Identification and quantification of immunological markers excreted in urine in response to urinary tract infection

Morris N1, Drake M3, Thompson R1, Luxton R2, Barnett J2, Jacobson K4
1Bristol Urological Institute, Bristol, United Kingdom, 2University of West of England, Bristol, United Kingdom, 3University of Bristol, Bristol, United Kingdom, 4North Bristol NHS Trust, Bristol, United Kingdom

Introduction:
Inflammation is the body's innate response to bacterial infections. Certain proteins are excreted into the urine as a consequence of infection, these proteins are called immunological markers. A lack of information exists regarding the quantity and type of immunological markers excreted in human urine in response to a urinary tract infection. Could these markers be utilised to develop a diagnostic test for UTI that improves upon the dip-stick and enhances clinical decision making regarding the safeguarding of antibiotics.
Materials and Methods: In this study we collected urines infected with either E.coli, P.mirabilis or K.pneumoniae and utilised enzyme-linked immunosorbent assays to compare levels of a range of immunological markers with healthy individuals. We investigated Interleukin 8, Interleukin 6, Procalcitonin, Lactoferrin, and Uromodulin (Tamm-Horsfall).

Results:
We found that levels of these markers indeed change with infection by differing bacterial species. Levels of Interleukin 8, Interleukin 6, and Lactoferrin were more concentrated in patients with UTI compared to healthy controls. Uromodulin was present in significantly lower quantities in urines infected with E. coli compared to all other urines tested.

Conclusions:
Lactoferrin and Interleukin 8 were the best markers of infection with E.coli, P.mirabilis and K.pneumoniae. It is our hope that this information could be used to develop a rapid diagnostic test for UTI, ensuring more accurate detection of symptomatic UTI resulting in more appropriate perscribing of antibiotics.