[Microbiological diagnosis of urinary tract infections]

For the diagnosis of urinary tract infection (UTI), besides the quantification of bacteria in the urine, cellular elements contained in the urine, the collection method used and the clinical syndrome should also be considered. Therefore, the microbiological diagnosis of UTI should be performed by an experienced person who takes into account the diversity of situations that may influence the result of each of the cultures. The processing of urine samples depends on the number of samples received daily. In laboratories with a high number, it is impossible to culture each of them, so negative urines have to be ruled out by using automated systems and cultivate only those that are positive. This review includes an analysis of the methods currently available for this screening. It also includes procedures to be performed in special situations such as prostatitis, UTI caused by fastidious microorganisms and other kind of infections that may be diagnosed in a urine test.