Here's a mathematical riddle for doctors: A bacteria colony in the urinary tract doubles itself once every x hours. If we take a urine sample to diagnose whether a patient has contracted a certain disease, we'll get an answer within 24-48 hours, assuming that we haven't caught the laboratory on its day off. If, in the meantime, we give antibiotics, and the patient actually does not have an infection, we will increase his resistance to bacteria, cause him to suffer from various side effects, and, in general, we will strengthen the bacteria in the world. If, on the other hand, we wait, the infection could spread, and then we'll need a lot more antibiotics to fight it. The patient's condition will be far more painful, and it could even be life threatening. The more an infection is allowed to develop, the wider it will spread into the bladder, and even into the kidneys. So what can be done?
Doctors are usually in a quandary. If there are other symptoms such as fever, a burning sensation during urination, and so forth, they will usually give antibiotics even before a diagnosis has been made. Meanwhile, they are crying out for a procedure that will enable them decide on the spot whether there is an infection or not.
Dr. Issachar Regev, now director of microbiology at Migdal Ha'Emek-based medical device start-up, BacterioScan Ltd., saw the dilemmas his colleagues were finding themselves in, and the patients who were taking antibiotics needlessly. He decided to solve the problem and come up with a test that would determine immediately whether urine has bacteria in it. "The problem with today's tests is that you can't see the bacteria directly, but only indirectly," explains BacterioScan CEO Dr. Jaime de la Zerda. "First, you let the bacteria multiply, and once there's enough of them, you try to color the sample by using a substance that bonds with either the bacteria, or with substances they secrete." The disadvantage of this test is, as mentioned earlier, the time it takes to carry it out.
A quicker test for bacteria in urine also exists, but it is indirect and not very accurate. The method in question is the "dip stick test", in which a certain substance on the dip stick combines with two substances in urine that are supposed to indicate indirectly, the presence of infection. The result is a stain on the stick itself, like in a pregnancy test. The first factor that stick detects is the presence of white blood cells, or leukocytes, which are present in the urine when there is an infection. The problem is that other infections in the body, not just those of the urinary tract, can also cause leukocytes to appear. The second substance is nitrate. This is secreted into the urine only if there are bacteria in the urinary tract, but it takes four hours to accumulate enough nitrate to trigger a response to the dip stick. Most people, especially those suffering from an infection of the urinary tract or from other conditions with similar symptoms, have difficulty holding urine in for four hours. Likewise, vegetarians produce almost no nitrate, no matter how long they hold back.
De la Zerda says, "There's a saying in Colombia: 'You can get into this restaurant with 15 pesos and a stick. And without a stick? Also. That's how it is with this test. With or without a stick, it's the same thing."
BacterioScan realized that the most accurate and reliable result would be obtained by looking directly at the cause itself - the bacteria. After consulting with optics experts, the company realized that bacteria in a sample could be diagnosed using a laser. "At this stage, we took a urine sample in a transparent cell, and using highly primitive means, we passed a laser beam through it. This confirmed our hypothesis - the sample with the bacteria diffracted the laser light differently from the sample without bacteria," says de la Zerda.
The diffraction of different types of light beams by fluid samples of differing compositions was known before BacterioScan came along, but the company is the first to demonstrate how this could be applied in bacteria diagnosis. It later realized that the diffraction also had a quantitative dimension to it, that is to say, the concentration of bacteria can be determined by the angle of the diffraction. Following the completion of the preliminary trials of product in the primitive version, BacterioScan was admitted to the Yozmot HaEmek Ltd. incubator.
Screening the sample
BacterioScan's next task was to improve its sampling method. "Urine is a very complex body fluid," explains de la Zerda. "It also has other crystalline particles, cells that have completed their task, mucosa, and others. It can be quite turbid, and even red or black." The company's next idea was to screen the sample with a perforated filter, five microns in size, that allows the passage of bacteria, but not larger particles. Much to its surprise, the new idea was innovative, and BacterioScan even patented it. The screening greatly improved the precision of sampling by laser.
The next breakthrough was more complicated. The sensors used to capture the diffraction of the laser as it passed through the sample were replaced by video cameras that document the laser diffraction over time. Any bacteria present in the sample could be identified by their movement, thereby improving the accuracy of the test. Not all the bacteria causing infection in the urinary tract move around in a sample, but the ones most commonly found in this disease do.
Another improvement was in the glass container the holds the sample while the laser beam passes through it, called a cuvette. "If we had passed the light through a sample in a regular cuvette, which looks like a kind of square test tube, the diffraction we would have received would not have been sufficient to genuinely differentiate between samples. So we developed a cuvette. First, it sits along the width of the device, rather than its length, meaning that the laser travels further for each sample, and has a greater opportunity for diffraction.
"Also, we wanted to make sure the laser was not reflected by the glass on both sides of the chamber, thereby interfering with measurement, so we designed the device so that the glass through which the laser passes is angled, so that the light that hits it is reflected sideways, and does not get in the way. The rest of the chamber's sides are painted black, so that the light that reaches them is absorbed and not reflected. These components were developed by us and we have a patent on them. They will be sold alongside the device as disposable single-use components, and they will give us a revenue stream over and above the sales of the device itself."
Diagnosing any type of fluid
Globes: Have there been no other attempts aside from yours, to observe bacteria directly, rather than indirectly, or after a culture has been formed?
De la Zerda: "There was an attempt to fuse various bacteria with substances called reagents, which following fusion reflect light directed at them. If they are not fused with bacteria, they don't reflect light. The problem is that diagnosis through reagents is an entire process on its own. You have to monitor their development, and expiry date, they are believed to be carcinogenic and so they are somewhat risky to use and expensive. They are seldom used nowadays."
How far on are you with your development?
"Three months ago we completed a trial in the US and Israel, in which we found that our results were on a par with those of cultures, and we believe that we can improve them even further. We have filed a product approval application with the US Food and Drug Administration (FDA), and we hope to get an answer within three to four months. The collaboration with the FDA was fantastic - we called them frequently, and the people there agreed to almost anything we asked for, and helped us solve any problems we had. The next stage will be to secure insurance cover, and we intend to commence sales in the second half of 2008."
BacterioScan has raised finance from the Chief Scientist, and an additional $400,000 from a group of private healthcare investors. "We're interested in raising a further $2.5 million, and we've contacted a number of funds in the US," says de la Zerda. "Later on, we hope to develop methods for diagnosing the presence of bacteria in any type of body fluid. In addition, it will also be possible to use the diagnosis method in the veterinary market, as well diagnosing the presence of bacteria in water. The opportunities are vast."
Published by Globes [online], Israel business news - www.globes.co.il - on September 17, 2007
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