06/21/2001 11:00PM

Tiny virus helps in bacteria fight


LEXINGTON, Ky. - In recent years, medical experts have expressed concern that bacteria are becoming resistant to some of the antibiotics used to combat them. The same issue, to a lesser degree, also has been on the minds of some equine veterinarians and researchers. Now, researchers at Texas A & M University say they might have found a new way of dealing with the resistance problem: by using a protein made by a tiny virus to prevent bacteria from multiplying.

The journal Science reports this week that the research team, headed by Dr. Ryland Young, has found that Q Beta, a small, bacteria-attacking virus - or bacteriophage - employs a protein to prevent bacteria from forming cell walls. Without the ability to create a new cell wall, bacteria rupture when they try to split and multiply.

That raises the possibility that pharmaceutical company researchers will ultimately be able to use the protein - or create a similar one - to develop new antibiotics based on these bacteria-killer "phages" that can fight drug-resistant bacteria.

"There are more than a ton of bacteriophages for any single human," said Tom Bernhardt, one of the lead authors of the study. "Luckily, they don't attack humans; they only attack bacteria. Now, an entirely new avenue or approach to antibiotic design is available."

The question for equine practitioners is whether this discovery can help treat resistant bacterial infections in horses. The drug-resistance problem in large animals is not as acute as it is in humans. But virus-produced protein antibiotics could well have a role in equine treatment for common ailments like pneumonia, gastrointestinal diseases, and septicemia, among others.

"I would think it would definitely be translatable to horses," Bernard said of the research. "But not all bacteria produce their cell walls the same. Different bacteria function in different ways, and one antibiotic might kill some bacteria and not others. It's possible that the protein is specific for a bacterium, not for bacteria in general. You might want that, because there are 'good' bacteria. Obviously, you wouldn't want to kill all the bacteria in the horse's gastrointestinal tract, for example."

Bernhardt said that the Texas laboratory's findings suggest that bacteriophages can be selected to be as general or as specific as required.

Some companies are already working on development of bacteriophage "cocktails" to target infections.

"Phages won't hurt anything but bacteria, and, if you choose the phages right, they will only affect the bacteria you want to kill off," he said.

Lameness detectors

A mechanical engineer at the University of Maryland-Baltimore County is trying to build a better lameness detector.

Uri Tasch, a UMBC professor, has developed a machine for the dairy industry that detects early lameness in cattle by measuring limb load, weight distribution, and other aspects of stride. But he also has conducted a small, preliminary study in horses and found that his machine accurately identified lameness in six of seven horses using load and stride analysis.

"We can 'see' lameness quicker this way than by the traditional way," Tasch said, noting that some developing lameness doesn't become apparent to a handler until the horse actually begins nodding his head at a walk or noticeably limps at a trot.

The machine, which is three feet wide and six feet long, uses a wooden platform and load-measuring devices in its floor plates to detect subtle differences in the way an animal places weight on its legs and feet. The load-measuring devices, called load cells, are attached to a computer that calculates and quantifies those differences instantly.

Tasch is hoping to build a larger model of his machine, which he estimates will cost about $40,000 to build, in order to accommodate two equine strides per test.

* The Grayson-Jockey Club Research Foundation received a total of $35,940 from donations connected to contenders in the 2001 Triple Crown and associated filly races. John and Debby Oxley, owners of Kentucky Derby winner Monarchos and Acorn Stakes winner Forest Secret; shareholders in Maria's Mon, sire of Monarchos; and The Thoroughbred Corp., owner of Belmont and Preakness winner Point Given, all contributed percentages of their horses' earnings to the foundation, which supports equine veterinary research.