Comprehensive analysis of disinfectants on the horizontal transfer of antibiotic resistance genes.

The propagation of antimicrobial resistance (AMR) is constantly paralyzing our healthcare systems. In addition to the pressure of antibiotic selection, the roles of non-antibiotic compounds in disseminating antibiotic resistance genes (ARGs) are a matter of great concerns. This study aimed to explore the impact of different disinfectants on the horizontal transfer of ARGs and their underlying mechanisms. First, the effects of different kinds of disinfectants on the conjugative transfer of RP4-7 plasmid were evaluated. Results showed that quaternary ammonium salt, organic halogen, alcohol and guanidine disinfectants significantly facilitated the conjugative transfer. Conversely, heavy-metals, peroxides and phenols otherwise displayed an inhibitory effect. Furthermore, we deciphered the mechanism by which guanidine disinfectants promoted conjugation, which includes increased cell membrane permeability, over-production of ROS, enhanced SOS response, and altered expression of conjugative transfer-related genes. More critically, we also revealed that guanidine disinfectants promoted bacterial energy metabolism by enhancing the activity of electron transport chain (ETC) and proton force motive (PMF), thus promoting ATP synthesis and flagellum motility. Overall, our findings reveal the promotive effects of disinfectants on the transmission of ARGs and highlight the potential risks caused by the massive use of guanidine disinfectants, especially during the COVID-19 pandemic.

Genome-Wide Analysis of CqCrRLK1L and CqRALF Gene Families in Chenopodium quinoa and Their Roles in Salt Stress Response.

Chenopodium quinoa is a halophyte with exceptional nutritional qualities, and therefore it is potentially an ideal crop to grow in saline soils, not only addressing the problem of land salinization, but also providing nutrient food for the health of humans. Currently, the molecular mechanisms underlying salt tolerance in quinoa are still largely unknown. In Arabidopsis thaliana, Catharanthus roseus receptor-like kinase (CrRLK1Ls) FERONIA (FER) and its ligands rapid alkalinization factors (RALFs) have been reported that participate in the regulation of salt tolerance. Here, we performed a genome-wide analysis and identified 26 CqCrRLK1L and 18 CqRALF family genes in quinoa genome. Transcriptomic profiling of the leaf, root, stamen, and pistil tissues of quinoa reveals that different CqCrRLK1L and CqRALF genes exhibit tissue-specific expression patterns, which is consistent with that observed in other plant species. RNA-seq data show that three CqCrRLK1L genes are highly up-regulated after salt treatment, suggesting that some CqCrRLK1L family genes are transcriptionally responsive to salt stress in quinoa. Biochemical study indicates that CqRALF15, a paralog of Arabidopsis RALF22, is physically associated with CrRLK1L proteins CqFER and AtFER. CqRALF15 and AtRALF22 are functionally conserved in inducing the internalization of AtFER and in triggering root growth inhibition in both quinoa and Arabidopsis. Moreover, overexpression of CqRALF15 in Arabidopsis results in enhanced leaf bleaching under salt stress, indicating that CqRALF15 is involved in salt stress response. Together, our study characterizes CqCrRLK1L and CqRALF family genes in quinoa at genomic, transcriptional, and protein levels, and provides evidence to support their roles in salt stress response.

Rapid Detection of MCR-Mediated Colistin Resistance in Escherichia coli.

Colistin is one of the last-resort antibiotics for infections caused by multidrug-resistant Gram-negative bacteria. However, the wide spread of novel plasmid-carrying colistin resistance genes mcr-1 and its variants substantially compromise colistin's therapeutic effectiveness and pose a severe danger to public health. To detect colistin-resistant microorganisms induced by mcr genes, rapid and reliable antibiotic susceptibility testing (AST) is imminently needed. In this study, we identified an RNA-based AST (RBAST) to discriminate between colistin-susceptible and mcr-1-mediated colistin-resistant bacteria. After short-time colistin treatment, RBAST can detect differentially expressed RNA biomarkers in bacteria. Those candidate mRNA biomarkers were successfully verified within colistin exposure temporal shifts, concentration shifts, and other mcr-1 variants. Furthermore, a group of clinical strains were effectively distinguished by using the RBAST approach during the 3-h test duration with over 93% accuracy. Taken together, our findings imply that certain mRNA transcripts produced in response to colistin treatment might be useful indicators for the development of fast AST for mcr-positive bacteria. IMPORTANCE The emergence and prevalence of mcr-1 and its variants in humans, animals, and the environment pose a global public health threat. There is a pressing urgency to develop rapid and accurate methods to identify MCR-positive colistin-resistant bacteria in the clinical samples, providing a basis for subsequent effective antibiotic treatment. Using the specific mRNA signatures, we develop an RNA-based antibiotic susceptibility testing (RBAST) for effectively distinguishing colistin-susceptible and mcr-1-mediated colistin-resistant strains. Meanwhile, the detection efficiency of these RNA biomarkers was evidenced in other mcr variants-carrying strains. By comparing with the traditional AST method, the RBAST method was verified to successfully characterize a set of clinical isolates during 3 h assay time with over 93% accuracy. Our study provides a feasible method for the rapid detection of colistin-resistant strains in clinical practice.

Effects of pregabalin on central sensitization in patients with migraine.

PURPOSE: Despite the fact that the most recently articulated theory of migraine is the central sensitization hypothesis, few basic and clinical research studies on central sensitization have been conducted in patients with migraine. Here, we aim to reveal the risk factors of migraine with allodynia and to illustrate the effects of pregabalin on alleviating allodynia. METHODS: 63 migraine patients meeting the International Headache Society criteria were prospectively included. The cutaneous allodynia (CA) symptoms that occurred during headache attacks were examined with the Allodynia Symptom Checklist (ASC). The risk factors of allodynia were determined using logistic regression analysis. 41 patients with allodynia were treated with pregabalin (150 - 600 mg/d) for 12 weeks. The improvements in allodynia and headache severity as well as the side effects of the drug were recorded at 1 and 3 months following drug administration. RESULTS: Among the 63 patients, there were 41 cases (65.1%) of allodynia, including 35 cases (85.4%) of thermal allodynia, 12 cases (29.4%) of static mechanical allodynia, and 9 cases (22.0%) of dynamic mechanical allodynia. The allodynia appeared to be associated with gender (female), disease duration, and medication overuse. Compared with baseline, both the ASC scores in the three types of CA and the number of patients with allodynia were significantly decreased (p < 0.05) in patients treated with pregabalin. The frequency, severity, and duration of headache as well as the migraine disability assessment (MIDAS) and headache impact test (HIT-6) scores were significantly decreased (p < 0.05) when compared with baseline. The overall efficiency of drug therapy was 85.4% among all patients who received pregabalin. There were few side effects detected, and the patients showed good tolerability to drug therapy. CONCLUSIONS: Our results showed that 65.1% of patients with migraine had allodynia and that migraine with allodynia was related to the patient gender (female), disease duration, and medication overuse. Pregabalin was effective at relieving allodynia in migraine.