P150
UTILITY OF URINE DIPSTICK AND SYMPTOMS IN SCREENING FOR URINARY
TRACT INFECTIONS IN RENAL TRANSPLANT RECEPIENTS
Gunawan A, Mahalingasivam V, Piso L, Rajakariar R, Yaqoob M
Barts and The London Renal Centre, Royal London Hospital
PROBLEM: Urinary Tract Infection (UTI) poses a major problem in renal transplantation (RT)
with prevalence predicted to be as high as 60% in the first year. UTI is associated with a high risk
of graft impairment and/or loss. Transplant centres may adopt different protocols in screening for
UTI among RT population. Moreover, there are studies which look into the effectiveness of urine
dipstick in the normal population but none which look specifically at the RT population which has a
higher risk due to underlying disease, immunosuppression, and surgical manipulations.
PURPOSE: This prospective study was conducted to look at the effectiveness of urine dipstick in
screening for UTI among the RT population, covering both acute and long-term recipients.
DESIGN: All RT outpatient attendees from 04/07/11 – 29/07/11 had mid-stream urine (MSU)
samples dipsticked and sent to the laboratory for microscopy, culture, and sensitivity (MC&S)
analysis. Urine dipstick analysis was considered positive when either nitrite was positive or white
cell count (WCC) count was more than ++. MC&S analysis was considered positive when
identifiable bacteria were cultured with more than 105 bacterial CFUs. The results were then
correlated with clinical signs and symptoms reported from clinic.
FINDINGS: A total of 504 MSU samples were analyzed using dipstick and laboratory MC&S. 24
samples were positive for nitrites and 38 samples were positive for WCC. 25 samples were culturepositive in MC&S. The most frequently isolated organism was Escherichia coli. 10 (40%) of the
culture-positive samples were urine dipstick negative. Out of these 10 samples, 7 (28%) samples
came from asymptomatic patients. Further analyses showed that female gender and previous history
of pyelonephritis to be statistically significant risk factors of developing UTI in our RT sampled
population (p values = 0.03 and <0.001 respectively).
CONCLUSION: This study demonstrates that UTI can be missed by using urine dipstick and/or
symptoms as prerequisite for formal MC&S testing. Some studies have shown that asymptomatic
bacteriuria in RT may lead to graft pyelonephritis, especially in the early transplant period. Thus,
identification of asymptomatic bacteriuria for possible treatment needs to be improved. We
recommend re-evaluation of protocols in screening for UTI among RT population. It may be
desirable to modify existing protocols to target high risk groups, such as female gender, first year of
RT, and previous history of pyelonephritis, by sending all samples for MC&S analysis, regardless
of dipstick analysis.