If reducing the risk of surgical infections is as simple as giving the correct amount of the correct antibiotic at the correct time, then why are so many of you struggling to get it right?

It's apparently all in the timing. A new study that looked at more than 2,900 hospitals found that these facilities properly administered antibiotics only about 55 percent of the time. It's not that the hospitals failed to give most of the 34,000 study patients antibiotics before surgery. But the drugs were often wrong, the researchers found, and, more importantly, so was the timing.

"What's important is the correct amount of the correct antibiotic at the correct time," says Dan Mayworm, our resident infection prevention expert. "This sounds easy, but the fact is that there are no clear-cut and definitive guidelines -and what is there is subject to interpretation."

Researchers also noted many instances where patients were given the right drugs, but were also given unnecessary medications or were kept on antibiotics too long. Either action could contribute to the growth of antibiotic-resistant bacteria, says the study, which appears in the current Archives of Surgery.

The precise timing of preoperative antibiotic delivery to prevent surgical infections is critical, but often not strictly regulated. Though researchers have known for years that you should administer antibiotics about 60 minutes before the first surgical incision is made, surgeons don't always adhere to the guidelines. If you give a drug too early, its effects might wear off by the time a wound is opened, and an infection could occur. If it's given after surgery begins, an infection might have already set in.

It used to be common practice to overprescribe antibiotics before surgery. This covered a multitude of sins, says Mr. Mayworm, but this overuse created a whole new strain of antibiotic-resistant bacteria. Today, guidelines restrict the use of antibiotics unless there's a clear medical need for them. The surgeons' dilemma: "Which is worse, overprescribing or underprescribing?" asks Mr. Mayworm.

So, yes, it sounds simple: Give all surgical patients antibiotics on time and you'll reduce the human and financial costs of surgical infections. But while the surgeon probably orders the drug correctly, the pre-op process is complex, as our safety columnist, obstetrician/gynecologist Mark S. Davis, MD, points out. The pre-op nurse or anesthesia personnel may or may not give the drug on time because they're doing so many other things for that patient (and all other pre-op patients) to get patients to the OR on time.

"We should study and clone the surgical services that get it right all the time," says Dr. Davis.