WO2000009649A1 - Dispositif et procede de detection de micro-organismes - Google Patents

Dispositif et procede de detection de micro-organismes Download PDF

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Publication number
WO2000009649A1
WO2000009649A1 PCT/US1999/018649 US9918649W WO0009649A1 WO 2000009649 A1 WO2000009649 A1 WO 2000009649A1 US 9918649 W US9918649 W US 9918649W WO 0009649 A1 WO0009649 A1 WO 0009649A1
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WO
WIPO (PCT)
Prior art keywords
bottle
vessel
sensor
stopper
microorganisms
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Application number
PCT/US1999/018649
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English (en)
Inventor
Christopher S. Ronsick
Original Assignee
Akzo Nobel N.V.
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Publication date
Application filed by Akzo Nobel N.V. filed Critical Akzo Nobel N.V.
Priority to AU57764/99A priority Critical patent/AU5776499A/en
Publication of WO2000009649A1 publication Critical patent/WO2000009649A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M41/00—Means for regulation, monitoring, measurement or control, e.g. flow regulation
    • C12M41/30—Means for regulation, monitoring, measurement or control, e.g. flow regulation of concentration
    • C12M41/36—Means for regulation, monitoring, measurement or control, e.g. flow regulation of concentration of biomass, e.g. colony counters or by turbidity measurements
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M41/00—Means for regulation, monitoring, measurement or control, e.g. flow regulation
    • C12M41/26—Means for regulation, monitoring, measurement or control, e.g. flow regulation of pH
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M41/00—Means for regulation, monitoring, measurement or control, e.g. flow regulation
    • C12M41/30—Means for regulation, monitoring, measurement or control, e.g. flow regulation of concentration
    • C12M41/32—Means for regulation, monitoring, measurement or control, e.g. flow regulation of concentration of substances in solution
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
    • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/02—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving viable microorganisms
    • C12Q1/04—Determining presence or kind of microorganism; Use of selective media for testing antibiotics or bacteriocides; Compositions containing a chemical indicator therefor

Definitions

  • the present invention provides a method and device for detecting/monitoring changes in pH, gas production (C0 2 , NH 2 , H 2 S, etc.) or volatile acid production of a specimen using a growth medium and a sealed container without entering the container after the sample is prepared and added to the container.
  • a gas permeable membrane with a gas impermeable removable seal thereon is provided in a wall of the vessel. If the microorganism to be detected is an anaerobic organism, then the gas impermeable seal is left in place. If the microorganism to be detected is an aerobic organism, then the gas impermeable seal is removed so as to allow the passage of oxygen into the vessel.
  • the gas permeable membrane is constructed so as to withstand high positive or negative pressure within the vessel, and/or to allow the passage of oxygen into the vessel while at least partly restricting the passage of carbon dioxide to outside of the vessel.
  • a sensor is provided which changes due to differences in concentrations of gas, volatile acid and/or pH within the vessel (e.g., within the medium in the vessel) .
  • Patent 4,152,213 a method is claimed by which the presence of oxygen consuming bacteria in a specimen is determined in a sealed container by detecting a reduction in the amount of oxygen in the atmosphere over the specimen through monitoring the pressure of the gas in the container.
  • U.S. Patent 4,073,691 provides " a method for determining the presence of biologically active agents, including bacteria, in a sealed container containing a culture medium by measuring changes in the character of the gaseous atmosphere over the specimen after a period of time.
  • a method for non-invasive detection of C0 2 changes in the gaseous atmosphere is taught by Suppman et al , as disclosed in EPO application 83108468.6, published April 4, 1984.
  • the methods and apparatus described in these and other publications all require either a radiometric method or the invasion of the sealed container to measure changes in the gaseous atmosphere after culturing or require special materials that permit infra-red light to pass.
  • the biologically active agent is an aerobic organism
  • a system must be provided for insuring sufficient oxygen within the vessel so that biological activity can take place.
  • One way of providing oxygen to the vessel is by adding oxygen to the atmosphere within the vessel containing the culture medium, at the time of manufacture of the vessel. Then, when a specimen is added to the vessel by the user of the vessel, oxygen will already be present within the vessel. (A problem with this method, however, is that the shelf life of such vessels containing the pre-added oxygen and culture medium, is short.)
  • Another method for providing oxygen to the vessel when the microorganism is an aerobic organism is by "spiking" the vessel at the time of culturing the organism. Often, a needle or a cannula is pierced through a stopper on the vessel so as to allow a free flow of oxygen into the vessel during culturing.
  • One problem with this method is that it requires an extra step, some skill in piercing the vessel by the user, and some danger of specimen contamination or of injury to the user by the needle.
  • the method of culturing includes shaking for better oxygenating the culture medium, care must be taken so that the liquid culture medium does not leak outside the vessel through the needle.
  • a pierced vessel would not allow for control of the passage of carbon dioxide from out of the vessel (changes in carbon dioxide within the vessel being desirable for indicating the presence of a particular microorganism) .
  • the present invention relates to a device and method for detecting the presence of microorganisms in clinical specimens, such as blood or other body fluids, by culturing the specimens with a sterile growth medium in a transparent sterile container having a gas permeable membrane.
  • the presence of microorganisms is determined by detecting or measuring changes in the pH of the specimen or the production of gases (e.g., C0 2 ) or volatile acids within-, the container using a disposable sensor affixed to the interior surface of the container.
  • gases e.g., C0 2
  • microorganisms can be detected in the presence of interfering materials, such as large concentrations of red blood cells, through non-invasive means.
  • a gas impermeable seal can be removed from the gas permeable membrane when the vessel is to be used for culture of aerobic organisms. Otherwise, if the seal is left in place, the vessel can be used for the culture of anaerobic organisms .
  • the gas permeable membrane allows for the passage of oxygen into the vessel, preferably withstands high positive or negative pressures and restricts to a sufficient degree the passage of carbon dioxide to outside the vessel, and fully restricts the passage of liquid medium to outside the vessel, even during autoclaving and shaking of the vessel.
  • Figure 1 Blood culture instrument
  • This drawing shows the overall appearance of the functional part of the instrument, the detector assembly, with (1) the vessel, (2) sensor, (3) culture medium, the (4) light source, (5) photodetector, and the associated electronics including (6) current source, (7) current to voltage converter and (8) low pass filter.
  • each detector assembly consists of a photodiode in a countersunk hole and one or more LED's arrayed such that light falls on the surface to be viewed, but not directly onto the detector itself.
  • the electronic circuits in this embodiment include amplifiers and filters to condition the signals from the detectors, multiplexers to select among the signals available, and constant current sources for the illuminators.
  • the entire device is placed on an agitator inside an incubator, which provides a suitable environment for microbial growth and excludes room light from the photodetectors .
  • FIG. 3 pH and atmosphere change with microbial growth
  • the instrument was used to detect microbial growth by both pH change and by gas or volatile production.
  • This figure shows the change in pH and in C0 2 resulting from growth of the bacterium, E_;_ coli .
  • this system can be used to detect the growth of a very wide range of microorganisms.
  • This figure shows the detection of gases (C0 2 ) and/or volatile acids produced during the growth of E . coli, a Gram negative bacterium; S_;_ pyogenes , a Gram positive bacterium; P_;_ aeru ⁇ inosa, a Gram negative non-fermenting bacterium;
  • the units indicate relative gas concentration in the medium based on C0 2 concentration at the beginning of the assay.
  • Figures 5A - 5D illustrate one embodiment of the permeable membrane, where the permeable membrane is disposed within a cavity in a stopper of the bottle having the sensor therein.
  • Figure 6 is a cross-sectional view of a stopper having a particular permeable membrane and support grid.
  • Figure 7A is a top view of one of the support grids for the permeable membrane
  • Figure 7B is an exploded view the membrane supports .
  • Figures 8A - 8C are views of membrane support grids for holding a membrane molded with an O-ring.
  • Figure 9 is a cross-sectional view of the culture bottle of the present invention having the sensor and permeable membrane therein.
  • Figure 10A illustrates the culture bottle with the bottle opening in the center of the bottle cap, and in Figure 10B, the bottle -access opening is off-center.
  • Figure 11 illustrates the culture bottle of the present invention having the sensor therein, as well as the gas permeable membrane and an impermeable removable seal .
  • Figures 12A - 12C illustrate an additional embodiment of the gas permeable membrane within the cap of the culture bottle.
  • FIGS 13A and 13B illustrate an embodiment of the invention where the grid and permeable membrane are C-shaped.
  • Figure 14 is a cross-sectional view of particular features of the culture bottle cap and retaining ring for the permeable membrane .
  • Figures 15A and 15B are cross-sectional illustrations -of additional embodiments of the retaining ring for the permeable membrane .
  • Figure 16 is an illustration of the overall culture bottle.
  • the apparatus and device of the invention provide a non- invasive means for detecting the presence of microorganisms in clinical specimens, such as blood samples or other body fluids, and in non-clinical specimens by measuring an increase in metabolic products produced by microorganisms .
  • the specimen is added to a specially formulated medium that enhances the production of certain microbial metabolic products, which are detected by a unique disposable sensor located at the bottom of a culture container or in the sealing means of the container.
  • the sensor comprises a solid composition or membrane, which is referred to as an attachment or support medium, with an indicator medium immobilized on' or within it.
  • the sensor is located flush against the inside surface of a container, in the sealing means used to seal the container or attached to the sealing means, such that the indicator medium is visible from outside. It may be affixed to the container to prevent cells, proteins, other solids or other opaque or colored components from getting between it and the container surface. In certain embodiments the sensor is separated from the specimen and its growth medium by a membrane or solid layer that permits the passage of gas molecules but prevents passage of ions.
  • One embodiment of this invention comprises a sealing means, such as a cap or lid, which may be transparent or which may have a transparent section.
  • the sensor can be placed in proximity to the transparent cap or section of cap or is made part of the cap. When the cap is used to seal the container, the changes in indicator are read through the transparent sealing means .
  • An advantage seen to this embodiment is that this may be the most economical way to produce the containers on a large scale.
  • the sealing means may also be made of a material, such as a polymer, which contains encapsulated indicator micelles.
  • a transparent section in either the container or the sealing means is not needed, as long as the material is permeable to the metabolic products of the microorganisms and the changes in the indicator are visible on the surface of the sealing means.
  • Microorganisms in specimens of body fluids, such as blood, containing as few as 1 organism per milliliter, can be detected using this invention. Such specimens may require up to 7 days incubation before the population of organisms reaches a critical level and where an increase in metabolic products can be measured.
  • concentration of 10 6 CFU/ml for certain types of organisms provided measurable changes in pH or C0 2 . All organisms showed measurable results at concentrations of 10 7 to 10 8 CFU/ml.
  • the sensor is useful in that: 1) the microbial metabolic products are measured in the liquid phase of the culture bottle rather than in the atmosphere over the specimen, 2) because the unique disposable sensor is affixed to the interior surface of the bottle or the closure or sealing means or attached through the outside of the closure or sealing means, measurements can be made from outside the transparent wall of the bottle or the sealing means without having to violate the integrity of the bottle, 3) the external measurements can be made by visual inspection or with an instrument that measures by reflectance, 4) opaque or colored components in the specimen do not interfere with the ability of the sensor to detect changes or the measurement of those changes, and 5) a high concentration of indicator molecules is maintained within a small volume in the sensor, i.e., within the polymer emulsion or on the membrane, such that a color change can be easily observed.
  • the nutritional components that make up a complex microbial medium influence the metabolic pathways used by microorganisms .
  • Organic acids, bases and various gases are produced in proportions dependent on the nutrients available. These products also vary from species to species of microorganism. The presence of these products in the liquid medium can change its pH.
  • the sensors used in the invention contain pH sensitive indicators that give a measurable change in response to a pH change in the environment . In the embodiment in which the pH sensor is covered by a gas- permeable, ion- impermeable membrane, the presence of gases that affect the pH of the indicator, such as C0 2 , is measured.
  • gases that affect the pH of the indicator such as C0 2
  • microbial growth can be detected either by changes in pH of the liquid culture medium or by measurement of gases dissolved in the medium, both indications are caused by metabolic gaseous products produced by microorganisms. • Carbon dioxide is a common metabolite produced by most organisms and, therefore, is the preferred metabolite for detection of microbial growth.
  • the C0 2 and pH sensors share two common components, a molecular species useful as a pH indicator and an attachment/support medium.
  • the pH indicator can be attached either covalently or non- covalently to the support medium. Alternately, the indicator can be encapsulated within a polymer matrix such as being emulsified within a polymer matrix prior to curing. To perform as a pH sensor, indicator must be in contact with the liquid medium.
  • the C0 2 sensor has a third component, a semi-permeable substance that completely separates the indicator membrane from the specimen and growth medium.
  • the semi-permeable layer may be a separate membrane, alternatively, the cured polymer adjacent to the specimen and growth medium may form an integral semi-permeable membrane.
  • sensors are affixed inside a suitable transparent vessel or a transparent sealing means with an appropriate adhesive. They may also comprise an integral part of the sealing means or be affixed to the sealing means or within the vessel as an indicator emulsified within a polymer matrix cured in situ. They can also be placed outside the container, as long as a method is provided that allows the metabolic products of the microorganisms or the growth medium containing the specimen to contact the sensor.
  • a variety of different fluorescent and visible pH indicators can be used as the active molecular species in pH or C0 2 sensors . Generally, the only limitations on the selection of indicators are the requirements that they have acceptable dynamic pH ranges and wavelength changes that are readily detectable by existing front surface fluorescence or reflectance technologies.
  • Sensors for detecting pH changes in the culture medium according to the invention preferably exhibit a change in fluorescence intensity or visible color over a pH range of about 5.0 to about 8.0.
  • Indicators for the C0 2 sensor should exhibit a change in fluorescence intensity or visible color preferably between about pH 13 and about 5 , and most preferably between about pH 13 to about 9 , in order to detect changes in C0 2 concentration. Only certain pH indicator molecules can be bound covalently or non-covalently to a support medium and retain their pH indicating properties. Indicators belonging to the xanthene, phenolphthalein and phenolsulfonphthalein groups are useful. Examples of these include fluorescein, coumarin, phenolphthalein, thymolphthalein, bromothymol blue, thymol blue, xylenol blue and ⁇ -naphthol benzein.
  • the attachment/support medium can be a substance such as cellulose, to which a pH indicator can be covalently attached using organic reactions.
  • Non-covalent attachment of pH indicators can be achieved using ionic support materials, such as nylon membranes that have a positive or negative zeta potential.
  • Other ionic support materials that can be used are positive or negatively charged ionic resins, such as diethylamino ethyl (DEAE) resin or DEAE cellulose.
  • Pretreatment of the support material with a protein may be required if the indicator membrane is to be in direct ..contact with the microbial growth medium.
  • the pH indicator sensors directly detect pH changes due to the pH environment of the microbial growth medium.
  • these sensors can be made to selectively react to gases (e.g., carbon dioxide, ammonia) in the liquid growth medium by covering them with a selectively semi-permeable composition or membrane, such as silicone, latex, teflon, or various plastics characterized by the capacity to selectively permit the diffusion of a gas while preventing the passage of ions.
  • gases e.g., carbon dioxide, ammonia
  • a selectively semi-permeable composition or membrane such as silicone, latex, teflon, or various plastics characterized by the capacity to selectively permit the diffusion of a gas while preventing the passage of ions.
  • the polymer forming the matrix can act as the semi-permeable barrier that permits the passage of gases but not ions.
  • the C0 2 sensor is comprised of four components.
  • the first component is a visual or fluorescent pH indicator, which is reactive at the pH range between 6 and 10. Examples of indicators meeting these criteria are bromothymol blue, thymol blue, xylenol blue, phenolphthalein, coumarin, and fluorescein.
  • the second component is sodium hydroxide or an equivalent base, which maintains an optimal pH environment for detection of C0 2 by the selected pH indicator.
  • the third component is glycerol or an equivalent emulsifier, which can produce droplets of indicator solution emulsified within the uncured polymer.
  • the fourth component is the uncured polymer such as silicone, which maintains a proper environment for the indicator.
  • Any polymer can be used that does not affect the chemical activity of the indicator, either from its own chemical or physical properties or its requirements for curing, as long as it is permeable to gases but not ions, and does not have these properties altered when subjected to sterilization.
  • Other silicone polymers that are also satisfactory are those that are cured by high temperature, by catalytic activity, or by ultraviolet vulcanization.
  • An emulsion is prepared from the four components and the polymer is cured to form a semipermeable matrix around the droplets of pH indicator, which permits selective diffusion of C0 2 and other gases from the liquid microbial growth medium, resulting in a measurable change in the indicator.
  • the sensor can be prepared separately, such as in a mold, cured, and then attached to the culture bottle with an appropriate adhesive, such as a silicone adhesive. Alternatively, and preferably, the sensor is formed on the bottom of the bottle and cured in situ. After curing the bottle with the sensor is sterilized, such as by autoclaving. Conveniently, the growth medium can be introduced into the bottle before autoclaving and also • sterilized by that process.
  • the culturing of aerobic microorganisms requires a supply of oxygen within the culture bottle.
  • automated, semi- automated and some manual culture bottles are transiently vented in some manner, for example by insertion and removal of a venting device (a venting spike or needle, for example) , loosening and/or exchange of a cap, or mechanical withdrawal of gas from and forced gas return to the bottle.
  • a venting device a venting spike or needle, for example
  • Some non-agitating manual systems employ an indwelling venting device that remains in place for the duration of testing.
  • a selective hydrophobic barrier is provided in the bottle which allows passage of ambient atmosphere into the culture bottle while preventing leakage of media and specimen out of the bottle.
  • the permeable barrier of the present invention preferably prevents contaminants, such as contaminating organisms, from entering the bottle, as well as discourages the passage of carbon dioxide out of the bottle.
  • Preferred materials for the permeable membrane/hydrophobic barrier include silicone, polypropylene, fluorinated ethylene propylene, low density polyethylene, Porex, polytetrafluoroethylene and polymethylpentene membranes and materials as selective barriers (polymethylpentene having negligible C0 2 permeability and high 0 2 permeability -- 270 (cc-m) /sec-cm 2 -cmHg x 10 "10 ) .
  • Other permeable membranes are also feasible if sufficiently permeable to oxygen, preferably if the membrane discourages the passage of carbon dioxide out of the bottle, and if the material is autoclavable and resistant to leaking under pressure.
  • materials lacking sufficient rigidity can be reinforced by forming a support structure integral with the permeable membrane, or by placing the permeable membrane on or between support means .
  • Adhesives can be utilized in some embodiments of the present invention for securing the permeable membrane to a support material.
  • Adhesives such as Elmers Stix-All can be used to seal Porex plugs securely within a stopper.
  • Adcare adhesive though not sufficient for providing a hermetic seal, is permeable to gas and can be used to adhere a membrane to a Porex plug in a sandwich-like configuration.
  • a hermetic seal is provided for covering the gas permeable membrane . The impermeable seal covers and hermetically seals the permeable membrane during bottle preparation, gassing, autoclaving and storage.
  • the seal is removed at the time of bottle inoculation (if the microorganism is aerobic) to allow exchange of gasses during incubation of the media bottle.
  • plastic coated aluminums are generally suitable.
  • a pore size of 0.2 microns or less is desirable for preventing contamination of the media by ambient organisms during the transfer of gas across the membrane.
  • a support system for securing the gas permeable membrane in place is needed, and the same or a separate support structure should support the gas permeable membrane if necessary, against interior pressure and vacuum effects due to autoclaving.
  • PTFE with an internal polypropylene support grid is particularly beneficial for use as the gas permeable membrane.
  • FIGs 5A to 5D One embodiment of the invention is illustrated in Figures 5A to 5D.
  • a stopper 10 such as illustrated in Figure 5A, is provided with an internal cavity 12 as illustrated in Figure 5B .
  • a filter 14 is disposed within the cavity of the stopper, " with a gas impermeable removable seal 16 disposed adjacent filter 14 (see Figure 5C) .
  • Gas permeable membrane 14 can be, for example, a Porex filter.
  • a gas impermeable seal 16 is provided above two supports 20, 21 having a gas permeable membrane 22 therebetween.
  • a support grid 25 is provided in both upper support 20 and lower support 21.
  • the two supports 20, 21 are snapped together, the gas permeable membrane 22 is securely held therebetween.
  • a membrane 28 held between supports 20 and 21 can be molded with an "O-ring" seal 29 so as to improve the impermeability of the membrane to the passage of liquids out of the culture bottle.
  • the supports and membrane therebetween are provided in a stopper, which is likewise provided in a culture bottle having the sensor of the present invention.
  • the gas permeable membrane is not provided in the stopper, but rather adjacent the stopper in an upper portion of the culture bottle.
  • a gas permeable membrane 31 is provided below a gas impermeable removable seal, such as a foil seal 32.
  • a stopper 23 is provided such as a 20mm stopper, as well as a metal seal 34 and a flip top 35.
  • Bottle 36 can be a plastic bottle with sensor 37 and membrane 38 disposed at the bottom thereof, as discussed previously.
  • the stopper 33 which can be a 12mm stopper, is disposed in a center position of plastic cap 30 on bottle 36.
  • the stopper can be provided off-center on the cap.
  • a foil seal 32 As illustrated in Figure 11, above membrane 31 is disposed a foil seal 32.
  • Seal 32 can be a plastic coated aluminum. Of course other materials for the removable seal are contemplated as long as such materials have sufficient impermeability and ease of removability from the bottle at the time of culturing.
  • a tab 39 not adhered to the bottle is provided as part of seal 32, for ease of grasping and removing the seal.
  • a grid 40 is formed within the bottle cap itself.
  • a plurality of holes 41 are formed through the bottle cap.
  • layers 43 of Porex can be disposed adjacent the gas permeable membrane 45 and held in place by retaining rings 42. This assembly, as seen in Figure 12B, is disposed beneath grid 40 of the bottle cap.
  • the grid can be such as grid 47 illustrated in Figures 13A and 13B, where the plurality of holes 41 are in a C-shape around the central stopper 33. In this way, the surface area of the gas permeable membrane 48 disposed below the grid, can be increased.
  • the culture bottle of the present invention can be manufactured in a number of ways. In a preferred embodiment, the culture bottle and the culture bottle cap are manufactured separately, and then subsequently adhered together, such as by gluing the top onto the bottle . Another method of adhering the bottle top and bottle is by spin welding, where the bottle top and bottom are rotated relative to each other such that the generated friction melts the plastic, which resolidifies with the top and bottle thus welded together.
  • bottle cap 59 is provided with external surfaces 50, 51 and 52, each having a different external diameter.
  • Surface 52 is of a dimension so as to be flush with the outer circumferential surface of the bottle.
  • Surface 50 the surface with the smallest external diameter, fits exactly within the bottle, such that the internal diameter of the bottle and the external diameter defined by surface 50, are essentially the same.
  • Surface 51 has an external diameter greater than the internal diameter of the bottle. As such, during spin welding, surface 51 having a greater diameter than the internal diameter of the bottle, creates a high degree of friction as the bottle cap is spun and pressed into the bottle. In this way, the bottle top and bottle are firmly adhered to each other.
  • membrane 58 is held in place by retaining ring 54 having a projection 56 for improved impermeability to fluid flow around the retaining ring and membrane.
  • Another method of adhering the bottle cap to the bottle is by ultrasonic welding.
  • the retaining ring for holding the gas permeable membrane in place can also be adhered by ultrasonic welding.
  • the retaining ring 54 illustrated in cross-section is provided with an annular peak 60. When ultrasonic energy is applied at point 65 directly below peak 60, the retaining ring 54 can be welded in place.
  • a sloped internal surface 66 can be provided to decrease the likelihood of liquid being trapped in the retaining ring during shaking of the bottle.
  • a sensor 37 is disposed in the bottom of the culture bottle, with membrane 58 held in place by retaining ring 54. Also illustrated is an annular recess 70 for excess melted plastic generated during spin welding of the cap to the bottle due to the melting of surface 51 (see Figure 14) . Due to annular recess 70, melted plastic does not flow to exterior surfaces of the bottle cap or bottle.
  • the gas permeable membrane is more permeable to oxygen (entering the bottle) than to carbon dioxide (exiting the bottle) .
  • a membrane at least partially impermeable to carbon dioxide will allow for a higher sensitivity of the sensor.
  • a membrane more permeable to oxygen than carbon dioxide is not necessary for the present invention.
  • a culture bottle would not be workable that allows for a free flow of carbon dioxide out of the bottle as well as requires carbon dioxide within the bottle for altering the sensor therein (so as- to indicate the presence of, for example, a ' microorganism) .
  • the sensor acts as some type "sink" for the carbon dioxide in the bottle such that the sensor will properly indicate the presence of a microorganism even with the gas permeable membrane as part of the bottle.
  • Bottles were prepared and gassed with 100% nitrogen. Representative bottles were unsealed by removing the heat seal and allowed to shake on a rotary shaker at room temperature for 1 hour. At the end of the time period, p0 2 was measured on a blood gas instrument and readings compared to a control bottle without a permeable membrane and to a predetermined p0 2 of 20 - 30 mm Hg (found in previous testing to represent bottles gassed with 100% nitrogen) . An increase in the p0 2 of these bottles as compared to the control and reference value indicated permeability of the material to oxygen within 1 hour.
  • Stoppers were prepared with test materials as described without a heat seal then crimp sealed onto bottles containing water., A 60cc syringe was fitted with a 16g needle, the plunger pulled back to the 50cc mark, and the needle inserted into the stopper. Pressure was then applied to the plunger until leakage occurred through the material. When leakage occurred, the amount of pressure required was determined by subtracting the plunger position from 50.
  • Representative bottles were incoculated. Bottles were prepared as described above. Representative bottles were then inoculated with C. alb i cans , P. aeruginosa and M. luteus , 2 bottles per test material using standard growth performance protocols. Negative control bottles were prepared with an atmosphere of 5% carbon dioxide in nitrogen. These bottles were not transiently vented and did not have a permeable membrane. Positive control bottles were prepared in the same manner but vented or were standard aerobic adult bottles. Inoculated bottles were left in the BTA for 3 days and readings were then graphed. By comparison of the graphs, it was determined that M. luteus was the best indicator of oxygen passage into the bottles at a rate that did not inhibit growth. Also, since this was a low carbon dioxide producing organism, the effect of carbon dioxide diffusion could be observed.
  • Bottles were filled with 40ml of media, overlaid with heat-sealed stoppers, gassed with 100% nitrogen and autoclaved for 12 minutes at 121°C, 15 psi. After equilibration for a minimum of 24 hours, p0 2 of representative bottles was measured on the NOVA STAT 3 using standard protocols. Remaining bottles were held at room temperature for a period of time to determine if the heat seals allowed leakage of oxygen into the bottle. Comparison of the p0 2 initially vs. control bottles without a cored stopper vs. end p0 2 after the holding time determined if the material was permeable to oxygen .
  • the ⁇ gas permeable membrane material is attached to the cap of the bottle by heat sealing. A removable seal is then attached over the permeable material, outside of the bottle. The cap is welded into place on the bottle. In a separate port, the sensor is added and heat cured. Subsequently, media is added to the bottle, and the headspace of the bottle is evacuated and replaced with an appropriate gas mixture. A residual vacuum can then be applied. A stopper is secured in place with a seal, after which the assembled bottle is autoclaved.
  • the gas permeable membrane structure, as well as the gas impermeable removable seal are constructed so as to withstand pressures of from 5 to over 30 psi.
  • the permeable membrane structure and removable seal are capable of withstanding pressures of at least 15 psi.
  • the gas permeable membrane structure and the removable seal are each constructed so as to be capable of withstanding pressures of from 15 to 25 psi, and in one preferred embodiment, the membrane and seal are constructed so as to withstand pressures of 25 psi or more.
  • the bottles are allowed to cool, and can then be labeled for packaging and shipping.
  • a blood sample is taken from a patient such as by using a butterfly needle with tubing secured to a vacutainer adapter. The top of a stoppered port is decontaminated and the adapter is slipped over the port. Then, the bottle will draw the appropriate amount of sample.
  • the bottle Once inoculated, the bottle is identified and ready for culturing. If the bottle is to be used for aerobic culture, the removable seal is peeled off, exposing the gas permeable membrane and thus allowing for the free passage of oxygen into the bottle .
  • the bottle can be placed into an automated culturing instrument such as the BacT/Alert instrument by Organon Teknika. The bottle is incubated at a temperature of 35 - 37°C.
  • the culture bottle of the present invention is particularly suitable for being shaken during culturing as the gas permeable membrane allows for a free flow of oxygen into the culture bottle but at the same time restricts fluid flow out of the bottle.
  • the present invention is particularly suitable for vigorous shaking, as well as shaking the culture between upright and inverted positions . A spiked bottle from the prior art would leak and thus could not be shaken or rocked in this way.
  • a hydrophobic vent is provided within a rubber stopper that is sealed with a crimp seal to the bottle .
  • a hydrophobic vent allows for transmission of gases into the bottle, but is a barrier for water liquids and microorganisms.
  • the atmosphere in the bottle does not leak through the vent since the vent is covered with a rubber ring. The ring is removed after inoculating the bottle and the vacuum in the bottle draws in air.
  • adhesives and heat need not be used for sealing the vent. Rather, a mechanical seal via a rubber stopper is used. The hazard of venting the bottle with a needle is also avoided.
  • the atmosphere in an aerobic bottle could be an inert atmosphere, such as nitrogen, rather than air, thus prolonging storage life. The inert gas would be displaced with air through the vent, after inoculation, allowing aerobic microorganisms to grow.
  • Fig. 17 is an exploded view
  • Fig. 18 illustrates a quarter cut-away of the assembly.
  • the insert is first placed into the finish of the blood culture bottle. It is injection molded of a rubber material and contains a flange that rests on the bottle rim and several channels passing all the way through.
  • the vent in the shape of a ring, is placed in a slight recess at the top of the insert. This can be a hydrophobic vent with a 0.2 micrometer cut- off allowing gases and vapors, even water vapor, to transpire, but not water itself.
  • the small pore size blocks microorganisms from passing out of the bottle.
  • the vent cover On top of the vent and insert is placed the vent cover. Just like the insert, this can be an injection molded rubber piece and also has channels that are in line with the insert channels. During storage, the channels are blocked by a channel stopper which has a 360 degree revolved prong that fits into the vent cover (Figs. 17 and 18) . This may be made from a molded plastic or a soft rubber material . The prongs are not sharp and thus are not a puncture hazard to the operator.
  • the channel stopper seals the atmosphere during storage and also during autoclaving, however it can easily be removed by hand after the bottle is inoculated to allow for fresh air to be drawn into the bottle. Thus, the stopper gets around the difficulty of covering the vent during autoclaving. Rubber and plastic materials are preferred for withstanding autoclaving ⁇ e.g. 121 degrees C for 15 min.) .
  • the insert and vent cover channels are designed such that there is no possibility of blocking a free path from the bottle up through the assembly by overlapping a channel with a solid area of rubber.
  • a channel with a solid area of rubber For example, in Fig. 17, there are four insert channels that subtend twice the angle of those in the vent cover. Regardless how the insert is rotated in relation to the vent cover, at least half the area of the vent cover channels will not be blocked. To maximize the amount of channel area exposed, it is desirable to have as large a channel area as possible. If the channels subtend too large an angle of the vent cover, the center could deform under any pressure build-up in the bottle, or if it is pierced with a needle.
  • the vent may be used to vent the bottle transiently right after inoculation or to continuously vent the bottle during incubation (transient venting is inserting a sharp object through the stopper to allow air into the bottle; continuous venting is leaving a venting mechanism in the stopper during incubation of- the bottle) .
  • transient venting the vacuum in the bottle draws in air within a few seconds, a further increase in area will not increase the amount of dissolved oxygen after the short venting process.
  • a larger channel area may help increase the growth rate by allowing air to enter the bottle to make up for the uptake by aerobes .
  • the vent ring is compressed between the insert and vent cover.
  • the entire rim of the vent is in contact with the vent cover and insert, and this seal blocks the transport of gas .
  • Directly through the vent is the only route for gas into or out of the bottle. Because the vent blocks water and microorganisms from passing, there is no danger of contaminated samples leaving the bottle.
  • Fig. 19 sections through the channels of the vent cover and insert are illustrated.
  • the section on the left in Fig. 19 is through the insert, below the flange that sits on top of the bottle.
  • the section on the right is taken through the vent cover just up from where the vent is placed.
  • Fig. 20 illustrated a half cut-away of the vent cover and insert. The vent is omitted for clarity.
  • Fig. 21 is a cut-away of the vent assembly crimp sealed into a bottle. The crimp seal not only holds the assembly in the bottle, but also presses the vent cover and insert together to seal in the vent .
  • Figs . 22a and b are illustrations of two section through the vent assembly and bottle.
  • Fig. 22a is a section 30 degrees rotated from Fig 22b.
  • Fig. 22a shows a clear channel through the insert passing through the vent and finally through the stopper cover. In this figure the channel cover is in place, but would be removed after inoculating the bottle.
  • Fig 22b illustrates that there are sections of the assembly in which a clear channel does not pass all the way from the interior of the bottle out through the vent cover.
  • the invention allows for ease of assembling the stoppers and vent.
  • the vent cover depicted in Figs. 17-22 can be a serum type stopper, but it could also be a lyophilization stopper to allow for introducing gas into the bottle similar to methods used with standard lyophilization stoppers.
  • the channel stopper is placed into the recess in the vent cover, these two parts are then placed into the insert.
  • the rotation of the insert to the vent cover is not critical.
  • the bottle can be flushed with gas and a vacuum applied.
  • the vent cover and connected channel stopper are then pressed down and held in place by the vacuum.
  • a crimp seal is applied. The crimp seal will hold the vent cover and insert together which seal the vent.
  • the bottle can then be autoclaved and labeled.
  • the channel stopper would be a clear indicator that a vent is directly below, so that the vent would not be punctured.
  • a physical deterrent would be offered if the channel stopper were made from a hard plastic material rather than rubber.
  • the channel stopper which has blocked the channels during storage would be removed by hand, leaving the channels free for air to be drawn into the bottle, this channel stopper remains out of the assembly while the bottle is incubated.
  • the crimp seal and stopper could be substituted with a crimp seal which has a rubber tear-away septum under the seal. This crimp seal would completely cover the top of the vent cover, except in a small section in the center in which only the septum would be exposed. The sample would be inoculated through this septum and through the vent cover. then the septum would be ripped off to expose the vent to the atmosphere outside the bottle. Air would be drawn into the bottle due to the vacuum as described above.
  • both the sensor and permeable membrane can be provided in other parts of the culture bottle, other than disclosed.
  • the permeable membrane could be disposed in a side wall of the bottle, or the sensor could be disposed within the cap of the bottle.
  • a plurality of sensors or membranes might be provided.
  • other arrangements for support grids and sizes and shapes of permeable membranes would also be within the scope of the invention.
  • other materials for the permeable membrane and impermeable removable seal would also be within the scope of this invention.

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Abstract

La présente invention concerne un procédé et une enceinte scellable stérilisable permettant de détecter la présence de micro-organismes dans un échantillon, cette enceinte comprenant un milieu de culture liquide et un capteur contenant un milieu indicateur. Un trou hydrophobe (3) est pratiquée dans un bouchon de l'enceinte stérilisable. Si le micro-organisme à détecter est un organisme anaérobie, l'enceinte est maintenue hermétiquement scellée par le bouchon. Si le micro-organisme à détecter est un organisme aérobie, on retire alors le bouchon à passage (1) pour permettre au gaz de passer dans l'enceinte. Par ailleurs, on détecte depuis l'extérieur de l'enceinte les modifications du milieu indicateur provoquées par la modification du gaz à l'intérieur de l'enceinte, ainsi que la production d'acide volatil ou la concentration du pH dans le milieu en question.
PCT/US1999/018649 1998-08-14 1999-08-16 Dispositif et procede de detection de micro-organismes WO2000009649A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU57764/99A AU5776499A (en) 1998-08-14 1999-08-16 Device and method for detecting microorganisms

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US13431498A 1998-08-14 1998-08-14
US09/134,314 1998-08-14

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3559834A (en) * 1969-06-18 1971-02-02 Walter S Taylor Closure for aging still wine in bottle
US3951293A (en) * 1974-01-24 1976-04-20 Riedel-De Haen Aktiengesellschaft Gas-permeable, liquid-tight closure
US5180073A (en) * 1991-05-17 1993-01-19 Biomedical Polymers, Inc. Permeable cap for flask
US5795773A (en) * 1995-03-24 1998-08-18 Akzo Nobel N.V. Device for detecting microorganisms

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3559834A (en) * 1969-06-18 1971-02-02 Walter S Taylor Closure for aging still wine in bottle
US3951293A (en) * 1974-01-24 1976-04-20 Riedel-De Haen Aktiengesellschaft Gas-permeable, liquid-tight closure
US5180073A (en) * 1991-05-17 1993-01-19 Biomedical Polymers, Inc. Permeable cap for flask
US5795773A (en) * 1995-03-24 1998-08-18 Akzo Nobel N.V. Device for detecting microorganisms

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