Non-typhoidal Salmonella provides an exemplar for the One Health approach as it encompasses public and animal health, food safety, and environmental considerations. The contribution of environmental aspects is currently less well-defined. The purpose of this study was to determine the carriage occurrence of non-typhoidal Salmonella in migratory birds in Bangladesh and assess the potential significance to public and animal health. Cloacal swabs (N = 453) were collected in the years 2018–2020 from Tanguar and Hakaluki Haors, important wetland ecosystems in Northeastern Bangladesh. The prevalence of Salmonella was 13.5% (61 positive swabs). Classical serotyping identified six serovars: Salmonella enterica subsp. enterica serovars Perth, Kentucky, Albany, Infantis, Weltevreden, and Brancaster. Resistance towards 14 antimicrobials was assessed by broth microdilution minimum inhibitory concentration determination and the antimicrobial resistance (AMR) genotype established by whole-genome sequencing. S. Perth and S. Weltevreden isolates were susceptible and harbored no acquired AMR genes. Isolates from the remaining serovars were multidrug resistant, commonly possessing resistance to tetracycline, ampicillin, chloramphenicol, sulfamethoxazole, trimethoprim, and ciprofloxacin. Salmonella resistant to ciprofloxacin meets WHO criteria for priority pathogens. There was excellent concordance between resistance phenotype and the presence of corresponding AMR genes, many of which reside on Salmonella Genomic Islands. High-level ciprofloxacin resistance correlated with the presence of mutations in the chromosomal gyrB and/or parC genes. The S. Kentucky isolates were ST198, a widely distributed multidrug-resistant lineage reported in humans and animals, and constituting an ongoing risk to public health worldwide. We have demonstrated that multidrug-resistant non-typhoidal Salmonella of public health significance can be recovered from migratory birds. A potential for risk can manifest through direct interaction, transmission to food-producing livestock on farms, and dissemination via the long range migratory movements of birds. Risks can be mitigated by measures including continued surveillance and implementation of good farm biosecurity practices.

The surveillance of antimicrobial resistance (AMR) in commensal Escherichia coli from livestock at slaughter is widely employed to assess the potential for risk to humans. There is currently a limited understanding of AMR in Bangladesh poultry at retail in live bird markets, with studies focussing solely on phenotypic characterisation of resistance. To address this evidence gap we performed antimicrobial susceptibility testing and whole genome sequencing on E. coli obtained from chickens from live bird markets in Dhaka in 2018 (n = 38) and 2020 (n = 45). E. coli were isolated from caeca samples following ISO guidelines and sequenced using short and long read methods. Multidrug resistance was extremely common (n = 77) and there was excellent concordance between AMR phenotype and the presence of corresponding AMR genes or mutations. There was considerable genomic diversity, with 43 different sequence types detected. Public health considerations included the high occurrence of resistance to ciprofloxacin (n = 75) associated with plasmid-residing qnrS or mutations in the gyrA and parC chromosomal genes; and the detection of a tigecycline resistant isolate harbouring tet(X4) on an IncHI1A/B-IncFIA mosaic plasmid. Thirty-nine isolates were resistant to azithromycin and harboured mphA, with a significant increase in the incidence of resistance between 2018 and 2020. Although azithromycin is banned for veterinary use in Bangladesh it remains an important treatment option for humans. Interestingly, mphA confers high-level resistance to azithromycin and erythromycin, and the latter is commonly used on poultry farms in Bangladesh. Seven isolates were colistin resistant and carried mcr1. For two isolates hybrid assemblies revealed that mcr1 resided on a highly conserved IncHI2 plasmid that had 93% nucleotide identity to a plasmid from the published genome of an E. coli isolate of Bangladeshi human origin. Six isolates had resistance to third generation cephalosporins, associated with plasmid-residing bla_CTX-M-55, bla_CTX-M-65, or bla_DHA-1. By employing phenotypic and genomic approaches for AMR surveillance we have provided new insights into the potential for One Health AMR linkages in Bangladesh. Employing similar approaches in human and environmental sectors will help inform the One Health approach to addressing AMR, and generate evidence to support mitigation measures such as improved antimicrobial stewardship.

The World Health Organization considers antimicrobial resistance as one of the most pressing global issues which poses a fundamental threat to human health, development, and security. Due to demographic and environmental factors, the marine environment of the Gulf Cooperation Council (GCC) region may be particularly susceptible to the threat of antimicrobial resistance. However, there is currently little information on the presence of AMR in the GCC marine environment to inform the design of appropriate targeted surveillance activities. The objective of this study was to develop, implement and conduct a rapid regional baseline monitoring survey of the presence of AMR in the GCC marine environment, through the analysis of seawater collected from high-risk areas across four GCC states: (Bahrain, Oman, Kuwait, and the United Arab Emirates). 560 Escherichia coli strains were analysed as part of this monitoring programme between December 2018 and May 2019. Multi-drug resistance (resistance to three or more structural classes of antimicrobials) was observed in 32.5% of tested isolates. High levels of reduced susceptibility to ampicillin (29.6%), nalidixic acid (27.9%), tetracycline (27.5%), sulfamethoxazole (22.5%) and trimethoprim (22.5%) were observed. Reduced susceptibility to the high priority critically important antimicrobials: azithromycin (9.3%), ceftazidime (12.7%), cefotaxime (12.7%), ciprofloxacin (44.6%), gentamicin (2.7%) and tigecycline (0.5%), was also noted. A subset of 173 isolates was whole genome sequenced, and high carriage rates of qnrS1 (60/173) and bla_CTX-M-15 (45/173) were observed, correlating with reduced susceptibility to the fluoroquinolones and third generation cephalosporins, respectively. This study is important because of the resistance patterns observed, the demonstrated utility in applying genomic-based approaches to routine microbiological monitoring, and the overall establishment of a transnational AMR surveillance framework focussed on coastal and marine environments.

Campylobacter spp. are a leading cause of bacterial foodborne zoonosis worldwide, with poultry meat and products recognised as a significant source of human infection. In Vietnam there are few data regarding the occurrence, antimicrobial resistance, and genomic diversity of Campylobacter in poultry and poultry meat. The aim of this study was to estimate the prevalence of Campylobacter in chicken meat at retail in Hanoi, determine antimicrobial sensitivities of the Campylobacter isolated, and assess their genetic diversity. A total of 120 chicken meat samples were collected from eight traditional retail markets (n=80) and four supermarkets (n=40). Campylobacter was isolated following ISO 10272-1 : 2017 and identification verified by PCR. The prevalence of Campylobacter was 38.3 % (46/120) and C. coli was the most prevalent species in both retail markets (74 %) and supermarkets (88 %). The minimum inhibitory concentrations for ciprofloxacin, erythromycin, gentamicin, nalidixic acid, streptomycin, and tetracycline were determined by broth microdilution for 32 isolates. All characterised Campylobacter were resistant to ciprofloxacin, nalidixic acid, and tetracycline, with corresponding resistance determinants detected in the sequenced genomes. Most C. coli were multidrug resistant (24/28) and two harboured the erythromycin resistance gene ermB on a multiple drug-resistance genomic island, a potential mechanism for dissemination of resistance. The 32 isolates belonged to clonal complexes associated with both poultry and people, such as CC828 for C. coli . These results contribute to the One Health approach for addressing Campylobacter in Vietnam by providing detailed new insights into a main source of human infection and can inform the design of future surveillance approaches.

There is scant information on Salmonella in indigenous poultry in Nigeria. We investigated the occurrence and characterized Salmonella serovars in indigenous poultry and their drinking water sources to enhance the monitoring of the infection in poultry and to promote public health. We collected 1208 samples, poultry droppings (n = 1108), and water (n = 100) across 15 markets in North Central Nigeria. Salmonella spp. were isolated following World Organisation for Animal Health guidelines. Salmonella spp., confirmed through invA gene detection by a polymerase chain reaction assay, were 6.8% (75/1108) droppings and 3% (3/100) water. Susceptibility testing against 13 antimicrobials showed 60.3% (47/78) susceptibility to all the antimicrobials tested while 14.1% (11/78) were multidrug resistant. Serotyping and whole-genome sequencing were carried out on 44 of the isolates, and 23 different serovars were identified. Genomes of serovars Luedinghausen, Laredo, Widemarsh, and Lansing are being documented in Africa for the first time. Twenty (20) antimicrobial resistance (AMR) gene markers encoding for resistance to aminoglycosides, tetracyclines, sulphonamides, quinolones, trimethoprim, penicillins and phenicols were found. Phylogenetic cluster analysis showed close relatedness among isolates from different sources. This study shows both low Salmonella prevalence and AMR, but since uncommon serovars are circulating, continuous monitoring is recommended so as to ensure food safety and poultry health.