RESUMEN
The rise of antimicrobial resistance (AMR) in bacterial pathogens such as Klebsiella pneumoniae (Kp) is a pressing public health and economic concern. The 'One-Health' framework recognizes that effective management of AMR requires surveillance in agricultural as well as clinical settings, particularly in low-resource regions such as Pakistan. Here, we use whole-genome sequencing to characterise 49 isolates of Klebisella spp. (including 43 Kp) and 2 presumptive Providencia rettgeri isolates recovered from dairy farms located near 3 cities in Pakistan-Quetta (n = 29), Faisalabad (n = 19), and Sargodha (n = 3). The 43 Kp isolates corresponded to 38 sequence types (STs), and 35 of these STs were only observed once. This high diversity indicates frequent admixture and limited clonal spread on local scales. Of the 49 Klebsiella spp. isolates, 41 (84%) did not contain any clinically relevant antimicrobial resistance genes (ARGs), and we did not detect any ARGs predicted to encode resistance to carbapenems or colistin. However, four Kp lineages contained multiple ARGs: ST11 (n = 2), ST1391-1LV (n = 1), ST995 (n = 1) and ST985 (n = 1). STs 11, 1391-1LV and 995 shared a core set of five ARGs, including blaCTX-M-15, harboured on different AMR plasmids. ST985 carried a different set of 16 resistance genes, including blaCTX-M-55. The two presumptive P. rettgeri isolates also contained multiple ARGs. Finally, the four most common plasmids which did not harbour ARGs in our dataset were non-randomly distributed between regions, suggesting that local expansion of the plasmids occurs independently of the host bacterial lineage. Evidence regarding how dairy farms contribute to the emergence and spread of AMR in Pakistan is valuable for public authorities and organizations responsible for health, agriculture and the environment, as well as for industrial development.
RESUMEN
Mucosal antibodies maintain gut homeostasis by promoting spatial segregation between host tissues and luminal microbes. Whether and how mucosal antibody responses influence gut health through modulation of microbiota composition is unclear. Here, we use a CD19-/- mouse model of antibody-deficiency to demonstrate that a relationship exists between dysbiosis, defects in bile acid homeostasis, and gluten-sensitive enteropathy of the small intestine. The gluten-sensitive small intestine enteropathy that develops in CD19-/- mice is associated with alterations to luminal bile acid composition in the SI, marked by significant reductions in the abundance of conjugated bile acids. Manipulation of bile acid availability, adoptive transfer of functional B cells, and ablation of bacterial bile salt hydrolase activity all influence the severity of small intestine enteropathy in CD19-/- mice. Collectively, results from our experiments support a model whereby mucosal humoral immune responses limit inflammatory disease of the small bowel by regulating bacterial BA metabolism.
Asunto(s)
Ácidos y Sales Biliares/metabolismo , Homeostasis , Inmunidad Humoral , Enfermedades Inflamatorias del Intestino/metabolismo , Intestino Delgado/metabolismo , Animales , Antígenos CD19/genética , Bacterias , Enfermedad Celíaca , Modelos Animales de Enfermedad , Disbiosis/metabolismo , Disbiosis/patología , Microbioma Gastrointestinal/fisiología , Enfermedades Inflamatorias del Intestino/patología , Mucosa Intestinal/metabolismo , Intestino Delgado/patología , Ratones , SimbiosisRESUMEN
BACKGROUND: The cyclic nucleotide-gated ion channel (CNGC) family affects the uptake of cations, growth, pathogen defence, and thermotolerance in plants. However, the systematic identification, origin and function of this gene family has not been performed in Brassica oleracea, an important vegetable crop and genomic model organism. RESULTS: In present study, we identified 26 CNGC genes in B. oleracea genome, which are non-randomly localized on eight chromosomes, and classified into four major (I-IV) and two sub-groups (i.e., IV-a and IV-b). The BoCNGC family is asymmetrically fractioned into the following three sub-genomes: least fractionated (14 genes), most fractionated-I (10), and most fractionated-II (2). The syntenic map of BoCNGC genes exhibited strong relationships with the model Arabidopsis thaliana and B. rapa CNGC genes and provided markers for defining the regions of conserved synteny among the three genomes. Both whole-genome triplication along with segmental and tandem duplications contributed to the expansion of this gene family. We predicted the characteristics of BoCNGCs regarding exon-intron organisations, motif compositions and post-translational modifications, which diversified their structures and functions. Using orthologous Arabidopsis CNGCs as a reference, we found that most CNGCs were associated with various protein-protein interaction networks involving CNGCs and other signalling and stress related proteins. We revealed that five microRNAs (i.e., bol-miR5021, bol-miR838d, bol-miR414b, bol-miR4234, and bol-miR_new2) have target sites in nine BoCNGC genes. The BoCNGC genes were differentially expressed in seven B. oleracea tissues including leaf, stem, callus, silique, bud, root and flower. The transcript abundance levels quantified by qRT-PCR assays revealed that BoCNGC genes from phylogenetic Groups I and IV were particularly sensitive to cold stress and infections with bacterial pathogen Xanthomonas campestris pv. campestris, suggesting their importance in abiotic and biotic stress responses. CONCLUSION: Our comprehensive genome-wide analysis represents a rich data resource for studying new plant gene families. Our data may also be useful for breeding new B. oleracea cultivars with improved productivity, quality, and stress resistance.