274 Infection 29 · 2001 · No. 5 © URBAN & VOGEL Infection Brief Report Urine Interleukin-8 Is a Marker for Urinary Tract Infection in Postoperative Patients D.P. Olszyna, H. Vermeulen, A.H. Baan, P. Speelman, S.J.H. van Deventer, D.J. Gouma, T. van der Poll Abstract Background: Urine of patients with urinary tract infection (UTI) contains high levels of interleukin (IL)-6 and IL-8. However, knowledge of the kinetics of their release in urine is limited. We therefore compared the appearance of IL-6 and IL-8 in urine after uncomplicated surgery and surgery complicated by UTI. Patients and Methods: 165 patients undergoing abdominal surgery who received a urinary catheter were studied. Urine IL-6 and IL-8 were prospectively measured in patients who did (n = 10) or did not (n = 20) develop UTI. Statistical analysis was done by one-way ANOVA and the Mann-Whitney test. Results: Although urine IL-6 increased in the 2 to 4 days preceding the bacteriological documentation of UTI, a similar increase was observed in patients who did not develop UTI. Urine IL-8 was elevated on the day UTI was diagnosed, while remaining low in controls. Conclusion: In this patient group with postoperative UTI, urine IL-8 was a better marker for the early host response than urine IL-6. Key Words Interleukin-6 · Interleukin-8 · Urinary tract infection · Surgery · Leukocyturia Infection 2001; 29: 274–277 DOI 10.1007/s15010-001-1157-z Introduction Hospital-acquired urinary tract infections (UTIs) amount to approximately 500,000 cases a year in the United States alone.The presence of a urethral catheter is associated with 80 – 95% of cases [1]. Besides bacterial factors, such as the presence of fimbriae and the production of hemolysin, host factors are considered to play an important role in the pathogenesis of UTI [2]. In particular, the inflammatory re- sponse mounted in the urinary tract may be involved in host defense against ascending UTI. Interleukin (IL-)6 is an immunoregulatory cytokine with a wide spectrum of biological activities [3]. IL-8 is a prototypic member of the CXC chemokine family, which primarily targets neutrophils, cells commonly found in urine from patients with UTI [4]. Elevated levels of IL-6 and IL-8 have been found in urine of patients with asymp- tomatic bacteruria [5] and acute pyelonephritis [6, 7]. De- spite mounting evidence that both cytokines play a role in these conditions, knowledge of the kinetics of their release in urine directly before and after the development of UTI and of their potential value as early markers for UTI is lim- ited. Therefore, in the present study we prospectively fol- lowed a large group of surgical patients who received a uri- nary catheter (and thus were at risk for UTI), and com- pared sequentially measured urinary IL-6 and IL-8 con- centrations in patients who did and those who did not de- velop UTI. Patients and Methods Study Design Patients above 18 years of age, who were about to undergo major abdominal surgery, were eligible for this study.Written informed consent was obtained from all study participants and the study was approved by the ethics and research committees of the Academic Medical Center. Surgical procedures included hepato-pancreatico- biliary, esophageal, colon and stomach procedures, i.e. none of which involved the urinary tract. Exclusion criteria were: serum creatinine levels higher than 110 mmol/l (men) or higher than 95 mmol/l (women), bacteriuria or any other urological disease, a uri- nary catheter in situ or incontinence. Patients randomly received either a suprapubical or a transurethral catheter. Catheterization was performed under general anesthesia (directly before surgery) and the catheter was connected to a closed collection system. D.P. Olszyna, S.J.H. van Deventer, T. van der Poll (corresponding author). Dept. of Experimental Internal Medicine, Academic Medical Center, Room G2-132, Meibergdreef 9, NL-1105 AZ Amsterdam, The Netherlands; Phone: (+31/20)-5669111, Fax: -6977192, e-mail: t.vanderpoll@amc.uva.nl P. Speelman Dept. of Internal Medicine, Division of Infectious Diseases,Tropical Medi- cine and AIDS, University of Amsterdam, Amsterdam, The Netherlands D.J. Gouma, H. Vermeulen Dept. of Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Received: October 5, 2000 • Revision accepted: July 14, 2001