Detecting microbial infections in wounds

Abstract

Provided herein are microbial infection indicator devices, including dressing with indicators, standalone indicator inserts or disks that can be freely placed at a wound site or dressing, and applications thereof for displaying a visible or detectable signal to a user upon detection of an analyte or biomarker indicative of an infection, such as a color change.

What is claimed is: 
     
         1 . A wound dressing comprising
 a) a wound contacting layer;   b) a reagent layer comprising one or more testing regions, wherein the reagent layer is in fluid communication with the wound contacting layer; and   c) an outer layer that overlays the reagent layer.   
     
     
         2 . The wound dressing of  claim 1 , wherein the wound contacting layer comprises gel-forming polymers. 
     
     
         3 . The wound dressing of  claim 1 , wherein each of the one or more testing regions comprises one or more of each of a back-flow trap, a reagent pad, a filter pad, an indicator trap, and an absorbent area, and wherein one or more viewing windows are located either above the reagent pad or the indicator trap. 
     
     
         4 . The wound dressing of  claim 3 , wherein:
 a) the reagent pad is in fluid communication with the filter pad;   b) the filter pad is in fluid communication with the indicator trap; and   c) the indicator trap is in fluid communication with the absorbent area.   
     
     
         5 . The wound dressing of  claim 1 , wherein each of the one or more testing regions comprises one or more reagents selected from the group consisting of enzyme-reactive indicators, reagents that are sources of peroxide, enzymes that produce colored products, pH indicators, protein responsive reagents, and moisture-detecting reagents. 
     
     
         6 . The wound dressing of  claim 5 , wherein enzyme-reactive indicators are protein-indicator conjugates. 
     
     
         7 . The wound dressing of  claim 6 , wherein the protein-indicator conjugates are deposited in or on the reagent pad. 
     
     
         8 . The wound dressing of  claim 6 , wherein the protein-indicator conjugate has the structure of Formula (I):
   A-B   Formula (I)
   wherein:   A is an anchor region or moiety that helps to bind an enzyme-reactive region to the reagent pad; and   B is the enzyme-reactive region.   
     
     
         9 . The wound dressing of  claim 8 , wherein the enzyme-reactive region comprises a peptide. 
     
     
         10 . The wound dressing of  claim 8 , wherein the enzyme-reactive region comprises an indicator region having an enzyme-reaction indicator. 
     
     
         11 . The wound dressing of  claim 8 , wherein B further comprises an indicator region. 
     
     
         12 . The wound dressing of  claim 11 , wherein the indicator region, after having been cleaved by the target enzyme is transformed into a colored species by accessory enzymes selected from the group consisting of lipase, esterase, hexosaminidase, peroxidase, oxidase, glycosidase, glucosidase, laccase, and a combination of two or more thereof. 
     
     
         13 . The wound dressing of  claim 10 , wherein the enzyme-reactive indicators interact with one or more enzymes selected from the group consisting of elastase, lysozyme, cathepsin G, myeloperoxidase, and any combination thereof. 
     
     
         14 . The wound dressing of  claim 10 , wherein the enzyme-reactive indicators comprise a moiety capable of producing a visible color or a detectable electronic change upon interaction of the enzyme-labile or enzyme-reactive region with one or more enzymes, wherein the moiety is selected from the group consisting of a peroxidase substrate, arylamine, an amino phenol, a neutral dye, a charged dye, a nanoparticle, a colloidal gold particle, and an analog thereof. 
     
     
         15 . The wound dressing of  claim 8 , wherein the anchor region is covalently attached to the reagent pad. 
     
     
         16 . The wound dressing of  claim 8 , wherein the anchor region is non-covalently attached to the reagent pad. 
     
     
         17 . The wound dressing of  claim 16 , wherein the anchor region is ionically attached to the reagent pad. 
     
     
         18 . The wound dressing of  claim 1 , further comprising one or more lines of wicking stitching or wicking tufting throughout all layers of the wound dressing except the outer layer, and wherein the wicking stitching or wicking tufting provides fluid communication between the reagent layer and the wound contacting layer. 
     
     
         19 . The wound dressing of  claim 18 , wherein one or more lines of wicking stitching or wicking tufting comprise fibers that are wettable and exhibit capillary action. 
     
     
         20 . The wound dressing of  claim 19 , wherein the fibers comprise cotton, rayon, viscose, wool, silk, polyester, polyamide, CMC, polypropylene, or any combination thereof. 
     
     
         21 . The wound dressing of  claim 1 , wherein one or more testing regions comprise a leach-back trap in fluid communication with a reagent pad and one or more lines of wicking stitching or wicking tufting crossing through one or more testing regions only at the leach-back trap. 
     
     
         22 . The wound dressing of  claim 1 , further comprising a foam layer between the wound contacting layer and the reagent layer. 
     
     
         23 . The wound dressing of  claim 22 , further comprising one or more perforations in the wound contacting layer. 
     
     
         24 . The wound dressing of  claim 22 , further comprising one or more perforations in the foam layer and the wound contacting layer. 
     
     
         25 . The wound dressing of  claim 21 , wherein each of the one or more testing regions further comprises a leach-back trap in fluid communication with the reagent pad and one or more perforations aligned with the leach-back trap. 
     
     
         26 . The wound dressing of  claim 1 , wherein each of the one or more testing regions comprises a multichannel testing region, wherein each channel is separated from an adjacent channel by one or more impermeable separators or borders. 
     
     
         27 . The wound dressing of  claim 26 , comprising a plurality of testing regions. 
     
     
         28 . The wound dressing of  claims 26 , wherein the testing regions are arranged in a linear configuration. 
     
     
         29 . The wound dressing of  claim 26 , wherein the testing regions are arranged in a radial configuration. 
     
     
         30 . The wound dressing of  claim 1 , wherein the outer layer has one or more windows that permit visualization of a signal from the reagent layer. 
     
     
         31 . The wound dressing of  claim 30 , wherein the signal is a color change. 
     
     
         32 . The wound dressing of  claim 30 , wherein the signal is a fluorescent signal, a luminescent signal, or a signal mediated by physical means, such as an electrical change. 
     
     
         33 . A method of detecting the level of one or more enzymes in a mammalian wound, the method comprising:
 a) contacting the mammalian wound with a wound dressing of  claim 1 ;   b) observing one or more signals in the reagent layer, wherein the signal is a color change, a fluorescent signal, a luminescent signal, or an electrical change; and   c) comparing the signal to a reference or a control to determine the level of an enzyme.   
     
     
         34 . A method of detecting the presence of one or more enzymes in a mammalian wound, the method comprising:
 a) contacting the mammalian wound with a wound dressing of  claim 1 ; and   b) observing one or more signals in the reagent layer, wherein the signal is a color change, a fluorescent signal, a luminescent signal, or an electrical change.   
     
     
         35 . A method of detecting an infection in a mammalian wound, the method comprising:
 a) contacting the wound with a wound dressing of  claim 1 ; and   b) observing one or more signals in the reagent layer, wherein the signal is a color change, a fluorescent signal, a luminescent signal, or an electrical change.   
     
     
         36 . A method of treating an infection in a wound of a mammal, the method comprising:
 a) contacting the wound with a wound dressing of  claim 1 ;   b) observing one or more signals in the reagent layer indicative of an infection, wherein the signal is a color change, a fluorescent signal, a luminescent signal, or an electrical change; and   c) administering a medical treatment to the mammal.   
     
     
         37 . A device for detecting an infection in a wound, comprising:
 a) a wound contacting layer;   b) a reaction layer comprising one or more reagents that can indicate the presence of one or more analytes associated with an infection, wherein the reagents are affixed to a solid phase and produce a detectable signal in a reporter area;   c) a cover on top of the reaction layer, wherein the cover comprises one or more windows or clear areas to allow visualization of the detectable signal; and   d) fluid communication between the wound contacting layer and the reaction layer.   
     
     
         38 . The device of  claim 37 , wherein the reagents comprise enzyme-reactive regions that interact with one or more target enzymes selected from the group consisting of lysozyme, MPO, cathepsin G, elastase, catalase, lipase, esterase, and any combination thereof. 
     
     
         39 . The device of  claim 37 , wherein one or more reagents produce a visible color upon a change in the pH, at an acidic pH, or at a basic pH, and wherein the pH-sensitive reagent comprises bromothymol blue, phenol red, bromophenol red, chlorophenol red, thymol blue, bromocresol green, bromocresol purple; nitrazine yellow; or other sulfophthalein dyes. 
     
     
         40 . The device of  claim 38 , wherein the enzyme-reactive regions comprise a moiety capable of producing a visible color or detectable electronic change upon interaction with one or more target enzymes, wherein the moiety is a peroxidase substrate, arylamine, an amino phenol, an indoxyl, a neutral dye, a charged dye, a nanoparticle, a colloidal gold particle, or an analog thereof. 
     
     
         41 . The device of  claim 40 , wherein the reagent interacts with a target enzyme to produce a colored species or to produce an intermediate product that interacts with an accessory enzyme selected from the group consisting of a lipase, esterase, hexosaminidase, peroxidase, oxidase, glycosidase, glucosidase, and laccase. 
     
     
         42 . The device of  claim 37 , wherein the fluid communication comprises wicking stitching or wicking tufting of an absorbent material that allows fluid communication between the wound contacting layer and the reaction layer. 
     
     
         43 . The device of  claim 37 , wherein the reagents are printed, sprayed, or deposited on the solid phase. 
     
     
         44 . The device of  claim 37 , wherein the solid phase is selected from the group consisting of paper, viscose, regenerated cellulose, glass fiber, and any combination thereof. 
     
     
         45 . The device of  claim 37 , wherein the detectable signal is a color change, a fluorescent signal, a luminescent signal, or an electrical change. 
     
     
         46 . The device of  claim 37 , wherein the device is a wound dressing. 
     
     
         47 . A device for detection of infection associated enzymes that is provided as an independent entity and can be placed in any dressing system, comprising a sample inlet in fluid communication with reagent cells, wherein reagent cells comprise indicators for sample delivery and/or pH, and one or more indicators for biomarkers of an infection selected from the group consisting of lysozyme, MPO, cathepsin G, elastase, catalase, lipase, and esterase. 
     
     
         48 . The device of  claim 47 , wherein the indicators comprise enzyme-reactive indicators, reagents that are sources of peroxide, enzymes that produce colored products, pH indicators, protein responsive reagents, or moisture-detecting reagents. 
     
     
         49 . The device of  claim 47 , wherein the indicators are enzyme-reactive indicators or protein-indicator conjugates. 
     
     
         50 . The device of  claim 47 , wherein the protein-indicator conjugates are deposited in or on the reagent pad. 
     
     
         51 . The device of  claim 47 , wherein the protein-indicator conjugate has the structure of Formula (I): A-B, wherein A is an anchor region or moiety that helps to bind an enzyme-reactive region to the reagent pad; B is the enzyme-reactive region; and wherein the enzyme-reactive region comprises a peptide or an indicator region. 
     
     
         52 . The device of  claim 51 , wherein the indicator region interacts with an enzyme to produce a colored species or wherein an intermediate species interacts with an accessory enzyme selected from a group consisting of a lipase, esterase, hexosaminidase, peroxidase, oxidase, glycosidase, glucosidase, and laccase to produce a colored species. 
     
     
         53 . The device of  claim 47 , wherein the fluid communication comprises one to ten indicator channels separated by impermeable lanes, borders, or separators, wherein each indicator channel comprises a different reagent or control. 
     
     
         54 . The device of  claim 47 , wherein the fluid communication comprises a plurality of separate indicator channels, and wherein each indicator channel comprises a different reagent or control. 
     
     
         55 . The device of  claim 47 , wherein the reagents are printed, sprayed, or deposited on a solid phase in a radial configuration to form a disk. 
     
     
         56 . The device of  claim 47 , wherein the reagents are printed, sprayed, or deposited on a solid phase in a linear configuration to form a testing strip or dipstick-type device. 
     
     
         57 . The device of  claim 55 , wherein the disk comprises reagents printed, sprayed, or deposited on the top surface of the disk with a trap material and a substrate material on the bottom surface, wherein the substrate can be digested by one or more enzymes in the sample to release one or more products that migrate toward the trap. 
     
     
         58 . The device of  claim 57 , wherein one or more products are colored or produce a color change through interaction with an accessory enzyme, and wherein the color change can be visualized on the top surface of the disk. 
     
     
         59 . A diagnostic disk for detecting an infection in a wound, comprising:
 a) a reaction layer comprising one or more reagents that interact with a target enzyme indicative of an infection, wherein the reagents are affixed to a solid phase;   b) each reagent is sprayed, printed, or deposited in a reagent area in a lane separated from adjacent lanes by impermeable separators;   c) each lane comprises a reporter area wherein a color, color change, or other detectable signal is observed; and   d) a cover comprising a window for visualizing the signal in the reporter area.   
     
     
         60 . The diagnostic disk of  claim 59 , wherein one or more reagents produce a visible color upon a change in the pH, at an acidic pH, or at a basic pH, wherein the pH-sensitive reagent comprises bromothymol blue, phenol red, bromophenol red, chlorophenol red, thymol blue, bromocresol green, bromocresol purple; nitrazine yellow; or other sulfophthalein dyes. 
     
     
         61 . The diagnostic disk of  claim 59 , wherein multiple lanes are arranged in a linear or radial configuration about a cut access, perforation, or wicking material that allows fluid communication between a wound contacting area to the reagents in the reaction layer. 
     
     
         62 . The diagnostic disk of  claim 59 , wherein one or more reagents produce a color signal or other detectable signal upon interaction with an enzyme selected from the group consisting of lysozyme, MPO, cathepsin G, elastase, catalase, lipase, and esterase. 
     
     
         63 . The diagnostic disk of  claim 59 , wherein the reagents comprise a moiety selected from the group consisting of peroxidase substrate, arylamine, an amino phenol, an indoxyl, a neutral dye, a charged dye, a nanoparticle, and a colloidal gold particle, and an analog thereof. 
     
     
         64 . The diagnostic disk of  claim 59 , wherein the reagents comprise accessory enzymes that produce a colored species or color signal, and wherein the accessory enzyme is a lipase, esterase, hexosaminidase, peroxidase, oxidase, glycosidase, glucosidase, laccase, or a combination of one or more thereof. 
     
     
         65 . The diagnostic disk of  claim 59 , wherein the solid phase is selected from the group consisting of paper, viscose, regenerated cellulose, glass fiber, and similar material. 
     
     
         66 . The diagnostic disk of  claim 59 , wherein there are a plurality of lanes, each with a different reagent or control. 
     
     
         67 . The diagnostic disk of  claim 59 , wherein the detectable signal comprises a color change, appearance or disappearance of a color, a fluorescent signal, a luminescent signal, or an electrical change or signal. 
     
     
         68 . A lateral flow or dipstick device for detecting an infection in a wound, comprising: one or more reagent disks arranged in a linear configuration, wherein each reagent disk is impregnated with a reagent that interacts with an enzyme to produce a color change and/or is pH-sensitive, comprising bromothymol blue, phenol red, bromophenol red, chlorophenol red, thymol blue, bromocresol green, bromocresol purple; nitrazine yellow; or other sulfophthalein dyes, and wherein the disks are affixed to a solid phase. 
     
     
         69 . The device in  claim 68 , wherein the reagents produce a color signal upon interaction with an enzyme selected from the group consisting of lysozyme, MPO, cathepsin G, elastase, catalase, lipase, and esterase. 
     
     
         70 . The device in  claim 68 , wherein the solid phase is selected from the group consisting of paper, viscose, regenerated cellulose, glass fiber, and any combination thereof. 
     
     
         71 . A device for detecting an infection in a wound or a sample, comprising a housing, wherein the housing comprises:
 a) a sampling component for collecting the sample;   b) a sample preparation chamber in fluid communication with a reaction chamber, wherein the sample preparation chamber receives the sample;   c) the reaction chamber comprising one or more reaction cells containing reagents that interact with one or more enzymes in the sample to indicate the presence of an infection and/or pH of the sample; and   d) a window or a clear area for visualizing a detectable signal, wherein the signal is a color change.   
     
     
         72 . The device in  claim 71 , wherein one or more reagents produce a color signal upon interaction with an enzyme selected from a group consisting of lysozyme, MPO, cathepsin G, elastase, catalase, lipase, and esterase. 
     
     
         73 . The device in  claim 71 , wherein one of the reagents produces a color change in response to a change in pH, a basic pH, or an acidic pH. 
     
     
         74 . The device in  claim 71 , wherein the reagents perform in a primarily liquid medium. 
     
     
         75 . The device in  claim 71 , wherein the reagents are provided in tablet form for use in the reaction cells. 
     
     
         76 . The device in  claim 71 , wherein the reagents are printed, sprayed, or deposited in separate reagent fields on a support material to form a panel of tests for use in the reaction chamber. 
     
     
         77 . The device in  71 , wherein the support material is selected from the group consisting of paper, viscose, regenerated cellulose, and glass fiber, arrayed in a line along a carrier strip. 
     
     
         78 . The device in  claim 76 , wherein the reagent fields are arrayed in a line along a carrier strip capable of absorbing the sample in the reaction chamber. 
     
     
         79 . The device in  claim 71 , wherein the sampling component is a swab device. 
     
     
         80 . The device in  claim 71 , wherein the sampling component is a hook or needle device adapted to removing a thread from a wound dressing without disturbing the wound dressing. 
     
     
         81 . A kit for detecting an infection in a sample, comprising:
 a) a sampling component for collecting the sample;   b) a test device comprising a housing surrounding a tube to define an opening in the housing for receiving the sampling component, the housing comprising:   c) a diluent chamber that holds a liquid diluent;   d) a reaction well in liquid communication with the tube, wherein the reaction well holds one or more reagents that interact with one or more analytes to produce a color change or a detectable signal;   e) a viewing window or reporter area wherein the color change or detectable signal can be observed; and   f) wherein the liquid diluent flows from the sample component into the reaction well to mix the sample with the reagents in the reaction well.   
     
     
         82 . The kit of  claim 81 , wherein the reagents comprise one or more enzyme-reactive indicators and/or pH indicator. 
     
     
         83 . The kit of  claim 81 , wherein one or more reagents produce a color signal upon interaction with an enzyme selected from a group consisting of lysozyme, MPO, cathepsin G, elastase, catalase, lipase, and esterase. 
     
     
         84 . The kit of  claim 81 , wherein the reagents comprise a moiety selected from the group consisting of peroxidase substrate, arylamine, an amino phenol, an indoxyl, a neutral dye, a charged dye, a nanoparticle, a colloidal gold particle, and an analog thereof. 
     
     
         85 . The kit of  claim 81 , wherein the detectable signal comprises a color signal or color change, a fluorescent signal, a luminescent signal, or an electrical signal. 
     
     
         86 . The kit of  claim 81 , wherein at least one reagent produces a color signal in response to a basic pH, an acidic pH, or a change in pH, wherein the pH-sensitive reagent is bromothymol blue, phenol red, bromophenol red, chlorophenol red, thymol blue, bromocresol green, bromocresol purple; nitrazine yellow; or other sulfophthalein dyes. 
     
     
         87 . The kit of  claim 81 , wherein the sample is obtained from a wound, a wound dressing, or a surgical site. 
     
     
         88 . The kit of  claim 81 , wherein the sampling component is a swab device or a hook or needle device. 
     
     
         89 . The kit of  claim 81 , wherein the reagents are deposited in separate fields on a testing strip to form a panel of tests. 
     
     
         90 . The kit of  claim 81 , wherein there are a plurality of reaction wells, wherein each reaction well comprises a different reagent or control. 
     
     
         91 . The kit of  claim 90 , wherein the reaction wells are arranged in a linear configuration. 
     
     
         92 . The kit of  claim 90 , wherein the reaction wells are arranged in a radial configuration.