Vitek ms automatic microbiological analyzer

The ^△ strain DYY3 was isolated from a critically ill patient’s blood sample with a catheter-associated bloodstream infection. Briefly, the blood specimen was inoculated in a blood culture bottle (BD BACTEC Plus aerobic/F Culture Vials, Becton, Dickinson and Company, United States) at 35°C until it showed a positive result. For the isolation of ^△ strain DYY3, blood agar plates (bioMérieux, Marcy l’Etoile, France) were used, and the plates were incubated in a CO₂ incubator for 48 h. Later, dozens of single colonies were picked up from the blood agar plates. VITEK-MS automatic microbiological analyzer (bioMérieux, Marcy l’Etoile, France) was used to identify the taxonomic classification of the ^△ strain DYY3 according to the standard operation process using the VITEK MS IVD KB V3.2 database as the reference. The total length of the 16S rRNA sequence was amplified by PCR using the primers of 27F (5′-AGAGTTTGATCMTGGCTCAG-3′) and 1492R (5′-GGTTACCTTGTTACGACTT-3′), and the amplified fragments were sequenced using a 3730XL sequencer (Applied Biosystems, United States).

All of the preliminary identified A. baumannii isolates from seven different ICUs at the Chinese PLA General Hospital during January 2018 and December 2019 were included in this study (Table S1). Briefly, clinical specimens were inoculated on Columbia Blood Agar Plates (Autobio, China) and cultured at 37°C for 24 hours. Species identification of the isolated single colonies was performed based on VITEK-MS automatic microbiological analyzer (bioMérieux, France). To filter the contaminated samples, the isolates were screened a second time by species identification using VITEK-MS system after activation culture on China Blue Lactose Acid Agar Plates (Thermofisher Scientific, USA) before sequencing. A total of 724 clinical isolates were recovered for whole genome sequencing. The overall study designs and analysis work flow were plotted in Fig. S1.