Thanks for the question
In direct answer to your question : In almost all cases the answer would be no antibiotics are suitable to treat pyometra as they are rarely effective in the face of this disease and immediate surgery is the normal course of action. The following is an excerpt from an article I wrote on the subject of pyometra which has been published elsewhere.
Pyometra is a potentially fatal very serious disease which can easily be treated with surgery and this is almost always the only way forward. Ultrasound would be a reliable way to come to a diagnosis. I will tell you what I know of the condition, the following is from an article I wrote about this disease which was published elsewhere ...
Cause: The cause of this disease is quite complex, it usually follows cystic endometrial hyperplasia which is a type of womb disease, this changes the internal environment of the womb and makes it prone to bacterial infections. Once the bacterial infection is established it goes wild and a full blown pyometra is the result. Other contributory factors would be the use of drugs to postpone or control the dog’s seasons. Pyometra can also occur in stumps left after spaying and on occasion following womb infection after the animal has given birth.
Clinical Signs: [Symptoms] These dogs will be lethargic, will have no appetite and will be drinking much more than normal. Some will have a vaginal discharge which cases are called an open pyometra, others will have no vaginal discharge and these are termed closed pyometras. Obviously these dogs are not spayed, they are usually more than six years of age in my experience and they will have been in season just prior to the onset of symptoms.
Diagnosis: The above clinical signs would on their own be very suggestive of pyometra. I found ultrasound very useful to confirm the diagnosis in these cases, X-rays could be used as well, and a high white cell count is also indicative.
Treatment: The main treatment for this disease is an immediate hysterectomy operation [ Spay ]. It differs from a normal spay operation in that as the dog is usually quite sick you need to provide additional support like putting it on a drip and a higher level of post operative care.
If I have not covered your question fully enough or you would like to ask more I will be online for the next hour or so and I will be at your disposal.Scott Nimmo BVMS MRCVS