What disease kills dogs quickly

Researchers discovered antibiotic in dog saliva: Bacterial virus kills disease pathogens in wounds

As early as the beginning of the 20th century it was found that licking wounds by dogs not only cleanses them, but also inhibits bacterial growth in the wound tissue. The strange thing was that this antibiotic effect of dog saliva could never be imitated in the laboratory in a test tube. Now it has also been found out why that is so.

The current research began a few years ago when the National Institutes of Health (NIH) beagle colony in Bethesda was infected with a non-disease-causing strain of bacteria and dental researchers found an almost complete absence of bacterial infections in gum wounds. It was shown that the dog saliva only works on wounds of dogs or humans, but not on other animals, for example cats; this suggests that the relationship between humans and dogs is older than previously thought.

Bacterium called Annie. . .

NIH researchers Polly Matzinger and Heinz Arnheiter discovered a harmless oral bacterium that is linked to the antibiotic activity of dog saliva. They named the bacterium Annie. The name is composed of the first letters of Antibiotically Novel Natural Innate Epiflora (antibiotic novel, natural, innate over-flora).

In the May issue of the magazine "Graft" the two researchers reported that the antibiotic effect does not come from Annie herself, but from a benign and harmless bacteriophage (literally, but incorrectly, bacterial eater; short form: phage), a virus, which resides inside her that does not affect animals or plants, but bacteria.

In honor of the bitch Lilly, from whom it was originally isolated, the bacteriophage was named Lil1. He is a natural symbiote, that is, he lives in symbiosis - for mutual benefit - with Annie, and obviously always; no phage-free colonies of Annie could be found.

. . . in symbiosis with Lil1

As a "broad spectrum antibiotic", Lil1 destroys a large number of different types of wound bacteria, but only - and this explains why the experiments in the test tube failed - if they are exposed to certain components of the wound exudate (the fluid that escapes from the vessels in the event of inflammation) and are thus to a certain extent damaged are.

Matzinger and Arnheiter found that undiluted saliva from dogs infected with Annie killed 92.5 percent of all bacteria within eight hours. In contrast, in dogs in which Annie was removed from the mouth by sterilization, only 8.7 percent of the bacteria were destroyed.

Lil1's discovery raised several questions: What is preventing the phage from destroying the dog's natural bacterial flora? Answer: The wound exudate or rather still unknown components of it must be added so that the phage can become a bacteria killer.

Why does Lil1 work against so many different bacteria while other phages only have a small number of "victims"? Answer: Possibly because the wound substances make the various bacteria ready for attack, so to speak.

How do dogs get the oral bacterium Annie? (All normal dogs examined, including wild ones, house Annie and Lil1.) Answer: The young dogs lick the snouts of adult dogs. (A warning should be given if you try to do this yourself: dog saliva can contain disease-causing viruses, for example rabies viruses, for which a wound is an entry point into the body and against which antibiotics are ineffective, and in some people it can trigger allergies.)

The dog has been associated with humans for more than 200,000 years. In primitive societies, in exchange for food and shelter, the four-legged friends were hunting companions, guards, warmers on cold nights and perhaps also a source of antibiotics - long before penicillin was discovered.

Further research for human medicine

Future research will show whether Lil1's antibacterial properties can be used for human or veterinary purposes to help solve the serious problem of bacterial resistance to conventional antibiotics. The fact that its antibiotic effect lasted for so many millennia without the bacterial invaders being able to develop an effective defense against it indicates that this bacteriophage, together with factors still to be investigated in wound exudate, could be an excellent candidate for treatment applications in medicine.