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Objective@#To investigate the serotype and drug resistance of 815 Salmonella isolates from Hunan Province, so as to provide insights into management of Salmonella infections.@*Methods@#Salmonella isolates were collected from stool samples of foodborne diarrheal patients and food samples in Hunan Province from 2020 to 2021, and serotyped. Antimicrobial susceptibility test was performed using the broth microdilution method.@*Results@#A total of 10 groups and 39 serotypes were characterized in 815 Salmonella isolates. Among the 646 Salmonella isolates of human sources, 388 isolates were identified as serogroup B (60.06%), with S. typhimurium and its variants aspredominant serotypes (364 isolates, 56.35%), and among 169 foodborne isolates, 61 isolates were characterized as serogroup B (36.09%) with S. london as the predominant serotype (26 isolates, 15.38%). There were 597 antimicrobial resistant Salmonella isolates of human sources, with a drug resistance rate of 92.41%, and the percentage of ampicillin resistance was 81.58%. There were 140 foodborne antimicrobial resistant isolates, with a drug resistance rate of 82.84%, and the proportion of tetracycline resistance was 72.78%. However, Salmonella isolates from both humans and foods were sensitive to imipenem. In addition, there were 577 multidrug resistant Salmonella isolates, including 490 multidrug resistant isolates of human sources and 87 foodborne multidrug resistant isolates.@*Conclusions@#S. typhimurium and its variants and S. london were predominant serotypes of Salmonella isolates from 815 foodborne diarrheal patients and food samples in Hunan Province from 2020 to 2021, and a high rate of multidrug resistance was detected.
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The tadpole extract without large molecular protein(T-871) was prepared from dry tadpoles. This extract and RPMI1640 medium were mixed in the ratio of 1:50(V/V) to form T-871 medium. HeLa cells were cultured in the T-871 medium in order to study the possible mechanism of HeLa cell differentiation induced by tadpole extract. We found that there was a decreased acitivity of LDH which may be released through HeLa cell membrane in the 2 day's cultured T-871 medium. After 3 day's culture in the T-871 medium we found that on the HeLa cell membranes, Na-K-ATPase activity reduced and the content of Con A receptors increased. When these cells were analyzed by flow cytometry(FACS-420), the results indicated that HeLa cells accumulated in G_2 and M phases of the cell cycle and the influence on DNA and RNA content of the HeLa cells was insignificant. HeLa cells cultured by RPMI 1640 medium or T-871 medium for 3 days were inoculated into the dorsal hypodermis of 12 nude mice, respectively. Then after 24 hours this extract was injected to each nude mouse at dose of 0.3 ml each day. Our study showed that T-871 could result in decrease of tumor formation such as delay of tumor nodule appearance and reduce of tumor weight. This study suggested that the changes of the cell membrane may be caused by the tadpole extract. It may also reduce malignancy of the HeLa cells.