Bacteria tolerant to colistin in coastal marine environment: Detection, microbiome diversity and antibiotic resistance genes' repertoire. - Related Documents




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257801.0000Bacteria tolerant to colistin in coastal marine environment: Detection, microbiome diversity and antibiotic resistance genes' repertoire. The global spread of mobilized colistin resistance (mcr) genes in clinical and natural environments dangerously diminishes the effectiveness of this last-resort antibiotic, becoming an urgent health threat. We used a multidisciplinary approach to detect mcr-1 gene and colistin (CL)-resistant bacteria in seawater from two Croatian public beaches. Illumina-based sequencing of metagenomic 16S rRNA was used to assess the taxonomic, functional, and antibiotic resistance genes (ARGs) profiling of the bacterial community tolerant to CL regarding different culture-based isolation methodologies. Data revealed that the choice of methodology alters the diversity and abundance of taxa accounting for the CL-resistance phenotype. The mcr-1 gene was identified by cloning and sequencing in one sample, representing the first report of mcr-1 gene in Croatia. Culturing of CL-resistant strains revealed their resistance phenotypes and concurrent production of clinically significant β-lactamases, such as CTX-M-15, CTX-M-3 and SHV-12. We also report the first identification of bla(CTX-M-15) gene in Klebsiella huaxiensis and K. michiganensis, as well as the bla(TEM-1+CTX-M-3) in Serratia fonticola. ARGs profiles derived from metagenomic data and predicted by PICRUSt2, showed the highest abundance of genes encoding for multidrug efflux pumps, followed by the transporter genes accounting for the tetracycline, macrolide and phenicol resistance. Our study evidenced the multidrug resistance features of CL-tolerant bacterial communities thriving in surface beach waters. We also showed that combined application of the metagenomic approaches and culture-based techniques enabled successful detection of mcr-1 gene, which could be underreported in natural environment.202134289613
257710.9999Molecular Detection of bla(TEM) and bla(SHV) Genes in ESBL-Producing Acinetobacter baumannii Isolated from Antarctic Soil. The phenomenon of antimicrobial resistance (AMR) in cold environments, exemplified by the Antarctic, calls into question the assumption that pristine ecosystems lack clinically significant resistance genes. This study examines the molecular basis of AMR in Acinetobacter spp. Isolated from Antarctic soil, focusing on the bla(TEM) and bla(SHV) genes associated with extended-spectrum beta-lactamase (ESBL) production; Soil samples were collected and processed to isolate Antarctic soil bacteria. Molecular detection was then conducted using polymerase chain reaction (PCR) to identify the bacteria species by 16S rRNA/rpoB and 10 different beta-lactamase-producing genes. PCR amplicons were sequenced to confirm gene identity and analyze genetic variability. Acinetobacter baumannii were identified by both microbiological and molecular tests. Notably, both the bla(TEM) and bla(SHV) genes encoding the enzymes responsible for resistance to penicillins and cephalosporins were identified, indicating the presence of resistance determinants in bacteria from extreme cold ecosystems. The nucleotide sequence analysis indicated the presence of conserved ARGs, which suggest stability and the potential for horizontal gene transfer within microbial communities. These findings emphasize that AMR is not confined to human-impacted environments but can emerge and persist in remote, cold habitats, potentially facilitated by natural reservoirs and global microbial dispersal. Understanding the presence and role of AMR in extreme environments provides insights into its global dissemination and supports the development of strategies to mitigate the spread of resistance genes in both environmental and clinical contexts.202540142377
331720.9999Prevalence and Diversity of Antibiotic Resistance Genes in Swedish Aquatic Environments Impacted by Household and Hospital Wastewater. Antibiotic-resistant Enterobacteriaceae and non-lactose fermenting Gram-negative bacteria are a major cause of nosocomial infections. Antibiotic misuse has fueled the worldwide spread of resistant bacteria and the genes responsible for antibiotic resistance (ARGs). There is evidence that ARGs are ubiquitous in non-clinical environments, especially those affected by anthropogenic activity. However, the emergence and primary sources of ARGs in the environment of countries with strict regulations for antibiotics usage are not fully explored. The aim of the present study was to evaluate the repertoire of ARGs of culturable Gram-negative bacteria from directionally connected sites from the hospital to the wastewater treatment plant (WWTP), and downstream aquatic environments in central Sweden. The ARGs were detected from genomic DNA isolated from a population of selectively cultured coliform and Gram-negative bacteria using qPCR. The results show that hospital wastewater was a reservoir of several class B β-lactamase genes such as bla (IMP-1) , bla (IMP-2), and bla (OXA-23), however, most of these genes were not observed in downstream locations. Moreover, β-lactamase genes such as bla (OXA-48), bla (CTX-M-8), and bla (SFC-1), bla (V IM-1), and bla (V IM-13) were detected in downstream river water but not in the WWTP. The results indicate that the WWTP and hospital wastewaters were reservoirs of most ARGs and contribute to the diversity of ARGs in associated natural environments. However, this study suggests that other factors may also have minor contributions to the prevalence and diversity of ARGs in natural environments.201931019498
256430.9998Comparative metagenomics reveals poultry and swine farming are hotspots for multidrug and tetracycline resistance. Antibiotic misuse in livestock is a major threat to human health, as bacteria are quickly developing resistance to them. We performed a comparative analysis of 25 faecal metagenomes from swine, poultry, cattle, and humans to investigate their resistance profiles. Our analysis revealed that all genes conferring resistance to antibiotic classes assessed except tetracyclines were more prevalent in poultry manure than in the remaining species. We detected clinically relevant antibiotic resistance genes, such as mcr-1 which confers resistance to polymyxins. Among them, extended-spectrum β-lactamase blaCTX-M genes were particularly abundant in all species. Poultry manure was identified as a hotspot for multidrug resistance, which may compromise medical treatment options. Urgent actions in the livestock industry are imperative to hamper the emergence and spread of antibiotic resistance.202336758925
283640.9998Waste water effluent contributes to the dissemination of CTX-M-15 in the natural environment. OBJECTIVES: Multidrug-resistant Enterobacteriaceae pose a significant threat to public health. We aimed to study the impact of sewage treatment effluent on antibiotic resistance reservoirs in a river. METHODS: River sediment samples were taken from downstream and upstream of a waste water treatment plant (WWTP) in 2009 and 2011. Third-generation cephalosporin (3GC)-resistant Enterobacteriaceae were enumerated. PCR-based techniques were used to elucidate mechanisms of resistance, with a new two-step PCR-based assay developed to investigate bla(CTX-M-15) mobilization. Conjugation experiments and incompatibility replicon typing were used to investigate plasmid ecology. RESULTS: We report the first examples of bla(CTX-M-15) in UK river sediment; the prevalence of bla(CTX-M-15) was dramatically increased downstream of the WWTP. Ten novel genetic contexts for this gene were identified, carried in pathogens such as Escherichia coli ST131 as well as indigenous aquatic bacteria such as Aeromonas media. The bla(CTX-M-15) -gene was readily transferable to other Gram-negative bacteria. We also report the first finding of an imipenem-resistant E. coli in a UK river. CONCLUSIONS: The high diversity and host range of novel genetic contexts proves that evolution of novel combinations of resistance genes is occurring at high frequency and has to date been significantly underestimated. We have identified a worrying reservoir of highly resistant enteric bacteria in the environment that poses a threat to human and animal health.201424797064
335250.9998Analysis of antibiotic multi-resistant bacteria and resistance genes in the effluent of an intensive shrimp farm (Long An, Vietnam). In Vietnam, intensive shrimp farms heavily rely on a wide variety of antibiotics (ABs) to treat animals or prevent disease outbreak. Potential for the emergence of multi-resistant bacteria is high, with the concomitant contamination of adjacent natural aquatic habitats used for irrigation and drinking water, impairing in turn human health system. In the present study, quantification of AB multi-resistant bacteria was carried out in water and sediment samples from effluent channels connecting a shrimp farming area to the Vam Co River (Long An Province, Vietnam). Bacterial strains, e.g. Klebsiella pneumoniae and Aeromonas hydrophila, showing multi-resistance traits were isolated. Molecular biology analysis showed that these strains possessed from four to seven different AB resistance genes (ARGs) (e.g. sul1, sul2, qnrA, ermB, tetA, aac(6)lb, dfrA1, dfr12, dfrA5), conferring multidrug resistance capacity. Sequencing of plasmids present within these multi-resistant strains led to the identification of a total of forty-one resistance genes, targeting nine AB groups. qPCR analysis on the sul2 gene revealed the presence of high copy numbers in the effluent channel connecting to the Vam Co River. The results of the present study clearly indicated that multi-resistant bacteria present in intensive shrimp cultures may disseminate in the natural environment. This study offered a first insight in the impact of plasmid-born ARGs and the related pathogenic bacteria that could emerged due to inappropriate antibiotic utilization in South Vietnam.201829524670
257460.9998Detection of Antibiotic Resistance Genes in Source and Drinking Water Samples from a First Nations Community in Canada. Access to safe drinking water is now recognized as a human right by the United Nations. In developed countries like Canada, access to clean water is generally not a matter of concern. However, one in every five First Nations reserves is under a drinking water advisory, often due to unacceptable microbiological quality. In this study, we analyzed source and potable water from a First Nations community for the presence of coliform bacteria as well as various antibiotic resistance genes. Samples, including those from drinking water sources, were found to be positive for various antibiotic resistance genes, namely, ampC, tet(A), mecA, β-lactamase genes (SHV-type, TEM-type, CTX-M-type, OXA-1, and CMY-2-type), and carbapenemase genes (KPC, IMP, VIM, NDM, GES, and OXA-48 genes). Not surprisingly, substantial numbers of total coliforms, including Escherichia coli, were recovered from these samples, and this result was also confirmed using Illumina sequencing of the 16S rRNA gene. These findings deserve further attention, as the presence of coliforms and antibiotic resistance genes potentially puts the health of the community members at risk. IMPORTANCE: In this study, we highlight the poor microbiological quality of drinking water in a First Nations community in Canada. We examined the coliform load as well as the presence of antibiotic resistance genes in these samples. This study examined the presence of antibiotic-resistant genes in drinking water samples from a First Nations Community in Canada. We believe that our findings are of considerable significance, since the issue of poor water quality in First Nations communities in Canada is often ignored, and our findings will help shed some light on this important issue.201627235436
283570.9998Wastewater used for urban agriculture in West Africa as a reservoir for antibacterial resistance dissemination. State of art metagenomics were used to investigate the microbial population, antibiotic resistance genes and plasmids of medical interest in wastewater used for urban agriculture in Ouagadougou (Burkina Faso). Wastewater samples were collected from three canals near agricultural fields in three neighbourhoods. Assessment of microbial population diversity revealed different microbial patterns among the different samples. Sequencing reads from the wastewaters revealed different functional specializations of microbial communities, with the predominance of carbohydrates and proteins metabolism functions. Eleven pathogen-specific and 56 orthologous virulence factor genes were detected in the wastewater samples. These virulence factors are usually found in human pathogens that cause gastroenteritis and/or diarrhoea. A wide range of antibiotic resistance genes was identified; 81 are transmissible by mobile genetic elements. These included seven different extended spectrum β-lactamase genes encoding synthesis of four enzyme families, including two metallo-β-lactamases (bla(AIM-1) and bla(GES-21)). Ten different incompatibility groups of Enterobacteriaceae plasmid replicons (ColE, FIB, FIC, FII, P, Q, R, U, Y, and A/C), and 30 plasmid replicon types from Gram-positive bacteria. All are implicated in the wide distribution of antibiotic resistance genes. We conclude that wastewater used for urban agriculture in the city represents a high risk for spreading bacteria and antimicrobial resistance among humans and animals.201930253312
193380.9998Antibiotic 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
257690.9998Freshwater and Marine Environments in California Are a Reservoir of Carbapenem-Resistant Bacteria. Carbapenems are last-resort antibiotics used to treat multidrug-resistant bacterial infections. Resistance to carbapenems has been designated as an urgent threat and is increasing in healthcare settings. However, little is still known about the distribution and characteristics of carbapenem-resistant bacteria (CRB) outside of healthcare settings. Here, we surveyed the distribution of CRB in ten diverse freshwater and seawater environments in California, U.S., ranging from San Luis Obispo County to San Bernardino County, combining both direct isolation and enrichment approaches to increase the diversity of isolated CRB. From the locations surveyed, we selected 30 CRB for further characterization. These isolates were identified as members of the genera Aeromonas, Enterobacter, Enterococcus, Paenibacillus, Pseudomonas, Sphingobacterium, and Stenotrophomonas. These isolates were resistant to carbapenems, other β-lactams, and often to other antibiotics (tetracycline, gentamicin, or ciprofloxacin). We also found that nine isolates belonging to the genera Aeromonas, Enterobacter (bla(IMI-2)), and Stenotrophomonas (bla(L1)) produced carbapenemases. Overall, our findings indicate that sampling different types of aquatic environments and combining different isolation approaches increase the diversity of the environmental CRB obtained. Moreover, our study supports the increasingly recognized role of natural water systems as an underappreciated reservoir of bacteria resistant to carbapenems and other antibiotics, including bacteria carrying carbapenemase genes.202438674746
3310100.9998Metagenome and Resistome Analysis of Beta-Lactam-Resistant Bacteria Isolated from River Waters in Surabaya, Indonesia. Antimicrobial agents are administered to humans and livestock, and bacterial antimicrobial resistance (AMR) and antimicrobial agents are released into the environment. In this study, to investigate the trend of AMR in humans, livestock, and the environment, we performed a metagenomic analysis of multidrug-resistant bacteria with CHROMagar ESBL in environmental river water samples, which were collected using syringe filter units from waters near hospitals, downtown areas, residential areas, and water treatment plants in Surabaya, Indonesia. Our results showed that Acinetobacter, Pseudomonas, Aeromonas, Enterobacter, Escherichia, and Klebsiella grew in CHROMagar ESBL; they were most frequently detected in water samples from rivers surrounding hospitals contaminated with various AMR genes (ARGs) in high levels. These results identified bacteria as ARG reservoirs and revealed that hospitals could be sources for various ARGs disseminated into the environment. In conclusion, this study details a novel metagenomic analysis of collected bacteria in environmental water samples using a syringe filter unit for an AMR epidemiological study based on the One Health approach.202438258025
3306110.9998Using Culture-Enriched Phenotypic Metagenomics for Targeted High-Throughput Monitoring of the Clinically Important Fraction of the β-Lactam Resistome. High bacterial community diversity and complexity greatly challenge the cost-efficient monitoring of clinically prevalent antibiotic-resistant bacteria, which are usually present as rare and important populations involved in the environmental dissemination of clinical resistance. Here, we introduce culture-enriched phenotypic metagenomics that integrates culture enrichment, phenotypic screening, and metagenomic analyses as an emerging standardized methodology for targeted resistome monitoring and apply it to decipher the extended-spectrum β-lactam resistome in a municipal wastewater treatment plant (WWTP) and its receiving river. The results showed that clinically prevalent carbapenemase genes (e.g., the NDM and KPC families) and extended-spectrum β-lactamase genes (e.g., the CTX-M, TEM, and OXA families) were prevalent in the WWTP and showed prominent potential in horizontal dissemination. Strikingly, carbapenem and polymyxin resistance genes co-occurred in the highly virulent nosocomial pathogens Enterobacter kobei and Citrobacter freundii. Overall, this study exemplifies phenotypic metagenomics for high-throughput surveillance of a targeted clinically important fraction of antibiotic resistomes and substantially expands current knowledge on extended-spectrum β-lactam resistance in WWTPs.202235930686
5313120.9998Treated wastewater: A hotspot for multidrug- and colistin-resistant Klebsiella pneumoniae. Wastewater treatment plants are hotspots for the release of antimicrobial resistant pathogenic bacteria into aquatic ecosystems, significantly contributing to the cycle of antimicrobial resistance. Special attention should be paid to antimicrobial resistant ESKAPE bacteria, which have been identified as high-priority targets for control measures. Among them, Klebsiella pneumoniae is particularly noteworthy. In this study, we collected wastewater samples from the inlet, sedimentation tank, and effluent water of a wastewater treatment plant in June, July, October, and November of 2018. We detected and characterized 42 K. pneumoniae strains using whole genome sequencing (15 from the inlet, 8 from the sedimentation tank, and 19 from the effluent). Additionally, the strains were tested for their antimicrobial resistance phenotype. Using whole genome sequencing no distinct patterns were observed in terms of their genetic profiles. All strains were resistant to tetracycline, meanwhile 60%, 47%, and 37.5% of strains isolated from the inlet, sedimentation tank, and effluent, respectively, were multidrug resistant. Some of the multidrug resistant isolates were also resistant to colistin, and nearly all tested positive for the eptB and arnT genes, which are associated with polymyxin resistance. Various antimicrobial resistance genes were linked to mobile genetic elements, and they did not correlate with detected virulence groups or defense systems. Overall, our results, although not quantitative, highlight that multidrug resistant K. pneumoniae strains, including those resistant to colistin and genetically unrelated, being discharged into aquatic ecosystems from wastewater treatment plants. This suggests the necessity of monitoring aimed at genetically characterizing these pathogenic bacteria.202439053799
3318130.9998Antibiotic resistance genes in bacteriophages from wastewater treatment plant and hospital wastewaters. Antibiotic resistant bacteria (ARB) are a major health risk caused particularly by anthropogenic activities. Acquisition of antibiotic resistances by bacteria is known to have happened before the discovery of antibiotics and can occur through different routes. Bacteriophages are thought to have an important contribution to the dissemination of antibiotic resistance genes (ARGs) in the environment. In this study, seven ARGs (bla(TEM), bla(SHV), bla(CTX-M), bla(CMY), mecA, vanA, and mcr-1) were investigated, in the bacteriophage fraction, in raw urban and hospital wastewaters. The genes were quantified in 58 raw wastewater samples collected at five WWTPs (n = 38) and hospitals (n = 20). All genes were detected in the phage DNA fraction, with the bla genes found in higher frequency. On the other hand, mecA and mcr-1 were the least frequently detected genes. Concentrations varied between 10(2) copies/L and 10(6) copies/L. The gene coding for the resistance to colistin (mcr-1), a last-resort antibiotic for the treatment of multidrug-resistant Gram-negative infections, was identified in raw urban and hospital wastewaters with positivity rates of 19 % and 10 %, respectively. ARGs patterns varied between hospital and raw urban wastewaters, and within hospitals and WWTP. This study suggests that phages are reservoirs of ARGs, and that ARGs (with particularly emphasis on resistance to colistin and vancomycin) in the phage fraction are already widely widespread in the environment with potential large implications for public health.202337315610
2843140.9998High 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
3444150.9998Multidrug 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
3311160.9998Appearance of mcr-9, bla(KPC), cfr and other clinically relevant antimicrobial resistance genes in recreation waters and sands from urban beaches, Brazil. The co-occurrence of mcr-like and carbapenemase-encoding genes have been reported mainly in humans and animals, whereas, in the environment, studies are gradually increasing due to the One Health approach. In this study, we investigated antimicrobial resistance genes (ARGs) in water and sand samples from marine environments in Brazil. Total DNA from 56 samples (33 sands and 23 waters) was obtained and 27 different ARGs were detected, highlighting the presence of mcr-9, bla(KPC) and cfr genes. Additionally, the microbiological analysis revealed that sand samples of all analyzed beaches were not recommended for primary use, whereas water samples from most beaches were classified as unsuitable for bathing. The presence of clinically relevant ARGs in urban beaches suggests the presence of antimicrobial-resistant bacteria. Furthermore, to the best of our knowledge, this is the first report of mcr-9 and cfr genes in the environment from Brazil and recreational areas worldwide.202133839570
5314170.9998High prevalence of colistin resistance genes in German municipal wastewater. Bacterial resistance against the last-resort antibiotic colistin is of increasing concern on a global scale. Wastewater is suspected to be one of the pathways by which resistant bacteria and the respective genes are disseminated. We employed a metagenomics approach to detect and quantify colistin resistance genes in raw municipal wastewater sampled at 9 locations all over Germany (14 samples in total, collected in 2016/2017). Our data support the findings of earlier studies according to which the prevalence of the colistin resistance gene mcr-1 is still low. However, we were able to demonstrate that the total prevalence of colistin resistance genes is dramatically underestimated if the focus is put on that specific gene alone. In comparison to mcr-1, other gene variants like mcr-3 and mcr-7 proved to be 10 to 100 times more abundant in samples of untreated wastewater. The average relative abundances expressed as copies per 16S rRNA gene copies were 2.3×10(-3) for mcr-3, 2.2×10(-4) for mcr-4, 3.0×10(-4) for mcr-5, and 4.4×10(-4) for mcr-7. While these four gene variants were ubiquitous in all 14 samples, mcr-1 was detected only once at a relative abundance of 1.4×10(-5). Our results suggest a high risk of increasing incidence of colistin resistance as large amounts of mcr genes are continuously disseminated to diverse microbial communities via the wastewater path.201931398645
2571180.9998Multidrug-resistant Enterobacter spp. in wastewater and surface water: Molecular characterization of β-lactam resistance and metal tolerance genes. Among the ESKAPE group pathogens, Enterobacter spp. is an opportunistic Gram-negative bacillus, widely dispersed in the environment, that causes infections. In the present study, samples of hospital wastewater, raw and treated urban wastewater, as well as surface receiving water, were collected to assess the occurrence of multidrug-resistant (MDR) Enterobacter spp. A molecular characterization of β-lactam antibiotic resistance and metal tolerance genes was performed. According to identification by MALDI-TOF MS, 14 isolates were obtained: 7 E. bugandensis, 5 E. kobei, and 2 E. cloacae. The isolates showed resistance mainly to β-lactam antibiotics, including those used to treat infections caused by MDR bacteria. Multiple antibiotic resistance index was calculated for all isolates. It allowed verify whether sampling points showed a high risk due to antibiotic resistant Enterobacter spp., as well as to determine if the isolates have been in environments with a frequent antibiotic use. Twelve isolates showed β-lactam antibiotic resistance gene, being the bla(KPC) widely detected. Regarding metal tolerance, 13 isolates showed at least two genes that encode metal tolerance mechanisms. Overall, metal tolerance mechanisms to silver, copper, mercury, arsenic and tellurium were found. New data on metal tolerance mechanisms dispersion and antibiotic-resistance characterization of the E. bugandensis and E. kobei species were here provided. The occurrence of MDR Enterobacter spp. in analyzed samples draws attention to an urgent need to put control measures into practice. It also evidences waterborne spread of clinically important antibiotic-resistant bacteria recognized as critical priority pathogens.202337356524
2575190.9998A systematic scoping review of antibiotic-resistance in drinking tap water. Environmental matrices have been considered of paramount importance in the spread of antibiotic-resistance; however, the role of drinking waters is still underexplored. Therefore, a scoping review was performed using a systematic approach based on PRISMA guidelines, with the aim of identifying and characterizing antibiotic-resistance in tap water, specifically, water treated at a potabilization plant and provided for drinking use through a water distribution system. The review included 45 studies, the majority of which were conducted in upper-middle-income economies (42.2%), mainly from the Western Pacific region (26.7%), followed by Europe (24.4%). Most of the papers focused on detecting antibiotic-resistant bacteria (ARB), either alone (37.8%) or in combination with antibiotic-resistant genes (ARGs) (26.7%). Multidrug-resistance profile was often identified in heterotrophic bacteria, including various species of nontuberculous mycobacteria, Pseudomonas spp., and Aeromonas spp., which were especially resistant to penicillins, cephalosporins (including 3rd-generation), and also to macrolides (erythromycin) and tetracyclines. Resistance to a wide range of antibiotics was also prevalent in fecal bacteria, e.g., the Enterobacteriaceae family, with common resistance to (fluoro)quinolones and sulfonamide groups. ARGs were investigated either in bacterial strains isolated from tap waters or directly in water samples, and the most frequently detected ARGs belonged to β-lactam, sulfonamide, and tetracycline types. Additionally, mobile genetic elements were found (i.e., int1 and tnpA). Sulfonamides and macrolides were the most frequently detected antibiotics across countries, although their concentrations were generally low (<10 ng/L) in Europe and the United States. From a health perspective, tap water hosted ARB of health concern based on the 2024 WHO bacterial priority pathogens list, mainly Enterobacteriaceae resistant to 3rd-generation cephalosporin and/or carbapenem. Despite the fact that tap water is treated to meet chemical and microbiological quality standards, current evidence suggests that it can harbor antibiotic-resistance determinants, thus supporting its potential role in environmental pathways contributing to antibiotic resistance.202439341535