WO1995003423A1

WO1995003423A1 - An amine tester for diagnosing bacterial vaginosis and vaginitis

Info

Publication number: WO1995003423A1
Application number: PCT/GB1994/001515
Authority: WO
Inventors: John Bolbot; Eric D'costa
Original assignee: Cambridge Research & Innovation Limited
Priority date: 1993-07-26
Filing date: 1994-07-13
Publication date: 1995-02-02
Also published as: AU7130794A; EP0711358A1; HU9600167D0; GB9315440D0

Abstract

An amine tester for diagnosing bacterial vaginosis comprises a plurality of receptacles including a control receptacle and a plurality of swabs including a control swab. The control swab is contaminated with the amine compound and the smell from this is compared with a test swab which is contaminated with a sample from a vaginal discharge so that the smells can be compared.

Description

Title of the Invention

AN AMINE TESTER FOR DIAGNOSING BACTERIAL

VAGINOSIS AND VAGINITIS

Field of the Invention

The present invention relates to an amine tester for diagnosing bacterial vaginosis and vaginitis and is particularly but not exclusively suited for use as a home test kit.

Background to the Invention

Bacterial vaginosis is one of the commonest causes of abnormal vaginal discharge. The condition is underdiagnosed partly because of the lack of an easy and acceptable method of diagnosis. Genito-urinary medical physicians make the diagnosis of bacterial vaginosis by various means including examining stained preparations of vaginal discharge under the microscope and relating this to the patient's symptoms. This is rarely performed by general practitioners, family planning doctors, gynaecologists and other health care workers because of the lack of time and expertise. An easier and more rapidly performed method of diagnosis is therefore required.

Bacterial vaginosis is a mixed infection with anaerobic bacteria and another bacterium, Gardnerella vaginalis, being present in varying concentrations. These bacteria produce chemical substances called amines which are present as "salts" in the vaginal discharge. The amines may be volatilised and hence freed from the "salts" by the addition of alkali. The volatilised amines have a pronounced fishy odour which is easily detected by smell. Certain other causes of vaginitis (e.g. Trichomonas vaginalis) may also produce amines and hence may be detected in the same manner. However, when relying upon the chemical reaction described above for diagnosing bacterial vaginosis or some causes of vaginitis it is sometimes difficult for those unfamiliar with the odour of volatilised amines to be certain that the smell they detect, if any, is an indication of bacterial vaginosis and vaginitis. The present invention therefore seeks to provide an amine tester which enables rapid diagnosis of bacterial vaginosis and certain other causes of vaginitis in a simple and convenient • manner and which overcomes the disadvantages outlined above.

Summary of the Invention

The present invention provides an amine tester for diagnosing bacterial vaginosis and vaginitis comprising at least one receptacle containing an alkaline medium; a test swab; and at least one control assembly for producing as a control smell volatilised amines, said test swab being, in use, contaminated with a sample from a vaginal discharge whereby a comparison of the smells resulting from the exposure of the test swab to the alkaline medium and from the control assembly enables the detection of volatilised amines from the test swabs.

Thus, a user of the amine tester kit may familiarise themselves with the odour to be detected by using the control assembly before performing a formal test on a sample on the vaginal discharge.

The control assembly can comprise a control swab, a control receptacle containing a stable amine compound and a further receptacle containing an alkaline medium. In this case, each of the receptacles has a first opening closable by a closure member and a second opening spaced from the first opening through which the volatilised amines may be smelt. Thus, with this preferred embodiment the swabs may be each mounted on a closure member and are capable of movement relative to the closure member whereby when the swab is inserted into a corresponding receptacle, an end of the swab may be brought into contact with the alkaline medium and thereafter positioned adjacent the second opening so that any volatilised amine may be smelt through the second opening whilst the first opening is held closed by the closure member. As an alternative the control smell can be provided by a container holding predispensed trimethylamine hydrochloride at an alkaline pH which releases volatilised amines when the container is opened. This arrangement is simpler and cheaper and particularly useful for self tests to be conducted at home.

Ideally, the amine compound is trimethylamine hydrochloride and the alkaline medium consists of a fluid or a gel of sufficient alkalinity to volatilise any protonated amines on the swab. The alkaline medium may be potassium hydroxide or sodium carbonate.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings.

Brief description of the drawings

Figure 1 shows an amine tester kit according to the present invention;

Figure 2 shows in greater detail one of the test containers of the amine tester kit of Figure 1;

Figure 3 shows one of the swabs provided with the amine tester kit of Figure 1; and

Figures 4a, 4b and 4c show the amine tester kit of Figure 1, in use.

Description of the preferred embodiment

The amine tester kit 1 has a plurality of hollow, plastic or glass test containers 2,3 only two of which are shown in Figure 1. Each of the test containers 2,3 is sealed with a closure member 4 in the form of a cap, lid or stopper. As seen in more detail in Figure 2 each of the test containers 2,3 also has a small opening or window 5 distant from the closed end of the test container. Before use, the window 5 in the containers 2,3 is closed by means, for example, of an adhesive label 6 sealed over the window 5 to the surrounding exterior surface of the test containers 2,3. In addition, a predetermined amount of an alkaline gel or fluid 7 is provided within each of the test containers 2,3. The alkaline gel or fluid 7 may be, for example, potassium hydroxide.

The amine tester kit 1 also includes a plurality of swab members 8,9, only two of which are shown in Figure 1. As shown in Figure 3, each of the swab members 8,9 has an elongate handle 10 at one end of which an absorbent material in the form of cotton-wool 11, for example, is provided. Distant from the end of the swab member 8,9 bearing the cotton-wool 11, the handle 10 passes through a hole provided in -a closure member or stopper 12 which is conformed to engage with and seal the open ends of the test container 2,3. A portion 13 of the handle 10 extends beyond the stopper 12 so that the swab member 8,9 may be securely held by a user of the kit 1. The swab members 8,9 may be provided with the kit 1 in sterile packages or, as shown in Figure 1, may be mounted in containers 14 similar to the test containers 2,3 but without the windows 5.

The swab members 8,9 are capable of moving relative to the stoppers 12 through which they pass. This enables the swab members 8,9 to be inserted into the test containers 2,3 with the stoppers 12 closing the open end of the test containers 2,3. Once closed, the swab members 8,9 may still be moved with respect to the test containers 2,3 without the stoppers being removed from the end of the containers 2,3. Thus, whilst closed the swab members 8,9 may be moved so that the cotton-wool 11 is brought into contact with the potassium hydroxide 7 and can then be moved so that it is positioned adjacent the window 5 so that the nose can be placed in close proximity to the cotton-wool 11. During this manoeuvre the container 2,3 is kept closed by the -stopper 12 so that any amines volatilised pass through the window .5 and not through the main opening of the container. As shown in Figure 1, the test containers 2,3 and the swab members 8,9 in the containers 14 are mounted in a rack 15 which has a plurality of openings 16 equal or greater in number than the number of containers 2,3,14, where the swab members 8,9 are provided in containers 14. The rack 15 is arranged to support each of the containers 2,3,14 in an upright position, with each of the containers 2,3,14 being held in a respective one of the openings 16. Where the swab members 8,9 are provided in sterile packages a channel portion conforming to the size and shape of the sterile packages may be provided in the rack 15. A spare closure member 17 may also be included with the amine tester kit 1 along with additional openings 16 in the rack 15 to receive and support the caps 4 of the test containers 2,3 after use.

One of the swab members 8 is a control swab with the rest of the swab members 9 being test swabs, only one is shown in Figure 1. With the amine tester kit 1 shown in Figure 1, the control swab 8 is mounted in a container 14 which contains a predetermined amount of trimethylamine hydrochloride 18 which is in the form of a liquid or gel, at a pH of about 5. Alternatively, the trimethylamine hydrochloride may be absorbed in a porous material, such as paper. Where the control swab 8 is instead provided in a sterile package, the trimethylamine hydrochloride18 is provided in a separate sealed openable container. The rack 15 with the test containers 2,3, the control swab 8 and the test swab 9 is enclosed in an outer sealable receptacle 19. This ensures that the kit 1 may be disposed of, after use, safely without fear of contamination.

As an alternative to providing a control swab for contact with trimethylamine hydrochloride and insertion into a hydroxide, a separate control package can be provided which, when opened, releases volatilised amines to produce a smell for comparison with a sample.

The sterile package can be a foil sachet. The whole package

RECTIFIED SHEET (RULE 91) ISA/EP may be dispensed aseptically or may be irradiated with gamma irradiation to reduce any microbial contaminants to very low levels. The package contains trimethylamine hydrochloride. The trimethylamine hydrochloride may be adjusted during manufacturing to a pH slightly more acidic than pH 9.8, its pK value, such as pH 9.5. This will ensure that on opening the package, trimethylamine vapour will continue to be released from the preparation for some time, so allowing the user to sniff the characteristic smell of trimethylamine again.

The amine tester kit 1 enables a user of the kit 1 to first establish what smell they should be looking for before performing the actual test. Thus, when in use, the control swab 8 is removed from its container 14. Whilst the control swab 8 has been within the container 14, the trimethylamine hydrochloride 18, which is also within the container 14, has contaminated the cotton-wool 11 on the control swab 8. A first of the test containers 2 is then opened by removal of the cap 4 and the adhesive label 6. The cap 4 which has been removed may be placed in one of the spare openings 16 in the rack 15. The contaminated swab 8 is then inserted into the test container 2 so that the cotton-wool 11 is brought into contact with the potassium hydroxide enabling the chemical reaction between the trimethylamine hydrochloride and the potassium hydroxide to occur. The control swab 8 is then pulled back so that the cotton-wool 11 is positioned adjacent the window 5. The user may then smell the odour coming from the cotton-wool 11 through the window 5. The odour corresponds to the odour which would be smelt if the test had been performed with a vaginal swab having bacterial vaginosis or vaginitis. Thus, the user familiarises themselves with the expected smell before performing the actual test. This is achieved because the amines present on the swab are volatilised by the alkaline gel or liquid 7 and can be detected by placing the nose in close proximity to the window 5. It will be appreciated that in order to ensure that the user is familiarised with an appropriate odour, the concentration of the trimethylamine hydrochloride 18, provided in the container 14 is chosen to be close to the clinical "cut-off level", for example, between one and fifty millimolar concentration. Moreover, the kit is arranged so that the amount withdrawn on the cotton-wool 11 of the control swab 8 is representative of the amount of clinical sample that would be obtained on a vaginal swab. The sense of smell to trimethylamine is quickly lost. This could be caused by a blockade of the nasal receptors so that it can be advantageous in a commercial kit for the user to smell the clinical sample first before sniffing the control sample. The control sample has to be formulated at a concentration which puts it at the high end of the range for clinically positive samples.

Where the control swab 8 is provided in the kit in a sterile package, the control swab 8 is removed from the package and the container 14 containing the trimethylamine hydrochloride 18 is opened so that the control swab 8 may be inserted into the container 14 to bring the cotton-wool 11 into contact with the trimethylamine hydrochloride 18. The control swab 8 is then removed with a suitable sample before opening the test container 2 for performing the control test.

As a similar and cheaper alternative to the above, the control package can be opened to release the control smell.

Once the user has familiarised themselves with the smell which they should be looking for in the test to be performed, the steps recited above are then repeated using the test swab 9. The test swab 9 is removed from the container 14 or its sterile package and a sample is obtained from the vagina using the swab directly or from a speculum, the second of the two test containers 3 is then opened by removal of its cap 4 and the adhesive label 6. The test swab 9 with the vaginal sample is then inserted into the test container 3, as before, so that the cotton-wool 11 at the end of the swab is brought into contact with the potassium hydroxide. Thereafter, the cotton-wool 11 is positioned beneath the window 5 of the test container 3 so that the user may detect any odour coming from the cotton-wool 11 following its insertion into the potassium hydroxide. If the smell detected by the user coming through the window is the same as that detected earlier in the control test then the user has confirmation of the presence of bacterial vaginosis or vaginitis.

After use, all of the containers 2,3,14 are closed and mounted in the rack within the outer receptacle which is then sealed so that the tester kit 1 may be disposed of.

Thus, it will be appreciated that with the amine tester kit 1 the user is first able to familiarise themselves with the smell that they should detect if there is the presence of bacterial vaginosis or vaginitis in the vaginal sample and thereafter a test on the vaginal discharge is performed to confirm the diagnosis of bacterial vaginosis or vaginitis. With the amine tester kit 1 described above the test may be performed both simply and conveniently either by medical practitioners, health care workers or women themselves at home. The amine tester kit is sufficiently small and discreet as well as being simple to use to enable the kit to be used by women at home. The provision of a control to familiarise the user with the smell to be detected is particularly important where the test is to be performed at home by women who otherwise may not be familiar with the smell they should be identifying. The kit is also useful in the training of health care workers etc. who otherwise would also be unfamiliar with the smell to be detected.

Furthermore, it will be appreciated that where the amine tester kit 1 is to be used in hospitals or on other medical premises the kit may include additional test containers and test and control swabs so that more than one test can be performed and the control test repeated where necessary so that the user does not get confused as to the smell they should be detecting where the same test is being repeated on a number of different samples. Where the control is provided by predispensed trimethylamine hydrochloride at an alkaline pH, it is advantageous that the smell is produced over a time period for the same reason.

In addition, the caps 4 to the test containers 2,3 may be colour coded to assist the user in identifying which test container to use with the control swab 8 and separately the test swab 9.

Finally, the amine tester kit 1 described above uses test containers 2,3 having windows 5 for enabling the user to smell the odour from the cotton-wool 11. It will be appreciated that such containers need not be used and instead ordinary test tubes may be used. However, where ordinary test tubes are used the swabs must be removed fully from the test tube before being sniffed by the user and this can result in contamination from the chemicals on the cotton-wool. It is for this reason that the use of a container having a window 5 is preferred. In addition, it should be noted that potassium hydroxide is used as the chemical reagent to enable the trimethylamine gas to be released. The use of potassium hydroxide has the additional advantage that it will help to inactivate most bacteria and viruses which might be present on the vaginal swab including such infectious agents as the HIV virus, the Hepatitis B virus etc. It will be understood that this is of particular importance where the amine-tester kit is to be used in the home where children and other people are present and where there are not the usual clinical facilities for the disposal of such waste.

The patient's vaginal swab sample can be made alkaline to release trimethylamine by immersion in potassium hydroxide (e.g. 10% KOH) . However, potassium hydroxide is very caustic and would not be suitable for use in the home, in a product that could be sold over-the-counter.

Sodium and potassium hydroxides also react slowly with carbon dioxide in air to form sodium carbonate. This effect might be more pronounced in a tiny tube or other container which might have to be used in an over-the-counter product compared with the much larger reagent containers which are used conventionally in laboratories.

As carbonates are formed slowly so the composition of the reagent will change over time and this is not desirable in a product that must perform consistently over its shelf life of up to two years.

I place of potassium hydroxide, a less alkaline substance such as sodium carbonate may be used. A 0.1 molar solution of sodium carbonate has a pH of approximately 11.5 and is safer and more stable than potassium hydroxide (pH of a 10% solution of KOH is approximately pH14).

It is important that the patient's vaginal swab sample contacts the alkali in a consistent way. Where the test format is for the patient's vaginal -swab sample to be immersed into a solution of sodium carbonate it has been found that it is easier for the user to do this consistently if a marker dye is formulated into the alkaline solution. The user can verify by colour if the swab has been contacted fully with the alkali.

A blue marker dye has been found best. Unfortunately, most of the widely-used food and household-type dyes are unstable and loose colour on storage in alkaline solution. The use of sodium carbonate solution is beneficial here as it is less alkaline than sodium hydroxide solution and so promotes long term stability of the blue dye. The type of dyes which are suitable as a marker for sodium carbonate solution include Brilliant Blue FCF and Polar Blue, at concentrations in the region of 0.001% w/v.

Claims

CLAIMS ;

1. An amine tester for diagnosing bacterial vaginosis and vaginitis comprising at least one receptacle containing an alkaline medium; a test swab; and at least one control assembly for producing as a control smell volatilised amines, said test swab being, in use, contaminated with a sample from a vaginal discharge whereby a comparison of the smells resulting from the exposure of the test swab to the alkaline medium and from the control assembly enables the detection of volatilised amines from the test swabs.

2. An amine tester as claimed in claim 1 wherein the control assembly comprises a container holding trimethylamine hydrochloride at an alkaline pH.

3. An amine tester as claimed in claim 2 wherein the container is a foil package.

4. An amine tester as claimed in claim 1 wherein the control assembly comprises a control swab, a control receptacle containing a stable amine compound and a further receptacle containing an alkaline medium wherein the control swab is contaminated with the amine compound and exposed to the alkaline medium for producing the control smell.

5. An amine tester as claimed in any preceding claim wherein the or each receptacle has a first opening closable by a closure member and a second opening spaced from the first opening through which the volatilised amines may be smelt.

6. An amine tester as claimed in claim 5, wherein the or each swab is mounted on a closure member and is capable of movement relative to the closure member whereby when the swab is inserted into a corresponding receptacle, an end of the swab may be brought into contact with the alkaline medium and thereafter positioned adjacent the second opening so that any volatilised amine may be smelt through the second opening whilst the first opening is held closed by the closure member.

7. An amine tester as claimed in any one of the preceding claims, wherein said amine compound is trimethylamine hydrochloride.

8. An amine tester as claimed in any one of the preceding claims, wherein the alkaline medium consists of a fluid or a gel of sufficient alkalinity to volatilise any protonated amines on the swab.

9. An amine tester as claimed in claim 8, wherein said alkaline medium is potassium hydroxide.

10. An amine tester as claimed in claim 8, wherein said alkaline medium is a carbonate solution, such as sodium carbonate.

11. An amine tester as claimed in any preceding claim wherein the alkaline medium includes a colour dye to indicate immersion of the swab into the medium.

12. An amine tester for diagnosing bacterial vaginosis and vaginitis substantially as hereinbefore described with reference to and as shown in the accompanying drawings.