Antimicrobial resistance and genetic relatedness of Salmonella serotypes isolated from food, asymptomatic carriers, and clinical cases in Shiyan, China.

Salmonella is a primary cause of foodborne diseases globally. Despite food contamination and clinical infections garnering substantial attention and research, asymptomatic Salmonella carriers, potential sources of infection, have been comparatively overlooked. In this study, we conducted a comparative analysis of serotype distribution, antimicrobial resistance phenotypes, and genetic profiles of archived Salmonella strains isolated from food (26), asymptomatic carriers (41), and clinical cases (47) in Shiyan City, China. Among the 114 Salmonella strains identified, representing 31 serotypes and 34 Sequence Types (STs), the most prevalent serovars included Typhimurium, Derby, Enteritidis, Thompson, and London, with the most predominant STs being ST11, ST40, ST26, ST34, and ST155. Antimicrobial resistance testing revealed that all strains were only sensitive to meropenem, with 74.6% showing antimicrobial resistance (AMR) and 53.5% demonstrating multidrug resistance (MDR). Strains resistant to five and six classes of antibiotics were the most common. Pearson's chi-square test showed no statistically significant difference in the occurrence of AMR (p = 0.105) or MDR (p = 0.326) among Salmonella isolates from the three sources. Our findings underscore associations and diversities among Salmonella strains isolated from food, asymptomatic carriers, and clinical patients, emphasizing the need for increased vigilance towards asymptomatic Salmonella carriers by authorities.

Expression of ß-adrenergic receptor subtypes in human normal and dilated ureter.

BACKGROUND: Ureter peristalsis is a basic physiological function regulated by myogenic and neurogenic factors. The distribution and function of ß-adrenergic receptors (ß-AR) in the human ureter remain unknown. The aim of this study was to investigate the expression of ß-AR subtypes in the normal and dilated human ureter. METHODS: The upper, middle, and lower segments of normal and dilated ureters were collected from patients undergoing surgery for carcinoma of the kidney and upper urinary tract and ureteral stenosis. The mucosa and muscular layers were separated. Expression of ß1-AR, ß2-AR, and ß3-AR mRNA and protein levels were detected by real-time PCR, western blot, and immunohistochemistry. RESULTS: In both mucosa and muscular layers, the mRNA and protein expressions of ß1-AR, ß2-AR, and ß3-AR were lower in the dilated ureter compared with the normal ureter. ß1-AR mRNA was significantly decreased (by 76.64%; P < 0.01) in the mucosa layer of the middle segment of the dilated ureter. ß1-AR and ß3-AR mRNA were significantly decreased (by 75.53 and 53.62%, respectively; P < 0.01) in the muscular layer of the lower segment of the dilated ureter. Similar findings were observed for protein expression. CONCLUSIONS: The downregulation of ß-ARs after ureter dilation, particularly for ß1-AR and ß3-AR in the muscular layer, suggests a potential compensatory mechanism involving increased contraction of the ureter to push urine through the obstruction. Thus, ß-ARs may be a potential target for treatment of ureter obstruction.