[Dailydrool] Bacteria and antibiotics

[Pamela McQuade]

Poor Rosie, with a massive bladder infection. Our hounds will sling some drool her way and hope that she feels better soon.

I am by no means an expert on antibiotics and bacterial infections, but for a number of years I freelanced for a pharmaceutical company, and I was fascinated by how antibiotics work.

Carol, it sounds to me as if your vet followed standard practice with the antibiotics. Because it's easy to build up a resistance to an antibiotic (which means it will not work), vets usually start with a less powerful antibiotic that frequently works on the problem in question. Why don't they start with the most powerful drugs first? Because overuse of powerful antibiotics when they are not needed tends to makes them less effective when you really need them to pack a punch.

Every antibiotic works on certain bacteria. Some work on a few strains, while others, the "broad spectrum" antibiotics, work on many. A vet starts out by using an antibiotic that targets the most likely cause of infection. But that's no guarantee that the bacteria that caused the problem IS the most common one. Your vet has no way of knowing just what bacteria caused the problem without running a test that identifies it. That's why he's running a second test The first test said, "Urinary tract infection." The second one will say, "Urinary tract infection caused by _____," and it will identify the best drugs to use for that bacteria. In the meantime, he put Rosie on a broad-spectrum antibiotic, which works on more of the bacteria that typically cause UTIs.

In my experience with antibiotics, both for myself and hounds, it's not unusual to have to switch to a broad-spectrum one. That second drug often works. He gave you the second drug because he does not want to wait days while the test comes back without treating her, possibly with a drug that will be effective. If the broad-spectrum drug does the job, and you're home free. But sometimes it may work to some degree, but does not entirely kill off the bacteria. Or it may not work at all. In either of the second two situations a third drug that's more effective on that bacteria should solve the problem. No matter what the case is, you want a drug that really works optimally on the bacteria that has invaded Rosie's system.

Do not worry that the first drug did not work. Your vet did nothing wrong. there are a lot of bacteria out there, and UTIs can be caused by a number of them. If the second drug works, great. You probably think of it as a waste to have to use a third drug, but if you have to, it may be just the thing to wipe out the infection quickly.

I hope, Carol that this makes more sense to you. Your vet is not jerking you around. It's just that tests take time, and while that time is passing, your vet wants to try to get Rosie some relief.

May Rosie soon be feeling perky again.
Pam, food slave to the Dashing Bassets