Transmission of human-pet antibiotic resistance via aerosols in pet hospitals of Changchun.

In recent years, aerosols have been recognized as a prominent medium for the transmission of antibiotic-resistant bacteria and genes. Among these, particles with a particle size of 2 µm (PM2.5) can directly penetrate the alveoli. However, the presence of antibiotic-resistant genes in aerosols from pet hospitals and the potential risks posed by antibiotic-resistant bacteria in these aerosols to humans and animals need to be investigated. In this study, cefotaxime-resistant bacteria were collected from 5 representative pet hospitals in Changchun using a Six-Stage Andersen Cascade Impactor. The distribution of bacteria in each stage was analyzed, and bacteria from stage 5 and 6 were isolated and identified. Minimal inhibitory concentrations of isolates against 12 antimicrobials were determined using broth microdilution method. Quantitative Polymerase Chain Reaction was employed to detect resistance genes and mobile genetic elements that could facilitate resistance spread. The results indicated that ARBs were enriched in stage 5 (1.1-2.1 µm) and stage 3 (3.3-4.7 µm) of the sampler. A total of 159 isolates were collected from stage 5 and 6. Among these isolates, the genera Enterococcus spp. (51%), Staphylococcus spp. (19%), and Bacillus spp. (14%) were the most prevalent. The isolates exhibited the highest resistance to tetracycline and the lowest resistance to cefquinome. Furthermore, 56 (73%) isolates were multidrug-resistant. Quantitative PCR revealed the expression of 165 genes in these isolates, with mobile genetic elements showing the highest expression levels. In conclusion, PM2.5 from pet hospitals harbor a significant number of antibiotic-resistant bacteria and carry mobile genetic elements, posing a potential risk for alveolar infections and the dissemination of antibiotic resistance genes.

Baicalin inhibits the TGF-ß1/p-Smad3 pathway to suppress epithelial-mesenchymal transition-induced metastasis in breast cancer.

TGF-ß1 is an epithelial-mesenchymal transition (EMT)-inducing factor that is critical in tumor progression. However, whether the effect of TGF-ß1 on breast cancer is through the EMT pathway remains to be determined, and drug development based on this mechanism needs to be improved. Results of this study showed that TGF-ß1 dysregulation significantly correlated with the expression levels of EMT-associated markers and transcriptional factors. Exogenous expression of TGF-ß1 promoted breast cancer cell metastasis and EMT progression. In addition, direct binding of baicalin to TGF-ß1 caused its inactivation, which subsequently blocked signal transduction and inhibited breast cancer cell metastasis. In vivo experiment results further invalidated the inhibitory effect of baicalin on TGF-ß1-induced tumor metastasis. These results suggest that baicalin, an active ingredient used in traditional Chinese medicine, exhibits a potential therapeutic effect on breast cancer metastasis by regulating TGF-ß1-dependent EMT progression.