Reservoir Of Antimicrobial Resistance Research Articles

Genomic epidemiological analysis of mcr-1-harboring Escherichia coli collected from livestock settings in Vietnam.

Livestock has been implicated as a reservoir for antimicrobial resistance (AMR) genes that can spread to humans when antimicrobials are used in animals for food production to treat clinical diseases and prevent and control common disease events. In Vietnam, mcr-1-harboring Escherichia coli (MCRPEC) strains have been isolated from humans, animals (chickens, pigs, and dogs) feces, flies, foods, and the environment (rainwater, well water, and irrigation water) in communities and from clinical specimens in hospitals. The relationship between levels of AMR in livestock and its occurrence in humans is complex and is driven by many factors. We conducted whole genome sequencing of MCRPEC to analyze the molecular epidemiological characteristics, history, and relatedness of 50 isolates obtained in 2019 from different reservoirs in farms and markets in Ha Nam province, Vietnam. 34 sequence types (STs) with 3 new STs were identified in multilocus sequence typing analysis: ST12945 and ST12946 from chicken feces, and ST12947 from flies. The AMR phenotypes of 50 MCRPEC isolates were as follows: ampicillin (100%, 50/50), cefotaxime (10%, 5/50), gentamicin (60%, 30/50), amikacin (8%, 4/50), meropenem (6%, 3/50), ceftazidime (18%, 9/50), colistin (24%, 12/50) and ciprofloxacin (80%, 40/50). All 50 MCRPEC isolates were identified as MDR. 100% (50/50) isolates carried AMR genes, ranging from 5 to 22 genes. The most prevalent plasmid replicon types carrying mcr-1 were IncP-1 (17/37, 45.9%), IncX4 (7/37, 18.9%), and IncHI2/IncHI2A (6/37, 16.2%). These data suggest that the epidemiology of the mcr-1 gene is mostly determined by plasmid spreading instead of clonal dissemination of MCRPE strains. The co-occurrence of several STs such as ST10, ST48, ST155, ST206, ST2705 in various sample types, joined to the higher prevalence of a few types of Inc plasmids, confirms the dissemination of the mcr-1 carrying plasmids in E. coli clones established in livestock. 5 over 8 STs identified in flies (ST206, ST2705, ST155, ST10, and ST48) suggested the fly contribution in the transmission of AMR bacteria in environments. These popular STs also occur in human samples and 100% of the human samples were positive for the mcr-1 gene.

Lactic acid bacteria and bifidobacteria deliberately introduced into the agro-food chain do not significantly increase the antimicrobial resistance gene pool

ABSTRACT Lactic acid bacteria (LAB) and bifidobacteria may serve as reservoirs of antimicrobial resistance, but the risk posed by strains intentionally introduced into the agro-food chain has not yet been thoroughly investigated. The aim of our study was to evaluate whether probiotics, starter and protective cultures, and feed additives represent a risk to human health. In addition to commercial strains of LAB and bifidobacteria, isolates from human milk or colostrum, intestinal mucosa or feces, and fermented products were analyzed. Phenotypic susceptibility data of 474 strains showed that antimicrobial resistance was more common in intestinal isolates than in commercial strains. Antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) were characterized in the whole genome sequences of 1114 strains using comparative genomics. Intrinsic ARGs were abundant in enterococci, bifidobacteria, and lactococci but were considered non-risky due to the absence of MGEs. The results revealed that 13.8% of commercial strains contained acquired ARGs, most frequently for tetracycline. We associated 75.5% of the acquired ARGs with known or novel MGEs, and their potential for transmission was assessed by examining metagenomic sequences. We confirmed that ARGs and MGEs were not as abundant or diverse in commercial strains as in human intestinal isolates or isolates from human milk, suggesting that strains intentionally introduced into the agro-food chain do not pose a significant threat. However, attention should be paid especially to individual probiotic strains containing elements that have been shown to have high potential for transferability in the gut microbiota. Abbreviations: ARG, antimicrobial resistance gene; ICE, integrative and conjugative element; IME, integrative and mobilizable element; LAB, lactic acid bacteria; MDR, multidrug resistance; MIC, minimum inhibitory concentration; MGE, mobile genetic element; TRRPP, tetracycline-resistant ribosomal protection protein; WGS, whole genome sequences

Clonality and Persistence of Multiresistant Methicillin-Resistant Coagulase-Negative Staphylococci Isolated from the Staff of a University Veterinary Hospital.

The aim of this study was to characterize methicillin-resistant coagulase-negative staphylococci (MRCoNS) isolates from the healthy staff of a university veterinary hospital in order to assess their importance as a reservoir of antimicrobial resistance and to determine their population structure and evolution. The study duration was over two years (2020–2021), 94 individuals were analyzed in duplicate, and 78 strains were obtained. The overall prevalence of methicillin-resistant strains detected throughout the study was 61.7%, with point prevalence values of 53.2% in 2020 and 31.5% in 2021. A total of 19.1% of the individuals analyzed were carriers throughout the study. The most frequently identified MRCoNs were Staphylococcus epidermidis (92.3%) and S. warneri (3.8%). A total of 75.6% of the isolates obtained showed the development of multi-resistance, preferentially against erythromycin, gentamicin, and tetracycline, and to a lesser extent against fusidic acid, norfloxacin, and clindamycin; these antimicrobials are frequently used in the veterinary field. Although most of the S. epidermidis isolates obtained showed wide genetic variability and low dispersion, which are characteristic of community-associated isolates, a small number of strains spread between individuals in close physical proximity and were maintained over time, forming stable clones. These clones generally maintained the same type of staphylococcal cassette chromosome mec (SCCmec) and had a similar antimicrobial resistance pattern.

Global Distribution of Extended Spectrum Cephalosporin and Carbapenem Resistance and Associated Resistance Markers in Escherichia coli of Swine Origin - A Systematic Review and Meta-Analysis.

Third generation cephalosporins and carbapenems are considered critically important antimicrobials in human medicine. Food animals such as swine can act as reservoirs of antimicrobial resistance (AMR) genes/bacteria resistant to these antimicrobial classes, and potential dissemination of AMR genes or resistant bacteria from pigs to humans is an ongoing public health threat. The objectives of this systematic review and meta-analysis were to: (1) estimate global proportion and animal-level prevalence of swine E. coli phenotypically resistant to third generation cephalosporins (3GCs) and carbapenems at a country level; and (2) measure abundances and global distribution of the genetic mechanisms that confer resistance to these antimicrobial classes in these E. coli isolates. Articles from four databases (CAB s, PubMed/MEDLINE, PubAg, and Web of Science) were screened to extract relevant data. Overall, proportion of E. coli resistant to 3GCs was lower in Australia, Europe, and North America compared to Asian countries. Globally, <5% of all E. coli were carbapenem-resistant. Fecal carriage rates (animal-level prevalence) were consistently manifold higher as compared to pooled proportion of resistance in E. coli isolates. blaCTX–M were the most common 3GC resistance genes globally, with the exception of North America where blaCMY were the predominant 3GC resistance genes. There was not a single dominant blaCTX–M gene subtype globally and several blaCTX–M subtypes were dominant depending on the continent. A wide variety of carbapenem-resistance genes (blaNDM–, VIM–, IMP–, OXA–48, and KPC–) were identified to be circulating in pig populations globally, albeit at very-low frequencies. However, great statistical heterogeneity and a critical lack of metadata hinders the true estimation of prevalence of phenotypic and genotypic resistance to these antimicrobials. Comparatively frequent occurrence of 3GC resistance and emergence of carbapenem resistance in certain countries underline the urgent need for improved AMR surveillance in swine production systems in these countries.

Identification and characterisation of a novel multidrug-resistant streptococcus, Streptococcus toyakuensis sp. nov., from a blood sample

In 2018, we isolated multidrug-resistant α-haemolytic streptococci TP1632 from the blood of a 34-year-old patient with bacteraemia. This study aimed to characterise α-haemolytic streptococci TP1632 and elucidate its multidrug resistance mechanisms. TP1632 was characterised by whole genome sequencing and biochemical testing. Based on the genome sequence, digital DNA-DNA hybridization (dDDH) and average nucleotide identity based on BLAST (ANIb) values were calculated. In addition, antimicrobial-resistance mechanisms were evaluated by ResFinder and transformation assay using Streptococcus mitis. TP1632 showed resistance to β-lactams, macrolides, and quinolones. Genomic analysis revealed that dDDH and ANIb values between TP1632 and S. mitis were 56.3% and 93.63%, respectively, indicating TP1632 as the novel species. TP1632 exhibited macrolide resistance genes such as mef(A), msr(D), and erm(B) and tetracycline resistance gene tet(M). In addition, amino acids at position 81 in GyrA and 79 in ParC were tyrosine and isoleucine, respectively. When penicillin-binding proteins of TP1632 were introduced into S. mitis, recombinants showed β-lactam resistance. Thus, acquired resistance genes and low affinities towards antimicrobial agents contribute to multidrug resistance. Our findings indicated that multidrug-resistant TP1632 is a novel species in the genus Streptococcus. Furthermore, antimicrobial resistance of this strain could transfer horizontally among α-haemolytic streptococci. These data indicated the risk of emergence of multidrug-resistant streptococci not only as a pathogen but also a reservoir of antimicrobial resistance. This isolate was proposed as a novel species, Streptococcus toyakuensis sp. nov. The type strain is TP1632T (= JCM 34623T=CCUG 75492T).

Identification and genetic characterization of two conjugative plasmids that confer azithromycin resistance in Salmonella

ABSTRACT With the development of multidrug resistance in Salmonella spp. in recent years, ciprofloxacin, ceftriaxone, and azithromycin have become the principal antimicrobial agents used for the treatment of Salmonella infections. The underlying mechanisms of plasmid-mediated ciprofloxacin and ceftriaxone resistance have attracted extensive research interest, but not much is focused on azithromycin resistance in Salmonella. In this study, we investigated the genetic features of two conjugative plasmids and a non-transferable virulence plasmid that encode azithromycin resistance in food-borne Salmonella strains. We showed that the azithromycin resistance phenotype of these strains was conferred by erm(B) gene and/or the complete genetic structure IS26-mph(A)-mrx-mphR-IS6100. Comparative genetic analysis showed that these conjugative plasmids might originate from Escherichia coli and play a role in the rapid dissemination of azithromycin resistance in Salmonella. These conjugative plasmids may also serve as a reservoir of antimicrobial resistance (AMR) genes in Salmonella in which these AMR genes may be acquired by the virulence plasmids of Salmonella via genetic transposition events. Importantly, the formation of a novel macrolide-resistance and virulence-encoding plasmid, namely pS1380-118 kb, was observed in this study. This plasmid was found to exhibit transmission potential and pose a serious health threat as the extensive transmission of azithromycin resistant and virulent Salmonella strains would further compromise the effectiveness of treatment for salmonellosis. Further surveillance and research on the dissemination and evolution routes of pS1380-118kb-like plasmids in potential human pathogens of the family of Enterobacteriaceae are necessary.

BlaKPC-2-Encoding IncP-6 Plasmids in Citrobacter freundii and Klebsiella variicola Strains from Hospital Sewage in Japan.

Klebsiella pneumoniae carbapenemase (KPC) producers are an emerging threat to global health, and the hospital water environment is considered an important reservoir of these life-threatening bacteria. We characterized plasmids of KPC-2-producing Citrobacter freundii and Klebsiella variicola isolates recovered from hospital sewage in Japan. Antimicrobial susceptibility testing, whole-genome sequencing analysis, bacterial conjugation, and transformation experiments were performed for both KPC-2 producers. The blaKPC-2 gene was located on the Tn3 transposon-related region from an IncP-6 replicon plasmid that could not be transferred via conjugation. Compared to the blaKPC-2-encoding plasmid of the C. freundii isolate, alignment analysis of plasmids with blaKPC-2 showed that the blaKPC-2-encoding plasmid of the K. variicola isolate was a novel IncP-6/IncF-like hybrid plasmid containing a 75,218-bp insertion sequence composed of IncF-like plasmid conjugative transfer proteins. Carbapenem-resistant transformants harboring blaKPC-2 were obtained for both isolates. However, no IncF-like insertion region was found in the K. variicola donor plasmid of the transformant, suggesting that this IncF-like region is not readily functional for plasmid conjugative transfer and is maintained depending on the host cells. The findings on the KPC-2 producers and novel genetic content emphasize the key role of hospital sewage as a potential reservoir of pathogens and its linked dissemination of blaKPC-2 through the hospital water environment. Our results indicate that continuous monitoring for environmental emergence of antimicrobial-resistant bacteria might be needed to control the spread of these infectious bacteria. Moreover, it will help elucidate both the evolution and transmission pathways of these bacteria harboring antimicrobial resistance. IMPORTANCE Antimicrobial resistance is a significant problem for global health, and the hospital environment has been recognized as a reservoir of antimicrobial resistance. Here, we provide insight into the genomic features of blaKPC-2-harboring isolates of Citrobacter freundii and Klebsiella variicola obtained from hospital sewage in Japan. The findings of carbapenem-resistant bacteria containing this novel genetic context emphasize that hospital sewage could act as a potential reservoir of pathogens and cause the subsequent spread of blaKPC-2 via horizontal gene transfer in the hospital water environment. This indicates that serial monitoring for environmental bacteria possessing antimicrobial resistance may help us control the spread of infection and also lead to elucidating the evolution and transmission pathways of these bacteria.

Use of genomics to explore AMR persistence in an outdoor pig farm with low antimicrobial usage.

Food animals may be reservoirs of antimicrobial resistance (AMR) passing through the food chain, but little is known about AMR prevalence in bacteria when selective pressure from antimicrobials is low or absent. We monitored antimicrobial-resistant Escherichia coli over 1 year in a UK outdoor pig farm with low antimicrobial usage (AMU) compared to conventional pig farms in the United Kingdom. Short and selected long-read whole-genome sequencing (WGS) was performed to identify AMR genes, phylogeny and mobile elements in 385 E. coli isolates purified mainly from pig and some seagull faeces. Generally, low levels of antimicrobial-resistant E. coli were present, probably due to low AMU. Those present were likely to be multi-drug resistant (MDR) and belonging to particular Sequence Types (STs) such as ST744, ST88 or ST44, with shared clones (<14 Single Nucleotide Polymorphisms (SNPs) apart) isolated from different time points indicating epidemiological linkage within pigs of different ages, and between pig and the wild bird faeces. Although importance of horizontal transmission of AMR is well established, there was limited evidence of plasmid-mediated dissemination between different STs. Non-conjugable MDR plasmids or large AMR gene-bearing transposons were stably integrated within the chromosome and remained associated with particular STs/clones over the time period sampled. Heavy metal resistance genes were also detected within some genetic elements. This study highlights that although low levels of antimicrobial-resistant E. coli correlates with low AMU, a basal level of MDR E. coli can still persist on farm potentially due to transmission and recycling of particular clones within different pig groups. Environmental factors such as wild birds and heavy metal contaminants may also play important roles in the recycling and dissemination, and hence enabling persistence of MDR E. coli . All such factors need to be considered as any rise in AMU on low usage farms, could in future, result in a significant increase in their AMR burden.

Soil Bacteria in Urban Community Gardens Have the Potential to Disseminate Antimicrobial Resistance Through Horizontal Gene Transfer

Fifteen soil and 45 vegetable samples from Detroit community gardens were analyzed for potential antimicrobial resistance contamination. Soil bacteria were isolated and tested by antimicrobial susceptibility profiling, horizontal gene transfer, and whole-genome sequencing. High-throughput 16S rRNA sequencing analysis was conducted on collected soil samples to determine the total bacterial composition. Of 226 bacterial isolates recovered, 54 were from soil and 172 from vegetables. A high minimal inhibitory concentration (MIC) was defined as the MIC greater than or equal to the resistance breakpoint of Escherichia coli for Gram-negative bacteria or Staphylococcus aureus for Gram-positive bacteria. The high MIC was observed in 63.4 and 69.8% of Gram-negative isolates from soil and vegetables, respectively, against amoxicillin/clavulanic acid, as well as 97.5 and 82.7% against ampicillin, 97.6 and 90.7% against ceftriaxone, 85.4 and 81.3% against cefoxitin, 65.8 and 70.5% against chloramphenicol, and 80.5 and 59.7% against ciprofloxacin. All Gram-positive bacteria showed a high MIC to gentamicin, kanamycin, and penicillin. Forty of 57 isolates carrying tetM (70.2%) successfully transferred tetracycline resistance to a susceptible recipient via conjugation. Whole-genome sequencing analysis identified a wide array of antimicrobial resistance genes (ARGs), including those encoding AdeIJK, Mex, and SmeDEF efflux pumps, suggesting a high potential of the isolates to become antimicrobial resistant, despite some inconsistency between the gene profile and the resistance phenotype. In conclusion, soil bacteria in urban community gardens can serve as a reservoir of antimicrobial resistance with the potential to transfer to clinically important pathogens, resulting in food safety and public health concerns.

A closer look on the variety and abundance of the faecal resistome of wild boar

Antimicrobial resistance (AMR) is a serious problem for public and animal health, and also for the environment. Monitoring and reporting the occurrence of AMR determinants and bacteria with the potential to disseminate is a priority for health surveillance programs around the world and critical to the One Health concept. Wildlife is a reservoir of AMR, and human activities can strongly influence their resistome.The main goal of this work was to study the resistome of wild boar faecal microbiome, one of the most important game species in Europe using metagenomic and culturing approaches. The most abundant genes identified by the high-throughput qPCR array encode mobile genetic elements, including integrons, which can promote the dissemination of AMR determinants. A diverse set of genes (n = 62) conferring resistance to several classes of antibiotics (ARGs), some of them included in the WHO list of critically important antimicrobials were also detected. The most abundant ARGs confer resistance to tetracyclines and aminoglycosides. The phenotypic resistance of E. coli and Enterococcus spp. were also investigated, and together supported the metagenomic results.As the wild boar is an omnivorous animal, it can be a disseminator of AMR bacteria and ARGs to livestock, humans, and the environment. This study supports that wild boar can be a key sentinel species in ecosystems surveillance and should be included in National Action Plans to fight AMR, adopting a One Health approach.

Study of Antimicrobial Resistance in Recreational Water Bodies

Thc development and proliferation of antibiotic resistance in pathogen, commensal and environmcntal microorganisms is a major heallh conccrn. The natural environment may act as a site of propagation and maintenance of antibiotic resistance and greatly depends on various human activities. The anthropogenic activities leading to rise and dissemination of antibiotic resistance should be studied extensively. Recreational water bodies can act both as the recipient and reservoir of antimicrobial resistance (AMR) and thus serve as a potent site of horizntal transfer of antibiotic resistant genes and dissemination of the same to environmental microbes. In the current study, water samples of recreational water bodies were investigated as possible sources of antibiotic resistant bacterial population. Water samples from RabindraSarobar of Kolkata was surveyed and antibiotic resistance patern of gram negative fecal coliforrnswere mainly evaluated. Many of them were found to be Multidrug resistant(MDR) which is of great concem to the public health.

Emerging Electrochemical Sensors for Real-Time Detection of Tetracyclines in Milk.

Antimicrobial drug residues in food are strictly controlled and monitored by national laws in most territories. Tetracyclines are a major broad-spectrum antibiotic class, active against a wide range of Gram-positive and Gram-negative bacteria, and they are the leading choice for the treatment of many conditions in veterinary medicine in recent years. In dairy farms, milk from cows being treated with antibiotic drugs, such as tetracyclines, is considered unfit for human consumption. Contamination of the farm bulk tank with milk containing these residues presents a threat to confidence of supply and results in financial losses to farmers and dairy. Real-time monitoring of milk production for antimicrobial residues could reduce this risk and help to minimise the release of residues into the environment where they can cause reservoirs of antimicrobial resistance. In this article, we review the existing literature for the detection of tetracyclines in cow’s milk. Firstly, the complex nature of the milk matrix is described, and the test strategies in commercial use are outlined. Following this, emerging biosensors in the low-cost biosensors field are contrasted against each other, focusing upon electrochemical biosensors. Existing commercial tests that identify antimicrobial residues within milk are largely limited to beta-lactam detection, or non-specific detection of microbial inhibition, with tests specific to tetracycline residues less prevalent. Herein, we review a number of emerging electrochemical biosensor detection strategies for tetracyclines, which have the potential to close this gap and address the industry challenges associated with existing tests.

Antimicrobials and Food-Related Stresses as Selective Factors for Antibiotic Resistance along the Farm to Fork Continuum.

Antimicrobial resistance (AMR) is a global problem and there has been growing concern associated with its widespread along the animal–human–environment interface. The farm-to-fork continuum was highlighted as a possible reservoir of AMR, and a hotspot for the emergence and spread of AMR. However, the extent of the role of non-antibiotic antimicrobials and other food-related stresses as selective factors is still in need of clarification. This review addresses the use of non-antibiotic stressors, such as antimicrobials, food-processing treatments, or even novel approaches to ensure food safety, as potential drivers for resistance to clinically relevant antibiotics. The co-selection and cross-adaptation events are covered, which may induce a decreased susceptibility of foodborne bacteria to antibiotics. Although the available studies address the complexity involved in these phenomena, further studies are needed to help better understand the real risk of using food-chain-related stressors, and possibly to allow the establishment of early warnings of potential resistance mechanisms.

The Gut Microbiome as a Reservoir for Antimicrobial Resistance.

This review will consider the gut as a reservoir for antimicrobial resistance, colonization resistance, and how disruption of the microbiome can lead to colonization by pathogenic organisms. There is a focus on the gut as a reservoir for β-lactam and plasmid-mediated quinolone resistance. Finally, the role of functional metagenomics and long-read sequencing technologies to detect and understand antimicrobial resistance genes within the gut microbiome is discussed, along with the potential for future microbiome-directed methods to detect and prevent infection.

Urban birds: An important source of antimicrobial resistant Salmonella strains in Central Spain

Antimicrobial resistance (AMR) is one of the most important threats of the 21 st century. Wild birds have been described as reservoirs of AMR in different bacterial species, such as Salmonella spp. Privation of food, climate change and overpopulation have forced many wild species to modify their feeding habits, attending urban areas. In this context, the aim of this study was to study Salmonella presence, as well as related AMR in urban birds that inhabit the city and its surroundings. A total of 300 urban birds were sampled for Salmonella detection according to the ISO 6579-1:2017 (Annex D) recommendations, and serotyping was carried out according to the White-Kauffman-Le Minor scheme. Antimicrobial susceptibility was tested following 2013/652/EU Decision guides. Wild birds analysed were positive for Salmonella in 12.3 % of cases, with white storks fed in landfills as the most Salmonella prevalent species (p < 0.05). The most common serovars isolated were zoonotic (S. Enteritidis, S. Typhimurium and S. Typhimurium monophasic variant). From Salmonella isolated strains, 40.5 % were resistant to the most prevalent AMRs found in urban birds were ciprofloxacin (36.4 %), nalidixic acid (36.4 %) and colistin (27.3 %). The scientific community, public administration and population in general should work together to control antimicrobial administration and drug waste management in order to decrease the development and spread of AMR.

Chromosomal Conjugative and Mobilizable Elements in Streptococcus suis: Major Actors in the Spreading of Antimicrobial Resistance and Bacteriocin Synthesis Genes.

Streptococcus suis is a zoonotic pathogen suspected to be a reservoir of antimicrobial resistance (AMR) genes. The genomes of 214 strains of 27 serotypes were screened for AMR genes and chromosomal Mobile Genetic Elements (MGEs), in particular Integrative Conjugative Elements (ICEs) and Integrative Mobilizable Elements (IMEs). The functionality of two ICEs that host IMEs carrying AMR genes was investigated by excision tests and conjugation experiments. In silico search revealed 416 ICE-related and 457 IME-related elements. These MGEs exhibit an impressive diversity and plasticity with tandem accretions, integration of ICEs or IMEs inside ICEs and recombination between the elements. All of the detected 393 AMR genes are carried by MGEs. As previously described, ICEs are major vehicles of AMR genes in S. suis. Tn5252-related ICEs also appear to carry bacteriocin clusters. Furthermore, whereas the association of IME-AMR genes has never been described in S. suis, we found that most AMR genes are actually carried by IMEs. The autonomous transfer of an ICE to another bacterial species (Streptococcus thermophilus)—leading to the cis-mobilization of an IME carrying tet(O)—was obtained. These results show that besides ICEs, IMEs likely play a major role in the dissemination of AMR genes in S. suis.

Use of whole genome sequencing of commensal Escherichia coli in pigs for antimicrobial resistance surveillance, United Kingdom, 2018.

BackgroundSurveillance of commensal Escherichia coli, a possible reservoir of antimicrobial resistance (AMR) genes, is important as they pose a risk to human and animal health. Most surveillance activities rely on phenotypic characterisation, but whole genome sequencing (WGS) presents an alternative.AimIn this retrospective study, we tested 515 E. coli isolated from pigs to evaluate the use of WGS to predict resistance phenotype.MethodsMinimum inhibitory concentration (MIC) was determined for nine antimicrobials of clinical and veterinary importance. Deviation from wild-type, fully-susceptible MIC was assessed using European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off (ECOFF) values. Presence of AMR genes and mutations were determined using APHA SeqFinder. Statistical two-by-two table analysis and Cohen’s kappa (k) test were applied to assess genotype and phenotype concordance.ResultsOverall, correlation of WGS with susceptibility to the nine antimicrobials was 98.9% for test specificity, and 97.5% for the positive predictive value of a test. The overall kappa score (k = 0.914) indicated AMR gene presence was highly predictive of reduced susceptibility and showed excellent correlation with MIC. However, there was variation for each antimicrobial; five showed excellent correlation; four very good and one moderate. Suggested ECOFF adjustments increased concordance between genotypic data and kappa values for four antimicrobials.ConclusionWGS is a powerful tool for accurately predicting AMR that can be used for national surveillance purposes. Additionally, it can detect resistance genes from a wider panel of antimicrobials whose phenotypes are currently not monitored but may be of importance in the future.

Characterization of a Linezolid- and Vancomycin-Resistant Streptococcus suis Isolate That Harbors optrA and vanG Operons.

Linezolid and vancomycin are among the last-resort antimicrobial agents in the treatment of multidrug-resistant Gram-positive bacterial infections. Linezolid- and vancomycin-resistant (LVR) Gram-positive bacteria may pose severe threats to public health. In this study, three optrA- and vanG-positive Streptococcus suis strains were isolated from two farms of different cities. There were only 1 and 343 single-nucleotide polymorphisms in coding region (cSNPs) of HCB4 and YSJ7 to YSJ17, respectively. Mobilome analysis revealed the presence of vanG, erm(B), tet(O/W/32/O), and aadE-apt-sat4-aphA3 cluster on an integrative and conjugative element, ICESsuYSJ17, and erm(B), aphA3, aac(6′)-aph(2″), catpC194, and optrA on a prophage, ΦSsuYSJ17-3. ICESsuYSJ17 exhibited a mosaic structure and belongs to a highly prevalent and transferable ICESa2603 family of Streptococcus species. ΦSsuYSJ17-3 shared conserved backbone to a transferable prophage Φm46.1. A novel composite transposon, IS1216E-araC-optrA-hp-catpC194-IS1216E, which can be circulated as translocatable unit (TU) by IS1216E, was integrated on ΦSsuYSJ17-3. Vancomycin resistance phenotype and vanG transcription assays revealed that the vanG operon was inducible. The LVR strain YSJ17 exhibited moderate virulence in a zebrafish infection model. To our knowledge, this is the first report of LVR isolate, which is mediated by acquired resistance genes optrA and vanG operons in Gram-positive bacteria. Since S. suis has been recognized as an antimicrobial resistance reservoir in the spread of resistance genes to major streptococcal pathogens, the potential risks of disseminating of optrA and vanG from S. suis to other Streptococcus spp. are worrisome and routine surveillance should be strengthened.

Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli Isolated from Flies in the Urban Center of Berlin, Germany.

Background: The monitoring of antimicrobial resistance (AMR) in microorganisms that circulate in the environment is an important topic of scientific research and contributes to the development of action plans to combat the spread of multidrug-resistant (MDR) bacteria. As a synanthropic vector for multiple pathogens and a reservoir for AMR, flies can be used for surveillance. Methods: We collected 163 flies in the inner city of Berlin and examined them for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli genotypically and phenotypically. Results: The prevalence of ESBL-producing E. coli in flies was 12.9%. Almost half (47.6%) of the ESBL-positive samples showed a co-resistance to ciprofloxacin. Resistance to carbapenems or colistin was not detected. The predominant ESBL-type was CTX-M-1, which is associated with wildlife, livestock, and companion animals as a potential major source of transmission of MDR E. coli to flies. Conclusions: This field study confirms the permanent presence of ESBL-producing E. coli in an urban fly population. For continuous monitoring of environmental contamination with multidrug-resistant (MDR) bacteria, flies can be used as indicators without much effort.

Prevalence of antimicrobial resistance and potential pathogenicity, and possible spread of third generation cephalosporin resistance, in Escherichia coli isolated from healthy chicken farms in the region of Dakar, Senegal.

Escherichia coli is a normal inhabitant of the intestinal microbiota of chickens, a small proportion of which may be avian pathogenic E. coli (APEC) or potential extraintestinal pathogenic E. coli (ExPEC), capable of causing disease in humans. These E. coli may also be resistant to antimicrobials of critical importance in human or veterinary health. This study aims to 1) determine the prevalence of antimicrobial resistance (AMR) and resistance genes, multidrug resistance (MDR), chromosomal mechanisms of quinolone-resistance and virulence profiles of E. coli isolated from healthy chicken farms in the region of Dakar, Senegal, 2) investigate the spread of third-generation cephalosporins (3GC) resistance in E. coli isolated from healthy chicken farms with respect to virulence and resistance genes, serogroups, Pulsed-Field Gel Electrophoresis (PFGE), phylogenetic groups, plasmid types and transferability and 3) determine whether nonsusceptibility against 3GC on farms could be linked to risk factors. More than 68% of isolates from environmental faecal and drinking water samples, carcasses and carcass washes collected on 32 healthy chicken farms were multidrug resistant (MDR), resistance to antimicrobials critical in human health (3GC or ciprofloxacin) being found in all types of samples. Ciprofloxacin resistance was due to mutations in the gyrA and parC genes, 95% of tested farms harboring isolates carrying three mutations, in gyrA (Ser83Ile and Asp87Asn) and parC (Ser80Ile). Nine of the 32 farms (28.1%) demonstrated the presence of one or more 3GC-nonsusceptible indicator isolates but none of the potential risk factors were significantly associated with this presence on farms. Following ceftriaxone enrichment, presumptive extended-spectrum beta-lactamase/AmpC-beta-lactamase (ESBL/AmpC)-producer isolates were found in 17 of the 32 farms. 3GC resistance was mediated by blaCMY-2 or blaCTX-M genes, blaCTX-M being of genotypes blaCTX-M-1, blaCTX-M-8 and for the first time in chickens in Senegal, the genotype blaCTX-M-15. Clonally related ESBL/AmpC-producer isolates were found on different farms. In addition, blaCTX-M genes were identified on replicon plasmids I1 and K/B and blaCMY-2 on K/B, I1 and B/O. These plasmids were found in isolates of different clusters. In addition, 18 isolates, some of which were ESBL/AmpC-producers, were defined as potential human ExPEC. In conclusion, E. coli isolates potentially pathogenic for humans and demonstrating MDR, with resistance expressed against antimicrobials of critical importance in human health were found in healthy chickens in Senegal. Our results suggest that both clonal spreading and horizontal gene transfer play a role in the spread of 3GC-resistance and that chickens in Senegal could be a reservoir for AMR and ExPEC for humans. These results highlight the importance of raising awareness about compliance with biosecurity measures and prudent use of antimicrobials.