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Objective: Pertussis cases have increased markedly since 2018 in Guangxi. The aim of this study was to evaluate antibody levels and the infection status of pertussis in the resident population., Method: A total of 10,215 serum samples from residents were collected from August-November 2018 and tested for anti-pertussis IgG and toxin IgG using the enzyme-linked immunosorbent assay (ELISA)., Results: Of the collected samples, 1,833 (17.94%) tested positive for anti-pertussis IgG, with the median concentration of 16.06 IU/mL. Antibody level < 10 IU/mL accounted for more than 60% in children under 4 years of age, but declined with age, whereas the percentages of the other three levels (10-40, 40-50, and ≥ 50 IU/mL) increased almost with age ( P < 0.001). Moreover, 7,924 samples were selected for anti-pertussis toxin IgG, of which 653 (8.24%) tested positive (≥ 40 IU/mL) with the median concentration of 5.89 IU/mL, and 204 participants (2.56%) had recent pertussis infection (≥ 100 IU/mL). Among the different age groups, the highest rates of positivity and recent infection were observed at 11-20 years of age, the lowest positivity rate at 5 years of age, and the lowest recent infection rate at 4 years of age ( P < 0.001, P = 0.005, respectively)., Conclusion: The survey results showed that all age groups in Guangxi lacked immunity against pertussis, which was one of the main factors contributing to the resurgence of pertussis in 2018. In addition, the prevalence of pertussis is relatively high in Guangxi, and its incidence is seriously underestimated, especially in adolescents and adults., (Copyright © 2024 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.)

High-speed counte-recurrent chromatography (HSCCC) is a continuous liquid-liquid partition chromatography without solid matrix, which has the significant features of high resolution and high recovery. The separation of bio-macromolecule in aqueous two-phase systems (ATPs) with HSCCC is still under research, and the establishment of high-speed counter-current aqueous two-phase chromatography (HSCCC-ATP) relies on the improvement of equipment structure and optimization of operation parameters. By using a multi-column high-speed counter-current chromatograph, the separation of protein mixture and the purification of ovalbumin from hen egg white were studied. The effects of pH and PEG concentration on the partition coefficients of proteins were tested in PEG1000-phosphate ATPs, and distinct differences among partition coefficients of proteins were found at pH 9.2 and 15.0% (W/W) PEG concentration in said system. The separation of protein mixture, consisting of cytochrome C, lysozyme and myoglobin was successfully performed in 15.0% (W/W) PEG1000-17.0% (W/W) potassium phosphate ATPs at pH 9.2 with high-speed counter-current chromatograph at rotation speed of 850r/min and flow rate of 0.8mL/min, using upper phase as stationary phase. pH and PEG concentration also had distinct effects on the partition coefficients of the major protein components in hen egg white, including ovaltransferrin, ovalbumin and lysozyme. The optimal pH value and PEG concentration for the purification of ovalbumin by HSCCC-ATP were found to be 9.2 and 16.0% (W/W) respectively. Ovalbumin was successfully purified to homogeneity from the hen egg white sample in 16.0% (W/W) PEG1000-17.0% (W/W) potassium phosphate ATPs at pH 9.2 with high-speed counter-current chromatograph at rotation speed of 850r/min and flow rate of 1.8mL/min, using upper phase as stationary phase. The purification recovery of ovalbumin was around 95%.