Objective To develop a new method for the rapid determination of lomefloxacin,gatifloxacin,ciprofloxacin and oflox-acin in plasm and urine by solid phase extraction(SPE)and capillary electrophoresis.Methods The capillary was fused silica capil-lary with id/od of 75/365 μm and effective/total length of 40/47 cm.The running buffer was 40 mmol/L borate buffer at pH 9.0. Separation voltage was 13 kV.Temperature was 20 ℃.Detection wave-length was set at 280 nm.The sample was analyzed after the pretreatment of SPE.Results The analysis of lomefloxacin,gatifloxacin,ciprofloxacin and ofloxacin was completed in 6 minutes with satisfied accuracy and precision.Good linearity was found within the range of 1-40 μg/mL,and the r was 0.998 7,0.997 6, 0.998 3 and 0.994 2 respectively.The recoveries of four quinolones in plasm and urine ranged from 80.1% to 107.6%,and the rel-ative standard deviations(RSD)ranged from 2.1% to 6.2%.Conclusion This method is fast,simple,precise and it might be feasi-ble for the determination of lomefloxacin,gatifloxacin,ciprofloxacin and ofloxacin in plasm and urine samples.

Objective　To perform the pathogenic and genomics analyses on isolates of Streptococcus suis (Ss) from three human infections in Shenzhen, aiming to provide a basis for the prevention and control of Ss outbreaks. Methods　The suspected bacterial strains from three blood plate cultures of three critically ill patients in three hospitals were subjected to biochemical identification, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), and real-time fluorescent PCR identification, resulting in the identification of three strains positive for Streptococcus suis serotype 2(SS2). Pure positive cultures were taken for an antimicrobial susceptibility test and extracted nucleic acids for whole-genome sequencing and analysis. The whole-genome sequencing and analysis included species identification, antibiotic resistance genes alignment, multilocus sequence typing (MLST), virulence genes alignment, and coregene-based phylogenetic tree analysis. Results　The blood agar isolates from three patients were all identified as Ss, the VITEK 2 identified them as SS2, and MALDI-TOF-MS identified them as Ss. Real-time PCR results for the universal gene gdh and serotype 2 cps2 gene of Ss were both positive. The antimicrobial susceptibility test results showed that all three strains were resistant to erythromycin and clindamycin, with variable sensitivity to tetracycline. Whole-genome sequencing results showed that all three strains were identified as Ss, including one ST7 strain and two ST1 strains. The virulence gene prediction results based on the VFDB database showed that all three strains were positive for mrp, sly, and cps, indicating high virulence gene characteristics. The analysis of the phylogenetic tree based on coregene showed that the three strains were in different evolutionary branches, with two ST1 strains having a closer evolutionary distance. Conclusions　The pathogens responsible for these three critically ill patients were SS2, and all three strains were resistant to erythromycin and clindamycin. Genetically, they all carried virulence genes that are found in highly virulent strains, while showed differences in MLST typing and phylogenetic tree analysis, indicating the presence of different genotypes of high pathogenicity SS2 in Shenzhen area and had caused sporadic cases, which requires high attention.