OUP accepted manuscript

Genomic epidemiology of third-generation cephalosporin-resistant Escherichia coli from companion animals and human infections in Europe

In high-income countries, dogs and cats are often considered members of the family. Because of this proximity, it has been suggested that pets and humans might exchange bacterial species from their gut microbiota, with multidrug resistant bacteria being of particular concern. The aim of this study was to compare the genomes of third-generation cephalosporin-resistant (3GC-R) Escherichia coli responsible for human and pet infections in Europe. Whole-genome sequencing data from 3GC-R E. coli isolated from clinical samples of humans, dogs and cats, and published in eight European studies were re-analyzed using bioinformatics tools. The acquired genes responsible for 3GC-R were identified. The sequence type (ST) of all genomes were assessed by multilocus sequence typing. Alpha and beta diversities were measured within and between the two populations. We included genomes of 1327 3GC-R E. coli isolated from humans and animals with 109 (8.2 %) being responsible for infections in dogs and cat, and 1218 (91.8 %) responsible for human infections. Alpha diversity analysis suggested greater diversity within ST and 3GC-R genes in the animal population. Beta diversity analysis by principal coordinate analysis separated animal and human strains. ST131 was more abundant in human strains (43.4 %) than in animal strains (14.7 %) (p < 0.001). Six STs, including ST372, were identified almost exclusively in 3GC-R E. coli from animal origin. The bla CTX-M-15 gene was more frequent in humans (49.24 %) than in companion animals (17.9 %) (p < 0.001). The resistance genes bla CMY-2 (30.8 %) and bla CTX-M-1 (15.4 %) were more frequent in E. coli isolated from pets (p < 0.001). We found that populations of 3GC-R E. coli responsible for human and pet infections in Europe do not overlap. Although it cannot rule out occasional transmission of bacteria between pets and humans within a household, it suggests that dogs and cats are not a major source of human infection with this antibiotic-resistant pathogen.

Genomic characterization of extended-spectrum β-lactamase-producing Escherichia coli spread among chickens and healthy residents in Lombok, Indonesia

Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) poses a substantial public health challenge, particularly in developing countries where antimicrobial resistance is a growing concern. Although extensive research has documented the prevalence and impact of ESBL-Ec in clinical settings and farm animals, the intricate relationship between poultry farming practices and human health remains unclear. To elucidate the genomic relationships between isolates from chickens and humans, we conducted a whole-genome sequencing analysis of 200 E. coli isolates derived from chickens, chicken farmers, and non-farmer volunteers in Lombok, Indonesia. The isolates exhibited considerable diversity, with 78 distinct sequence types (STs) identified by multilocus sequence typing. Of these, 35% (n = 70) and 6% (n = 12) were positive for ESBL and AmpC-type β-lactamase genes, respectively, with blaCTX-M-55 being the most prevalent (n = 41). The most prevalent STs among those carrying ESBL or AmpC genes were ST48, ST1485, ST1727, and ST2690. Phylogenetic analysis of publicly available data indicated that ST1485, ST1727, and ST2690 strains had an indigenous spread in this region, whereas the ST48 isolates originated from different sources. The blaCTX-M-55 gene was identified in 22 different STs, predominantly carried by an IncHI1A-type plasmid, suggesting horizontal transmission of the plasmid over the clonal barrier. Long-read sequencing analysis of representative isolates revealed the presence of additional resistance genes against different classes of antibiotics, suggesting that the acquisition of the IncHI1A-type plasmid contributes to multidrug resistance in recipient clones. Our analysis provides unique insights into the dissemination of multidrug-resistant ESBL-Ec strains in Lombok, where humans and chickens are in close proximity.IMPORTANCEWe performed a genomic comparison of ESBL-producing E. coli (ESBL-Ec) isolated from chickens, chicken farmers, and non-farmers on Lombok Island, where indigenous chicken farming, which involves close proximity of humans and chickens, is a major industry. The detection of the same ESBL-Ec clones in both chickens and farmers indicated the potential of a zoonotic transmission pathway for antibiotic-resistant bacteria. Moreover, the presence of a common plasmid carrying an ESBL gene along with other antimicrobial resistance genes in various E. coli clonal groups highlights the dissemination of resistance determinants within both poultry and human populations. This cross-species amplification of antimicrobial resistance poses a substantial risk to public health, as it can lead to the proliferation of multidrug-resistant bacterial infections, complicating treatment options and increasing the burden on healthcare systems. Addressing these issues is crucial for implementing effective antimicrobial stewardship and improving biosecurity practices in poultry farming.

Characterization of antibiotic determinants and heavy metal resistance genes in Escherichia coli from pigs in Catalonia

More antibiotics are administered to livestock animals than to treat human infections. Industrialization, large animal densities and early weaning mean pigs are exposed to more antibiotics than any other livestock animal. Consequently, antimicrobial resistance (AMR) is common among commensal and pathogenic bacteria. Heavy metals (HMs) are also often used as feed additives for growth promotion and infection prevention alongside antimicrobials, and increased exposure to copper, zinc and cadmium can further encourage AMR through co-selection. In this study, we sequenced an archived collection of 112 Escherichia coli isolates from pigs in Catalonia using short- and long-read sequencing methods to detect AMR and HM tolerance genes. The most common AMR genes were mdfA (84.8%), aph(3″)-Ib (52.7%), bla TEM-1B (45.6%) and aph(6)-Id (45.6%). Genes relevant to public health, such as the extended-spectrum β-lactamases (15.4%), bla CTX-M type or bla SHV, or mobile colistin resistance (mcr) genes (13.4%), such as mcr-1, were also found. HM tolerance genes were present in almost every genome but were rarely located in plasmids, and, in most cases, AMR and HM tolerance genes were not located on the same plasmids. Of the genes predicted to increase tolerance to HMs, only those with activity to mercury were co-located on plasmids alongside other AMR determinants. However, mercury is rarely used in pig farming and does not support a scenario where AMR and HM genes are co-selected. Finally, we identified the exclusive association between mcr-4 and ColE10 plasmid, which may help target interventions to curtail its spread among pig Escherichia coli.

Genomic insights into extended-spectrum β-lactamase- and plasmid-borne AmpC-producing Escherichia coli transmission between humans and livestock in rural Cambodia

Introduction. The global spread of extended-spectrum cephalosporinase-producing Escherichia coli (producing extended-spectrum β-lactamase or plasmid-borne AmpC, hereafter ESC-Ec) is a major public health concern. Whilst extensively studied in high-income countries, the transmission pathways between humans and animals in low- and middle-income countries (LMICs) remain unclear. In rural Cambodia, the asymptomatic carriage and transmission dynamics of ESC-Ec between humans and animals living in close proximity are poorly understood, highlighting the need for targeted research in this area.Gap statement. An enhanced understanding of the genetic epidemiology of ESC-Ec can enable mitigation strategies to reduce the burden of disease and drug-resistant infections in LMIC settings.Aim. This study aimed to investigate the genetic relatedness and genotypic antibiotic resistance profiles of ESC-Ec strains from humans and livestock in rural Cambodia and to identify patterns of antimicrobial resistance (AMR) gene transmission between hosts and across households and villages.Methodology. Faecal samples were collected from 307 humans and 285 livestock in 100 households in or near Kampong Cham Province in rural Cambodia. From these samples, 108 ESC-Ec strains were subjected to whole-genome sequencing. Core genome MLST (cgMLST) and phylogenetic analysis determined genetic relationships between strains. All strains were screened for the presence of antibiotic resistance genes and plasmids.Results. Human and livestock isolates were assigned to six phylogroups, with phylogroup A being the most common (56.5%). MLST identified 50 sequence types (STs), 17 of which were shared between humans and animals, with ST155 being the most prevalent. cgMLST revealed 97 distinct cgMLST sequence types (cgST), indicating strain sharing between humans and animals. Additionally, AMR gene analysis showed widespread resistance, with genes from the bla CTX-M group detected in 84.2% of isolates. Notably, AMR genes such as aph(3'')-Ib-sul2 co-occurred in 50% of isolates. Finally, plasmid analysis identified IncF plasmids in 75.9% of isolates, likely facilitating AMR gene transmission across hosts.Conclusions. Our findings demonstrate that ESC-Ec strains and their AMR genes are transmitted between humans and livestock in rural Cambodia, likely driven by both clonal spread and plasmid-mediated horizontal gene transfer. These results highlight the urgent need for antimicrobial stewardship and infection control strategies to mitigate the spread of multidrug-resistant pathogens in both human and animal populations.

Prospective One-Health investigation into low-abundant extended-spectrum β-lactamase producing Enterobacterales enables detection of potential dissemination events and persistence

BACKGROUND

Following a one-health approach, we sought to determine reservoirs of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-PE), other than Escherichia coli or Klebsiella pneumoniae complex species (i.e., low-abundant species), and their associated ESBL genes and plasmid-replicon profiles.

METHODS

From 06/2017-05/2019, ESBL-PE isolates were recovered from clinical samples routinely collected at the University Hospital Basel (Basel, Switzerland), as well as from wastewater and foodstuffs collected monthly at predefined locations throughout the city of Basel. Whole-genome sequencing was performed for characterization of ESBL-PE isolates.

RESULTS

Among 1634 isolates recovered, 114 (7%) belonged to 17 low-abundant ESBL-PE species. Seven species originated from more than one compartment, mainly from clinical and wastewater samples (6/17). Sixteen different ESBL genes were identified, with blaCTX-M-15 (27%), blaFONA-6 (23%) and blaSHV-12 (16%) being most frequent. The blaCTX-M-1 gene was the only ESBL gene recovered from all three compartments. Putative plasmids constituted 60% of ESBL gene-containing contigs, while chromosomes comprised 40%. Foodstuff isolates showed the highest proportion (91%, 41/45) of ESBL genes located on chromosomes, whereas wastewater isolates had the highest proportion (95%, 37/39) of putative plasmids. Multi-replicon combinations were identified in 81% of the isolates. Epidemiological links were found among some clinical and wastewater isolates.

CONCLUSIONS

The dominance of blaCTX-M-15 among low-abundant ESBL-PE species supports its species-independent transmission potential beyond the E. coli and K. pneumoniae complex, and blaCTX-M-1 may be transmitted between strains recovered from different compartments. The substantial overlap between low-abundant ESBL-PE present in wastewater and clinical samples supports the utility of wastewater surveillance for antibiotic resistance monitoring.

Advancements in enzymatic reaction-mediated microbial transformation

Enzymatic reaction-mediated microbial transformation has emerged as a promising technology with significant potential in various industries. These technologies offer the ability to produce enzymes on a large scale, optimize their functionality, and enable sustainable production processes. By utilizing microbial hosts and manipulating their genetic makeup, enzymes can be synthesized efficiently and tailored to meet specific industrial requirements. This leads to enhanced enzyme performance and selectivity, facilitating the development of novel processes and the production of valuable compounds. Moreover, microbial transformation and biosynthesis offer sustainable alternatives to traditional chemical methods, reducing environmental impact and promoting greener production practices. Microbial transformations enrich drug candidate diversity and enhance active ingredient potency, benefiting the pharmaceutical industry. Continued advancements in genetic engineering and bioprocess optimization drive further innovation and application development in Enzymatic reaction-mediated microbial transformation. The integration of AI for predicting enzymatic reactions and optimizing pathways marks a promising direction for future research. In summary, these technologies have the potential to revolutionize several industries by providing cost-effective, sustainable solutions.

Gut colonization by extended-spectrum β-lactamase-producing Escherichia coli in dairy herd in Brazil: successful dissemination of a One Health clone

The overuse of antimicrobials in livestock has contributed to the emergence and selection of clinically relevant multidrug-resistant bacteria. In Brazil, there is no conclusive information on the occurrence of Escherichia coli producing extended-spectrum β-lactamase (ESβL) in cattle breeding, which is an important sector of agribusiness in this country. Herein, we investigated the presence of ESβL-positive E. coli strains in dairy cattle from a commercial farm with routine practice of therapeutic cephalosporins. Ninety-five rectal swab samples were collected from healthy dairy calves and cows under treatment with ceftiofur. Samples were screened for the presence of ESβL producers, and positive isolates were identified by MALDI-TOF, with subsequent screening for genes encoding ESβL variants by PCR and sequencing. The presence of ESβL (CTX-M-15)-producing E. coli was confirmed in calves, and lactating and dry cows. Most ESβL strains with genetic homologies ≥ 90% were grouped into two major PFGE clusters, confirming the suscessful expansion of clonally related lineages in animals from different lactating cycles, on the same property. Four representatives CTX-M-15-positive E. coli strains had their genomes sequenced, belonging to the clonal complex (CC) 23 and sequence type (ST) 90. A phylogeographical landscape of ST90 was performed revealing a global One Health linkage. Our results highlight the intestinal microbiota of dairy cattle as a hotspot for the spread of critical priority ESβL-producing E. coli and demonstrate that ST90 is an international clone genomically adapted to human and animal hosts, which deserve additional investigation to determine its zoonotic potential and impact in food chain.

Implementation of the WHO Tricycle protocol for surveillance of extended-spectrum β-lactamase producing Escherichia coli in humans, chickens, and the environment in Madagascar: a prospective genomic epidemiology study

BACKGROUND

Antimicrobial resistance (AMR) is a major public health threat, affecting not only people but also animals and the environment. The One Health dimension of AMR is well known; however, data are lacking on the circulation of resistance-conferring genes, particularly in low-income countries. In 2017, WHO proposed a protocol called Tricycle, focusing on extended-spectrum β-lactamase (ESBL)-Escherichia coli surveillance in the three sectors (humans, animals, and the environment). We implemented Tricycle in Madagascar to assess ESBL-E coli prevalence and describe intrasector and intersector circulation of ESBL-E coli and plasmids.

METHODS

In this prospective study, we collected blood culture data from hospitalised patients with a suspected bloodstream infection processed from May 1, 2018, to April 30, 2019, and rectal swabs from healthy pregnant women from July 30, 2018, to April 27, 2019, both from three hospitals in Antananarivo, Madagascar; and caeca from farm chickens and surface waters from the Ikopa river, wastewater, and slaughterhouse effluents in the Antananarivo area, Madagascar, from April 9, 2018, to April 30, 2019. All samples were tested for ESBL-E coli. The genomes of all isolates were sequenced using a short-read method on NextSeq 500 and NovaSeq 6000 platforms (Illumina, San Diego, CA, USA) and those carrying plasmid replicons using an additional long-read method on a MinION platform (Oxford Nanopore Technologies, Oxford, UK). We characterised genomes of isolated strains (sequence type, resistance and virulence gene content, and plasmid replicons). We then compared isolates using the variant calling method (single-nucleotide polymorphism).

FINDINGS

Data from 1056 blood cultures were collected and 289 pregnant women, 246 chickens, and 28 surface waters were sampled. Of the blood cultures, 18 contained E coli, of which seven (39%) were ESBL. ESBL-E coli was present in samples from 86 (30%) of 289 pregnant women, 140 (57%) of 246 chickens, and 28 (100%) of 28 surface water samples. The wet season (November to April) was associated with higher rates of carriage in humans (odds ratio 3·08 [1·81-5·27]) and chickens (2·79 [1·65-4·81]). Sequencing of 277 non-duplicated isolates (82 from pregnant women, 118 from chickens, and 77 from environmental samples) showed high genetic diversity (90 sequence types identified) with sector-specific genomic features. Single nucleotide polymorphism (SNP) analysis revealed that 169 (61%) of 277 isolates grouped into 44 clusters (two or more isolates) of closely related isolates (<40 SNPs), of which 24 clusters contained isolates from two sectors and five contained isolates from all three sectors. ESBL genes were all blaCTX-M variants (215 [78%] of 277 being blaCTX-M-15) and were located on a plasmid in 113 (41%) of 277 isolates. These ESBL-carrying plasmids were mainly IncF (63 [55%] of 114; one strain carried two plasmids) and IncY (42 [37%] of 114). The F31/36:A4:B1 (n=13) and F-:A-:B53 (n=8) pMLST subtypes, and the IncY plasmids, which were all highly conserved, were observed in isolates of differing genetic backgrounds from all sectors and were transferable in vitro by conjugation.

INTERPRETATION

Despite sector-specific population structures, both ESBL-E coli strains and plasmids are circulating among humans, chickens, and the environment in Antananarivo, Madagascar. The Tricycle protocol can be implemented in a low-income country and represents a powerful tool for investigating dissemination of AMR from a One Health perspective.

FUNDING

Fondation Mérieux and INSERM, Université Paris Cité.

Antimicrobial resistance and phylogenetic relatedness of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli in peridomestic rats (Rattus norvegicus and Rattus tanezumi) linked to city areas and animal farms in Hong Kong

Extended-spectrum β-lactamase-producing Escherichia (E.) coli (ESBL-EC) in the clinical setting have emerged as a major threat to public and animal health. Wildlife, including Rattus spp. may serve as reservoirs and spreaders of ESBL-EC in the environment. Peridomestic rats are well adapted to living in proximity to humans and animals in a variety of urban and agricultural environments and may serve as sentinels to identify variations of ESBL-EC within their different habitats. In this study, a set of 221 rats (Rattus norvegicus, R. tanezumi, R. andamanensis, and Niviventer huang) consisting of 104 rats from city areas, 44 from chicken farms, 52 from pig farms, and 21 from stables of horse-riding schools were screened for ESBL-EC. Overall, a total of 134 ESBL-EC were isolated from the caecal samples of 130 (59%) rats. The predominant blaESBL genes were blaCTX-M-14, blaCTX-M-15, blaCTX-M-55, and blaCTX-M-65. Phylogenetic analysis revealed a total of 62 sequence types (STs) and 17 SNP clusters. E. coli ST10 and ST155 were common to ESBL-EC from city areas and chicken farms, and ST44 were found among ESBL-EC from city areas and pig farms. Extra-intestinal pathogenic E. coli (ExPEC) ST69, ST131 and ST1193 were found exclusively among rats from city areas, and avian pathogenic E. coli (APEC) ST177 was restricted to ESBL-EC originating from chicken farms. Phylogenetic analysis showed that the populations of rodent ESBL-EC from city areas, chicken farms and pig farms were genetically different, suggesting a certain degree of partitioning between the human and animal locations. This study contributes to current understanding of ESBL-EC occurring in rats in ecologically diverse locations.

Burden of bacterial antimicrobial resistance in low-income and middle-income countries avertible by existing interventions: an evidence review and modelling analysis

National action plans enumerate many interventions as potential strategies to reduce the burden of bacterial antimicrobial resistance (AMR). However, knowledge of the benefits achievable by specific approaches is needed to inform policy making, especially in low-income and middle-income countries (LMICs) with substantial AMR burden and low health-care system capacity. In a modelling analysis, we estimated that improving infection prevention and control programmes in LMIC health-care settings could prevent at least 337 000 (95% CI 250 200-465 200) AMR-associated deaths annually. Ensuring universal access to high-quality water, sanitation, and hygiene services would prevent 247 800 (160 000-337 800) AMR-associated deaths and paediatric vaccines 181 500 (153 400-206 800) AMR-associated deaths, from both direct prevention of resistant infections and reductions in antibiotic consumption. These estimates translate to prevention of 7·8% (5·6-11·0) of all AMR-associated mortality in LMICs by infection prevention and control, 5·7% (3·7-8·0) by water, sanitation, and hygiene, and 4·2% (3·4-5·1) by vaccination interventions. Despite the continuing need for research and innovation to overcome limitations of existing approaches, our findings indicate that reducing global AMR burden by 10% by the year 2030 is achievable with existing interventions. Our results should guide investments in public health interventions with the greatest potential to reduce AMR burden.

Occurrence and persistence of multidrug-resistant Enterobacterales isolated from urban, industrial and surface water in Monastir, Tunisia

The One Health approach of antimicrobial resistance highlighted the role of the aquatic environment as a reservoir and dissemination source of resistance genes and resistant bacteria, especially due to anthropogenic activities. Resistance to extended-spectrum cephalosporins (ESC) conferred by extended-spectrum beta-lactamases (ESBLs) in E. coli has been proposed as the major marker of the AMR burden in cross-sectoral approaches. In this study, we investigated wastewater, surface water and seawater that are subjected to official water quality monitoring in Monastir, Tunisia. While all but one sample were declared compliant according to the official tests, ESC-resistant bacteria were detected in 31 (19.1 %) samples. Thirty-nine isolates, coming from urban, industrial and surface water in Monastir, were collected and characterized using antibiograms and whole-genome sequencing. These isolates were identified as 27 Escherichia coli (69.3 %) belonging to 13 STs, 10 Klebsiella pneumoniae (25.6 %) belonging to six STs, and two Citrobacter freundii (5.1 %). We observed the persistence and dissemination of clones over time and in different sampling sites, and no typically human-associated pathogens could be identified apart from one ST131. All isolates presented a blaCTX-M gene - blaCTX-M-15 (n = 22) and blaCTX-M-55 (n = 8) being the most frequent variants - which were identified on plasmids (n = 20) or on the chromosome (n = 19). In conclusion, we observed ESC resistance in rather ubiquitous bacteria that are capable of surviving in the water environment. This suggests that including the total coliform count and the ESBL count as determined by bacterial growth on selective plates in the official monitoring would greatly improve water quality control in Tunisia.

Global transmission of extended-spectrum cephalosporin resistance in Escherichia coli driven by epidemic plasmids

BACKGROUND

Extended-spectrum cephalosporins (ESCs) are third and fourth generation cephalosporin antimicrobials used in humans and animals to treat infections due to multidrug-resistant (MDR) bacteria. Resistance to ESCs (ESC-R) in Enterobacterales is predominantly due to the production of extended-spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases (AmpCs). The dynamics of ESBLs and AmpCs are changing across countries and host species, the result of global transmission of ESC-R genes. Plasmids are known to play a key role in this dissemination, but the relative importance of different types of plasmids is not fully understood.

METHODS

In this study, Escherichia coli with the major ESC-R genes blaCTX-M-1, blaCTX-M-15, blaCTX-M-14 (ESBLs) and blaCMY-2 (AmpC), were selected from diverse host species and other sources across Canada, France and Germany, collected between 2003 and 2017. To examine in detail the vehicles of transmission of the ESC-R genes, long- and short-read sequences were generated to obtain complete contiguous chromosome and plasmid sequences (n = 192 ESC-R E. coli). The types, gene composition and genetic relatedness of these plasmids were investigated, along with association with isolate year, source and geographical origin, and put in context with publicly available plasmid sequences.

FINDINGS

We identified five epidemic resistance plasmid subtypes with distinct genetic properties that are associated with the global dissemination of ESC-R genes across multiple E. coli lineages and host species. The IncI1 pST3 blaCTX-M-1 plasmid subtype was found in more diverse sources than the other main plasmid subtypes, whereas IncI1 pST12 blaCMY-2 was more frequent in Canadian and German human and chicken isolates. Clonal expansion also contributed to the dissemination of the IncI1 pST12 blaCMY-2 plasmid in ST131 and ST117 E. coli harbouring this plasmid. The IncI1 pST2 blaCMY-2 subtype was predominant in isolates from humans in France, while the IncF F31:A4:B1 blaCTX-M-15 and F2:A-:B- blaCTX-M-14 plasmid subtypes were frequent in human and cattle isolates across multiple countries. Beyond their epidemic nature with respect to ESC-R genes, in our collection almost all IncI1 pST3 blaCTX-M-1 and IncF F31:A4:B1 blaCTX-M-15 epidemic plasmids also carried multiple antimicrobial resistance (AMR) genes conferring resistance to other antimicrobial classes. Finally, we found genetic signatures in the regions surrounding specific ESC-R genes, identifying the predominant mechanisms of ESC-R gene movement, and using publicly available databases, we identified these epidemic plasmids from widespread bacterial species, host species, countries and continents.

INTERPRETATION

We provide evidence that epidemic resistance plasmid subtypes contribute to the global dissemination of ESC-R genes, and in addition, some of these epidemic plasmids confer resistance to multiple other antimicrobial classes. The success of these plasmids suggests that they may have a fitness advantage over other plasmid types and subtypes. Identification and understanding of the vehicles of AMR transmission are crucial to develop and target strategies and interventions to reduce the spread of AMR.

FUNDING

This project was supported by the Joint Programming Initiative on Antimicrobial Resistance (JPIAMR), through the Medical Research Council (MRC, MR/R000948/1), the Canadian Institutes of Health Research (CFC-150770), and the Genomics Research and Development Initiative (Government of Canada), the German Federal Ministry of Education and Research (BMBF) grant no. 01KI1709, the French Agency for food environmental and occupational health & safety (Anses), and the French National Reference Center (CNR) for antimicrobial resistance. Support was also provided by the Biotechnology and Biological Sciences Research Council (BBSRC) through the BBSRC Institute Strategic Programme Microbes in the Food ChainBB/R012504/1 and its constituent project BBS/E/F/000PR10348 (Theme 1, Epidemiology and Evolution of Pathogens in the Food Chain).

Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Other Antimicrobial-Resistant Gram-Negative Pathogens Isolated from Bovine Mastitis: A One Health Perspective

Antimicrobial resistance (AMR) poses an imminent threat to global public health, driven in part by the widespread use of antimicrobials in both humans and animals. Within the dairy cattle industry, Gram-negative coliforms such as Escherichia coli and Klebsiella pneumoniae stand out as major causative agents of clinical mastitis. These same bacterial species are frequently associated with severe infections in humans, including bloodstream and urinary tract infections, and contribute significantly to the alarming surge in antimicrobial-resistant bacterial infections worldwide. Additionally, mastitis-causing coliforms often carry AMR genes akin to those found in hospital-acquired strains, notably the extended-spectrum beta-lactamase genes. This raises concerns regarding the potential transmission of resistant bacteria and AMR from mastitis cases in dairy cattle to humans. In this narrative review, we explore the distinctive characteristics of antimicrobial-resistant E. coli and Klebsiella spp. strains implicated in clinical mastitis and human infections. We focus on the molecular mechanisms underlying AMR in these bacterial populations and critically evaluate the potential for interspecies transmission. Despite some degree of similarity observed in sequence types and mobile genetic elements between strains found in humans and cows, the existing literature does not provide conclusive evidence to assert that coliforms responsible for mastitis in cows pose a direct threat to human health. Finally, we also scrutinize the existing literature, identifying gaps and limitations, and propose avenues for future research to address these pressing challenges comprehensively.

Exploring Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli in Food-Producing Animals and Animal-Derived Foods

Antimicrobials serve as crucial treatments in both veterinary and human medicine, aiding in the control and prevention of infectious diseases. However, their misuse or overuse has led to the emergence of antimicrobial resistance, posing a significant threat to public health. This review focuses on extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in animals and their associated food products, which contribute to the proliferation of antimicrobial-resistant strains. Recent research has highlighted the presence of ESBL-producing E. coli in animals and animal-derived foods, with some studies indicating genetic similarities between these isolates and those found in human infections. This underscores the urgent need to address antimicrobial resistance as a pressing public health issue. More comprehensive studies are required to understand the evolving landscape of ESBLs and to develop strategic public health policies grounded in the One Health approach, aiming to control and mitigate their prevalence effectively.

[Tracking transfers of resistance-carrying bacteria between animals, humans and the environment]

The fight against antibiotic resistance must incorporate the "One Health" concept to be effective. This means having a holistic approach embracing the different ecosystems, human, animal, and environment. Transfers of resistance genes may exist between these three domains and different stresses related to the exposome may influence these transfers. Various targeted or pan-genomic molecular biology techniques can be used to better characterise the dissemination of bacterial clones and to identify exchanges of genes and mobile genetic elements between ecosystems.

Microplastics in the insular marine environment of the Southwest Indian Ocean carry a microbiome including antimicrobial resistant (AMR) bacteria: A case study from Reunion Island

The increasing threats to ecosystems and humans from marine plastic pollution require a comprehensive assessment. We present a plastisphere case study from Reunion Island, a remote oceanic island located in the Southwest Indian Ocean, polluted by plastics. We characterized the plastic pollution on the island's coastal waters, described the associated microbiome, explored viable bacterial flora and the presence of antimicrobial resistant (AMR) bacteria. Reunion Island faces plastic pollution with up to 10,000 items/km2 in coastal water. These plastics host microbiomes dominated by Proteobacteria (80 %), including dominant genera such as Psychrobacter, Photobacterium, Pseudoalteromonas and Vibrio. Culturable microbiomes reach 107 CFU/g of microplastics, with dominance of Exiguobacterium and Pseudomonas. Plastics also carry AMR bacteria including β-lactam resistance. Thus, Southwest Indian Ocean islands are facing serious plastic pollution. This pollution requires vigilant monitoring as it harbors a plastisphere including AMR, that threatens pristine ecosystems and potentially human health through the marine food chain.

Evaluating the OH-EpiCap tool using the Danish integrated surveillance program for AMU and AMR as a case study

Antimicrobial resistance (AMR) is considered a One Health (OH) challenge, ideally demanding concerted efforts from the animal, human and environmental side. DANMAP, the Danish Integrated Antimicrobial Resistance Monitoring and Research Program, is monitoring AMR and antimicrobial use in animals and humans. OH-EpiCap is an evaluation tool, developed to address essential elements in OH surveillance systems, such as the dimensions of the organization, operational activities and the impact of the surveillance activities. We aimed to evaluate DANMAP using OH-EpiCap and hereby assessed the suitability of OH-EpiCap to evaluate integrated AMR surveillance systems. During the evaluation, the strengths and weaknesses of DANMAP concerning the "OH-ness" of the program were discussed. Furthermore, possible adaptations of the standard operating procedures and governance structure were addressed. Attention was paid to the ability and easiness of DANMAP to cope with current and future challenges connected to integrated AMR surveillance. It was concluded that DANMAP has a strong OH approach covering relevant aspects for humans and animals, whereas environmental aspects are missing. OH-EpiCap proved to be straightforward to use and provided valuable insights. The authors recommend OH-EpiCap to be used by health authorities and stakeholders. It is not suitable for the technical evaluation of a surveillance program.

ESBL-producing Enterobacteriaceae in a rural Rwandan community: Carriage among community members, livestock, farm products and environment

OBJECTIVES

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) are spreading globally. However, respective data from African communities including livestock and environmental specimens are rare. In a rural community of southern Rwanda, we assessed intestinal carriage of ESBL-PE among residents and livestock as well as presence in household specimens and examined associated factors.

METHODS

Samples of humans and livestock (both rectal swabs), soil, water, vegetables and animal products were collected within 312 community households in Sovu, Southern Rwanda. Specimens were screened for ESBL-PE on chromogenic agar, and susceptibility to common antibiotics was determined by disc diffusion assays. Socio-demographic information was collected with questionnaires focusing on the socio-economic background, alimentation, living conditions, hygiene measures and medical history of the participants.

RESULTS

Data and specimens from 312 randomly selected households including 617 human beings, 620 livestock and of approximately each 300 kitchen vegetables, animal products, soil and drinking water were analysed. Overall, 14.8% of 2508 collected samples were positive for ESBL-PE; figures were highest for humans (37.9%) and livestock (15.6%), lower for vegetables (3.8%) and animal products (3.3%), and lowest for soil (1.6%) and water (0.6%). Most detected ESBL-PE were Escherichia coli (93.5%) in addition to Klebsiella pneumoniae (6.5%). Cross-resistance to ampicillin-sulbactam, ciprofloxacin and co-trimoxazole was common. Logistic regression identified increasing age, another ESBL-PE positive household member, prolonged time for fetching water, current diarrhoea and the ability to pay school fees as independent predictors of intestinal ESBL-PE carriage among community members.

CONCLUSIONS

ESBL-PE carriage is common in a rural Rwandan farming community. Carriage in livestock is not associated with human carriage. Associated factors suggest few addressable risk factors. The data indicate that in southern Rwanda, ESBL-PE are no longer primarily hospital-based but circulate in the community.

Introduction and benchmarking of pyMLST: open-source software for assessing bacterial clonality using core genome MLST

Core genome multilocus sequence typing (cgMLST) has gained in popularity for bacterial typing since whole-genome sequencing (WGS) has become affordable. We introduce here pyMLST, a new complete, stand-alone, free and open source pipeline for cgMLST analysis. pyMLST can create or import a core genome database. For each gene, the first allele is aligned against the bacterial genome of interest using BLAT. Incomplete genes are aligned using MAFT. All data are stored in a SQLite database. pyMLST accepts assembly genomes or raw data (with the option pyMLST-KMA) as input. To evaluate our new tool, we selected three genome collections of major bacterial pathogens (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) and compared them with pyMLST, pyMLST-KMA, ChewBBACA, SeqSphere and the variant calling approach. We compared the sensitivity, precision and false-positive rate for each method with those of the variant calling approach. Minimal spanning trees were generated with each type of software to evaluate their interest in the context of a bacterial outbreak. We found that pyMLST-KMA is a convenient screening method to avoid assembling large bacterial collections. Our data showed that pyMLST (free, open source, available in Galaxy and pipeline ready) performed similarly to the commercial SeqSphere and performed better than ChewBBACA and pyMLST-KMA.

Lessons from a global antimicrobial resistance surveillance network

The World Health Organization developed the Tricycle surveillance programme to obtain a global picture of antimicrobial resistance, especially in countries with limited surveillance capacity. The programme was developed within a One Health perspective. Tricycle provides a framework for applying a standardized technical protocol to determining the prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in three sectors: the human, animal and environment sectors. Regular use of the protocol would enable information to be obtained on time trends and on inter- and intraregional variations, thereby generating dynamic data on antibacterial resistance for decision-makers. To date, 19 countries have begun implementing the Tricycle protocol, while other countries will start implementation in the coming years. The Network for Enhancing Tricycle ESBL Surveillance Efficiency (NETESE) was established to support countries implementing the Tricycle protocol. Currently, NETESE includes representatives from 15 institutions in eight low- or middle-income countries at different stages of Tricycle protocol implementation, and from four European countries involved in devising the protocol. This paper describes the Tricycle protocol, reports the initial experiences of NETESE participants with its implementation and discusses future challenges and opportunities.

Impact of veterinary antibiotics on plasmid-encoded antibiotic resistance transfer

OBJECTIVES

Resistance genes can be genetically transmitted and exchanged between commensal and pathogenic bacterial species, and in different compartments including the environment, or human and animal guts (One Health concept). The aim of our study was to evaluate whether subdosages of antibiotics administered in veterinary medicine could enhance plasmid transfer and, consequently, resistance gene exchange in gut microbiota.

METHODS

Conjugation frequencies were determined with Escherichia coli strains carrying IncL- (blaOXA-48) or IncI1-type (blaCTX-M-1) plasmids subjected to a series of subinhibitory concentrations of antibiotics used in veterinary medicine, namely amoxicillin, ceftiofur, apramycin, neomycin, enrofloxacin, colistin, erythromycin, florfenicol, lincomycin, oxytetracycline, sulfamethazine, tiamulin and the ionophore narasin. Treatments with subinhibitory dosages were performed with and without supplementation with the antioxidant edaravone, known as a mitigator of the inducibility effect of several antibiotics on plasmid conjugation frequency (PCF). Expression of SOS-response associated genes and fluorescence-based reactive oxygen species (ROS) detection assays were performed to evaluate the stress oxidative response.

RESULTS

Increased PCFs were observed for both strains when treating with florfenicol and oxytetracycline. Increased expression of the SOS-associated recA gene also occurred concomitantly, as well as increased ROS production. Addition of edaravone to the treatments reduced their PCF and also showed a decreasing effect on SOS and ROS responses for both plasmid scaffolds.

CONCLUSIONS

We showed here that some antibiotics used in veterinary medicine may induce transfer of plasmid-encoded resistance and therefore may contribute to the worldwide spread of antibiotic resistance genes.

Faecal carriage of extended-spectrum β-lactamase-producing Escherichia coli in a remote region of Niger

OBJECTIVE

Whole genome sequencing (WGS) of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli) in developing countries is lacking. Here we describe the population structure and molecular characteristics of ESBL-E. coli faecal isolates in rural Southern Niger.

METHODS

Stools of 383 healthy participants were collected among which 92.4% were ESBL-Enterobacterales carriers. A subset of 90 ESBL-E. coli containing stools (109 ESBL-E. coli isolates) were further analysed by WGS, using short- and long-reads.

RESULTS

Most isolates belonged to the commensalism-adapted phylogroup A (83.5%), with high clonal diversity. The blaCTX-M-15 gene was the major ESBL determinant (98.1%), chromosome-integrated in approximately 50% of cases, in multiple integration sites. When plasmid-borne, blaCTX-M-15 was found in IncF (57.4%) and IncY plasmids (26.2%). Closely related plasmids were found in different genetic backgrounds. Genomic environment analysis of blaCTX-M-15 in closely related strains argued for mobilisation between plasmids or from plasmid to chromosome.

CONCLUSIONS

Massive prevalence of community faecal carriage of CTX-M-15-producing E. coli was observed in a rural region of Niger due to the spread of highly diverse A phylogroup commensalism-adapted clones, with frequent chromosomal integration of blaCTX-M-15. Plasmid spread was also observed. These data suggest a risk of sustainable implementation of ESBL in community faecal carriage.

Risk Factors for Community Colonization With Extended-Spectrum Cephalosporin-Resistant Enterobacterales (ESCrE) in Botswana: An Antibiotic Resistance in Communities and Hospitals (ARCH) Study

BACKGROUND

The epidemiology of extended-spectrum cephalosporin-resistant Enterobacterales (ESCrE) in low- and middle-income countries (LMICs) is poorly described. Identifying risk factors for ESCrE colonization is critical to inform antibiotic resistance reduction strategies because colonization is typically a precursor to infection.

METHODS

From 15 January 2020 to 4 September 2020, we surveyed a random sample of clinic patients at 6 sites in Botswana. We also invited each enrolled participant to refer up to 3 adults and children. All participants had rectal swabs collected that were inoculated onto chromogenic media followed by confirmatory testing. Data were collected on demographics, comorbidities, antibiotic use, healthcare exposures, travel, and farm and animal contact. Participants with ESCrE colonization (cases) were compared with noncolonized participants (controls) to identify risk factors for ESCrE colonization using bivariable, stratified, and multivariable analyses.

RESULTS

A total of 2000 participants were enrolled. There were 959 (48.0%) clinic participants, 477 (23.9%) adult community participants, and 564 (28.2%) child community participants. The median (interquartile range) age was 30 (12-41) and 1463 (73%) were women. There were 555 cases and 1445 controls (ie, 27.8% of participants were ESCrE colonized). Independent risk factors (adjusted odds ratio [95% confidence interval]) for ESCrE included healthcare exposure (1.37 [1.08-1.73]), foreign travel [1.98 (1.04-3.77]), tending livestock (1.34 [1.03-1.73]), and presence of an ESCrE-colonized household member (1.57 [1.08-2.27]).

CONCLUSIONS

Our results suggest healthcare exposure may be important in driving ESCrE. The strong links to livestock exposure and household member ESCrE colonization highlight the potential role of common exposure or household transmission. These findings are critical to inform strategies to curb further emergence of ESCrE in LMICs.

Antimicrobial Resistance and Clonal Lineages of Escherichia coli from Food-Producing Animals

Escherichia coli are one of the most important pathogenic bacteria readily found in the livestock and widely studied as an indicator that carries drug-resistant genes between humans, animals, and the environment. The use of antimicrobials in the food chain, particularly in food-producing animals, is recognized as a significant contributor to the development and spread of antimicrobial resistance (AMR) and resistance genes can be transferred from the farm through the food-chain. The objective of this review is to highlight the background of the antimicrobials use in food-producing animals, more specifically, to study clonal lineages and the resistance profiles observed in E. coli, as well as in extended spectrum beta-lactamases (ESBL) producing E. coli, in a set of food-production animals with greater relevance in food consumption, such as pigs, poultry, cattle, fish farming and rabbits. Regarding the prevalence of ESBL-producing E. coli among farm animals, high-to-moderate prevalence was observed, and the highest resistance rates to tetracycline and ampicillin was detected in different farms in all geographic regions. Worldwide pandemic clones and high-risk zoonotic E. coli clones have been identified in most food-producing animals, and some of these clones are already disseminated in different niches, such as the environment and humans. A better understanding of the epidemiology of E. coli and ESBL-producing E. coli in livestock is urgently needed. Animal production is one of the major causes of the antibiotic resistance problem worldwide and a One Health approach is needed.

Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolated from Food-Producing Animals in Tamaulipas, Mexico

Extended-spectrum β-lactamase (ESBL)-producing E. coli has become an important global problem for the public health sector. This study aims to investigate the E. coli antimicrobial resistance profile among living food-producing animals in Tamaulipas, Mexico. A total of 200 fecal samples were collected from bovines, pigs, chickens and sheep. A total of 5.0% of the strains were phenotypically confirmed as ESBL producers. A high percentage of phenotypic antimicrobial resistance was observed against gentamicin (93.3%), tetracycline (86.6%) and streptomycin (83.3%). The gentamicin-resistant strains showed MDR, distributed among 27 resistance patterns to different antimicrobials. The antimicrobial resistance gene tet(A) was detected in 73.3% of isolates, aadA1 in 60.0% and sul2 in 43.3% of strains. The bla_CTX-M gene was found in 23.3% of strains. The virulence gene hlyA was detected in 43.3% of isolates; stx1 and stx2 were not detected in any strain. The phylotyping indicated that the isolates belonged to groups A (33.3%), B1 (16.6%), B2 (40.0%) and D (10.0%). These results show that food-producing animals might be a reservoir of ESBL-producing bacteria and may play a role in their spread.

Interplay between OXA-10 β-Lactamase Production and Low Outer-Membrane Permeability in Carbapenem Resistance in Enterobacterales

The OXA-10 class D β-lactamase has been reported to contribute to carbapenem resistance in non-fermenting Gram-negative bacilli; however, its contribution to carbapenem resistance in Enterobacterales is unknown. In this work, minimum inhibitory concentrations (MICs), whole genome sequencing (WGS), cloning experiments, kinetic assays, molecular modelling studies, and biochemical assays for carbapenemase detection were performed to determine the impact of OXA-10 production on carbapenem resistance in two XDR clinical isolates of Escherichia coli with the carbapenem resistance phenotype (ertapenem resistance). WGS identified the two clinical isolates as belonging to ST57 in close genomic proximity to each other. Additionally, the presence of the bla_OXA-10 gene was identified in both isolates, as well as relevant mutations in the genes coding for the OmpC and OmpF porins. Cloning of bla_OXA-10 in an E. coli HB4 (OmpC and OmpF-deficient) demonstrated the important contribution of OXA-10 to increased carbapenem MICs when associated with porin deficiency. Kinetic analysis showed that OXA-10 has low carbapenem-hydrolysing activity, but molecular models revealed interactions of this β-lactamase with the carbapenems. OXA-10 was not detected with biochemical tests used in clinical laboratories. In conclusion, the β-lactamase OXA-10 limits the activity of carbapenems in Enterobacterales when combined with low permeability and should be monitored in the future.

Multidrug-Resistant ESBL-Producing E. coli in Clinical Samples from the UK

Globally, cephalosporin therapy failure is a serious problem for infection control. One causative agent of cephalosporin-resistant infections is multidrug-resistant (MDR) E. coli producing extended-spectrum β-lactamases (ESBLs) and/or plasmid-encoded AmpC (pAmpC) β-lactamases. We evaluated the occurrence of ESBL/pAmpC genetic determinants in phenotypically MDR E. coli isolated from clinical samples of blood, faeces, ear effusion, urine and sputum from a UK hospital. Phenotypic resistance profiling for 18 antibiotics (from seven classes) showed that 32/35 isolates were MDR, with resistance to 4-16 of the tested antibiotics. Of the isolates, 97.1% showed resistance to ampicillin, 71.4% showed resistance to co-amoxiclav, cefotaxime, ceftazidime and ceftiofur, and 68.5% showed resistance to cefquinome. blaCTX-M, blaTEM and blaOXA-1 genes were detected in 23, 13 and 12 strains, respectively, and Intl1 was detected in 17 isolates. The most common subtypes among the definite sequence types were CTX-M-15 (40%) and TEM-1 (75%). No E. coli isolates carried pAmpC genes. Significant correlations were seen between CTX-M carriage and cefotaxime, ceftiofur, aztreonam, ceftazidime and cefquinome resistance; between blaCTX-M, blaTEM and blaOXA-1 carriage and ciprofloxacin resistance; and between Intl1 carriage and trimethoprim/sulfamethoxazole resistance. Thus, MDR phenotypes may be conferred by a relatively small number of genes. The level and pattern of antibiotic resistance highlight the need for better antibiotic therapy guidelines, including reduced use and improved surveillance.

Know your Microbe Foes: The Role of Surveillance in Combatting Antimicrobial Resistance

Antibiotic-resistant organisms (AROs) are difficult and costly to treat, associated with high mortality rates, and are on the rise. In the United States, there is limited tracking of AROs, which can contribute to transmission and inhibit infection prevention interventions. Surveillance is limited by a lack of standardized methods for colonization screening and limited communication regarding patient ARO-status between healthcare settings. Some regional surveillance and reporting efforts are in place for extensively-resistant AROs such as carbapenem-resistant Enterobacterales (CRE), but need to be further expanded nationwide and to include other AROs such as extended-spectrum β-lactamase (ESBL) producing organisms. Increased surveillance of ARO infections and colonization will inform future targeted intervention and infection prevention strategies.

Comparative Analysis of Phylogenetic Relationships and Virulence Factor Characteristics between Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolates Derived from Clinical Sites and Chicken Farms

Antimicrobial resistance in bacteria is the most urgent global threat to public health, with extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli) being one of the most documented examples. Nonetheless, the ESBL-E. coli transmission relationship among clinical sites and chicken farms remains unclear. Here, 408 ESBL-E. coli strains were isolated from hospitals and chicken farms in Sichuan Province and Yunnan Province in 2021. We detected blaCTX-M genes in 337 (82.62%) ESBL-E. coli strains. Although the isolation rate, prevalent sequence type (ST) subtypes, and blaCTX-M gene subtypes of ESBL-E. coli varied based on regions and sources, a few strains of CTX-ESBL-E. coli derived from clinical sites and chicken farms in Sichuan Province displayed high genetic similarity. This indicates a risk of ESBL-E. coli transmission from chickens to humans. Moreover, we found that the high-risk clonal strains ST131 and ST1193 primarily carried blaCTX-M-27. This indicates that drug-resistant E. coli from animal and human sources should be monitored. As well, the overuse of β-lactam antibiotics should be avoided in poultry farms to ensure public health and build an effective regulatory mechanism of "farm to fork" under a One Health perspective. IMPORTANCE Bacterial drug resistance has become one of the most significant threats to human health worldwide, especially for extended-spectrum β-lactamase-producing E. coli (ESBL-E. coli). Timely and accurate epidemiological surveys can provide scientific guidance for the adoption of treatments in different regions and also reduce the formation of drug-resistant bacteria. Our study showed that the subtypes of ESBL-E. coli strains prevalent in different provinces are somewhat different, so it is necessary to individualize treatment regimens in different regions, and it is especially important to limit and reduce antibiotic use in poultry farming since chicken-derived ESBL-E. coli serves as an important reservoir of drug resistance genes and has the potential to spread to humans, thus posing a threat to human health. The use of antibiotics in poultry farming should be particularly limited and reduced.

Current Insights Regarding the Role of Farm Animals in the Spread of Antimicrobial Resistance from a One Health Perspective

Antimicrobial resistance (AMR) represents a global threat to both human and animal health and has received increasing attention over the years from different stakeholders. Certain AMR bacteria circulate between humans, animals, and the environment, while AMR genes can be found in all ecosystems. The aim of the present review was to provide an overview of antimicrobial use in food-producing animals and to document the current status of the role of farm animals in the spread of AMR to humans. The available body of scientific evidence supported the notion that restricted use of antimicrobials in farm animals was effective in reducing AMR in livestock and, in some cases, in humans. However, most recent studies have reported that livestock have little contribution to the acquisition of AMR bacteria and/or AMR genes by humans. Overall, strategies applied on farms that target the reduction of all antimicrobials are recommended, as these are apparently associated with notable reduction in AMR (avoiding co-resistance between antimicrobials). The interconnection between human and animal health as well as the environment requires the acceleration of the implementation of the 'One Health' approach to effectively fight AMR while preserving the effectiveness of antimicrobials.