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@#Abstract: Objective In order to provide reference for emergency treatment of a sudden food poisoning incident, pathogen detection and drug resistance analysis were carried out. Methods Diarrheal stool and surplus food samples were detected by GB 4789 and the isolates were identified by VITEK2 and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), at the same time, the bacterial drug sensitivity test was carried out by using the method of microbroth dilution, and the isolates from different sources were molecularly classified by pulsed field gel electrophoresis (PFGE), and the correlation between the strains was analyzed by BioNumerics software. Results Totaly 13 leftovers and 3 diarrhea patients were isolated and identified, The total number of colonies and coliforms in 7 leftovers samples all exceeded the standard, and Citrobacter freundii was detected in 5 leftovers and 2 stools. The results of drug sensitivity test showed that seven strains of Citrobacter freundii were sensitive to ciprofloxacin, tetracycline, chloramphenicol, gentamicin, amikacin, cefotaxime and meropenem, but completely resistant to ampicillin, and there was no multiple drug resistance. The results of pulsed field gel electrophoresis (PFGE) showed that 7 strains of Citrobacter freundii had the same PFGE bands and 100% homology, showing the same clone. Conclusions This food poisoning incident was caused by Citrobacter freundii. The pathogen of food poisoning can be quickly and accurately determined by MALDI-TOF MS, which is beneficial to the early diagnosis and treatment of infectious diseases. It is suggested to strengthen the corresponding management, improve food safety awareness and prevent similar incidents.
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@#【Objective】 To investigate the role of CFTR in visceral preadipocyte proliferation and differentiation.【Method】Primary preadipocytes were separated from visceral adipose tissue of the 4-week-old and 8-week-old CFTR-KO mice and age-matched littermates. Quantitative real time -PCR assay were used to measure the expression of proliferative and differentiation key transcriptional factors in visceral preadipocytes. An in vitro dexamethasone-methylisobutylxanthine- insulin（DMI）induced 3T3-L1 preadipocytes differentiation model was used. Western blot assay was used to measure the change of CFTR and key differentiation transcriptional factors. After knockdown or overexpression of CFTR，western blot， quantitative real time-PCR，MTT assay and Oil red O staining were used to measure the effects of CFTR on 3T3-L1 cells proliferation and differentiation. A mouse model of obesity with high-fat diet was used. Quantitative real time -PCR assay were used to measure the mRNA levels of proliferative and differentiation key transcriptional factors and CFTR in visceral preadipocytes.【Results】CFTR- KO mice displayed a decline in preadipocyte proliferation and differentiation，including Pref-1，CyclinD1，PPAR γ，and C/EBP α（P<0.05）. In vitro，DMI caused significant increases in CFTR expression in the early phase of differentiation （P<0.05）. DMI- stimulated preadipocyte transcriptional factors reflecting proliferative differentiation（C/EBPβ，C/EBP δ，CREB，and KLF4）and adipogenic differentiation（SREBP-1，PPAR γ，and C/EBP α） were markedly inhibited by knockdown，and reversed by overexpression of CFTR. CFTR is expressed in mouse visceral preadipocytes and increased with the enhanced preadipocyte proliferation and differentiation as evidenced by detecting key transcriptional factors including PPAR γ，C/EBP α，C/EBP β，C/EBP δ，SREBP-1 and FABP4 in mice fed with high- fat-diet for 2，4 weeks（P<0.05）.【Conclusions】These results demonstrate that CFTR may play a role in the preadipocyte proliferation and differentiation.