Antimicrobial resistance (AMR) is a major threat to global health. Understanding the emergence, evolution, and transmission of individual antibiotic resistance genes (ARGs) is essential to develop sustainable strategies combatting this threat. Here, we use metagenomic sequencing to analyse ARGs in 757 sewage samples from 243 cities in 101 countries, collected from 2016 to 2019. We find regional patterns in resistomes, and these differ between subsets corresponding to drug classes and are partly driven by taxonomic variation. The genetic environments of 49 common ARGs are highly diverse, with most common ARGs carried by multiple distinct genomic contexts globally and sometimes on plasmids. Analysis of flanking sequence revealed ARG-specific patterns of dispersal limitation and global transmission. Our data furthermore suggest certain geographies are more prone to transmission events and should receive additional attention.

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Extended spectrum β-lactamase (ESBL) and plasmid-mediated AmpC β-lactamase (pAmpC) producing Escherichia coli have been shown to be present in humans and animals representing a significant problem worldwide. This study aimed to search the presence of ESBL and/or AmpC-producing E. coli in retail meats (chicken and beef) in Turkey. A total of 88 β-lactamase-producing E. coli were isolated from chicken (n = 81/100) and beef meat (n = 7/100) samples and their susceptibility to several antimicrobials were tested using disc diffusion method. E. coli isolates were further characterized for their phylogenetic groups. β-Lactamase encoding (blaTEM , blaSHV , blaOXA , blaCTX-M , and blaAmpC ) and quinolone resistance genes (qnrA, qnrB, qnrS, qepA, and acc(6')-Ib-cr) were also secreened by polymerase chain reaction (PCR). However, in regard to β-lactamase genes, 84 of 88 isolates were positive for blaCTX-M-1 (n = 39), blaCTX-M-3 (n = 5), blaCTX-M-15 (n = 4), blaTEM-1b (n = 2), blaSHV-12 (n = 1), blaCTX-M-1 /blaTEM-1b (n = 10), blaCTX-M-1 /blaTEM-1b /blaSHV-5 (n = 1), blaCTX-M-1 /blaCMY-2 (n = 1) and blaTEM-1b /blaCMY-2 (n = 6), blaCTX-M-15 /blaSHV-12 (n = 1), blaCTX-M-15 /blaTEM-1b (n = 1), blaTEM-1b /blaSHV-12 (n = 1), and blaCMY-2 (n = 12) genes. Resistance to cefuroxime (75.6% and 85.7%), nalidixic acid (89% and 85.7%), tetracycline (91.4% and 100%), streptomycin (40.2% and 100%), and trimethoprim-sulfamethoxazole (36.6% and 85.7%) was observed among strains isolated from chicken and beef, respectively. However, all isolates were found to be susceptible to amikacin, imipenem, and cefepime. Resistance to ampicillin and cefoxitin was significantly linked to blaCMY-2 gene, while there was a significant correlation between CTX-M type ESBL and antimicrobial resistance to cefuroxime and streptomycin (P < 0.05). The results of this study suggest that raw chicken retail meats are highly contaminated with ESBL-producing E. coli implementing a great risk to human health in Turkey.

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Extended spectrum β‐lactamase producing Escherichia coli (ESBL‐EC) was detected in 86.6% of chicken and 22.6% of bulk tank milk (BTM) samples. Pulsed‐field gel electrophoresis analysis revealed 49 distinct restriction profiles among 66 isolates, and 62.3% of the isolates carried the blaCTX‐M gene, among which CTX‐M‐1 was found to be the predominant ESBL types in chicken isolates, whereas CTX‐M‐15 was the commonest among BTM samples. Additionally, of 52 ESBL‐EC isolates from chicken meat samples, 36.5%, 9.6%, and 7.7% harbored the blaTEM, blaCMY‐2, and blaSHV‐12 genes, respectively, compared with 28.5% of the blaTEM and 7.1% of the blaSHV‐12 markers among BTM isolates. The fimH gene was present in 51 isolates of chicken and in 14 isolates of BTM samples, while other virulence genes iutA (n = 31), iroN (n = 26), kpsMT II (n = 5), papC (n = 2), papG allele II (n = 2), papG allele II‐III (n = 2), and papEF (n = 2) were only present in chicken meat isolates. Overall, it can be said that contaminated chicken meat and BTM might serve as vehicles for playing potential role in zoonotic transmission of ESBL‐EC to humans in Turkey. Practical applications Extended spectrum β‐lactamase producing E. coli (ESBL‐EC) have been considered to be one of the major worldwide clinical problems and have been frequently isolated from the foods of animal origins such as chicken meat, fish, and raw milk. The current study aimed to isolate ESBL‐EC from chicken and bulk tank milk samples and further characterize the strains by PFGE, identifying resistance genes and as well as virulence genes. Given the high prevalence of CTX‐M‐15/55 type ESBL‐EC strains possessing important virulence genes in chicken and milk samples, it can be said that foods of animal origins might be an important risk factor for extraintestinal ESBL‐EC infections for humans.

The aim of this work was to test the potential use of plant-derived extracts and compounds to control Campylobacter jejuni in broiler chickens. Over a 7-wk feeding period, birds were fed a commercial diet with or without plant extracts (Acacia decurrens, Eremophila glabra), essential oil [lemon myrtle oil (LMO)], plant secondary compounds [terpinene-4-ol and α-tops (including α-terpineol, cineole, and terpinene-4-ol)], and the antibiotic virginiamycin. Traditional culture and real-time quantitative PCR techniques were used to enumerate the numbers of C. jejuni in chicken fecal and cecal samples. In addition, BW and feed intake were recorded weekly for the calculation of BW gain and feed conversion ratio. The mean log10 counts of C. jejuni were similar (P > 0.05) across treatments. However, significantly lower levels of fecal Campylobacter counts (P < 0.05) were recorded at d 41 for the α-tops treatment by culture methods. No differences (P > 0.05) in BW gain were obtained for dietary supplementation, except for the E. glabra extract, which had a negative impact (P < 0.001) on BW, resulting in sporadic death. Results from this study suggest that supplemental natural compounds used in the current study did not reduce the shedding of C. jejuni to desired levels.