A total of 692 midstream urine samples were cultivated on agar,and were identified by MALDI-TOF MS and Vitek 2 Compact automated microbial amalyslis system (Vitek 2 Compact). Direct identification of midstream urine samples were also conducted by MALDI-TOF MS after preparation.

Of the 692 midstream urine samples, 98 samples were positive for one kind of bacteria (>10⁴ CFU/mL). The overall detection rate of direct identification by MALDI-TOF MS was 75.5%,and 74 isolates were identified,among which 39 isolates were Escherichia coli with the detection rate of 79.6%,23 isolates were Enterococcus faecalis with the detection rate of 100.0%,and 5 isolates were Morganella morganii with the detection rate of 100.0%. Among the 64 midstream urine samples with multiple microorganisms,44 samples were detected with a dominant bacteria by direct identification. The consistency rate was 100.0% among the results by direct identification,the identification of colony by MALDI-TOF MS and Vitek 2 Compact.

MALDI-TOF MS could be applied to identify directly bacteria in midstream urine samples with high detection rate and accuracy, and MALDI-TOF MS also shows certain performance in identifying samples containing multiple bacteria. The identification results could be 42 h earlier available than regular methods. It is a revolutionary improvement for the clinical identification of bacteria in urine samples.