Abstract
Urinary tract infections (UTIs) are the second most common bacterial infection. Urine culture is the gold standard for diagnosis, but new techniques, such as flow cytometry analysis (FCA), have been introduced. The aim of the present study was to evaluate FCA characteristics regarding bacteriuria, leukocyturia, and erythrocyturia in relation to cultured uropathogens in specimens from patients with a suspected UTI. We also wanted to evaluate whether the FCA characteristics can identify uropathogens prior to culture. From a prospective study, 1,587 consecutive urine specimens underwent FCA prior to culture during January and February 2012. Outpatients and inpatients (79.6% and 19.4%, respectively) were included, of whom women represented 67.5%. In total, 620 specimens yielded growth, of whichEscherichia colirepresented 65%,Enterococcusspp. 8%,Klebsiellaspp. 7%, andStaphylococcusspp. 5%. For the uropathogens, the outcome of FCA was compared against the results for specimens withE. coliand those with a negative culture.E. colihad high bacterial (median, 17,914/μl), leukocyte (median, 348/μl), and erythrocyte (median, 23/μl) counts. With the exception ofKlebsiellaspp., the majority of the uropathogens had considerable or significantly lower bacterial counts than that ofE. coli. High leukocyte counts were found in specimens withStaphylococcus aureus,Proteus mirabilis,Pseudomonas aeruginosa, and group C streptococci. Elevated erythrocyte counts were found forP. vulgaris,P. aeruginosa, and group C streptococci, as well as forStaphylococcus saprophyticus. In essence, FCA adds new information about the bacterial, leukocyte, and erythrocyte counts in urine specimens for different uropathogens. Based on FCA characteristics, uropathogens can be classified and identified prior to culture.E. coliandKlebsiellaspp. have similar FCA characteristics.
Publisher
American Society for Microbiology