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Kidney stone surgery and antibiotics

Study examines the use of shorter courses of antibiotics given after kidney stone surgery

November 19, 2014

Kidney stones can be terribly painful. And for some patients, it gets worse.

When someone isn’t able to pass a stone, surgery may be necessary. Most patients easily recover, but others are at high risk for postoperative infections.

Several studies have suggested that a seven-day course of antibiotics significantly decreases this risk. But Washington University urologist Alana Desai, MD, thinks seven days is probably much too long.

Desai points out that no studies in kidney stone patients have compared a seven-day course of antibiotics with a shorter duration. Until now.

In 2013, Desai and colleagues began a retrospective study that looked at patients who are at high risk for infection. They compared those who were given antibiotics for two days versus those treated for seven days. The study is ongoing, and so far they have found no difference between the two patient groups in rates of fever, urinary tract infection (UTI), and other severe responses to infection, such as sepsis or inflammation.

Concern over antibiotic overuse

“There is growing concern over increasing antibiotic resistance due to overuse,” Desai says. There are also side effects caused by antibiotic use and the potential for patients to develop other infections, she adds. “If we are able to prove that a shorter duration of antibiotics confers the same protection against postoperative infectious complications, we can lessen the consequences of antibiotic overuse.”

Urologist Alana Desai, MD, is studying the effects of using a shorter course of antibiotics to prevent infection after kidney stone surgery.
Urologist Alana Desai, MD, is studying the effects of using a shorter course of antibiotics to prevent infection after kidney stone surgery.

Desai first started using the shorter course of antibiotics in late 2012. She had a 23-year-old spina bifida patient whose kidneys were both full of stones. This patient had been treated for recurrent UTIs for three years. It was a complex case, so Desai consulted with an infectious disease specialist, who suggested a two-day course of antibiotic treatment before stone removal surgery.

“I thought this was absurd considering the long-standing nature of this patient’s infections,” Desai says. But she went with the recommendation.

The patient did well, with no postoperative infections. And that’s when Desai began using the shorter antibiotic course regularly in patients at high risk for infection.

These patients include people who are unable to empty their bladders because of spinal cord injury or other neurological conditions. Other high-risk patients are those who have stones larger than 2 centimeters, recurrent UTI or urinary obstruction.

Desai presented results of the retrospective study at the 2014 American Urological Association annual meeting.

She has now applied for a grant to fund a prospective, randomized study comparing two-day and seven-day courses of prophylactic antibiotics in kidney stone patients undergoing surgery. Again she will compare rates of postoperative infection-related complications. In collaboration with the laboratory of molecular microbiologist Scott Hultgren, PhD, she will also investigate the mechanisms for bacterial resistance and survival inside kidney stones.

“There are no clear guidelines on antibiotic use for infection stones,” Desai says. “I would like to help establish those guidelines in this first prospective study comparing antibiotic duration, with the hope that a short course of antibiotics is as effective as a course of longer duration.”