In this study, eight Escherichia coli isolates were obtained from milk samples of dairy cattle suffering from clinical/subclinical mastitis. Isolates were characterized for antimicrobial resistance traits and virulence genes. Results revealed that one isolate was harbouring New Delhi metallo‐beta‐lactamase gene (bla_NDM). Cloning and sequencing of the PCR amplicon confirmed the identity of the gene (GenBank accession no. KC769583) having 100% homology with bla_NDM‐5 (GenBank accession no. JN104597.1), and this isolate was susceptible to colistin, chloramphenicol and tetracycline only. Moreover, another isolate carried extended‐spectrum beta‐lactamase (ESBL) gene – bla_CTX‐M, and all isolates possessed bla_TEM gene. Of the eight isolates, only one isolate was positive for shiga toxin gene (stx2), and none were harbouring stx1 gene. Occurrence of New Delhi metallo‐beta‐lactamase (bla_NDM) in one E. coli isolate and ESBL genes in other isolates poses a potential threat to human health following possible entry and spread through food chain.

Aim The aim of this study was to develop a saltatory rolling circle amplification (SRCA) assay for rapid, simple and visual detection of Salmonella in meat. Methods and Results SRCA assay was established using simple PCR primers targeting the invA gene of Salmonella enterica. The specificity of the SRCA assay was determined by using 28 Salmonella and 15 non‐Salmonella strains. The analytical sensitivity of the developed SRCA, conventional and real‐time PCR assays were 70 fg, 7 pg and 700 fg S.enterica DNA per tube, respectively. The limit of detection of the SRCA assay was 40 CFU per gram of meat without enrichment and 4 CFU/gram after including 6 h brief enrichment step. The detection limits of 40 CFU/gram and 4 CFU/gram of meat were achieved within 165 min and 9 h, respectively (including DNA extraction). To assess the real‐world relevance of the SRCA assay, it was used to screen Salmonella from the field pork samples (n = 82). The same samples were also tested with culture (ISO 6579: 2002) method, conventional and real‐time PCR assays. By using the developed assay with 6 h enrichment step, it could give accurate results as that of the culture method. Conclusions The results of this study showed that the SRCA assay is a rapid, simple, sophisticated‐equipment free and user‐friendly method for accurate detection of Salmonella in meat foods. To our information, this is the first study to deploy SRCA assay for screening foods for Salmonella. Significance and Impact of the Study The developed SRCA assay is cost‐effective, easy‐to‐perform and equipment free therefore has the potential to replace other molecular detection methods for regular screening of Salmonella in foods in field laboratories.

Introduction: Escherichia fergusonii is regarded as an emerging pathogen with zoonotic potential. In the current study, we undertook source-wise comparative genomic analyses (resistome, virulome, mobilome and pangenome) to understand the antimicrobial resistance, virulence, mobile genetic elements and phylogenetic diversity of E. fergusonii.Methods: Six E. fergusonii strains (5 multidrug resistant strains and 1 biofilm former) were isolated from poultry (duck faeces and retail chicken samples). Following confirmation by phenotypic and molecular methods, the isolates were further characterized and their genomes were sequenced. Comparative resisto-virulo-mobilome analyses and pangenomics were performed for E. fergusonii genomes, while including 125 other E. fergusonii genomes available from NCBI database.Results and discussion: Avian and porcine strains of E. fergusonii were found to carry significantly higher number of antimicrobial resistance genes (p < 0.05) and mobile genetic elements (plasmids, transposons and integrons) (p < 0.05), while the pathogenic potential of bovine strains was significantly higher compared to other strains (p < 0.05). Pan-genome development trends indicated open pan-genome for all strains (0 < γ < 1). Genomic diversity of avian strains was found to be greater than that from other sources. Phylogenetic analysis revealed close clustering among isolates of similar isolation source and geographical location. Indian isolates of E. fergusonii clustered closely with those from Chinese and a singleton Australian isolate. Overall, being the first pangenomic study on E. fergusonii, our analysis provided important cues on genomic features of the emerging pathogen E. fergusonii while highlighting the potential role of avian strains in dissemination of AMR.