Category: Clinical Stones: PCNL

MP7-9 - Are preoperative urine microbiology results representative of intraoperative stone culture in percutaneous nephrolithotomy?

Fri, Sep 21
10:00 AM - 12:00 PM

Introduction & Objective :

Percutaneous nephrolithotomy (PCNL) is a standard treatment for renal calculi >2cm and staghorn calculi. Guidance recommends the treatment of urinary infections pre-operatively, and the use of prophylactic antibiotics intra-operatively.1 All patients should have midstream specimens of urine (MSSU) preoperatively. Despite this practice, pyrexia, systemic inflammatory response, and sepsis remain the commonest complication of PCNL.2-4 

Antibiotic management of patients who develop symptoms is guided by stone cultures, blood cultures and MSSU. The aim of this study was to determine if urine and stone cultures showed consistency of organisms cultured.

Methods :

This was a retrospective audit of prospectively collected data by review of clinical and operative notes from patients undergoing PCNL by a single surgeon between September 2012 and November 2016. Patient demographics, preoperative blood biochemistry, midstream specimen of urine (MSSU), operative factors, lithiasis factors and post-operative sepsis, blood cultures and stone cultures were recorded, as well as details of the antibiotics given post operatively.

Results :

There were 181 PCNL procedures performed. 174/181 (96.1%) patients had a preoperative urine specimen (either mid stream, urinary catheter, suprapubic catheter, or nephrostomy samples). 56/174 (32.2%) patients had a positive urine samples preoperatively.
All 181 (100%) patients who underwent PCNL received antibiotics, positive MSSUs were treated preoperatively. Stone cultures were performed in 165/181 (91.2%) patients, and 96/165 of these were positive (58.2%).
Postoperatively 32 patients (17.7%) developed post-operative pyrexia, systemic inflammatory response or sepsis. Pre-operative urine cultures were positive in 18/32 (56.2%), compared to 26/32 (81.3%) positive stone cultures. 15/32 (46.9%) patients had both urine and stone cultures that were positive, and of these, 10/32 (31.2%) patients grew the same strain of organisms in both their preoperative urine and intra-operative stone culture.

Conclusions :

All patients were treated with prophylactic antibiotics based on preoperative urine cultures. Patients who develop postoperative symptoms had positive stone cultures more commonly than urine cultures, however 15/33 patients had both cultures positive and 10 cultured specimens identified corresponding organisms, suggesting preoperative urine culture and stone culture are both useful for guidance of antibiotic choice of postoperative infective complications.

Caroline Bradley

Academic Foundation Year 2
NHS Greater Glasgow and Clyde
Glasgow, Scotland, United Kingdom

Dr Caroline Bradley, MBChB BMedSci (Hons)
Academic Foundation Year 2, NHS Greater Glasgow and Clyde
Currently working at the Beatson West of Scotland Cancer Centre

Lynne Kerr

NHS Greater Glasgow and Clyde
Glasgow, Scotland, United Kingdom

Jane Hendry

Glasgow, Scotland, United Kingdom

Gareth E. Jones

Glasgow, Scotland, United Kingdom