Infections and urolithiasis : current clinical evidence in prophylaxis and antibiotic therapy

Urinary tract infections and urosepsis are complications which can precede or follow a kidney stone treatment. Often the stones themselves are the source of infection, whether they are infection stones or not. Systemic infections are difficult to foresee, and neither a pre-operative negative urine culture nor an antibiotic prophylaxis avoid infectious complications for certain. The primary predictive risk factors of urosepsis are: patient conditions, urinary tract infection or a history of recurrent infections, characteristics of the stone, and anatomy of the urinary tract. Infection stones are still a matter of debate, concerning both the aetiology of the disease and its treatment. Positive cultures are not only found with struvite stones, but also with apatite and calcium oxalate stones. Currently, a long-term antibiotic therapy is advised in patients affected by infection stones. Antibiotic therapy should prevent not only septic complications but also recurrence or re-growth of stones after treatment. Different antibiotic modalities are recommended, sometimes together with urease inhibitors. Mid-stream urine culture is the easiest available pre-treatment parameter notwithstanding its poor predictive value. In case of suspected or proven urinary infection, an appropriate antibiotic therapy should always be administered prior to surgical procedure. There is, however, controversy regarding the antibiotic use, its role, expediency, and duration of prophylaxis in relation to the various surgical procedures, and the way infectious complications are considered and classified. When antibiotic prophylaxis is considered, its duration should be clearly established prior to surgery; duration may vary depending on the type of surgery or the type of antibiotic. Furthermore, prophylaxis should be administered only for a limited amount of time. In infection stones, in immuno-compromised patients or in patients with anatomical anomalies or diabetes, the risk of post-treatment infection and sepsis is higher. Hence there is agreement on the need for prophylaxis and antibiotic therapy. The most recent literature has shown excellent results with fluoroquinolones both in prophylaxis and therapy, concerning post-operative infection control after percutaneous as well as ureteroscopic removal of stones. No agreement has yet been reached on antibiotic prophylaxis modalities prior to percutaneous or ureteroscopic removal and its usefulness for SWL.