FI62858B - ANORDING FROM THE MICROBERRY - Google Patents

Description

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Microbial dilution in the skin - Anordninp för utsnädninp av mi k Robe r

The invention relates to a comb-like microbial dilution device, with which the dilution is based on the adhesion of microbes to the peaks of the device 5 when the device is drawn along the microbial culture.

Microbiological assays in both clinical and non-clinical fields are still generally performed by conventional methods. Because colony counting is essentially related to this method, samples should almost always be diluted to allow printing. Dilution is also necessary in order to be able to draw conclusions based on the appearance of the bacterial colonies, for example on the purity of the culture.

Subcultures also require the presence of separate colonies on the plate, which is not usually achieved with an undiluted sample. Making a dilution series is a laborious procedure that requires time and equipment and 20 contributes to limiting the performance of traditional microbiological analyzes outside well-equipped laboratories.

When the dish is cultured without a quantitative result being desired, a culture loop or rod is used for both inoculation and "dilution", with the different parts of the dish being inoculated alternately in sequence. If expensive disposable loops are not used, the standard loop should always be sterilized by heating before making dilutions. In this case, there is a risk of working with a loop that is too hot, causing the bacteria to die. The use of non - disposable equipment outside the laboratory is usually very inconvenient.

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However, microbiological analyzes have been performed for several years also under so-called field conditions using so-called dip s Iido. In this method, an untreated primary sample is inoculated onto the media surfaces on a plastic strip either by dipping a 5 bar strip into the sample, pressing the strip onto the solid sample or inoculating the sample onto the loading surfaces, for example with a sterile cotton swab. Once the strip with inoculated medium is enclosed in a sealed plastic tube included in the device, it can be either placed in a 10-well oven to grow or conveniently transported to the laboratory for long periods of time without changing the culture result. Quantitative in this method is based on the fact that a similar sample inoculated with the same method is always adhered to the medium by an almost constant amount, so for Kuta-15 it is possible to create model tables showing the colony density of the sample on the medium, for example logarithmic units. Colonies are not counted. The method is, of course, not as accurate as standard plate culture 20, but in practice sufficient in many special cases, such as urine culture. However, even dip in their use is often a difficulty in subculturing the mat-growing medium or assessing the purity of the culture.

With the comb-like device according to the invention, a secondary inoculum can easily be obtained from the primary inoculum inoculated on the medium with a single stroke, in which separate colonies appear. The cultivation device is a disposable stem device in which, through 30 flexible spikes, bacteria adhered to the primary environment are drawn into the unused portion of the medium, where they eventually remain as individual colony-forming cells. The device can also be designed for use with dip slides, either unilaterally 35 as in the case or by placing two spike parts opposite each other, whereby by pushing the medium surfaces between these spikes, for example 3 62858, the inoculated dip slide simultaneously causes dilution draws for both e. A prerequisite for the operation of the device is that the bacterial concentration of the primary inoculum and the length of the unused medium surface to which the device spreads the primary inoculum bacteria are proportional to each other so that the number of bacteria adhering to the peaks decreases sufficiently. This functionality is also affected by the properties of the peaks.

Figure I shows a device suitable for cup cultivation. It consists of an arm (1), spikes (2) and guide parts (3). A suitable material is, for example, polyethylene, which is very flexible when the zinc is thin. The dimensions and shape of the arm (1) are designed so that the device stays comfortably in the hand. In the case of the spikes (2), the material is strongly thinned to achieve a suitable flexibility, for example 0.1 mm. The spines taper towards the tip and 20 may be either round or sharp at the tip. It is essential that both the choice of material and the design take into account that the sharp ends of the spikes do not damage the surface of the medium when used. The spikes should also be about 0.5 mm longer than the guide parts (3).

25 The purpose of the control parts (3) is to ensure repeatability in the use of the device. When the device is transported on the surface of the medium with the guide parts lightly pressed against the surface, the contact between the tips of the spikes and the surface is similar from time to time. Thus, the guide members 30 should be shaped to be round so as not to break the surface of the medium. The width of the whole device can be chosen either by pulling once perpendicularly against the primary circumference with a standard 90 mm dish, the dilution draws are as wide as possible from the eastern area at a time, ie approx. 40-60 mm, 35 or by using the same device first parallel traction, causing the dilution distance to increase. In this case, the width of the comb 4 62858 would be about 20-40 mm. The width of a single-sided dip slide device depends on the width of the dip slide, and other sizes also require different dimensions.

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The shape of the double-sided device may be, for example, as shown in Figure II. The exact dimensions and shape of the guide section depend on the dimensions and shapes of the dip slides in question. It is essential that the device has a guide hole (51) by means of which the contact of the spikes (2) with the material surface can be reproduced. In addition, the device has an essential opening (4) which allows it to be removed from the dip s after use.

The device can also be designed so that the contact of the spikes with the surface of the medium varies, for example, as shown in Figures III and IV. The operational reliability of such a device is less dependent on the bacterial concentration in the sample and not on the dilution mat. If the bacterial concentration is relatively low, the best dilution effect is obtained for the longest peaks, and when the bacterial concentration is very high, the peaks with the weakest contact with the surface give the best result.

Claims (2)

62858 A comb-like microbial dilution device, which can be used for diluting unilateral or double-sided cultures, characterized by flexible spikes (2) which are adhered to by the microbes when the device is pulled along the culture and which are arranged either unilaterally (II) or opposite (II) on the stem (1). ) with guide devices, either guide arms (3) or a guide slot (5) for adjusting the surface contact of the spikes (2) 10, and in the case of two-sided culture dilution devices, an opening (4) from which the device can be pulled out of the culture surface. Device according to Claim 1, characterized in that the heights of the spikes (2) vary.