Letter to the Editor: Diagnostic Criteria in Urological Diseases do not Always Match with Findings by Extended Culture Techniques and Metagenomic Sequencing of 16S rDNA

Vitaly Smelov1, Kurt Naber2, Truls E. Bjerklund Johansen3, *
1 Screening Group, International Agency for Research on Cancer, World Health Organization, 150 Cours Albert Thomas, 69372 Lyon, France
2 Technical University of Munich, Karl-Bickleder-Str. 44c, 94315 Straubing, Germany
3 Department of Urology, Oslo University Hospital, PO Box 4959, Nydalen, Oslo, Norway

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© Smelov et al. ; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution-Non-Commercial 4.0 International Public License (CC BY-NC 4.0) (, which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Department of Urology, Oslo University Hospital, 4959, Nydalen, Oslo, Norway; Tel: +47 91841063; E-mail:


Some diseases of the urinary tract are defined by the presence of microorganisms while others are defined by their absence. The underlying idea has always been that urine from healthy subjects is sterile and a negative urine culture has usually been taken as discriminative for an infection to be absent. Several disorders with symptoms that resemble infections are regarded as separate entities based on the exclusion of bacterial growth such as overactive neurogenic bladder and pelvic pain syndromes. During the recent years two paradigmata related to the role of bacteria in urological disease classification have changed completely. Firstly, bacteriuria does not necessarily mean an infection, and secondly, if extended sets of culture media for identification of fastidious and anaerobic bacteria or culture-independent metagenomic sequencing (MGS) is applied, a broad range of even non-culturable bacteria has been detected in the ”sterile” bladder urine in healthy individuals. The aim of this editorial is to initiate a discussion to redefine the criteria for urinary tract infections and non-infectious urological disorders with similar symptoms. Clinical studies, in which extended sets of culture media and MGS are integrated, are needed to clarify the pathogenesis of urological disorders where bacteria may play a role. The pure detection of bacteria in the urine does not by itself prove an infectious etiology of a specific disorder. It is important to avoid that results of new technologies lead to unnecessary antibiotic consumption with unwanted collateral damage and adverse events.

Keywords: Asymptomatic bacteriuria, metagenomic sequencing, non-infectious urological disorders, urinary tract infection.