Culture-independent methods reveal high diversity of OXA-48-like genes in water environments. - Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
274901.0000Culture-independent methods reveal high diversity of OXA-48-like genes in water environments. The carbapenemase OXA-48 was identified for the first time in 2001 and is now one of the greatest concerns in terms of antibiotic resistance. While many studies report clinical OXA-48-like producers, few reports refer bla(OXA-48-like) genes in environmental bacteria. The main goal of this study was to evaluate the diversity of bla(OXA-48-like) genes in aquatic systems, using culture-independent approaches. For that, environmental DNA was obtained from riverine and estuarine water and used to construct clone libraries of bla(OXA-48-like) gene polymerase chain reaction amplicons. bla(OXA-48-like) libraries from river and estuarine water DNA comprised 75 and 70 clones, respectively. Sequence analysis showed that environmental bla(OXA-48-like) genes show a broader diversity than that so far observed in clinical settings. In total, 50 new OXA-48 variants were identified as well as sequences identical to previously reported OXA-48, OXA-181, OXA-199, OXA-204 and OXA-162. Though we have no evidence that these genes were carried by bacteria that are members of the natural heterotrophic flora or bacteria that have entered this particular water environment through anthropogenic sources, these results reinforce the role of aquatic systems as antibiotic resistance reservoirs. The variants of bla(OXA-48) here described should be taken into account when designing molecular strategies for detecting this gene.201728771149
283610.9999Waste 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
191320.9999Citrobacter spp. and Enterobacter spp. as reservoirs of carbapenemase bla(NDM) and bla(KPC) resistance genes in hospital wastewater. Antibiotic resistance has emerged as a global threat to public health, generating a growing interest in investigating the presence of antibiotic-resistant bacteria in environments influenced by anthropogenic activities. Wastewater treatment plants in hospital serve as significant reservoirs of antimicrobial-resistant bacteria, where a favorable environment is established, promoting the proliferation and transfer of resistance genes among different bacterial species. In our study, we isolated a total of 243 strains from 5 hospital wastewater sites in Mexico, belonging to 21 distinct Gram-negative bacterial species. The presence of β-lactamase was detected in 46.9% (114/243) of the isolates, which belonging to the Enterobacteriaceae family. We identified a total of 169 β-lactamase genes; bla(TEM) in 33.1%, bla(CTX-M) in 25.4%, bla(KPC) in 25.4%, bla(NDM) 8.8%, bla(SHV) in 5.3%, and bla(OXA-48) in 1.1% distributed in 12 different bacteria species. Among the 114 of the isolates, 50.8% were found to harbor at least one carbapenemase and were discharged into the environment. The carbapenemase bla(KPC) was found in six Citrobacter spp. and E. coli, while bla(NDM) was detected in two distinct Enterobacter spp. and E. coli. Notably, bla(NDM-1) was identified in a 110 Kb IncFII conjugative plasmid in E. cloacae, E. xiangfangensis, and E. coli within the same hospital wastewater. In conclusion, hospital wastewater showed the presence of Enterobacteriaceae carrying a high frequency of carbapenemase bla(KPC) and bla(NDM). We propose that hospital wastewater serves as reservoirs for resistance mechanism within bacterial communities and creates an optimal environment for the exchange of this resistance mechanism among different bacterial strains. IMPORTANCE: The significance of this study lies in its findings regarding the prevalence and diversity of antibiotic-resistant bacteria and genes identified in hospital wastewater in Mexico. The research underscores the urgent need for enhanced surveillance and prevention strategies to tackle the escalating challenge of antibiotic resistance, particularly evident through the elevated frequencies of carbapenemase genes such as bla(KPC) and bla(NDM) within the Enterobacteriaceae family. Moreover, the identification of these resistance genes on conjugative plasmids highlights the potential for widespread transmission via horizontal gene transfer. Understanding the mechanisms of antibiotic resistance in hospital wastewater is crucial for developing targeted interventions aimed at reducing transmission, thereby safeguarding public health and preserving the efficacy of antimicrobial therapies.202439012101
159330.9999Epidemiological Description and Detection of Antimicrobial Resistance in Various Aquatic Sites in Marseille, France. Antibiotic resistance is a worldwide public health concern and has been associated with reports of elevated mortality. According to the One Health concept, antibiotic resistance genes are transferrable to organisms, and organisms are shared among humans, animals, and the environment. Consequently, aquatic environments are a possible reservoir of bacteria harboring antibiotic resistance genes. In our study, we screened water and wastewater samples for antibiotic resistance genes by culturing samples on different types of agar media. Then, we performed real-time PCR to detect the presence of genes conferring resistance to beta lactams and colistin, followed by standard PCR and gene sequencing for verification. We mainly isolated Enterobacteriaceae from all samples. In water samples, 36 Gram-negative bacterial strains were isolated and identified. We found three extended-spectrum β-lactamase (ESBL)-producing bacteria-Escherichia coli and Enterobacter cloacae strains-harboring the CTX-M and TEM groups. In wastewater samples, we isolated 114 Gram-negative bacterial strains, mainly E. coli, Klebsiella pneumoniae, Citrobacter freundii and Proteus mirabilis strains. Forty-two bacterial strains were ESBL-producing bacteria, and they harbored at least one gene belonging to the CTX-M, SHV, and TEM groups. We also detected carbapenem-resistant genes, including NDM, KPC, and OXA-48, in four isolates of E. coli. This short epidemiological study allowed us to identify new antibiotic resistance genes present in bacterial strains isolated from water in Marseille. This type of surveillance shows the importance of tracking bacterial resistance in aquatic environments. IMPORTANCE Antibiotic-resistant bacteria are involved in serious infections in humans. The dissemination of these bacteria in water, which is in close contact with human activities, is a serious problem, especially under the concept of One Health. This study was done to survey and localize the circulation of bacterial strains, along with their antibiotic resistance genes, in the aquatic environment in Marseille, France. The importance of this study is to monitor the frequency of these circulating bacteria by creating and surveying water treatments.202336976002
274540.9999Dissemination of multi-resistant Gram-negative bacteria into German wastewater and surface waters. Carbapenem antibiotics constitute the mainstay therapy of nosocomial infections with extended spectrum beta-lactamase producing Gram-negative bacteria; however, resistance against these compounds is increasing. This study was designed to demonstrate that carbapenemase-producing bacteria are disseminated from hospitals into the environment. To this end, resistant bacteria were isolated from a clinical/urban and from a rural catchment system in Germany in 2016/17. The study followed the dissemination of resistant bacteria from the wastewater through the wastewater treatment plant (WWTP) into the receiving surface waters. The bacteria were cultivated on selective agar and characterized by antibiotic testing, real-time PCR targeting carbapenemase genes and typing. Bacteria with resistance to third generation cephalosporins were isolated from all sample sites. 134 isolates harboring carbapenemase genes encoding VIM, NDM and OXA-48 and 26 XDR (extensively drug-resistant) strains with susceptibility to only one or two antibiotics were isolated from the clinical/urban system. The rural system yielded eight carbapenemase producers and no XDR strains. In conclusion, clinical wastewaters were charged with a high proportion of multidrug resistant bacteria. Although most of these bacteria were eliminated during wastewater treatment, dissemination into surface waters is possible as single carbapenemase producers were still present in the effluent of the WWTP.201829659796
275050.9999Extended-spectrum β-lactamases genes in Gram-negative isolates from an urban river in Nicaragua. Limited resources and inadequate surveillance systems in developing countries have hindered research on antibiotic resistance gene transfer in aquatic environments. In this context, our study aimed to identify extended-spectrum beta-lactamase gene variants in Gram-negative isolates from the Tipitapa River-a significant Central America ecosystem. Samples were collected and assessed for key water parameters: dissolved oxygen, electrical conductivity, pH, and temperature. We employed a mix of microbiological, biochemical and molecular techniques, including multiplex PCR and sequencing, to characterize bacteria and determine the bla gene variants. Water quality parameters indicated areas impacted by human activities with high mineralization and eutrophication conditions. Among the bacteria analyzed, 48% belonged to the Enterobacteriaceae family, and a significant 88% displayed extended-spectrum beta-lactamases. Sequencing revealed four distinct bla gene variants in 84% of the isolates: bla-SHV-24, bla-SHV-13, bla-TEM-1, and bla-TEM-116, with bla-SHV-24 being the most common (47.62%). This is the first report of bla gene variants in the Tipitapa River, revealing their presence in globally concerning bacteria. The robust methodology enhances surveillance, enables geographic profiling of bla gene variants, and improves our understanding of biochemical patterns and gene transmission dynamics, providing essential insights into the global distribution of antibiotic resistance genes in Central America's natural waters.202539907335
275460.9998Antimicrobial resistance in Aeromonas species isolated from aquatic environments in Brazil. AIM: The current study was conducted to determine the antimicrobial resistance profile and genetic relatedness of Aeromonas sp. isolated from healthcare and urban effluents, wastewater treatment plant (WWTP) and river water. METHODS AND RESULTS: We detected the presence of genes conferring resistance to β-lactam, quinolone and aminoglycoside. Multilocus sequence typing was carried out to differentiate the strains, and multilocus phylogenetic analysis was used to identify the species. A total of 28 cefotaxime-resistant Aeromonas sp. strains were identified, harbouring uncommon Guiana-extended-spectrum (GES)-type β-lactamases (GES-1, GES-5, GES-7 and GES-16). Multidrug-resistant Aeromonas sp. were found in hospital wastewater, WWTP and sanitary effluent, and A. caviae was identified as the most prevalent species (85·7%). CONCLUSION: The release of untreated healthcare effluents, presence of antimicrobials in the environment, in addition to multidrug-resistant Aeromonas sp., are all potential factors for the spread of resistance. SIGNIFICANCE AND IMPACT OF THE STUDY: We identified a vast repertoire of antimicrobial resistance genes (ARG) in Aeromonas sp. from diverse aquatic ecosystems, including those that encode enzymes degrading broad-spectrum antimicrobials widely used to treat healthcare-associated infections. Hospital and sanitary effluents serve as potential sources of bacteria harbouring ARG and are a threat to public health.202133306232
191470.9998Comprehensive analysis of distribution characteristics and horizontal gene transfer elements of bla(NDM-1)-carrying bacteria. The worldwide dissemination of New Delhi metallo-β-lactamase-1 (NDM-1), which mediates resistance to almost all clinical β-lactam antibiotics, is a major public health problem. The global distribution, species, sources, and potential transfer risk of bla(NDM-1)-carrying bacteria are unclear. Results of a comprehensive analysis of literature in 2010-2022 showed that a total of 6002 bla(NDM-1) carrying bacteria were widely distributed around 62 countries with a high trend in the coastal areas. Opportunistic pathogens or pathogens like Klebsiella sp., Escherichia sp., Acinetobacter sp. and Pseudomonas sp. were the four main species indicating the potential microbial risk. Source analysis showed that 86.45 % of target bacteria were isolated from the source of hospital (e.g., Hospital patients and wastewater) and little from surface water (5.07 %) and farms (3.98 %). A plasmid-encoded bla(NDM-1)Acinetobacter sp. with the resistance mechanisms of antibiotic efflux pump, antibiotic target change and antibiotic degradation was isolated from the wastewater of a typical tertiary hospital. Insertion sequences (IS3 and IS30) located in the adjacent 5 kbp of bla(NDM-1)-ble(MBL) gene cluster indicating the transposon-mediated horizontal gene transfer risk. These results showed that the worldwide spread of bla(NDM-1)-carrying bacteria and its potential horizontal gene transfer risk deserve good control.202438906294
273280.9998Biofilms in hospital effluents as a potential crossroads for carbapenemase-encoding strains. Bacterial resistance to carbapenem, which is mainly due to the successful dissemination of carbapenemase-encoding genes, has become a major health problem. Few studies have aimed to characterize the level of resistance in the environment, notably in hospital wastewater, which is a likely hotspot for exchange of antibiotic resistance genes. In this work, we looked for the presence of imipenem-resistant bacteria and imipenem in the effluent of the teaching hospital of Clermont-Ferrand, France. Selective growth of bacteria from 14-day old biofilms formed in the pipe sewer showed that 22.1% of the isolates were imipenem-resistant and identified as Aeromonas (n = 23), Pseudomonas (n = 10), Stenotrophomonas (n = 4) and Acinetobacter (n = 1). Fifteen of these strains harbored acquired carbapenemase-encoding genes bla(VIM) (n = 11), bla(OXA-48) (n = 2), bla(GES) (n = 1), bla(NDM) (n = 1). All isolates also harbored associated resistances to aminoglycosides, fluoroquinolones and/or tetracyclin. S1-nuclease pulsed-field gel electrophoresis analysis of eight selected isolates showed that four of them harbored one to two plasmids of molecular weight between 48.5 Kb and 194 Kb. In vitro transformation assays evidenced the presence of bla(VIM) and bla(NDM) on plasmids with the bla(VIM) harboring 80 Kb plasmid having conjugative capacity. The predicted environmental concentration of imipenem in the hospital effluent was 3.16 μg/L, suggesting that biofilm bacteria are subjected to sub-MICs of imipenem within the effluent. However, no imipenem molecule was detected in the hospital effluent, probably owing to its instability: in vitro assays indicated that imipenem's biological activity was no longer detectable after 45 h of storage. However, the predictive value of the hazard quotient relative to the development of resistance was >1.0 (HQr = 28.9 ± 1.9), which indicates a possible risk. The presence of carbapenemase-encoding genes in hospital effluent biofilm strains and their ability to transfer are therefore a potential hazard that should not be neglected and points to the need for monitoring antibiotic resistance in hospital wastewater.201930530220
257190.9998Multidrug-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
2734100.9998High Frequency of Antibiotic Resistance Genes (ARGs) in the Lerma River Basin, Mexico. The spread of beta-lactamase-producing bacteria is of great concern and the environment has been found to be a main source of contamination. Herein, it was proposed to determine the frequency of antimicrobial-resistant-Gram-negative bacteria throughout the Lerma River basin using phenotypic and molecular methods. Resistant bacteria were isolated with chromogenic media and antimicrobial susceptibility tests were used to characterize their resistance. ARGs for beta-lactams, aminoglycosides, and quinolones were detected by PCR. Species were identified by Sanger sequencing the 16S rRNA gene and the representative genomes of MDR strains were sequenced by NGS. A high variation in the number of isolates was observed in the 20 sampled sites, while observing a low diversity among the resistant bacteria. Of the 12 identified bacterial groups, C. freundii, E. coli, and S. marcescens were more predominant. A high frequency of resistance to beta-lactams, quinolones, and aminoglycosides was evidenced, where the bla(CTX,)qnrB, qnrS y, and aac(6')lb-cr genes were the most prevalent. C. freundii showed the highest frequency of MDR strains. Whole genome sequencing revealed that S. marcescens and K. pneumoniae showed a high number of shared virulence and antimicrobial resistance genes, while E. coli showed the highest number of unique genes. The contamination of the Lerma River with MDR strains carrying various ARGs should raise awareness among environmental authorities to assess the risks and regulations regarding the optimal hygienic and sanitary conditions for this important river that supports economic activities in the different communities in Mexico.202236360888
1824110.9998Subtype Screening of bla(IMP) Genes Using Bipartite Primers for DNA Sequencing. Genes conferring carbapenem resistance have spread worldwide among gram-negative bacteria. Subtyping of these genes has epidemiological value due to the global cross-border movement of people. Subtyping of bla(IMP) genes that frequently detected in Japan appears to be important in public health settings; however, there are few useful tools for this purpose. We developed a subtyping screening tool based on PCR direct sequencing, which targets the internal sequences of almost all bla(IMP) genes. The tool used bipartite multiplex primers with M13 universal sequences at the 5'-end. According to in silico analysis, among the 78 known IMP-type genes, except for bla(IMP-81), 77 detected genes were estimated to be differentiated. In vitro evaluation indicated that sequences of amplicons of IMP-1, IMP-6, IMP-7, and IMP-20 templates were identical to their respective subtypes. Even if the amplicons were small or undetectable through the first PCR, sufficient amplicons for DNA sequencing were obtained through a second PCR using the M13 universal primers. In conclusion, our tool can be possibly used for subtype screening of bla(IMP), which is useful for the surveillance of bacteria with bla(IMP) in clinical and public health settings or environmental fields.202133790070
1939120.9998Detection of microbial aerosols in hospital wards and molecular identification and dissemination of drug resistance of Escherichia coli. Antibiotic-resistant bacteria (ARB) present a global public health problem. Microorganisms are the main cause of hospital-acquired infections, and the biological contamination of hospital environments can cause the outbreak of a series of infectious diseases. Therefore, it is very important to understand the spread of antibiotic-resistant bacteria in hospital environments. This study examines the concentrations of aerobic bacteria and E. coli in ward environments and the airborne transmission of bacterial drug resistance. The results show that the three wards examined have an average aerobic bacterial concentration of 132 CFU∙m(-3) and an average inhalable aerobic bacterial concentration of 73 CFU∙m(-3), with no significant difference (P > 0.05) among the three wards. All isolated E. coli showed multi-drug resistance to not only third-generation cephalosporin antibiotics, but also quinolones, aminoglycosides, and sulfonamides. Furthermore, 51 airborne E. coli strains isolated from the air in the three wards and the corridor were screened for ESBLs, and 12 (23.53%) were ESBL-positive. The drug-resistance gene of the 12 ESBL-positive strains was mainly TEM gene, and the detection rate was 66.67% (8/12). According to a homology analysis with PFGE, 100% homologous E. coli from the ward at 5 m and 10 m outside the ward in the corridor shared the same drug-resistance spectrum, which further proves that airborne E. coli carrying a drug-resistance gene spreads out of the ward through gas exchange. This leads to biological pollution inside, outside, and around the ward, which poses a direct threat to the health of patients, healthcare workers, and surrounding residents. It is also the main reason for the antibiotic resistance in the hospital environment. More attention should be paid to comprehensive hygiene management in the surrounding environment of hospitals.202032070803
1592130.9998Identification of ESBL-Producing Enterobacterales From Vegetable Plants: Preliminary Findings From a Small Cross-Sectional Study in a Rural Area of Madagascar. Extended-spectrum beta-lactamases (ESBL)-producing enterobacterales are considered a key indicator for antimicrobial resistance (AMR) epidemiological surveillance in animal, human, and environment compartments. In this study, we aim to investigate the presence and genetic diversity of ESBL-producing enterobacterales on vegetable plants. We isolated beta-lactam resistant enterobacterales from several vegetable plants and sequenced their whole genome. Utilising standard genomic and phylogenetic methods, we sought to (i) characterise the resistance genes and plasmid content of the plant-isolated strains, (ii) investigate their genetic structure, and (iii) determine their relationships with strains from other reservoirs. Among the 22 strains collected from vegetable plants, 6 showed resistance to beta-lactam antibiotics, with 5 of them identified as ESBL producers. Our results indicated the presence of multidrug-resistant (MDR) strains containing multiple antibiotic resistance genes (ARGs). Importantly, no host-specific lineages were identified among the plant-isolated ESBL-producing E. coli (ESBL-Ec). Instead, these strains exhibited genetic and epidemiological connections with strains isolated from animals, humans, and the environment, suggesting transfer of ESBL-Ec between plants and other sources in rural Madagascar. These preliminary findings suggest that vegetable plants are contaminated as a result of human activities, posing a potential risk of human and animal exposure to antibiotic-resistant bacteria and genes.202540528688
2753140.9998Extended-spectrum beta-lactamase-producing Escherichia coli and antimicrobial resistance in municipal and hospital wastewaters in Czech Republic: Culture-based and metagenomic approaches. Wastewaters serve as important hot spots for antimicrobial resistance and monitoring can be used to analyse the abundance and diversity of antimicrobial resistance genes at the level of large bacterial and human populations. In this study, whole genome sequencing of beta-lactamase-producing Escherichia coli and metagenomic analysis of whole-community DNA were used to characterize the occurrence of antimicrobial resistance in hospital, municipal and river waters in the city of Brno (Czech Republic). Cefotaxime-resistant E. coli were mainly extended-spectrum beta-lactamase (ESBL) producers (95.6%, n = 158), of which the majority carried bla(CTX-M) (98.7%; n = 151) and were detected in all water samples except the outflow from hospital wastewater treatment plant. A wide phylogenetic diversity was observed among the sequenced E. coli (n = 78) based on the detection of 40 sequence types and single nucleotide polymorphisms (average number 34,666 ± 15,710) between strains. The metagenomic analysis revealed a high occurrence of bacterial genera with potentially pathogenic members, including Pseudomonas, Escherichia, Klebsiella, Aeromonas, Enterobacter and Arcobacter (relative abundance >50%) in untreated hospital and municipal wastewaters and predominance of environmental bacteria in treated and river waters. Genes encoding resistance to aminoglycosides, beta-lactams, quinolones and macrolides were frequently detected, however bla(CTX-M) was not found in this dataset which may be affected by insufficient sequencing depth of the samples. The study pointed out municipal treated wastewater as a possible source of multi-drug resistant E. coli and antimicrobial resistance genes for surface waters. Moreover, the combination of two different approaches provided a more holistic view on antimicrobial resistance in water environments. The culture-based approach facilitated insight into the dynamics of ESBL-producing E. coli and the metagenomics shows abundance and diversity of bacteria and antimicrobial resistance genes vary across water sites.202133232750
1709150.9998High prevalence of bla(VIM-1) gene in bacteria from Brazilian soil. This study investigated bacteria from soil samples to (i) determine the main bacterial genera and species having resistance to carbapenem and other β-lactams and (ii) establish if the mechanism of resistance was due to the production of metallo-β-lactamases. The isolates were characterized by PCR for metallo-β-lactamases and integrons, by antimicrobial susceptibility testing, and by sequencing. The antimicrobial profile of 40 imipenem-resistant Gram-positive soil isolates from all Brazilian regions demonstrated that 31 (77.5%) of them were multidrug resistant. Among the 40 isolates, 19 presented the bla(VIM) gene and class 1 integrons by PCR. Six of the 19 isolates were identified as Paenibacillus sp., 12 as Bacillus sp., and just 1 was classified as Staphylococcus sp., by sequencing of the 16S rRNA gene. These results suggest that bacteria from soil can act as a source of bla(VIM-1) genes, representing a threat to public health.201627392282
5314160.9998High 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
3313170.9998The Prevalence and Characterization of Extended-Spectrum β-Lactamase- and Carbapenemase-Producing Bacteria from Hospital Sewage, Treated Effluents and Receiving Rivers. Hospital sewage plays a key role in the dissemination of antibiotic-resistant genes (ARGs) by serving as an environmental antimicrobial resistance reservoir. In this study, we aimed to characterize the cephalosporin- and carbapenem-resistant isolates from hospital sewage and receiving rivers. The results showed that ESBL (bla(CTX-M)) and carbapenemase genes (bla(NDM) and bla(KPC)) were widely detected in a number of different bacterial species. These resistance genes were mainly harbored in Enterobacteriaceae, followed by Acinetobacter and Aeromonas isolates. More attention should be given to these bacteria as important vectors of ARGs in the environment. Furthermore, we showed that the multidrug resistance phenotype was highly prevalent, which was found in 85.5% Enterobacteriaceae and 75% Acinetobacter strains. Notably, the presence of carbapenemase genes in isolates from treated effluents and receiving rivers indicates that the discharges of wastewater treatment plants could be an important source for high-risk resistance genes propagation to the environment. In conclusion, this study shows a high prevalence of ESBL- and carbapenemase-producing bacteria in hospital sewage and receiving rivers in China. These findings have serious implications for human health, and also suggest the need for more efforts to control the dissemination of resistant bacteria from hospital sewage into the environment.202032069792
2733180.9998Prevalence and diversity of carbapenem-resistant bacteria in untreated drinking water in Portugal. We examined the prevalence and diversity of carbapenem-resistant bacteria (CRB) in untreated drinking water. Prevalence was estimated in plate count agar (PCA) and R2A media with or without antibiotics. Clonal relatedness of isolates was established by repetitive extragenic palindroitic (REP)-PCR. Phylogeny was based on the 16S rRNA gene. Antimicrobial susceptibility was assessed by disc diffusion methods. Genes encoding beta-lactamases and integrases were inspected by PCR. CRB ranged from 0.02% to 15.9% of cultivable bacteria, while ampicillin-resistant bacteria ranged from 1.5% to 31.4%. Carbapenem-resistant isolates affiliated with genera Stenotrophomonas, Pseudomonas, Janthinobacterium, Chryseobacterium, Sphingobacterium, Acidovorax, Caulobacter, Cupriavidus, and Sphingomonas. CRB were highly resistant to beta-lactams, but mostly susceptible to other classes. Transmissible beta-lactamase genes and integrase genes were not detected. The genus-specific bla(L1) was detected in 61% of the Stenotrophomonas isolates. Contrarily to what has been reported for extensively used antibiotics, low levels of carbapenem resistance were detected in untreated drinking water, often represented by intrinsically resistant genera. Production of chromosomal-encoded carbapenemases was the prevalent carbapenem resistance mechanism. Results suggest that the dissemination of anthropogenic-derived carbapenem resistance is at an early stage. This presents an opportunity to rationally develop monitoring strategies to identify dissemination routes and assess the impact of human actions in the environmental resistome.201222663561
879190.9998Detection of New Delhi metallo-beta-lactamase enzyme gene bla (NDM-1) associated with the Int-1 gene in Gram-negative bacteria collected from the effluent treatment plant of a tuberculosis care hospital in Delhi, India. BACKGROUND: Organisms possessing the bla (NDM-1) gene (responsible for carbapenem resistance) with a class-1 integron can acquire many other antibiotic resistance genes from the community sewage pool and become multidrug-resistant superbugs. In this regard, hospital sewage, which contains a large quantity of residual antibiotics, metals and disinfectants, is being recognized as a significant cause of antimicrobial resistance (AMR) origination and spread across the major centres of the world and is thus routinely investigated as a marker for tracing the origin of drug resistance. Therefore, in this study, an attempt has been made to identify and characterize the carbapenem-resistant microbes associated with integron genes amongst the organisms isolated from the effluent treatment plant (ETP) installed in a tertiary respiratory care hospital in Delhi, India. METHODS: One hundred and thirty-eight organisms belonging to Escherichia , Klebsiella , Pseudomonas and Acinetobacter spp. were collected from the incoming and outgoing sewage lines of the ETP. Carbapenem sensitivity and characterization was performed by the imipenem and imipenem-EDTA disc diffusion method. Later DNA extraction and PCR steps were performed for the Int-1 and bla (NDM-1) genes. RESULTS: Of the 138 organisms, 86 (62.3 %) were imipenem-resistant (P<0.05). One hundred and twenty-four (89.9 %) organisms had one or both of the genes. Overall, the bla (NDM-1) gene (genotypic resistance) was present in 71 % (98/138) of organisms. 53.6 % (74/138) organisms were double gene-positive (bla (NDM-1) + Int-1), of which 40 were producing the metallo-beta-lactamase enzyme, making up almost 28.9 % (40/138) of the collected organisms. CONCLUSION: The current study strengthens the hypothesis that Carbapenem resistant organisms are in a high-circulation burden through the human gut and hospital ETPs are providing an environment for resistance origination and amplification.202032974589