Search Results (30)

Kindergarten environments combine high microbial exposure with increased immunological vulnerability, yet antibiotic resistance genes (ARGs) in kindergarten dust remain poorly characterized. This systematic review synthesized evidence on the occurrence and potential health relevance of ARGs in kindergarten dust. Following PRISMA 2020 guidelines, PubMed, Scopus, and Web of Science were searched. Four studies from China, Hong Kong, and Norway (2018–2024) met the inclusion criteria. ARGs were detected in all kindergarten dust samples, indicating that dust is a consistent reservoir of antibiotic resistance determinants. A consensus resistome (classes detected in ≥2 studies) encompassed sulfonamide, macrolide–lincosamide–streptogramin B (MLSB), tetracycline, beta-lactam, aminoglycoside, and multidrug resistance genes; beta-lactam resistance genes were the only class reported in all four studies. Clinically important ARGs associated with last-resort antibiotics, including mecA, vanA, bla_NDM, and mcr-5, were reported in three studies. Class 1 integron-integrase genes (intI1) frequently co-occurred with ARGs, suggesting potential horizontal gene transfer. Limited evidence indicated higher ARG abundance in urban and winter samples. One study reported antibiotic-resistant bacteria carrying resistance markers concordant with those in kindergarten dust in the urine of children attending the same facilities; however, this cross-sectional, single-site evidence is consistent with, but not sufficient to establish, a dust-to-child exposure pathway. The available evidence supports the plausibility that kindergarten dust may contribute to children’s exposure to ARGs and ARG-carrying bacteria, but current studies do not establish causal transmission from dust to child colonization or infection. Standardized monitoring and longitudinal studies are needed to assess health risks and guide mitigation strategies in early childhood educational settings. Full article

Monitoring poultry microbiota and antimicrobial resistance genes is important, as they can reflect flock health, farm conditions, and the level of antimicrobial resistance. Although shotgun metagenomics has been widely applied worldwide to investigate poultry microbiota and antimicrobial resistance, comparable baseline datasets describing the cloacal microbiota and resistome of poultry in Kazakhstan are scarce. In this study, taxonomic and resistome profiles were characterized in pooled metagenomes of the cloacal microbiota of chickens sampled from household and industrial poultry farms in Kazakhstan. Cloacal swabs were collected from laying hens, pooled at the house level, and analyzed using high-throughput metagenomic sequencing. Taxonomic profiles were generated at the genus level, and antimicrobial resistance gene signals were summarized by drug class. Compositional patterns were assessed using CLR/Aitchison ordination, the Mantel test, and Procrustes analysis. The pooled samples exhibited heterogeneous microbiota profiles at the genus level and included taxa of veterinary interest, such as Chlamydia, Avibacterium, and Gallibacterium spp. Resistome profiling revealed a broad but uneven distribution of antimicrobial resistance signals, including those associated with tetracyclines, fluoroquinolones, aminoglycosides, and beta-lactams. Taxonomic and resistome profiles showed preliminary alignment at the matrix level, indicating that resistome variations are partially linked to microbial community structure. Full article

Introduction: Cefazolin is a first-generation cephalosporin with a moderate antimicrobial spectrum and the ability to induce the production of beta-lactamases by bacterial hosts. We investigated the effect of prophylactic cefazolin administration on the gut microbiome in patients undergoing orthopedic surgery. Methods: A total of 42 patients were included in this study, and fecal samples were collected before cefazolin administration, within 3 days after administration, and 1 month after surgery. Shotgun whole-metagenome sequencing was performed with DNA extracted from fecal samples to assess the taxonomic composition and antimicrobial resistance genes (ARGs). Results: Within 3 days after perioperative prophylactic cefazolin administration, both the diversity indices and the Gut Microbiome Health Index were significantly decreased. Furthermore, a decrease in two beneficial anaerobic Gram-positive taxa, Ruminococcus and Fusicatenibacter, and an increase in Enterobacterales was observed. The relative abundances of ARGs related to fluoroquinolone and beta-lactam antimicrobials including penicillin, cephalosporin, carbapenem, and monobactam, were also significantly increased. The changes in the taxonomic composition and resistome related to perioperative cefazolin administration partially reverted after one month. Conclusions: Our findings suggest that even perioperative administration of a single-class antimicrobial agent could be related to the decrease of the gut microbiome diversity with potentially unfavorable taxonomic changes and lead to an increase in ARGs. Full article

Background: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) has been added to the World Health Organization’s list as a high-priority pathogen for which new antibiotics are urgently needed. Herein, we investigated the association between resistance/virulence genes and high-risk CRPA clinical isolates by whole genome sequencing (WGS). Methods: Between 2019 and 2025, twenty-six CRPA strains from patients hospitalized in the “Renato Dulbecco” University Hospital were characterized. WGS analysis was performed using the next generation sequencing (NGS) technique. Multi-locus sequence typing (MLST) prediction was performed. Antibiotic resistance genes were detected using Antibiotic Resistance Gene-ANNOTation, Comprehensive Antibiotic Resistance Database, and ResFinder. Virulence genes were identified by the Virulence Factor Database. Results: The MLST analysis detected 14 different sequence types (ST). The 26 strains exhibited the same resistome profile: aac(3)-Ic, aphA15, catB7, catB10, cmlA, blaCARB, blaVIM-1, and tetG genes. The genes encoding enzymes involved in resistance to chloramphenicol and beta-lactams were found in all isolates using the three databases. Biofilm formation genes, metalloproteinase, chemotaxis, fimbriae, and pyoverdine were identified in all strains. Genes of the type III secretion system exoS, exoT, exoU, and exoY were found in 46.15%, 84.61%, 53.84%, and 84.61% of the strains, respectively. Conclusions: The analysis of the 26 clinical isolates showed high clonal heterogeneity, with a predominance of ST235, a high-risk clone associated with multiple resistances. Interestingly, cefiderocol resistance was carried by 4/8 isolates belonging to the ST235 strain. The surveillance based on resistome and virulome analysis could monitor the dynamic evolution of high priorityhigh-priority pathogens to guide clinical treatment and to adapt healthcare control measures, limiting their spread in the near future. Full article

The southern pudu (Pudu puda) faces significant threats from anthropogenic activities and infectious diseases. Using whole-genome sequencing (WGS) and forensic microbiology research, we describe a triple bacterial co-infection in a southern pudu impacted by wildfire disasters. The deer presented infected burn wounds on the extremities and dog bite wounds in the lumbosacral region, from which a multidrug-resistant CTX-M-1-producing Escherichia coli sequence type (ST) ST224 and a Klebsiella oxytoca ST145 were isolated, respectively. The patient died 13 days after admission in a wildlife rehabilitation center. During the necropsy, a sample from intracardiac blood was collected, and WGS analyses confirmed systemic dissemination of an E. coli ST224 clone. The broad virulome (adhesins, invasins, toxins, and immune evasion genes) and resistome against beta-lactams (bla_CTX-M-1), aminoglycosides [aac(3)-IId, aph(3′)-Ia, aph(3″)-Ib, aph(6)-Id], macrolides [mph(A)], sulfonamides (sul2), trimethoprim (dfrA17), and fluoroquinolones (gyrA and parC mutations) of E. coli ST224 contributed to the treatment failure and death of the wild animal. Additionally, an oval nodule was identified in the abdominal cavity caused by Acinetobacter baumannii ST1365, the first WGS-confirmed report in wildlife. This study highlights the value of applying forensic microbiology and WGS to investigate and understand One Health pathogens threatening wildlife impacted by natural and anthropogenic disasters. Full article

Introduction: In recent years, antimicrobial resistance (AMR) rates have increased significantly in bacterial pathogens, particularly extended beta-lactam resistance. This study aimed to investigate resistome and phylogenomics of Escherichia coli (E. coli) strains isolated from various sources in Jimma, Ethiopia. Methods: Phenotypic antibiotic resistance patterns of E. coli isolates were determined using automated Kirby–Bauer disc diffusion and minimum inhibitory concentration (MIC). Isolates exhibiting phenotypic resistance to beta-lactam antibiotics were further analyzed with a DNA microarray to confirm the presence of resistance-encoding genes. Additionally, multilocus sequence typing (MLST) of seven housekeeping genes was conducted using PCR and Oxford Nanopore-Technology (ONT) to assess the phylogenetic relationships among the E. coli isolates. Results: A total of 611 E. coli isolates from human, animal, and environmental sources were analyzed. Of these, 41.6% (254) showed phenotypic resistance to at least one of the tested beta-lactams, 96.1% (244) thereof were confirmed genotypically. More than half of the isolates (53.3%) had two or more resistance genes present. The most frequent ESBL-encoding gene was CTX-M-15 (74.2%; 181), followed by TEM (59.4%; 145) and CTX-M-9 (4.1%; 10). The predominant carbapenemase gene was NDM-1, detected in 80% (12 out of 15) of carbapenem-resistant isolates. A phylogenetic analysis revealed clonality among the strains obtained from various sources, with international high-risk clones such as ST131, ST648, ST38, ST73, and ST405 identified across various niches. Conclusions: The high prevalence of CTX-M-15 and NDM-1 in multidrug-resistant E. coli isolates indicates the growing threat of AMR in Ethiopia. The discovery of these high-risk clones in various niches shows possible routes of transmission and highlights the necessity of a One Health approach to intervention and surveillance. Strengthening antimicrobial stewardship, infection prevention, and control measures are crucial to mitigate the spread of these resistant strains. Full article

Antibiotic resistance represents a global health crisis with far-reaching implications, impacting multiple domains concurrently, including human health, animal health, and the natural environment. Wild birds were identified as carriers and disseminators of antibiotic-resistant bacteria (ARB) and their associated antibiotic resistance genes (ARGs). A majority of studies in this area have concentrated on migratory birds as carriers for the spread of antibiotic resistance over long distances. However, there has been scant research on the resistome of non-migratory Corvidae species that heavily overlap with human activities, which limits our understanding of antibiotic resistance in these birds and hinders the development of effective management strategies. This study employed a metagenomics approach to examine the characteristics of ARGs and mobile genetic elements (MGEs) in five common Corvidae species inhabiting the Qinghai–Tibetan Plateau. The ARGs were classified into 20 major types and 567 subtypes. Notably, ARGs associated with multidrug resistance, including to macrolide–lincosamide–streptogramins, tetracyclines, beta-lactam, and bacitracin, were particularly abundant, with the subtypes acrB, bacA, macB, class C beta-lactamase, and tetA being especially prevalent. A total of 5 types of MGEs (166 subtypes) were identified across five groups of crows, and transposase genes, which indicated the presence of transposons, were identified as the most abundant type of MGEs. Moreover, some common opportunistic pathogens were identified as potential hosts for these ARGs and MGEs. Procrustes analysis and co-occurrence network analysis showed that the composition of the gut microbiota shaped the ARGs and MGEs, indicating a substantial association between these factors. The primary resistance mechanisms of ARGs in crows were identified as multidrug efflux pumps, alteration of antibiotic targets, and enzymatic inactivation. High-risk ARGs which were found to potentially pose significant risks to public health were also analyzed and resulted in the identification of 81 Rank I and 47 Rank II ARGs. Overall, our study offers a comprehensive characterization of the resistome in wild Corvidae species, enhancing our understanding of the potential public health risks associated with these birds. Full article

Marine sediments are recognized as crucial reservoirs of antibiotic resistance genes (ARGs). However, the antibiotic resistome in sediments of the East China Sea, an area heavily impacted by human activities, has not been thoroughly studied. Here, we conducted a systematic investigation into the antibiotic resistome in these sediments using metagenomic analysis. Overall, we detected eighty ARG subtypes and nineteen ARG types. Beta-lactams were the dominant ARG type, and Gammaproteobacteria was the main ARG host in this study. Mobile genetic elements (MGEs) were not major drivers of ARG profiles. Although the ARG host communities significantly differed between the spring and autumn (p < 0.05), the antibiotic resistome remained stable across the two seasons. The assembly of ARGs and their hosts was governed by stochastic processes, and a high ratio of stochastic processes implied its crucial role in the assembly and stabilization of the antibiotic resistome. Co-occurrence network analysis revealed an important role of Deltaproteobacteria in the stabilization of ARG profiles across seasons. Environmental parameters (e.g., temperature and density) played certain roles in the stabilization of the antibiotic resistome between spring and autumn. Moreover, nine human pathogen bacteria (HPB) were detected in this study. We also found that the health risks caused by ARGs were relatively higher in the spring. Our results will provide a strong foundation for the development of targeted management strategies to mitigate the further dissemination and spread of ARGs in marine sediments. Full article

Proteus mirabilis (P. mirabilis) is an opportunistic pathogen involved in urinary tract infections as well as various nosocomial infections. Emerging resistances to beta-lactams in this species complicates potential treatment since it is intrinsically resistant to colistin. Eleven isolates of carbapenem-non-susceptible P. mirabilis were identified in Sousse Hospital, Tunisia, from January 2018 to December 2022. MICs were determined and isolates were sequenced to determine their resistomes, sequence types, virulence factors, and their clonal relationships. Susceptibility testing showed that all isolates were resistant to carbapenems, aminoglycosides, fluoroquinolones, chloramphenicol, and the trimethoprim/sulfamethoxazole combination. They remained susceptible to the aztreonam/avibactam combination. All isolates produced NDM-1 carbapenemase and ArmA 16S rRNA methylase. In addition, one isolate co-produced the bla_VEB-6 gene. All isolates belonged to ST135, and phylogenetic analysis revealed that they were closely related. This study described the first outbreak of NDM-1-producing P. mirabilis in Tunisia. Full article

The use of dairy slurries as organic fertilizer amendments is a common practice in agriculture as a cost-saving measure, as well as a residue management strategy. However, concerns related to the increase in antibiotic resistance in the environment under the scope of the One Health strategy are increasing. In this study, we aimed to assess resistome enrichment driven by dairy slurry application in four southern Chile dairy farms. Slurry pits, rhizospheres of Lolium perenne amended with those slurries, and bulk soils were sampled. Thirteen antibiotic-resistance genes (ARGs, tetA, tetG, tetM, tetQ, tetW, tetX, sul1, sul2, blaCTX_M, bla_OXA-1, blaTEM, ermB, and dfrA1) for five antibiotic classes (tetracyclines, sulfonamides, beta-lactams, macrolides, and trimethoprim–sulfamethoxazole), two related integrases (intl1 and intl2), and total bacteria (16S rRNA) abundance was measured by quantitative PCR (qPCR). Then, the abundance profiles of two enzyme-inactivated ARGs (tetX and blaTEM) were determined. The differences between the bacterial communities inhabiting the different sample types were explored with 16S rRNA metabarcoding. In general, all measured ARGs were detected in slurries. A decreasing trend in ARG copy numbers was observed with increasing soil depth, with the exception of tetX, whose abundance increased in the bulk soil at specific farms. The tetX and blaTEM communities revealed no differences in the relative abundance of variants in any of the samples. Finally, taxonomic and structural differences were found among all sample types. Thus, the enrichment of the sampled farm soil resistomes was driven by the application of the raw slurries as fertilizer. Full article

Background: The human oral microbiome is a critical reservoir for antibiotic resistance; however, subgingival peri-implant biofilms remain underexplored in this context. We aimed to explore the prevalence and distribution of antibiotic resistance genes (ARGs) in metagenomes derived from saliva and subgingival peri-implant biofilms. Methods: A total of 100 metagenome datasets from 40 individuals were retrieved from the Sequence Read Archive (SRA) database. Of these, 20 individuals had exclusively healthy implants and 20 had both healthy and affected implants with peri-implantitis. ARGs and their taxonomic assignments were identified using the ABRicate tool, and plasmid detection was performed with PlasmidFinder. Results: Four plasmid replicons were identified in 72 metagenomes, and 55 distinct ARGs from 13 antibiotic classes were detected in 89 metagenomes. ARGs conferring resistance to macrolides–lincosamides–streptogramins, tetracyclines, beta-lactams, and fluoroquinolones were the most prevalent. The msr(D) and mef(A) genes showed the highest prevalence, except in saliva samples from individuals with healthy implants, where mef(A) ranked fourth. A pairwise PERMANOVA of principal coordinate analysis based on Jaccard distances revealed that saliva samples exhibited significantly greater ARG diversity than subgingival biofilm samples (p < 0.05). However, no significant differences were observed between healthy and peri-implantitis-affected subgingival biofilm groups (p > 0.05). The taxonomic origins of ARGs were also analyzed to understand their distribution and potential impact on oral microbial communities. Conclusions: Resistome profiles associated with both peri-implant health and disease showed no significant differences and higher salivary abundance of ARGs compared to subgingival biofilm samples. Full article

Background: the widespread use of antibiotics in human and veterinary medicine has contributed to the global challenge of antimicrobial resistance, posing significant environmental and public health risks. Objectives: this study aimed to examine the microbiome and resistome dynamics across a salinity gradient, analyzing water and sediment samples from the Baltic Sea coast and the Curonian Lagoon between 2017 and 2023. Methods: the composition of the water and sediment bacterial community was determined by Full-Length Amplicon Metagenomics Sequencing, while ARG detection and quantification were performed using the SmartChipTM Real-Time PCR system. Results: the observed differences in bacterial community composition between the Baltic Sea coast and the Curonian Lagoon were driven by variations in salinity and chlorophyll a (chl a) concentration. The genera associated with infectious potential were observed in higher abundances in sediment than in water samples. Over 300 genes encoding antibiotic resistance (ARGs), such as aminoglycosides, beta-lactams, and multidrug resistance genes, were identified. Of particular interest were those ARGs that have previously been detected in pathogens and those currently classified as a potential future threat. Furthermore, our findings reveal a higher abundance and a distinct profile of ARGs in sediment samples from the lagoon compared to water. Conclusions: these results suggest that transitional waters such as lagoons may serve as reservoirs for ARGs, and might be influenced by anthropogenic pressures and natural processes such as salinity fluctuation and nutrient cycling. Full article

The global antibiotic resistance crisis, driven by overuse and misuse of antibiotics, is multifaceted. This study aimed to assess the microbiological and genetic characteristics of raw retail pork meat through various methods, including the isolation, antibiotic susceptibility testing (AST), whole-genome sequencing (WGS) of selected indicator bacteria, antibiotic residue testing, and metagenomic sequencing. Samples were purchased from 10 pre-selected retail stores in Gauteng, South Africa. The samples were aseptically separated, with portions sent to an external laboratory for isolating indicator bacteria and testing for antibiotic residues. Identification of the isolated bacteria was reconfirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). AST was performed using the Microscan Walkaway system (Beckman Coulter, Brea, CA, USA). WGS and metagenomic sequencing were performed using the Illumina NextSeq 550 instrument (San Diego, CA, USA). The isolated E. coli and E. faecalis exhibited minimal phenotypic resistance, with WGS revealing the presence of tetracycline resistance genes. Both the isolated bacteria and meat samples harboured tetracycline resistance genes and the antibiotic residue concentrations were within acceptable limits for human consumption. In the metagenomic context, most identified bacteria were of food/meat spoilage and environmental origin. The resistome analysis primarily indicated beta-lactam, tetracycline and multidrug resistance genes. Further research is needed to understand the broader implications of these findings on environmental health and antibiotic resistance. Full article

Chili powder is an important condiment around the world. However, according to various reports, the presence of pathogenic microorganisms could present a public health risk factor during its consumption. Therefore, microbiological quality assessment is required to understand key microbial functional traits, such as antibiotic resistance genes (ARGs). In this study, metagenomic next-generation sequencing (mNGS) and bioinformatics analysis were used to characterize the comprehensive profiles of the bacterial community and antibiotic resistance genes (ARGs) in 15 chili powder samples from different regions of Mexico. The initial bacterial load showed aerobic mesophilic bacteria (AMB) ranging between 6 × 10³ and 7 × 10⁸ CFU/g, sporulated mesophilic bacteria (SMB) from 4.3 × 10³ to 2 × 10⁹ CFU/g, and enterobacteria (En) from <100 to 2.3 × 10⁶ CFU/g. The most representative families in the samples were Bacillaceae and Enterobacteriaceae, in which 18 potential pathogen-associated species were detected. In total, the resistome profile in the chili powder contained 68 unique genes, which conferred antibiotic resistance distributed in 13 different classes. Among the main classes of antibiotic resistance genes with a high abundance in almost all the samples were those related to multidrug, tetracycline, beta-lactam, aminoglycoside, and phenicol resistance. Our findings reveal the utility of mNGS in elucidating microbiological quality in chili powder to reduce the public health risks and the spread of potential pathogens with antibiotic resistance mechanisms. Full article

Aquaculture located in urban river estuaries, where other anthropogenic activities may occur, has an impact on and may be affected by the environment where they are inserted, namely by the exchange of antimicrobial resistance genes. The latter may ultimately, through the food chain, represent a source of resistance genes to the human resistome. In an exploratory study of the presence of resistance genes in aquaculture sediments located in urban river estuaries, two machine learning models were applied to predict the source of 34 resistome observations in the aquaculture sediments of oysters and gilt-head sea bream, located in the estuaries of the Sado and Lima Rivers and in the Aveiro Lagoon, as well as in the sediments of the Tejo River estuary, where Japanese clams and mussels are collected. The first model included all 34 resistomes, amounting to 53 different antimicrobial resistance genes used as source predictors. The most important antimicrobial genes for source attribution were tetracycline resistance genes tet(51) and tet(L); aminoglycoside resistance gene aadA6; beta-lactam resistance gene blaBRO-2; and amphenicol resistance gene cmx_1. The second model included only oyster sediment resistomes, amounting to 30 antimicrobial resistance genes as predictors. The most important antimicrobial genes for source attribution were the aminoglycoside resistance gene aadA6, followed by the tetracycline genes tet(L) and tet(33). This exploratory study provides the first information about antimicrobial resistance genes in intensive and semi-intensive aquaculture in Portugal, helping to recognize the importance of environmental control to maintain the integrity and the sustainability of aquaculture farms. Full article