Study On Bacteria Count Of Using Urine Flow Cytometer UF1000i

Objective (1)To evaluate the accuracy of bacteria counting of Sysmex UF1000i Urine Sedimentary analyzer;(2)To establish reference intervals of urinary bacterial count by using the fully automated urine particle analyzer UF-1000i,as they are useful in screening for,and selecting the drugs of, urinary tract infection, and assessing the therapeutic effect of drugs for diagnosis of urinary tract infection(UTI).Methods (1)The ATCC25922(E. coli) and ATCC25923(S.aureus) strains were made of a certain concentration of bacterial suspension. Choosing103-108cfu/ml concentrations,UF-1000i and bacterial culture test which the number of colonies,then the linear of UF1000i was evaluated. Selecting the103-105cfu/ml concentrations,the accuracy and precision of UF1000i was evaluated. The primers were determinded targeting16SrDNA gene of bacteria,and the RQ-PCR amplification reaction system was established using SYBR Green I fluorescent dye. The standard curve was built based on the recombinant plasimid DNA containing the specifical amplicon of the target gene and the RQ-PCR detected DNA samples with different concentrations of E.col and evaluated its accuracy. Simulated samples with antibiotics and containing specimens of the dead bacteria, which the UF-1000i, bacterial culture and RQ-PCR methods test bacterial count of.From the molecular level,the accuracy of UF-1000i was assessed;(2)All of263mid-stream urine samples were collected from healthy adults(133males and130females).In this testing, urinary bacterial count and conductivity are performed by UF-1000i,and urinary creatinine performed by UNICEL DXC800.Then according to the Clinical and Laboratory Standards Institute(CLSI) guidelines, reference intervals of urinary bacterial count was established, which were regulated with conductivity and creatinine respectively.87urine samples obtained from outpatient were used to evaluate the three reference interval established by UF1000i compared to culture method.Results (1)The linearity of bacteria counts within the range of103-107/ml could be conformed using both E.coli and S.aureus. Average CV for the UF1000i was12.3%, compard to22.3%achieved from culture method,and bacteria count between UF1000i and culture was no significant differences(p>0.05).Average CV for RQ-PCR was13.2%,and bacteria count between RQ-PCR and culture was no significant differences(p>0.05).Accuracy of UF1000i and RQ-PCR,which obtained from samples with antibiotics and the dead bacteria, was110.5%,89.6%,111.3%,76.9%,50.1%and0%respectively;(2)The upper reference limits for BACT were23.3/ul for males and353.8/ul for females. The calculated reference values for BACT regulated with creatinine and conductivity were respectively2.0/mmolCr and1.4cm/ulms for males and49.5/mmolCr and28.1cm/ul ms for females. The sensitivity specificity and Youden’s index of the UF-1000i for UTI screening were0.675,80%,87.5%using the upper reference limits for BACT repectively. The sensitivity,specificity and Youden’s index of the UF-1000i were86.11%,80%,0.611and88.89%,86.67%,0.756using the calculated reference values for BACT regulated with creatinine and conductivity respectively.Conclusion (1)UF1000i have a higher accuracy compared to bacteria culture and RQ-PCR. Samples containing antibiotics or the damaged bacterial are also able to count accurately;(2) When urine creatinine was used, the bacterial count≤2.0/mmolCr for males and<49.5/mmolCr for females are valuable data as reference intervals of urinary bacterial count by using UF-1000i.