title: Direct identification of bacteria causing urinary tract infections by combining matrix-assisted laser desorption ionization-time of flight mass spectrometry with UF-1000i urine flow cytometry.
abstract: Rapid identification of bacterial pathogens from clinical specimens is essential to establish an adequate empirical antibiotic therapy to treat urinary tract infections (UTIs). We used matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) combined with UF-1000i urine flow cytometry of urine specimens to quickly and accurately identify bacteria causing UTIs. We divided each urine sample into three aliquots for conventional identification, UF-1000i, and MALDI-TOF MS, respectively. We compared the results of the conventional method with those of MALDI-TOF MS combined with UF-1000i, and discrepancies were resolved by 16S rRNA gene sequencing. We analyzed 1456 urine samples from patients with UTI symptoms, and 932 (64.0%) were negative using each of the three testing methods. The combined method used UF-1000i to eliminate negative specimens and then MALDI-TOF MS to identify the remaining positive samples. The combined method was consistent with the conventional method in 1373 of 1456 cases (94.3%), and gave the correct result in 1381 of 1456 cases (94.8%). Therefore, the combined method described here can directly provide a rapid, accurate, definitive bacterial identification for the vast majority of urine samples, though the MALDI-TOF MS software analysis capabilities should be improved, with regard to mixed bacterial infection.
authors.affiliation: The Clinical Laboratory, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, People's Republic of China.
authors.forename: X-H
authors.initials: XH
authors.lastname: Wang
authors.forename: G
authors.initials: G
authors.lastname: Zhang
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Fan
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: W-J
authors.initials: WJ
authors.lastname: Sui
authors.forename: X-X
authors.initials: XX
authors.lastname: Lu
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification*; D001431:Bacteriological Techniques / Q000379:methods*; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014552:Urinary Tract Infections / Q000175:diagnosis* / Q000382:microbiology; D014556:Urine / Q000382:microbiology