Source Tracking and Global Distribution of the Tigecycline Non-Susceptible tet(X). - Related Documents




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453701.0000Source Tracking and Global Distribution of the Tigecycline Non-Susceptible tet(X). The emergence of tet(X) genes has compromised the clinical use of the last-line antibiotic tigecycline. We identified 322 (1.21%) tet(X) positive samples from 12,829 human microbiome samples distributed in four continents (Asia, Europe, North America, and South America) using retrospective data from worldwide. These tet(X) genes were dominated by tet(X2)-like orthologs but we also identified 12 samples carrying novel tet(X) genes, designed tet(X45), tet(X46), and tet(X47), were resistant to tigecycline. The metagenomic analysis indicated these tet(X) genes distributed in anaerobes dominated by Bacteroidaceae (78.89%) of human-gut origin. Two mobile elements ISBf11 and IS4351 were most likely to promote the transmission of these tet(X2)-like orthologs between Bacteroidaceae and Riemerella anatipestifer. tet(X2)-like orthologs was also developed during transmission by mutation to high-level tigecycline resistant genes tet(X45), tet(X46), and tet(X47). Further tracing these tet(X) in single bacterial isolate from public repository indicated tet(X) genes were present as early as 1960s in R. anatipestifer that was the primary tet(X) carrier at early stage (before 2000). The tet(X2) and non-tet(X2) orthologs were primarily distributed in humans and food animals respectively, and non-tet(X2) were dominated by tet(X3) and tet(X4). Genomic comparison indicated these tet(X) genes were likely to be generated during tet(X) transmission between Flavobacteriaceae and E. coli/Acinetobacter spp., and ISCR2 played a key role in the transmission. These results suggest R. anatipestifer was the potential ancestral source of tet(X). In addition, Bacteroidaceae of human-gut origin was an important hidden reservoir and mutational incubator for the mobile tet(X) genes that enabled spread to facultative anaerobes and aerobes. IMPORTANCE The emergence of the tigecycline resistance gene tet(X) has posed a severe threat to public health. However, reports of its origin and distribution in human remain rare. Here, we explore the origin and distribution of tet(X) from large-scale metagenomic data of human-gut origin and public repository. This study revealed the emergency of tet(X) gene in 1960s, which has refreshed a previous standpoint that the earliest presence of tet(X) was in 1980s. The metagenomic analysis from data mining covered the unculturable bacteria, which has overcome the traditional bacteria isolating and purificating technologies, and the analysis indicated that the Bacteroidaceae of human-gut origin was an important hidden reservoir for tet(X) that enabled spread to facultative anaerobes and aerobes. The continuous monitoring of mobile tigecycline resistance determinants from both culturable and unculturable microorganisms is imperative for understanding and tackling the dissemination of tet(X) genes in both the health care and agricultural sectors.202134935428
344410.9996Multidrug resistance in bacteria associated with leafy greens and soil in urban agriculture systems. Urban farms and community gardens support local food production, though these agroecosystems can contain emerging environmental contaminants that may contribute to the dissemination of antimicrobial resistance (AMR). Our previous research enumerated AMR bacteria associated with leafy vegetable production environments in the greater Washington, D.C. area, identifying >100 isolates with multidrug-resistant (MDR) phenotypes. Here, we performed whole genome sequencing analysis of 87 of these strains recovered from leafy greens (n=29), root zone soil (n=42), and bulk soil (n=16) to comprehensively characterize their MDR genotypes, including taxonomy and any encoded ARGs, stress response genes, and mobile genetic elements (MGEs; e.g., plasmids, phages, conjugative elements). The MDR isolates spanned 4 phyla and 14 genera, with the majority identified as Pseudomonas (n = 29), Serratia (n = 22), Providencia (n = 11), and Bacillus (n = 11). Most of the ARGs were linked to multidrug efflux, while other abundant ARG classes reflected resistance to beta-lactams and tetracyclines. While the genotypes were often conserved within respective species and even genera, the observed phenotypes within taxonomic groups slightly varied, suggesting the potential roles of uncharacterized genetic elements in MDR function. Moreover, all of the MDR isolates encoded at least one gene annotated as a MGE, and there were 19 distinct ARGs located within 5,000 bp upstream or downstream of these sequences, suggesting potential implications for mobilization. Overall, our results indicate that the MDR bacteria in urban agriculture systems, including on fresh produce, are dominated by general soil-associated taxa that carry diverse ARGs and MGEs.202541059364
453620.9996Resistome Analysis of Global Livestock and Soil Microbiomes. Antimicrobial resistance (AMR) is a serious threat to public health globally; it is estimated that AMR bacteria caused 1.27 million deaths in 2019, and this is set to rise to 10 million deaths annually. Agricultural and soil environments act as antimicrobial resistance gene (ARG) reservoirs, operating as a link between different ecosystems and enabling the mixing and dissemination of resistance genes. Due to the close interactions between humans and agricultural environments, these AMR gene reservoirs are a major risk to both human and animal health. In this study, we aimed to identify the resistance gene reservoirs present in four microbiomes: poultry, ruminant, swine gastrointestinal (GI) tracts coupled with those from soil. This large study brings together every poultry, swine, ruminant, and soil shotgun metagenomic sequence available on the NCBI sequence read archive for the first time. We use the ResFinder database to identify acquired antimicrobial resistance genes in over 5,800 metagenomes. ARGs were diverse and widespread within the metagenomes, with 235, 101, 167, and 182 different resistance genes identified in the poultry, ruminant, swine, and soil microbiomes, respectively. The tetracycline resistance genes were the most widespread in the livestock GI microbiomes, including tet(W)_1, tet(Q)_1, tet(O)_1, and tet(44)_1. The tet(W)_1 resistance gene was found in 99% of livestock GI tract microbiomes, while tet(Q)_1 was identified in 93%, tet(O)_1 in 82%, and finally tet(44)_1 in 69%. Metatranscriptomic analysis confirmed these genes were "real" and expressed in one or more of the livestock GI tract microbiomes, with tet(40)_1 and tet(O)_1 expressed in all three livestock microbiomes. In soil, the most abundant ARG was the oleandomycin resistance gene, ole(B)_1. A total of 55 resistance genes were shared by the four microbiomes, with 11 ARGs actively expressed in two or more microbiomes. By using all available metagenomes we were able to mine a large number of samples and describe resistomes in 37 countries. This study provides a global insight into the diverse and abundant antimicrobial resistance gene reservoirs present in both livestock and soil microbiomes.202235875563
284230.9996Assessing antimicrobial and metal resistance genes in Escherichia coli from domestic groundwater supplies in rural Ireland. Natural ecosystems can become significant reservoirs and/or pathways for antimicrobial resistance (AMR) dissemination, with the potential to affect nearby microbiological, animal, and ultimately human communities. This is further accentuated in environments that provide direct human exposure, such as drinking water. To date, however, few studies have investigated AMR dissemination potential and the presence of co-selective stressors (e.g., metals/metalloids) in groundwater environments of human health significance. Accordingly, the present study analysed samples from rural (drinking) groundwater supplies (i.e., private wells) in the Republic of Ireland, where land use is dominated by livestock grazing activities. In total, 48 Escherichia coli isolates tested phenotypically for antimicrobial susceptibility in an earlier study were further subject to whole genome sequencing (WGS) and corresponding water samples were further analysed for trace metal/metalloid concentrations. Eight isolates (i.e., 16.7%) were genotypically resistant to antimicrobials, confirming prior phenotypic results through the identification of ten antimicrobial resistance genes (ARGs); namely: aph(3″)-lb (strA; n=7), aph(6)-Id (strA; n = 6), blaTEM (n = 6), sul2 (n = 6), tetA (n = 4), floR (n = 2), dfrA5 (n = 1), tetB (n = 1), and tetY (n = 1). Additional bioinformatic analysis revealed that all ARGs were plasmid-borne, except for two of the six sul2 genes, and that 31.2% of all tested isolates (n = 15) and 37.5% of resistant ones (n = 3) carried virulence genes. Study results also found no significant relationships between metal concentrations and ARG abundance. Additionally, just one genetic linkage was identified between ARGs and a metal resistance gene (MRG), namely merA, a mercury-resistant gene found on the same plasmid as blaTEM, dfrA5, strA, strB, and sul2 in the only isolate of inferred porcine (as opposed to bovine) origin. Overall, findings suggest that ARG (and MRG) acquisition may be occurring prior to groundwater ingress, and are likely a legacy issue arising from agricultural practices.202337343911
255640.9996Distribution of Antimicrobial Resistance Genes Across Salmonella enterica Isolates from Animal and Nonanimal Foods. ABSTRACT: Antimicrobial-resistant bacteria are a major public health problem. Of particular importance in the context of food safety is the prevalence of antimicrobial resistance (AMR) genes within nontyphoidal Salmonella, which is a leading bacterial cause of foodborne disease. We determined the prevalence of AMR genes across a very large number of Salmonella genomes (n = 25,647) collected from isolates from 16 common food sources. The average percentage of isolates from nonanimal foods, such as fruit, nuts and seeds, and vegetables, harboring at least one AMR gene was only marginally lower (72%) than that observed in isolates from animal foods such as beef, chicken, turkey, and pork (74%). This high prevalence of AMR genes was primarily driven by the high prevalence of aminoglycoside resistance genes in nearly all food isolates; genes for resistance to tetracycline and sulfonamide also were highly prevalent. However, evaluation of the number of genes per isolate revealed that the prevalence of AMR genes was higher in animal food isolates than in nonanimal food isolates (P = 0.018). A random forest analysis provided evidence that within a given serovar, resistance gene profiles differed according to isolate food source. AMR gene profiles could be used to correctly predict the food of origin for 71% of the isolates, but success differed according to serovar. This information can help inform AMR risk assessments of food commodities and refine processes for targeting interventions to limit the spread of AMR through the food supply.202031961231
256550.9996Phenotypic and genotypic characterization of antibiotic-resistant bacteria from Swiss ready-to-eat meat products. Antimicrobial resistance is a global health concern, which is partly driven by rising meat consumption, which has led to the intensive farming of livestock that relies on antibiotics. ready-to-eat animal products can carry antibiotic-resistant bacteria, posing risks to humans since they are often consumed without further cooking. While countries such as Switzerland limit antibiotic use in agriculture, contamination of meat with antibiotic-resistant bacteria can still occur during meat processing, and non-antibiotic agents such as heavy metals may contribute to the co-selection of resistance. This study aimed to characterize antibiotic-resistant bacteria in ready-to-eat meat products from various Swiss butcheries. Presumptive resistant bacteria were isolated using selective plating and analyzed phenotypically and genotypically. A total of 53 bacteria-antibiotic resistance combinations were identified, including Enterobacterales resistant to third-generation cephalosporins, vancomycin-resistant Enterococci, and one strain of methicillin-resistant Staphylococcus aureus. Of the 804 products sampled, 177 antibiotic-resistant bacteria were isolated, 148 of which showed multidrug resistance. Notably, these strains remained susceptible to last-resort antibiotics such as carbapenems and colistin. Whole-genome sequencing of 31 selected isolates revealed 164 antibiotic resistance genes spanning 25 classes, confirming resistance to beta-lactams, cephalosporins, and tetracyclines. We also detected genes conferring resistance to metals, suggesting co-selection pressures. Long-read sequencing revealed that the majority of the antibiotic resistance genes were chromosomal, while others were plasmid-encoded, indicating the potential for horizontal gene transfer. This study demonstrates that ready-to-eat meat products are reservoirs of antibiotic and metal resistance genes, as well as antibiotic-resistant bacteria, even at low levels. From a One Health perspective, our results highlight the importance of extending AMR surveillance across the food chain and underscore the need to include non-traditional bacterial indicators.202541001059
344260.9996Florfenicol and oxazolidone resistance status in livestock farms revealed by short- and long-read metagenomic sequencing. Antibiotic resistance genes (ARGs) as a novel type of environmental pollutant pose a health risk to humans. Oxazolidinones are one of the most important antibiotics for the treatment of Gram-positive bacterial infections in humans. Although oxazolidinones are not utilized in the livestock industry, florfenicol is commonly used on farms to treat bacterial infections, which may contribute to the spread of the cfr, optrA, and poxtA genes on farms. Using metagenomics sequencing, we looked into the antibiotic resistome context of florfenicol and oxazolidinone in 10 large-scale commercial farms in China. We identified 490 different resistance genes and 1,515 bacterial genera in the fecal samples obtained from 10 farms. Florfenicol-resistant Kurthia, Escherichia, and Proteus were widely present in these samples. The situation of florfenicol and oxazolidone resistance in pig farms is even more severe. The total number of genes and the abundance of drug resistance genes were higher in pigs than in chickens, including optrA and poxtA. All the samples we collected had a high abundance of fexA and floR. Through nanopore metagenomic analysis of the genetic environment, we found that plasmids, integrative and conjugative element (ICE), and transposons (Tn7-like and Tn558) may play an important role in the spread of floR, cfr, and optrA. Our findings suggest that florfenicol and oxazolidinone resistance genes have diverse genetic environments and are at risk of co-transmission with, for example, tetracycline and aminoglycoside resistance genes. The spread of florfenicol- and oxazolidinone-resistant bacteria on animal farms should be continuously monitored.202236338088
284470.9995High throughput qPCR analyses suggest that Enterobacterales of French sheep and cow cheese rarely carry genes conferring resistances to critically important antibiotics for human medicine. Bacteria present in raw milk can carry acquired or intrinsic antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs). However, only a few studies have evaluated raw milk cheese as a potential reservoir of ARGs. This study thus aimed at providing new data regarding resistance markers present in raw milk cheese. Sheep (n = 360) and cow (n = 360) cheese samples produced in France were incubated in buffered peptone water supplemented with acriflavin or novobiocin; as corroborated by 16S metabarcoding, samples were enriched in Gram-negative bacteria since Escherichia coli and Hafnia alvei respectively accounted for 40 % and 20 % of the samples' microbiota. Screening of the samples for the presence of 30 ARGs and 16 MGEs by high throughput qPCR array showed that nine ARGs conferring resistances to 1st-generation beta-lactams, aminoglycosides, trimethoprim/sulfonamides and tetracyclines occurred in >75 % of both sheep and cow samples. This is neither surprising nor alarming since these resistance genes are widely spread across the One Health human, animal and environmental sectors. Conversely, genes conferring resistances to last-generations cephalosporins were rarely identified, while those conferring resistances to carbapenems or amikacin, which are restricted to human use, were never detected. Multiple MGEs were detected, the most frequent ones being IncF plasmids, confirming the potential transmission of ARGs. Our results are in line with the few studies of the resistome of milk or milk cheese showing that genes conferring resistances to 1st-generation beta-lactams, aminoglycosides and tetracyclines families are widespread, while those conferring resistances to critically important antibiotics are rare or absent.202337384974
312280.9995Hybrid sequence-based analysis reveals the distribution of bacterial species and genes in the oral microbiome at a high resolution. Bacteria in the oral microbiome are poorly identified owing to the lack of established culture methods for them. Thus, this study aimed to use culture-free analysis techniques, including bacterial single-cell genome sequencing, to identify bacterial species and investigate gene distribution in saliva. Saliva samples from the same individual were classified as inactivated or viable and then analyzed using 16S rRNA sequencing, metagenomic shotgun sequencing, and bacterial single-cell sequencing. The results of 16S rRNA sequencing revealed similar microbiota structures in both samples, with Streptococcus being the predominant genus. Metagenomic shotgun sequencing showed that approximately 80 % of the DNA in the samples was of non-bacterial origin, whereas single-cell sequencing showed an average contamination rate of 10.4 % per genome. Single-cell sequencing also yielded genome sequences for 43 out of 48 wells for the inactivated samples and 45 out of 48 wells for the viable samples. With respect to resistance genes, four out of 88 isolates carried cfxA, which encodes a β-lactamase, and four isolates carried erythromycin resistance genes. Tetracycline resistance genes were found in nine bacteria. Metagenomic shotgun sequencing provided complete sequences of cfxA, ermF, and ermX, whereas other resistance genes, such as tetQ and tetM, were detected as fragments. In addition, virulence factors from Streptococcus pneumoniae were the most common, with 13 genes detected. Our average nucleotide identity analysis also suggested five single-cell-isolated bacteria as potential novel species. These data would contribute to expanding the oral microbiome data resource.202438708423
496590.9995Genomic Analysis Reveals the Genetic Determinants Associated With Antibiotic Resistance in the Zoonotic Pathogen Campylobacter spp. Distributed Globally. The genus Campylobacter groups 32 Gram-negative bacteria species, several being zoonotic pathogens and a major cause of human gastroenteritis worldwide. Antibiotic resistant Campylobacter is considered by the World Health Organization as a high priority pathogen for research and development of new antibiotics. Genetic elements related to antibiotic resistance in the classical C. coli and C. jejuni species, which infect humans and livestock, have been analyzed in numerous studies, mainly focused on local geographical areas. However, the presence of these resistance determinants in other Campylobacter species, as well as in C. jejuni and C. coli strains distributed globally, remains poorly studied. In this work, we analyzed the occurrence and distribution of antibiotic resistance factors in 237 Campylobacter closed genomes available in NCBI, obtained from isolates collected worldwide, in different dates, from distinct hosts and comprising 22 Campylobacter species. Our data revealed 18 distinct genetic determinants, genes or point mutations in housekeeping genes, associated with resistance to antibiotics from aminoglycosides, β-lactams, fluoroquinolones, lincosamides, macrolides, phenicols or tetracyclines classes, which are differentially distributed among the Campylobacter species tested, on chromosomes or plasmids. Three resistance determinants, the bla (OXA-493) and bla (OXA-576) genes, putatively related to β-lactams resistance, as well as the lnu(AN2) gene, putatively related to lincosamides resistance, had not been reported in Campylobacter; thus, they represent novel determinants for antibiotic resistance in Campylobacter spp., which expands the insight on the Campylobacter resistome. Interestingly, we found that some of the genetic determinants associated with antibiotic resistance are Campylobacter species-specific; e.g., the bla (OXA-493) gene and the T86V mutation in gyrA were found only in the C. lari group, whereas genes associated with aminoglycosides resistance were found only in C. jejuni and C. coli. Additional analyses revealed how are distributed the resistance and multidrug resistance Campylobacter genotypes assessed, with respect to hosts, geographical locations, and collection dates. Thus, our findings further expand the knowledge on the factors that can determine or favor the antibiotic resistance in Campylobacter species distributed globally, which can be useful to choose a suitable antibiotic treatment to control the zoonotic infections by these bacteria.202033042043
5737100.9995Survey of Colistin Resistance in Commensal Bacteria from Penaeus vannamei Farms in China. Aquatic environments are important reservoirs for drug resistance. Aquatic foods may act as carriers to lead antibiotic-resistant commensal bacteria into the human gastrointestinal system, then contacting gut microbiota and spreading antibiotic resistance. Here, several shrimp farms were investigated to identify colistin resistance among commensal bacteria of aquaculture. A total of 884 (41.6%) colistin-resistant isolates were identified among 2126 strains. Electroporation demonstrated that colistin-resistant fragments were present in some commensal bacteria that could be transferred to other bacteria. Most of the resistant bacteria were Bacillus spp., with 69.3% of the Bacillus species exhibiting multiple drug resistance. Bacillus licheniformis was prevalent, with 58 strains identified that comprised six sequence types (ST) based on multilocus sequence typing. Whole-genome sequencing and comparisons with previous B. licheniformis genomes revealed a high degree of genomic similarity among isolates from different regions. Thus, this species is widely distributed, and this study provides new insights into global antibiotic-resistant characteristics of B. licheniformis. Sequence analyses further revealed some of these strains are even pathogenic and virulent, suggesting the antibiotic resistance and hazards of commensal bacteria in aquaculture should be considered. Considering the "One Health" perspective, improved monitoring of aquatic food is needed to prevent the spread of drug-resistant commensal bacteria from food-associated bacteria to humans.202337297388
2845110.9995Florfenicol administration in piglets co-selects for multiple antimicrobial resistance genes. Antimicrobial use in food-producing animals such as pigs is a significant issue due to its association with antimicrobial resistance. Florfenicol is a broad-spectrum phenicol antibiotic used in swine for various indications; however, its effect on the swine microbiome and resistome is largely unknown. This study investigated these effects in piglets treated intramuscularly with florfenicol at 1 and 7 days of age. Fecal samples were collected from treated (n = 30) and untreated (n = 30) pigs at nine different time points up until 140 days of age, and the fecal metagenomes were sequenced. The fecal microbiomes of the two groups of piglets were most dissimilar in the immediate period following florfenicol administration. These differences were driven in part by an increase in the relative abundance of Clostridium scindens, Enterococcus faecalis, and Escherichia spp. in the florfenicol-treated piglets and Fusobacterium spp., Pauljensenia hyovaginalis, and Ruminococcus gnavus in the control piglets. In addition to selecting for florfenicol resistance genes (floR, fexA, and fexB), florfenicol also selected for genes conferring resistance to the aminoglycosides, beta-lactams, or sulfonamides up until weaning at 21 days of age. Florfenicol-resistant Escherichia coli isolated from these piglets were found to carry a plasmid with floR, along with tet(A), aph(6)-Id, aph(3″)-Ib, sul2, and bla(TEM-1)/bla(CMY-2). A plasmid carrying fexB and poxtA (phenicols and oxazolidinones) was identified in florfenicol-resistant Enterococcus avium, Enterococcus faecium, and E. faecalis isolates from the treated piglets. This study highlights the potential for co-selection and perturbation of the fecal microbial community in pre-weaned piglets administered florfenicol.IMPORTANCEAntimicrobial use remains a serious challenge in food-animal production due to its linkage with antimicrobial resistance. Antimicrobial resistance can reduce the efficacy of veterinary treatment and can potentially be transferred to humans through the food chain or direct contact with animals and their environment. In this study, early-life florfenicol treatment in piglets altered the composition of the fecal microbiome and selected for many unrelated antimicrobial resistance genes up until weaning at 21 days of age. Part of this co-selection process appeared to involve an Escherichia coli plasmid carrying a florfenicol resistance gene along with genes conferring resistance to at least four other antimicrobial classes. In addition, florfenicol selected for certain genes that provide resistance to multiple antimicrobial classes, including the oxazolidinones. These results highlight that florfenicol can co-select for multiple antimicrobial resistance genes, and their presence on mobile genetic elements suggests the potential for transfer to other bacteria.202439584815
2558120.9995Antimicrobial resistance in wild game mammals: a glimpse into the contamination of wild habitats in a systematic review and meta-analysis. BACKGROUND: Wild game meat has over the years gained popularity across the globe as it is considered a food source with high protein content, low fat content, and a balanced composition of fatty acids and minerals, which are requirements for a healthy diet. Despite this popularity, there is a concern over its safety as many species of wildlife are reservoirs of zoonotic diseases including those of bacterial origin, more so antibiotic-resistant bacteria. METHODS: This study aimed to describe the prevalence of antibiotic-resistant bacteria in mammalian wild game, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: The overall pooled prevalence of antibiotic resistance was established at 59.8% while the prevalence of multidrug resistance (MDR) was 17.2%. Resistance was reported in 32 wild game species and the meta-analysis revealed the highest prevalence of antibiotic resistance in Yersinia spp. (95.5%; CI: 76.8 - 100%) followed by Enterococcus spp. (71%; CI: 44.1 - 92%), Salmonella spp. (69.9%; CI: 44.3 - 90.0%), Staphylococcus spp. (69.3%; CI: 40.3 - 92.3%), and Escherichia coli (39.5%; CI: 23.9 - 56.4%). Most notably, resistance to highest priority, critically important antimicrobials, was recorded in all genera of bacteria studied. Additionally, a significantly higher prevalence of antibiotic resistance was observed in studies conducted in remote settings than those in the vicinity of anthropogenic activities, pointing to extensive contamination of wild habitats. CONCLUSION: This review shows the presence of antibiotic resistance and the carriage of antimicrobial resistance (AMR) genes by bacteria isolated from mammalian wild game species. This is a cause for concern if critical steps to prevent transmission to humans from meat and meat products are not applied in the wild game meat production chain. The extensive occurrence of antibiotic resistance in the wild calls for expansion and adaptation of future AMR surveillance plans to include areas with various anthropogenic pressures including in sylvatic habitats.202539799360
1933130.9995Antibiotic Resistance Genes Occurrence in Conventional and Antibiotic-Free Poultry Farming, Italy. Antimicrobial resistance is a complex and widespread problem threatening human and animal health. In poultry farms, a wide distribution of resistant bacteria and their relative genes is described worldwide, including in Italy. In this paper, a comparison of resistance gene distribution in litter samples, recovered from four conventional and four antibiotic-free broiler flocks, was performed to highlight any influence of farming systems on the spreading and maintenance of resistance determinants. Conventional PCR tests, targeting the resistance genes related to the most used antibiotics in poultry farming, along with some critically important antibiotics for human medicine, were applied. In conventional farms, n. 10 out of n. 30 investigated genes were present in at least one sample, the most abundant fragments being the tet genes specific for tetracyclines, followed by those for aminoglycosides and chloramphenicol. All conventional samples resulted negative for colistin, carbapenems, and vancomycin resistance genes. A similar trend was observed for antibiotic-free herds, with n. 13 out of n. 30 amplified genes, while a positivity for the mcr-1 gene, specific for colistin, was observed in one antibiotic-free flock. The statistical analysis revealed a significant difference for the tetM gene, which was found more frequently in the antibiotic-free category. The analysis carried out in this study allowed us to obtain new data about the distribution of resistance patterns in the poultry industry in relation to farming types. The PCR test is a quick and non-expensive laboratory tool for the environmental monitoring of resistance determinants identifying potential indicators of AMR dissemination.202236139170
2813140.9995Quantity of the tetracycline resistance gene tet(M) differs substantially between meat at slaughterhouses and at retail. Concentrations of the tetracycline resistance gene tet(M) per square centimeter were assessed in meat from the slaughterhouse (n = 100) and from retail (n = 100) by real-time quantitative PCR. The study revealed a substantial contamination of retail meat with the tetracycline resistance gene tet(M), with a mean of 4.34 log copies per cm² fasces in chicken and 5.58 log copies per cm² fasces in pork. Quantitative resistance gene analysis provides an interesting tool for risk assessment and is becoming increasingly important. For both chicken and pork, tet(M) concentrations were significantly higher in meat at retail, compared to meat at slaughter. Cultural investigations revealed substantial differences in the prevalence of listeria and enterococci, and of E. coli and coliforms, between meat at slaughter (n = 500) and at retail (n = 500). However, the differences in the prevalence of 2 investigated groups of potential tet(M)-carriers (enterococci, listeria) could not sufficiently explain the differences in tet(M) concentrations, since increasing concentrations of tet(M) were accompanied by decreasing prevalences of these potential tet(M)-carriers. The percentage of tetracycline susceptible indicator bacteria (E. faecalis, E. coli) did not differ between meat at slaughter and meat at retail. Higher concentrations of tet(M) at retail might correlate with the proliferation of other genera than enterococci and listeria, but there is also a reason to discuss whether secondary contaminants might carry tet(M) more often than the primary flora of meat. PRACTICAL APPLICATION: We successfully applied the direct quantitative monitoring of resistance genes in meat, which generally might aid as a useful and rapid additional tool for risk assessment. We know that bacteria provide a large pool of resistance genes, which are widely shared between each other-the larger the pool is, the more genes might be exchanged. Thus, in terms of resistance gene monitoring, we should sometimes overcome the restricted view on single bacteria and look at the gene pool, instead.201121729069
2843150.9995High Throughput Screening of Antimicrobial Resistance Genes in Gram-Negative Seafood Bacteria. From a global view of antimicrobial resistance over different sectors, seafood and the marine environment are often considered as potential reservoirs of antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs); however, there are few studies and sparse results on this sector. This study aims to provide new data and insights regarding the content of resistance markers in various seafood samples and sources, and therefore the potential exposure to humans in a global One Health approach. An innovative high throughput qPCR screening was developed and validated in order to simultaneously investigate the presence of 41 ARGs and 33 MGEs including plasmid replicons, integrons, and insertion sequences in Gram-negative bacteria. Analysis of 268 seafood isolates from the bacterial microflora of cod (n = 24), shellfish (n = 66), flat fishes (n = 53), shrimp (n = 10), and horse mackerel (n = 115) show the occurrence of sul-1, ant(3″)-Ia, aph(3')-Ia, strA, strB, dfrA1, qnrA, and bla(CTX-M-9) genes in Pseudomonas spp., Providencia spp., Klebsiella spp., Proteus spp., and Shewanella spp. isolates and the presence of MGEs in all bacterial species investigated. We found that the occurrence of MGE may be associated with the seafood type and the environmental, farming, and harvest conditions. Moreover, even if MGE were detected in half of the seafood isolates investigated, association with ARG was only identified for twelve isolates. The results corroborate the hypothesis that the incidence of antimicrobial-resistant bacteria (ARB) and ARG decreases with increasing distance from potential sources of fecal contamination. This unique and original high throughput micro-array designed for the screening of ARG and MGE in Gram-negative bacteria could be easily implementable for monitoring antimicrobial resistance gene markers in diverse contexts.202235744743
4549160.9995Genomic analysis of Salmonella Heidelberg isolated from the Brazilian poultry farms. The rapid expansion of broiler chicken production in Brazil has presented significant sanitation challenges within the poultry industry. Among these challenges, Salmonella enterica subsp. enterica serotype Heidelberg stands as a contributor to global salmonellosis outbreaks. This study analyzed 13 draft genomes of Salmonella Heidelberg isolated from the pre-slaughter broiler chickens farms in Brazil. By conducting in silico analysis of these genomes, the study investigated genome similarity based on single nucleotide polymorphisms (SNPs) and identified genes encoding resistance to antimicrobials, sanitizers, and virulence factors. Furthermore, mobile genetic elements (MGE) were identified to assess their potential role in propagating genes through horizontal gene transfer. A risk classification was also applied based on the resistomes. The genomes revealed a high prevalence of genes conferring resistance to aminoglycosides, fosfomycin, sulfonamides, tetracycline, and genes linked to quaternary ammonium resistance. The study also uncovered six Salmonella pathogenicity islands (SPI) and over 100 genes encoding virulence factors. The association of MGE with antibiotic-resistant genes sul2 and blaCMY-2 raised concerns about the potential transfer to other bacteria, posing a substantial risk for spreading resistance mechanisms according to established risk protocols. Additionally, SNP analysis indicated close phylogenetic relationships among some isolates, suggesting a common origin. This study enhances our understanding of Salmonella Heidelberg strains by identifying key risk factors for transmission and revealing the association between resistance genes and MGEs. This insight provides a foundation for developing and implementing effective control, monitoring, and treatment strategies in the poultry industry.202439441515
4966170.9995Whole Genome Analysis of 335 New Bacterial Species from Human Microbiota Reveals a Huge Reservoir of Transferable Antibiotic Resistance Determinants. BACKGROUND: The emergence and diffusion of strains of pathogenic bacteria resistant to antibiotics constitutes a real public health challenge. Antibiotic resistance genes (ARGs) can be carried by both pathogenic and non-pathogenic bacteria, including commensal bacteria from the human microbiota, which require special monitoring in the fight against antimicrobial resistance. METHODS: We analyzed the proteomes of 335 new bacterial species from human microbiota to estimate its whole range of ARGs using the BLAST program against ARGs reference databases. RESULTS: We found 278 bacteria that harbor a total of 883 potential ARGs with the following distribution: 264 macrolides-lincosamides-streptogramin, 195 aminoglycosides, 156 tetracyclines, 58 β-lactamases, 58 fosfomycin, 51 glycopeptides, 36 nitroimidazoles, 33 phenicols and 32 rifamycin. Furthermore, evolutionary analyses revealed the potential horizontal transfer with pathogenic bacteria involving mobile genetic elements such as transposase and plasmid. We identified many ARGs that may represent new variants in fosfomycin and β-lactams resistance. CONCLUSION: These findings show that new bacterial species from human microbiota should be considered as an important reservoir of ARGs that can be transferred to pathogenic bacteria. In vitro analyses of their phenotypic potential are required to improve our understanding of the functional role of this bacterial community in the development of antibiotic resistance.202235216256
4970180.9995Massive analysis of 64,628 bacterial genomes to decipher water reservoir and origin of mobile colistin resistance genes: is there another role for these enzymes? Since 2015, new worrying colistin resistance mechanism, mediated by mcr-1 gene has been reported worldwide along with eight newly described variants but their source(s) and reservoir(s) remain largely unexplored. Here, we conducted a massive bioinformatic analysis of bacterial genomes to investigate the reservoir and origin of mcr variants. We identified 13'658 MCR-1 homologous sequences in 494 bacterial genera. Moreover, analysis of 64'628 bacterial genomes (60 bacterial genera and 1'047 species) allows identifying a total of 6'651 significant positive hits (coverage >90% and similarity >50%) with the nine MCR variants from 39 bacterial genera and more than 1'050 species. A high number of MCR-1 was identified in Escherichia coli (n = 862). Interestingly, while almost all variants were identified in bacteria from different sources (i.e. human, animal, and environment), the last variant, MCR-9, was exclusively detected in bacteria from human. Although these variants could be identified in bacteria from human and animal sources, we found plenty MCR variants in unsuspected bacteria from environmental origin, especially from water sources. The ubiquitous presence of mcr variants in bacteria from water likely suggests another role in the biosphere of these enzymes as an unknown defense system against natural antimicrobial peptides and/or bacteriophage predation.202032249837
2863190.9995Detection of Aminoglycoside Resistant Bacteria in Sludge Samples From Norwegian Drinking Water Treatment Plants. Through a culture-based approach using sludge from drinking water treatment plants, this study reports on the presence of aminoglycoside resistant bacteria at 23 different geographical locations in Norway. Sludge samples are derived from a large environmental area including drinking water sources and their surrounding catchment areas. Aminoglycoside resistant bacteria were detected at 18 of the sample sites. Only five samples did not show any growth of isolates resistant to the selected aminoglycosides, kanamycin and gentamycin. There was a statistically significant correlation between the numbers of kanamycin and gentamycin resistant bacteria isolated from the 23 samples, perhaps suggesting common determinants of resistance. Based on 16S rRNA sequencing of 223 aminoglycoside resistant isolates, three different genera of Bacteroidetes were found to dominate across samples. These were Flavobacterium, Mucilaginibacter and Pedobacter. Further phenotypic and genotypic analyses showed that efflux pumps, reduced membrane permeability and four assayed genes coding for aminoglycoside modifying enzymes AAC(6')-Ib, AAC(3')-II, APH(3')-II, APH(3')-III, could only explain the resistance of a few of the isolates selected for testing. aph(3')-II was detected in 1.6% of total isolates, aac(6')-Ib and aph(3')-III in 0.8%, while aac(3')-II was not detected in any of the isolates. The isolates, for which potential resistance mechanisms were found, represented 13 different genera suggesting that aminoglycoside resistance is widespread in bacterial genera indigenous to sludge. The present study suggests that aminoglycoside resistant bacteria are present in Norwegian environments with limited anthropogenic exposures. However, the resistance mechanisms remain largely unknown, and further analyses, including culture-independent methods, could be performed to investigate other potential resistance mechanisms. This is, to our knowledge, the first large scale nationwide investigation of aminoglycoside resistance in the Norwegian environment.201930918503