Introduction and Objectives: In this study we assessed the usefulness of preoperative urine cultures as a tool to prevent infections due to Gram negative microorganisms in patients undergoing prosthetic surgery.

Materials and Methods: In 2007 procedures were carried out to implant 259 knee prostheses and 101 hip prostheses, 47 of these were revision procedures. Pre-operative exams included urine culture to detect asymptomatic bacteriurias which could be treated before surgery with positive results. A urinary catheter was placed in all patients and removed after 24 hours.

Results: Asymptomatic bacteriuria was found in 13% of patients. In 6 patients the urine culture was positive for more than one microorganism. The most frequently found pathogen was E. coli. All cases were treated with antibiotics and a new urinary culture was carried out before surgery. Our infection rate is 0.8% in primary hip replacements and 8.1% in revisions. And 1.9% in primary knee replacements and 6.7% in revisions. An infection caused by a Gram negative microorganism in a revision THR was caused by a subclavian catheter colonized by Pseudomona aeruginosa.

Discussion and Conclusions: Our preoperative studies protocol includes urine culture. We have not seen any TKR or THR infections caused by Gram negative microorganisms. Therefore, based on this, we suggest that preoperative urine culture is useful to identify asymptomatic bacteriuria and treat it, thereby avoiding infections caused by Gram negative microorganisms in patients undergoing prosthetic surgery.