Does flow cytometry have a role in preliminary differentiation between urinary tract infections sustained by gram positive and gram negative bacteria? An Italian polycentric study

作者：Gessoni Gianluca^*; Saccani Graziella; Valverde Sara; Manoni Fabio; Caputo Marco

来源：Clinica Chimica Acta, 2015, 440: 152-156.

DOI：10.1016/j.cca.2014.11.022

• Bacteriuria
• B_FSC
• UF-1000i
• Gram discrimination
• UTI

Background: Urine culture is the most frequently requested test for a Microbiology Lab. A reliable screening tool would be of paramount importance both to clinicians and laboratorians, provided that it could get fast and accurate negative results in order to rule-out urinary tract infection (UTI).
Materials and methods: We evaluated 1907 consecutive urine samples from outpatients. Culture was performed on chromogenic agar with 1 mu L loop, using 105 CFU/mL as a limit of positive growth. Using Sysmex Uf-1000i analyzer we evaluated bacteria forward scatter (B_FSC) and fluorescent light scatter (B_FLH) in a preliminary discrimination step for UTI caused by Gram+ or Gram- bacteria.
Results: We got 512 positive samples. A mono-microbial infection was observed in 490 samples; two bacterial strains were isolated in 22 samples, so 534 bacterial strains were found: 392 Gram, 133 Gram+ and 9 yeasts. Comparing Gram+ and Gram- bacteria we observed a statistically significant difference for B_FSC but not for B_FLH. In this application experimental cut-off value for B_FSC was 25ch. Using this cut-off to perform a presumptive identification of UTI sustained by Gram-+ bacteria, we observed a SE 0.68, SP 0.84.
Conclusion: Our data although preliminary suggest that B_FSC could be useful in presumptive exclusion of UTI caused by Gram-positive bacteria.

• 出版日期2015-2-2