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.

Fast construction of core-shell structured magnetic covalent organic framework as sorbent for solid-phase extraction of zearalenone and its derivatives prior to their determination by UHPLC-MS/MS.

Magnetic covalent organic framework nanocomposite denoted as Fe3O4@TAPB-Tp with core-shell structure was fabricated via a simple template-mediated precipitation polymerization method at mild conditions. The polyimine network shell was created through the polymerization of 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and 1,3,5-triformyl-phloroglucinol (Tp) in tetrahydrofuran (THF) by the Schiff-base reaction. Featuring with large specific surface area (163.19 m2 g-1), good solution dispersibility, and high stability, the obtained Fe3O4@TAPB-Tp exhibited high adsorption capacities and fast adsorption for zearalenone and its derivatives (ZEAs). The adsorption isotherms showed multilayer adsorption dominated at low concentration and monolayer adsorption at high concentration between the interface of ZEAs and Fe3O4@TAPB-Tp. With the Fe3O4@TAPB-Tp as sorbent, a magnetic solid-phase extraction-ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for simultaneous adsorption and detection of five ZEAs in complex samples. The proposed method displayed favorable linearity, low limits of detection (0.003 ~ 0.018 µg kg-1), and good repeatability (2.37~10.4%). The developed method has been applied for real sample analysis, with recoveries of 81.27~90.26%. These results showed that Fe3O4@TAPB-Tp has a good application potential for the adsorption of ZEAs in food samples. Magnetic covalent organic framework nanocomposite (Fe3O4@TAPB-Tp) were quickly fabricated at mild conditions and used as effective adsorbent for magnetic solid-phase extraction of zearalenone and its derivatives (ZEAs) from food samples prior to ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis.