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Performance of the S ysmex UF 1000i system in screening for significant bacteriuria before quantitative culture of aerobic/facultative fast‐growth bacteria in a reference hospital
Author(s) -
GutiérrezFernández J.,
Lara A.,
Bautista M.F.,
Dios Luna J.,
Polo P.,
Miranda C.,
Navarro J.M.
Publication year - 2012
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2012.05369.x
Subject(s) - bacteriuria , bacteria , microbiology and biotechnology , colony forming unit , predictive value , bacterial colony , aerobic bacteria , biology , medicine , urine , genetics
Objective To evaluate the performance of the S ysmex UF 1000i automatic urine screening system in the quantitative culture of fast‐growth aerobic/facultative bacteria. Methods and Results A standard procedure was used to recover fast‐growth aerobic/facultative micro‐organisms in 1225 samples, applying ( S ysmex ® ) flow cytometry for parallel bacteria and leucocyte counts. According to the area under the receiver operating characteristic curve, the optimal cut‐off values to detect bacteriuria >10 5 colony forming units ( CFU ) ml −1 were 690/μl for bacteria and 38/μl for leucocytes (sensitivity, 92%; specificity, 65%; positive predictive value [ PPV ], 39%; and negative predictive value [ NPV ], 97%). The use of a single cut‐off point of 150 bacteria μl −1 to detect significant bacteriuria of >10 5 CFU ml −1 or of ≥10 4 CFU ml −1 plus leucocyturia obtained similar results (sensitivity, 89%; specificity, 54%; PPV , 31%; and NPV , 96%) and allowed 45·7% of the samples to be rapidly excluded. Conclusions The S ysmex UF 1000i system can be adapted for bacteriuria screening by the use of an appropriate cut‐off point. Significance and Impact of the Study This screening system significantly reduces the workload and produces very few false positives and negatives.