160 Accuracy of dipstick urine analysis and urine flow cytometry to predict bacteriuria prior to GreenLight laservaporisation of the prostate

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Accuracy of dipstick urine analysis and urine flow cytometry to predict bacteriuria prior to GreenLight laservaporisation of the prostate Eur Urol Suppl 2016;15(3);e160          

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Bonkat G.1 , Halla A. 1 , Seifert H.1 , Müller G.1 , Egli A. 2 , Regeniter A. 3 , Gasser T.1 , Bachmann A. 1 , Rieken M. 1 1 University

Hospital Basel, Dept. of Urology, Basel, Switzerland, 2 University Hospital Basel, Dept. of Medical Microbiology, Basel,

Switzerland, 3 University Hospital Basel, Dept. of Laboratory Medicine, Basel, Switzerland INTRODUCTION & OBJECTIVES: Urine cultures (UC) are recommended prior to transurethral prostate surgery such as GreenLight laservaporisation of the prostate (GLV) to rule out bacteriuria. However, UC has a typical time delay of 24-48 hours between sample acquisition, pathogen identification and delivery of antimicrobial susceptibility testing results. The aim of our study was to determine the diagnostic accuracy of dipstick testing and urine flow cytometry to predict bacteriuria in patients undergoing GreenLight laservaporisation of the prostate. MATERIAL & METHODS: Retrospective analysis of 567 urine samples from 458 patients who underwent GLV with the 180-W XPS laser for benign prostatic obstruction between 04/2010 and 08/2015. Urine samples were obtained via clean catch (MSSU) technique 1 to 28 days prior to GLV. In patients with an indwelling transurethral catheter urine specimens were obtained after catheter removal via a freshly placed catheter. Specimens were sent for conventional culture (UC), urine flow cytometry (UFC) and automated dipstick analysis (DA). Results of UC were interpreted according to the European Urinalysis Guideline. UFC was performed using the Sysmex 1000i (TOA Medical Electronics, Kobe, Japan), DA by automated Roche Atlas Urisys System (Roche Diagnostics, Basel, Switzerland), respectively. Sensitivity and specificity of UFC and DA in predicting bacteriuria were compared to UC. Statistical analyses were performed with SPSS, version 20.0. RESULTS: Overall, UC culture, UFC and DA were positive in 22%, 52% and 53% of the cases, respectively. Samples obtained via MSSU were positive in 12%, 28% and 33% compared to 35%, 84% and 81% of specimens obtained from patients with indwelling catheter. In MSSU cases, the sensitivity and specificity of UFC (86% and 80%) were significantly (p<0.05) higher compared to DA (84% and 74%). In specimens obtained from patients with indwelling catheter, the sensitivity and specificity of UFC (98% and 24%) and automated DA (95% and 27%) were comparable and showed no statistically significant difference. In patients with a positive UC obtained by MSSU, Enterococcus spp. (26%), Escherichia coli (22%), and Pseudomonas aeruginosa (12%) were most commonly detected. In contrast, in patients with indwelling catheter, Enterococcus spp. (26%), Escherichia coli (14%), and Enterobacteriaceae not otherwise specified (11%) were the most frequent detected pathogens. CONCLUSIONS: Urine flow cytometry may be recommended to rule out bacteriuria in patients prior to GLV without indwelling catheter. Due to high sensitivity and high specificity, obtaining a urine culture may be regarded as unnecessary in patients with negative urine samples. In patients with indwelling transurethral catheters, urologists should ensure that the results of urine cultures are available prior to GLV.