Are these sentence's correctly punctuated?

The motor vehicle accident, however, was not the patient's fault.

Dr. Jones is an excellent surgeon, but does not have a good bedside manner.

She was tried on various antibiotics, and an infectious disease specialist was called in to advise on this.

The first and third are punctuated correctly. But there should not be a comma after surgeon in the second sentence. The words after but is a dependent clause so is not set off by a comma.