change the RETRIGGER
LOCK.
[0076] In any case, this embodiment of the invention allows the
nitric oxide gas composition to be injected into a patient's lung,
preferably when the patient is inhaling, of a sufficient quantity
that nitric oxide is capable of penetrating both the epithelial and
capillary basement membranes to allow the nitric oxide to contact
the numerous blood cells to reduce pathogens in the blood system
and throughout the body.
[0077] Other embodiments of the dispenser apparatus of the nitric
oxide gas are disclosed in U.S. Pat. No. 6,432,077, which is hereby
incorporated by reference herein.
[0078] The dispenser can be any device that can apply nitric oxide
to any object that can contain a biofilm. The object being selected
from a group consisting of a medical device, a conduit for
industrial, home, office space, municipal, or medical purposes, and
an animal for internal and/or external applications.
[0079] Alternatively, this latest method can provide the nitric
oxide gas continuously, just not when the patient 2 inhales.
[0080] In addition the gNO can be directed into application systems
via pressurized cylinders to the specific target interface.
[0081] A number of experiments were undertaken to determine the
efficacy of various dose concentrations of exogenously applied
gaseous nitric oxide on the microorganism Burkholderia cenocepacia.
B. cenocepacia is an opportunistic pathogen that plays a role in
the formation of biofilms and can cause marked lung infections in
cystic fibrosis patients. B. cenocepacia is also associated with
increased rates of sepsis and death.
EXAMPLE
[0082] Objective: To determine if exposure to gaseous nitric oxide
(gNO) affects the ability of B. cenocepacia C8963 to form a biofilm
in a 96-well microtiter dish assay.
[0083] Methods: B. cenocepacia C8963, a non-mucoid isolate from a
cystic fibrosis (CF) patient, and C9343, a mucoid isolate from the
same patient, were spotted on Luria Broth agar and grown at
37.degree. C. overnight. Luria broth containing 0.5% (w/v) casamino
acids was dispensed into 96-well polypropylene microtiter dishes
(100 .mu.l per well) and the wells inoculated with the C8963 or
C9343 using a pin-inoculation device. Blank wells were not
inoculated. Dishes were incubated in a humidified, closed plastic
container for 24 hours at 37.degree. C. (experiment 1) or in the
outer chamber of the matrix incubator (a humidified incubator with
controlled air flow) for 27 hours at 37.degree. C. (experiment 2).
At 24 hours (experiment 1) or 27 hours (experiment 2), one dish was
processed for staining of the bacterial biofilms. The remaining
dishes were incubated in the inner treatment arms of the matrix
incubator at 37.degree. C. in the presence or absence of 200 ppm
gNO. One dish for each of the conditions (+gNO or -gNO) was
processed for biofilm staining at 32, 36, and 48 hours.
[0084] To stain biofilm growth, planktonic bacteria were removed
from the microtitre dishes by discarding media and cells. Biofilms
were washed to remove remaining non-adherent bacteria in two
successive tap water washes. Water was shaken from the wells and
the dishes inverted and tapped vigorously on a stack of paper
towels to remove as much water as possible. Adherent growth was
stained by adding 125 .mu.lof a 0.1% (w/v) solution of crystal
violet to each well and incubating at room temperature for 15
minutes. Crystal violet was discarded as for the previous washes
and excess stain was removed in three successive tap-water washes.
Excess water was removed by vigorous tapping as before and the
stained dishes allowed to air dry.
[0085] To quantitate biofilm formation, 200 .mu.l of 95% ethanol
was added to each well, incubated at room temperature for 15
minutes, and 125 .mu.l from each well was removed to a clean
flat-bottomed polystyrene microtitre dish. The absorbance at 595 nm
was read on a Bio-Rad Model 3550 Microplate Reader. The average
reading from "Blank" (uninoculated) wells containing only media was
subtracted from each "Test" well. The [Test-Blank] averages and
standard errors of the mean (SEM) were calculated for each
condition and time.
[0086] Results: As expected, the mucoid C9343 isolate did not form
biofilm under any conditions (Chart 1). This is consistent with its
previous behavior since the mucoid exopolysaccharide interferes
with adherence to surfaces (1). Overall, the non-mucoid C8963
isolate continued to form biofilm in the presence of gNO but growth
was lower than in the absence of gNO. C8963 biofilm growth in the
presence of gNO was greater than in the absence of gNO at 32 hours,
but by 36 hours, growth in the presence of gNO was significantly
lower than in the absence of gNO in both experiment 1 (Chart 1) and
experiment 2 (Chart 2). Biofilm growth remained consistently lower
in the presence of gNO for the remaining time points up to 48 hours
in both experiments (FIGS. 11 and 12).
[0087] In experiment 1, maximum biofilm growth occurred at
approximately 36 hours (Chart 1) but in experiment 2, maximum
biofilm growth did not occur until 48 hours or more (Chart 2).
[0088] Discussion: B. cenocepacia C9343 was a mucoid pulmonary
isolate from a CF patient that was previously shown to be a poor
biofilm former (1). B. cenocepacia C8963 was a non-mucoid pulmonary
isolate from the same CF patient and was shown to be a competent
biofilm former (1). To determine if exposure to gNO affected
biofilm formation by these organisms, both were grown in the
presence and absence of 200 ppm gNO. The organisms were grown for
24 hours without gNO to establish the biofilm, then exposed to gNO
or air only in the final 24 hours of the assay. C9343 served as a
negative control since it did not form biofilm under any condition.
The presence of gNO did not induce biofilm formation by this
organism. For this reason, C9343 was not included in experiment
2.
[0089] C8963 formed biofilm in two independent assays. In both
cases, introduction of gNO after 24 hours (experiment 1) and 27
hours (experiment 2) resulted in increased biofilm growth at 32
hours compared to biofilm growth in the presence of the carrier gas
(air). At first, gNO likely provides a source of nitrogen to the
growing bacteria, and that this is advantageous while the effective
concentration of gNO dissolved in the media is low. At all
subsequent time points, C8963 biofilm growth was lower in the
presence of gNO. This implies that once the concentration of gNO
equilibrated to 200 ppm within the biofilm system, it decreased the
amount of biofilm formation by C8963 compared to the carrier gas.
Thus, gNO acted as a nutrient when present at a low effective
concentration and as a biofilm inhibitor at higher effective
concentrations.
[0090] The maximum amount of C8963 biofilm formation was higher in
experiment 2 (A.sub.595=0.507) than experiment 1 (A.sub.595=0.441).
This difference could be due to different initial inocula received
or due to differences in the way the organisms were grown on the
first day of the experiment. A more detailed time-course and
repetition of the growth conditions from experiment 2 would answer
this question.
[0091] Gaseous NO affected the biofilm growth of B. cenocepacia
C8963 in two ways: at low initial concentrations it enhanced
biofilm growth and at the 200 ppm final concentration it inhibited
biofilm formation in the 96-well microtiter dish assay.
TABLE-US-00001 Time (h) C8 Con C8 + NO C9 Con C9 + NO C8 Con SEM C8
+ NO SEM C9 Con SEM C9 + NO SEM 24 0.147 0.147 -0.008 -0.008 0.007
0.007 0.001 0.001 32 0.111 0.315 -0.001 -0.005 0.014 0.018 0.001
0.001 36 0.441 0.337 -0.001 0.008 0.033 0.016 0.002 0.003 48 0.202
0.135 -0.003 0.002 0.015 0.008 0.001 0.002
[0092] TABLE-US-00002 Time (h) C8 Con C8 + NO C8 Con SEM C8 + NO
SEM 27 0.076 0.076 0.008 0.008 32 0.257 0.282 0.014 0.015 36 0.383
0.252 0.020 0.025 48 0.507 0.334 0.023 0.027
[0093] The term "ambient" refers to the gases that surround the
targeted interface.
[0094] If the nitric oxide is exposed to blood, the nitric oxide
can work within the blood for a very brief period of time until it
is modified by the hemoglobin. The modification is normally when
the nitric oxide attaches to the hemoglobin. Once attached, the
nitric oxide is normally not able to destroy a biofilm with the
present apparatus.
[0095] It is appreciated that various modifications to the
inventive concepts described herein may be apparent to those of
ordinary skill in the art without departing from the scope of the
present invention as defined by the herein appended claims.
* * * * *