Low fluid shear force, including that encountered in microgravity models, induces bacterial responses, but the range of bacteria capable of responding to this signal remains poorly characterized. We systematically analyzed a range of Gram negative Enterobacteriaceae for conservation of the low-shear modeled microgravity (LSMMG) response using phenotypic assays, qPCR, and targeted mutations. Our results indicate LSMMG response conservation across Enterobacteriacae with potential variance in up- or down-regulation of a given response depending on genus. Based on the data, we analyzed the role of the trp operon genes and the TrpR regulator in the LSMMG response using targeted mutations in these genes in S. Typhimurium and E. coli. We found no alteration of the LSMMG response compared to WT in these mutant strains under the conditions tested here. To our knowledge, this study is first-of-kind for Citrobacter, Enterobacter, and Serratia, presents novel data for Escherichia, and provides the first analysis of trp genes in LSMMG responses. This impacts our understanding of how LSMMG affects bacteria and our ability to modify bacteria with this condition in the future.

Background Nepal’s poultry industry has increased with a growing middle class, which has translated to an increase in antimicrobial consumption and thus a rise in antimicrobial resistance (AMR). Describing and understanding antimicrobial use practices among commercial poultry producers in Nepal may help minimize the risks of AMR development in both humans and animals and determine the effectiveness of relevant policies. Methods From July to August 2018, poultry farmers were randomly recruited from Nepal’s Chitwan District to participate in a cross-sectional study. The lead producer in each poultry operation was administered a quantitative structured-survey via a 30-min interview. Participants were asked to provide demographics, production practices, and knowledge about their antimicrobial use practices. Descriptive data analysis was performed to obtain frequencies and compare practices. Results In total, 150 commercial poultry producers of whom raised between 300 and 40,000 birds completed the interviews. Only 33% (n = 49) of producers reported knowing what AMR was, and among them only 50% (n = 25) consulted a veterinarian for treatment options. Antimicrobial administration for growth promotion was still employed by 13% of poultry producers. Similarly, critically important antimicrobial drugs, specifically colistin, were identified at 35% of participating operations. Producers reported low overall understanding and compliance of withdrawal periods (n = 41; 27%), which may result in both AMR development and adverse health reactions among consumers who ingest antimicrobial residues. Although Nepal has publicized antimicrobial use policies and awareness campaigns to instill healthy production practices, most producers (82%) were unaware of them. Conclusion Many Nepalese poultry producers lack overall antimicrobial use and AMR awareness, which is evidenced by low antimicrobial withdrawal period compliance, use of antimicrobials for growth promotion, and the sustained use of critically important antimicrobials. Improved outreach and educational capacities, paired with increased veterinary resources and extensive monitoring in operations and retail meat products, may increase AMR awareness and policy enforcement.

Many studies require expression analysis of the same gene/promoter across a range of bacterial genera. However, there is currently a lack of availability of reporters based on the broad-host-range IncQ replicon, which is compatible with a popular improved IncP transfer system that is selftransfer defective. We report IncQ lacZ reporter plasmids with features including (1) compatibility with IncP, IncW, and pBHR/pBBR replicons, (2) a variety of antibiotic markers (Sp-r, Sm-r, Km-r, Cm-r), (3) convenient mobilization via a novel self-transfer-defective IncP conjugation system, and (4) GenBank DNA sequences. Utility is demonstrated using three different promoters in different Gram-negative genera.

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