Characterization of Bacteria and Antibiotic Resistance in Commercially Produced Cheeses Sold in China.

ABSTRACT: The consumption of cheese in the People's Republic of China is increasing rapidly. Little is known about the microbiota, the presence of antibiotic-resistant bacteria, or the distribution of antibiotic resistance genes (ARGs) in commercially produced cheeses sold in China. This information is important for evaluating quality and safety. This study was conducted using 16S rRNA gene sequencing to assess the metagenomics of 15 types of cheese. Fourteen bacterial genera were detected, and Lactococcus, Lactobacillus, and Streptococcus were dominant based on number of sequence reads. Multidrug-resistant lactic acid bacteria (i.e., resistant to two or more types of antibiotic) were isolated from most of the types of cheese. Of these isolates, 100 and 91.7% were resistant to streptomycin and sulfamethoxazole, respectively, and genes involved in acquired resistance to streptomycin (strB) and sulfonamides (sul2) were detected with high frequency. To analyze the distribution of ARGs in the cheeses overall, 309 ARGs from eight categories and nine transposase genes were profiled. A total of 169 ARGs were detected in the 15 cheeses; their occurrence and abundance varied significantly between cheeses. Our study revealed diverse bacteria and ARGs in cheeses sold in China. The risks associated with multidrug resistance among dominant lactic acid bacteria are of great concern.

miR-204 suppresses non-small-cell lung carcinoma (NSCLC) invasion and migration by targeting JAK2.

Aberrant expression of microRNA is associated with the development and progression of cancers. MicroRNA-204 (miR-204) down-regulation has been previously demonstrated in non-small-cell lung carcinoma (NSCLC); however, the underlying mechanism by which miR-204 suppresses tumorigenesis in NSCLC remains elusive. In this study, miR-204 expression was found to be down-regulated, and that of Janus kinase 2 (JAK2) was found to be up-regulated in four NSCLC cell lines (A549, H1299, H1650, and H358) compared to the normal lung cell line. The overexpression of miR-204 suppressed the invasive and migratory capacities of H1299 cells. A luciferase assay confirmed that the binding of miR-124 to the -untranslated region of JAK2 inhibited the expression of JAK2 proteins in H1299 cells. JAK-2 overexpression effectively reversed miR-204-repressed NSCLC metastasis. Taken together, our findings revealed that miR-204 functions as a tumor suppressor in NSCLC by targeting JAK2, and that miR-204 may therefore serve as a biomarker for the diagnosis and treatment of NSCLC.