Evaluation of the Sysmex UF1000i flow cytometer for ruling out bacterial urinary tract infection

Rosa, Rita De; Grosso, Shamanta; Bruschetta, Graziano; Avolio, Manuela; Stano, Paola; Modolo, Maria Luisa; Camporese, Alessandro

doi:10.1016/j.cca.2010.03.027

Cited by 91 publications

(94 citation statements)

References 14 publications

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“…in high levels of amorphous debris) or due to inherent reading errors of the detection system. Our results contrast with those of other studies (Broeren et al, 2011;De Rosa et al, 2010), where the authors demonstrated that at any specificity, the corresponding sensitivity was higher for bacteria than for leukocytes. Where the ROC curve for bacterial cells falls below the line of identification in Fig.…”

Section: Discussioncontrasting

confidence: 99%

Screening urine samples for the absence of urinary tract infection using the sediMAX automated microscopy analyser

Sterry-Blunt

Randall

Doughton

et al. 2015

Journal of Medical Microbiology

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Urinalysis culminates in a workload skew within the clinical microbiology laboratory. Routine processing involves screening via manual microscopy or biochemical dipstick measurement, followed by culture for each sample. Despite this, as many as 80 % of specimens are reported as negative; thus, there is vast wastage of resources and time, as well as delayed turnaround time of results as numerous negative cultures fulfil their required incubation time. Automation provides the potential for streamlining sample screening by efficiently (.30 % sample exclusion) and reliably [negative predictive value (NPV) ¢95 %] ruling out those likely to be negative, whilst also reducing resource usage and hands-on time. The present study explored this idea by using the sediMAX automated microscopy urinalysis platform. We prospectively collected and processed 1411 non-selected samples directly after routine laboratory processing. The results from this study showed multiple optimum cut-off values for microscopy. However, although optimum cut-off values permitted rule-out of 40.1 % of specimens, an associated 87.5 % NPV was lower than the acceptable limit of 95 %. Sensitivity and specificity of leukocytes and bacteria in determining urinary tract infection was assessed by receiver operator characteristic curves with area under the curve values found to be 0.697 [95 % confidence interval (CI): 0.665-0.729] and 0.587 (95 % CI: 0.551-0.623), respectively. We suggested that the sediMAX was not suitable for use as a rule-out screen prior to culture and further validation work must be carried out before routine use of the analyser.

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Section: Discussioncontrasting

confidence: 99%

Screening urine samples for the absence of urinary tract infection using the sediMAX automated microscopy analyser

Sterry-Blunt

Randall

Doughton

et al. 2015

Journal of Medical Microbiology

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“…Although these numbers are comparable to another recent study evaluating the UF-1000i (11), most studies have reported a percentage of negative culture samples around 70 to 80% (2,4,15,22). The organisms identified in our study correspond well with earlier published results (2,4,9).…”

Section: Discussionsupporting

confidence: 91%

“…Within 2 h after Gram staining and culture plate inoculation, the second aliquots were transported batch-wise to the clinical chemistry laboratory and analyzed for bacteria and leukocytes with the Sysmex UF-1000i according to the manufacturer's guidelines using 800 l of each sample. The Sysmex UF-1000i performs an analysis of particles in urine by flow cytometry (4,11,12,14,20). A urine sample is diluted and stained in two different reaction chambers, one for bacteria and one for all other urine particles.…”

Section: Methodsmentioning

confidence: 99%

Screening for Urinary Tract Infection with the Sysmex UF-1000i Urine Flow Cytometer

et al. 2011

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The diagnosis of urinary tract infection (UTI) by urine culture is time-consuming and can produce up to 60 to 80% negative results. Fast screening methods that can reduce the necessity for urine cultures will have a large impact on overall turnaround time and laboratory economics. We have evaluated the detection of bacteria and leukocytes by a new urine analyzer, the UF-1000i, to identify negative urine samples that can be excluded from urine culture. In total, 1,577 urine samples were analyzed and compared to urine culture. Urine culture showed growth of >10 3 CFU/ml in 939 samples (60%). Receiver operating characteristics (ROC) curves and ROC decision plots were been prepared at three different gold standard definitions of a negative urine culture: no growth, growth of bacteria at <10 4 CFU/ml, and growth of bacteria at <10 5 CFU/ml. Also, the reduction in urine cultures and the percentage of false negatives were calculated. At the most stringent gold standard definition of no growth, a chosen sensitivity of 95% resulted in a cutoff value of 26 bacteria/l, a specificity of 43% and a reduction in urine cultures of only 20%, of which 14% were false negatives. However, at a gold standard definition of <10 5 CFU/ml and a sensitivity of 95%, the UF-1000i cutoff value was 230 bacteria/l, the specificity was 80%, and the reduction in urine cultures was 52%, of which 0.3% were false negatives. The applicability of the UF-1000i to screen for negative urine samples strongly depends on population characteristics and the definition of a negative urine culture. In our setting, however, the low workload savings and the high percentage of false-negative results do not warrant the UF-1000i to be used as a screening analyzer.

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“…The contamination of the analyzer thus does not interfere with the final result as long as the culture is performed either before the processing on the analyzer (as in our laboratory) or on a distinct sample tube. However, in both case scenarios, the economic benefit of the UF1000i, which lies in the simplification of the workflow and the prevention of unnecessary cultures (2,4), is lower than expected, not to mention the biohazard to the laboratory technicians working with the analyzer.…”

Section: Discussionmentioning

confidence: 91%

“…This automated system, which has been used in our 800-bed university hospital laboratory since January 2010, is established as a rapid and sensitive screening method with high negative predictive value which avoids the unnecessary culture of negative urine samples and presents large beneficial effects for both result turnaround time and laboratory economics (2,4). The present report describes a pseudo-outbreak that took place in our hospital from May to July 2010 that was caused by the contamination of this urinary sediment analyzer by an extremely drug-resistant (XDR) isolate of P. aeruginosa.…”

mentioning

confidence: 99%

Pseudo-Outbreak of Extremely Drug-Resistant Pseudomonas aeruginosa Urinary Tract Infections Due to Contamination of an Automated Urine Analyzer

et al. 2012

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By the end of May 2010, an increase in the number of urine specimens that were culture positive for extremely drug-resistant (XDR) Pseudomonas aeruginosa was observed in our 800-bed university hospital. This led to an infection control alert. No epidemiological link between the patients and no increase in the frequency of XDR P. aeruginosa in non-urine samples were observed. Therefore, a pseudo-outbreak due to analytical contamination in the laboratory was rapidly suspected. A prospective and retrospective search of cases was initiated, and the sampling of the automated urine analyzers used in the laboratory was performed. Antibiotypes were determined by disc diffusion, and genotypes were determined by pulsed-field gel electrophoresis (PFGE). From February to July 2010, 17 patients admitted to 12 different departments and 6 outpatients were included. The mixing device of the cytometric analyzer used for the numeration of urinary particles (Sysmex UF1000i) proved to be heavily contaminated. Isolates recovered from 12 patients belonged to the same antibiotype and PFGE type as the isolate recovered from the analyzer. Extensive disinfection with a broad-spectrum disinfectant and the replacement of the entire tubing was necessary to achieve the complete negativity of culture samples taken from the analyzer. A pseudo-outbreak caused by an XDR P. aeruginosa clone was proven to be due to the contamination of the cytometric analyzer for urinary sediment. Users of such analyzers should be aware that contamination can occur and should always perform culture either before the processing of the urine sample on the analyzer or on a distinct sample tube. Pseudomonas aeruginosa is a Gram-negative aerobic rodshaped bacterium that inhabits a wide range of environments, such as water, soil, the rhizosphere, and animals (11). It also is known as a frequent opportunistic pathogen in both animals and humans. Due to its potential for developing resistance against multiple antibiotic and antiseptic compounds, P. aeruginosa also has emerged as a major, difficult-to-treat nosocomial pathogen. P. aeruginosa is an important cause of morbidity and mortality in high-risk patients, such as immunosuppressed, cystic fibrosis, burn, cancer, and ventilated intensive care patients (11). To date, countless P. aeruginosa nosocomial outbreaks have been described that were caused by patient-topatient transmission, environmental sources, or contaminated medical devices (5,(8)(9)(10). P. aeruginosa also has been reported as a cause of pseudo-outbreaks due to the contamination of media used for clinical specimen collection, transport, or analysis (6, 12, 13).The Sysmex UF1000i is an automated fluorescence flow cytometer used to count and classify cells and particles in urine samples. This automated system, which has been used in our 800-bed university hospital laboratory since January 2010, is established as a rapid and sensitive screening method with high negative predictive value which avoids the unnecessary culture of negative urine samples and presen...

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Evaluation of the Sysmex UF1000i flow cytometer for ruling out bacterial urinary tract infection

Cited by 91 publications

References 14 publications

Screening urine samples for the absence of urinary tract infection using the sediMAX automated microscopy analyser

Screening urine samples for the absence of urinary tract infection using the sediMAX automated microscopy analyser

Screening for Urinary Tract Infection with the Sysmex UF-1000i Urine Flow Cytometer

Pseudo-Outbreak of Extremely Drug-Resistant Pseudomonas aeruginosa Urinary Tract Infections Due to Contamination of an Automated Urine Analyzer

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