Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 57.258
Filtrar
1.
Bioresour Technol ; 309: 122802, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32361615

RESUMEN

This experiment investigated the effect of adding a microbial inoculum (M) and ferric chloride (F) on the fate of antibiotic resistance genes (ARGs) during chicken manure composting. Adding M and F improved the microbial activity in the compost and facilitated the removal of ARGs, whereas the combined treatment achieved the best results, especially in reducing the enrichment of sul resistance genes. Tn916/1545 and intI1 were important genetic elements that affected the transfer of ARGs, and Tn916/1545 was closely related to the transfer of tetM, tetW, and ermQ in Firmicutes. Kyoto Encyclopedia of Genes and Genomes functional predictions indicated that M and F could reduce the abundance of membrane transport and signal transduction molecules in the compost products. Thus, these findings suggest that the combined application of M and F is a promising strategy that could potentially inhibit the transfer of ARGs during composting.


Asunto(s)
Compostaje , Animales , Antibacterianos , Pollos , Cloruros , Farmacorresistencia Microbiana , Compuestos Férricos , Genes Bacterianos , Estiércol
2.
Sci Total Environ ; 730: 139042, 2020 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-32402966

RESUMEN

The inappropriate disposal of medical waste allows bacteria to acquire antibiotic resistance, which results in a threat to public health. Antibiotic resistance gene (ARG) profiles were determined for 45 different soil samples containing medical waste and 15 nearby soil samples as controls. Besides physical and chemical analyses (i.e., dry matter content, pH value, and metal content), the genomes of microorganisms from the soil samples were extracted for high-throughput sequencing. ARG abundances of these samples were obtained by searching the metagenomic sequences against the antibiotic resistance gene database and the copies of ARGs per copy of the 16S rRNA gene at different levels were assessed. The results showed medical waste accumulation significantly enriched the contents of Cu, Cr, Pb, and As in the tested soil samples. Compared to the controls, the samples collected from areas containing medical waste were significantly enriched (p < 0.05, t-test) with ARGs annotated as sulfonamide and multidrug resistance genes, and in particular, the subtypes sul1 and sul2 (sulfonamide resistance genes), and multidrug_transporter (multidrug resistance gene). Moreover, the ARGs of the samples from the polluted areas were more diverse than those of the control samples (p < 0.05, t-test). The comparatively higher abundance and diversity of ARGs in contaminated soil pose a potential risk to human health.


Asunto(s)
Suelo , Antibacterianos , Farmacorresistencia Microbiana , Genes Bacterianos , Eliminación de Residuos Sanitarios , ARN Ribosómico 16S
3.
Sci Total Environ ; 734: 139341, 2020 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-32473450

RESUMEN

Originating from a long history of competition between microbes, antibiotic resistance is a serious global health concern. To avoid the risk of antibiotic resistance, tremendous efforts have been directed towards restricting antibiotic consumption worldwide, but to date with limited success. Resistance is governed by multiple pressures from natural and anthropogenic origins which further create problems with control. This study identifies a chain of links from antibiotic resistant genes (ARGs) to microbial communities to environmental pressures in the surface sediments of forty-two lake clusters across the 1000-km Yangtze Basin of China, and attempts to expound on a control pathway for this resistance risk. Results show that eleven of the 670 bacterial families can be classified as antibiotic-resistant or nonresistant communities which antagonize each other. In natural systems, antagonistic competition controls the increase and decrease in ARGs. Superiority of antibiotic-resistant strains initiates a loss in microbial diversity associated with the prevalence of resistance risk. This study shows that, antibiotics shape the evolution of ARGs in resistant communities through a nonlinear role of orientor; other selected pressures serve as a facilitator to enhance the antibiotic resistance through an investigated chain of links. Furthermore, according to tolerances of the classified communities, abiogenetic development through temperature, salinity and Mg were identified and selected for study from seventy lake parameters. Linear feedbacks to selected pressures make the nonresistant communities outcompete the resistant communities, theoretically modulating the risk of antibiotic resistance.


Asunto(s)
Interacción Gen-Ambiente , Sedimentos Geológicos , Antibacterianos , China , Farmacorresistencia Microbiana , Genes Bacterianos
4.
Water Res ; 180: 115880, 2020 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-32438141

RESUMEN

The natural aquatic environment is a significant contributor to the development and circulation of clinically significant antibiotic resistance genes (ARGs). The potential for the aquatic environment to act as a reservoir for ARG accumulation in areas receiving anthropogenic contamination has been thoroughly researched. However, the emergence of novel ARGs in the absence of external influences, as well as the capacity of environmental bacteria to disseminate ARGs via mobile genetic elements remain relatively unchallenged. In order to address these knowledge gaps, this scoping literature review was established focusing on the detection of two important and readily mobile ARGs, namely, extended spectrum beta-lactamase (ESBL) and carbapenemase genes. This review included 41 studies from 19 different countries. A range of different water bodies including rivers (n = 26), seawaters (n = 6) and lakes (n = 3), amongst others, were analysed in the included studies. ESBL genes were reported in 29/41 (70.7%) studies, while carbapenemase genes were reported in 13/41 (31.7%), including joint reporting in 9 studies. The occurrence of mobile genetic elements was evaluated, which included the detection of integrons (n = 22), plasmids (n = 18), insertion sequences (n = 4) and transposons (n = 3). The ability of environmental bacteria to successfully transfer resistance genes via conjugation was also examined in 11 of the included studies. The findings of this scoping review expose the presence of clinically significant ARGs in the natural aquatic environment and highlights the potential ability of environmental isolates to disseminate these genes among different bacterial species. As such, the results presented demonstrate how anthropogenic point discharges may not act as the sole contributor to the development and spread of clinically significant antibiotic resistances. A number of critical knowledge gaps in current research were also identified. Key highlights include the limited number of studies focusing on antibiotic resistance in uncontaminated aquatic environments as well as the lack of standardisation among methodologies of reviewed investigations.


Asunto(s)
Genes Bacterianos , beta-Lactamasas , Antibacterianos , Proteínas Bacterianas , Farmacorresistencia Microbiana
5.
Int J Syst Evol Microbiol ; 70(5): 3255-3263, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32375985

RESUMEN

The strain KG01T was isolated from a soil sample from King George Island, Antarctica. Cells of KG01T are rod-shaped and motile by means of multiple polar flagella. The absence of arginine dihydrolase activity could be a key feature to readily distinguish KG01T from its closest phylogenetic relative species. The main fatty acids of the strain include summed feature 3 (C16 : 1 ω7c and/or C15 : 0 iso 2-OH), C16 : 0 and C18 : 1 ω7c. Phylogenetic analysis based on the 16S rRNA gene sequence and on a multilocus sequence analysis (MLSA) using housekeeping genes (16S rRNA, rpoB, rpoD, gyrB) were carried out. These analyses allowed us to include the strain within the Pseudomonas fluorescens group, presenting the highest similarity of multilocus sequence with Pseudomonas veronii LMG 17761T (96.67 %). The genome of KG01T was sequenced and in silico compared with genomes of the most closely related species of the P. fluorescens group. The average nucleotide identity (ANIb) and average amino acid identity (AAI) values of the species phylogenetically closest to KG01T were less than 95-96 %, threshold currently accepted to define strain as belonging to a bacterial species, the highest scores being those to Pseudomonas veronii LMG 17761T (87.98 %) and Pseudomonas marginalis ICMP 3553T (91.90 %). Therefore, the phenotypic and genotypic analyses results, allow us to propose that KG01T represents a member of a novel species of the genus Pseudomonas, for which the name Pseudomonas fildesensis is proposed, and KG01T (=CECT 9084T;=DSM 102036T) is established as the type strain .


Asunto(s)
Filogenia , Pseudomonas/clasificación , Microbiología del Suelo , Regiones Antárticas , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Genes Bacterianos , Islas , Tipificación de Secuencias Multilocus , Pseudomonas/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
6.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(2): 132-139, 2020 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-32458601

RESUMEN

OBJECTIVE: To evaluate the effects of water body environments on the microbial community of Oncomelania hupensis snails in marshlands of the eastern Dongting Lake where natural extinction of O. hupensis snails are found, so as to explore the correlation between the natural extinction of O. hupensis snails and the microbial community in snails. METHODS: Snails were caged water bodies in the Qianliang Lake marshland (Qianliang Lake regions) where natural extinction of snails was found and in the Junshan Park marshland (Junshan Park regions) in the eastern Dongting Lake for 30 days, and then all snails were collected and identified for survival or death. DNA sequencing of the fungi and bacteria was performed in snails before and after immersion in waters, and the biodiversity and abundance were analyzed. RESULTS: The survival rates of O. hupensis snails were 28.0% (70/250) and 64.8% (162/250) in Qianliang Lake regions and Junshan Park regions 30 days after immersion in waters, respectively (χ2 = 81.365, P < 0.01). The number of the fungal community and the biodiversity of the bacterial community were both greater in snails caged in Qianliang Lake regions post-immersion than pre-immersion, and there was a significant difference in the structure of the fungal and bacterial communities. The microbial community with a significant difference included Flavobacteriaceae,which was harmful to O. hupensis snails. CONCLUSIONS: The water body environment affects the composition of the microbial community in O. hupensis snails in marshlands with natural snail distinction around the eastern Dongting Lake; however, further studies are required to investigate whether the natural distinction of snails is caused by water body environments-induced changes of the microbial spectrum in O. hupensis snails.


Asunto(s)
Biodiversidad , Lagos , Microbiota , Caracoles , Animales , China , Genes Bacterianos/genética , Microbiota/genética , Caracoles/microbiología , Caracoles/fisiología , Humedales
7.
Bioresour Technol ; 311: 123510, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32446235

RESUMEN

In this study, the effects of different temperature transitions on the dynamics of antibiotic resistance genes (ARGs) and bacterial community were investigated during start-up of thermophilic anaerobic digestion (AD) of sewage sludge. Although two thermophilic reactors showed dissimilar removal efficiencies of ARGs in batch mode, both the removal efficiency and reduction patterns of ARGs were similar in continuous stirred tank reactor (CSTR) mode, resulting in significant reduction of the total sum of the relative abundance of ARGs. Using network analysis to explore the correlation between bacterial community and some specific ARGs revealed that composition of the bacterial community played a vital role in the fluctuations in the relative abundance of the antibiotic resistome, demonstrating that shaping the development of ARGs was facilitated by vertical gene transfer. To facilitate eliminating ARGs, minimizing their hosts which persist even under long-term operations is vital in thermophilic AD.


Asunto(s)
Antibacterianos , Aguas del Alcantarillado , Anaerobiosis , Farmacorresistencia Microbiana , Genes Bacterianos
8.
Bioresour Technol ; 311: 123584, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32471691

RESUMEN

The transcription and expression of functional genes governed the biotransformation of nutrients during composting. In this study, the diversities of functional genes were investigated in 50 days chicken manure composting through six treatments amended with different dosage of red kaolin. Results showed that based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation, Metabolism possessed largest proportion and richest genes number among six pathways, of which carbohydrate metabolism (81007) were significantly greater than others; while Human Disease and Organismal Systems were relatively lower. Meanwhile, the addition of red kaolin has an important impact on dynamics of KEGG genes, the relative abundance of detected genes were distinctively different in all treatments. Similarity analysis also showed the varying influence of different proportion of red kaolin on functional genes during chicken manure composting. In conclusion, application of red kaolin in chicken manure composting effectively improved the relative abundance of functional genes.


Asunto(s)
Compostaje , Animales , Pollos , Genes Bacterianos , Caolín , Estiércol , Suelo
9.
Water Res ; 179: 115878, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32417561

RESUMEN

Antibiotic resistance has been recognized as a major threat to public health worldwide. Inactivation of antibiotic resistant bacteria (ARB) and degradation of antibiotic resistance genes (ARGs) are critical to prevent the spread of antibiotic resistance in the environment. Conventional disinfection processes are effective to inactivate water-borne pathogens, yet they are unable to completely eliminate the antibiotic resistance risk. This study explored the potential of the photo-Fenton process to inactivate ARB, and to degrade both extracellular and intracellular ARGs (e-ARGs and i-ARGs, respectively). Using Escherichia coli DH5α with two plasmid-encoded ARGs (tetA and blaTEM-1) as a model ARB, a 6.17 log ARB removal was achieved within 30 min of applying photo-Fenton under visible LED and neutral pH conditions. In addition, no ARB regrowth occurred after 48-h, demonstrating that this process is very effective to induce permanent disinfection on ARB. The photo-Fenton process was validated under various water matrices, including ultrapure water (UPW), simulated wastewater (SWW) and phosphate buffer (PBS). The higher inactivation efficiency was observed in SWW as compared to other matrices. The photo-Fenton process also caused a 6.75 to 8.56-log reduction in eARGs based on quantitative real-time PCR of both short- and long amplicons. Atomic force microscopy (AFM) further confirmed that the extracellular DNA was sheared into short DNA fragments, thus eliminating the risk of the transmission of antibiotic resistance. As compared with e-ARGs, a higher dosage of Fenton reagent was required to damage i-ARGs. In addition, the tetA gene was more easily degraded than the blaTEM-1 gene. Collectively, our results demonstrate the photo-Fenton process is a promising technology for disinfecting water to prevent the spread of antibiotic resistance.


Asunto(s)
Antibacterianos , Purificación del Agua , Bacterias , Farmacorresistencia Microbiana , Genes Bacterianos , Concentración de Iones de Hidrógeno , Aguas Residuales
10.
Int J Syst Evol Microbiol ; 70(3): 1571-1577, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32228746

RESUMEN

The present study aimed to determine the taxonomic positions of strains designated R-5-52-3T, R-5-33-5-1-2, R-5-48-2 and R-5-51-4 isolated from hot spring water samples. Cells of these strains were Gram-stain-negative, non-motile and rod-shaped. The strains shared highest 16S rRNA gene sequence similarity with Vulcaniibacterium thermophilum KCTC 32020T (95.1%). Growth occurred at 28-55 °C, at pH 6-8 and with up to 3 % (w/v) NaCl. DNA fingerprinting, biochemical, phylogenetic and 16S rRNA gene sequence analyses suggested that R-5-52-3T, R-5-33-5-1-2, R-5-48-2 and R-5-51-4 were different strains but belonged to the same species. Hence, R-5-52-3T was chosen for further analysis and R-5-33-5-1-2, R-5-48-2 and R-5-51-4 were considered as additional strains of this species. R-5-52-3T possessed Q-8 as the only quinone and iso-C15:0, iso-C11:0, C16 : 0 and iso-C17 : 0 as major fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified polar lipids and two unidentified phospholipids. The genomic G+C content was 71.6 mol%. Heat shock proteins (e.g. Hsp20, GroEL, DnaK and Clp ATPases) were noted in the R-5-52-3T genome, which could suggest its protection in the hot spring environment. Pan-genome analysis showed the number of singleton gene clusters among Vulcaniibacterium members varied. Average nucleotide identity (ANI) values between R-5-52-3T, Vulcaniibacterium tengchongense YIM 77520T and V. thermophilum KCTC 32020T were 80.1-85.8 %, which were below the cut-off level (95-96 %) recommended as the ANI criterion for interspecies identity. Thus, based on the above results, strain R-5-52-3T represents a novel species of the genus Vulcaniibacterium, for which the name Vulcaniibacterium gelatinicum sp. nov. is proposed. The type strain is R-5-52-3T (=KCTC 72061T=CGMCC 1.16678T).


Asunto(s)
Manantiales de Aguas Termales/microbiología , Filogenia , Xanthomonadaceae/clasificación , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Genes Bacterianos , Fosfolípidos/química , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Ubiquinona/química , Microbiología del Agua , Xanthomonadaceae/aislamiento & purificación
11.
Int J Syst Evol Microbiol ; 70(3): 1578-1584, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32228749

RESUMEN

A Gram-stain-positive strain, 8 H-2T, was isolated from faeces of Reeves' muntjac (Muntiacus reevesi) barking deer in Taiwan. Cells of the strain were short rod-shaped, non-motile, non-haemolytic, asporogenous, facultatively anaerobic, heterofermentative and did not exhibit catalase and oxidase activities. Comparative analyses of 16S rRNA, pheS and dnaA gene sequences demonstrated that the novel strain was a member of the genus Weissella. On the basis of 16S rRNA gene sequence similarities, the type strains of Weissella oryzae (99.2 %), Weissella confusa (97.8 %), Weissella cibaria (97.6 %) and Weissella soli (97.3 %) were the closest neighbours to strain 8 H-2T. The concatenated housekeeping gene sequence (pheS and dnaA) similarities of 8 H-2T to closely related type strains were 72.5-84.9 %, respectively. The genomic DNA G+C content was 40.5 mol%. The average nucleotide identity and digital DNA-DNA hybridization values with these type strains were 70.2-75.4% and 25.1-30.1 %, respectively. Phenotypic and genotypic test results demonstrated that strain 8 H-2T represents a novel species belonging to the genus Weissella, for which the name Weissella muntiaci sp. nov. is proposed. The type strain is 8 H-2T (=BCRC 81133T=NBRC 113537T).


Asunto(s)
Ciervos/microbiología , Heces/microbiología , Filogenia , Weissella/clasificación , Animales , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Fermentación , Genes Bacterianos , Ciervo Muntjac , Hibridación de Ácido Nucleico , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Taiwán , Weissella/aislamiento & purificación
12.
J Environ Manage ; 262: 110375, 2020 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-32250829

RESUMEN

The extensive application of antibiotics, and the occurrence and spread of antibiotic resistance genes (ARGs) shade health risks to human and animal. The long-term effects of sulfamethoxazole (SMX) and tetracycline (TC) on denitrification process were evaluated in this study, with the focus on nitrogen removal performance, microbial community and ARGs. Results showed that low-concentration SMX and TC (<0.2 mg L-1) initially caused a deterioration in nitrogen removal performance, while higher concentrations (0.4-20 mg L-1) of both antibiotics had no further inhibitory influences. The abundances of ARGs in both systems generally increased during the whole period, and most of them had significant correlations with intI1, especially efflux-pump genes. Castellaniella, which was the dominant genus under antibiotic pressure, might be potential resistant bacteria. These findings provide an insight into the toxic effects of different antibiotics on denitrification process, and guides future efforts to control antibiotics pollution in ecosystems.


Asunto(s)
Antibacterianos , Microbiota , Animales , Desnitrificación , Farmacorresistencia Microbiana , Genes Bacterianos
13.
J Med Microbiol ; 69(5): 728-738, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32310744

RESUMEN

Introduction. Nocardia spp. can cause several ocular infections, such as keratitis, endophthalmitis and scleral abscesses. Molecular identification of Nocardia spp. by 16S rDNA sequencing is the gold standard method at present for species identification, but closely related species can only be identified by multilocus sequence analysis (MLSA) of housekeeping genes.Aim. The major objective was to profile Nocardia species, antibiotic susceptibility patterns and clinical outcomes in endophthalmitis patients.Methodology. Between January 2009 and December 2018, endophthalmitis patients who were diagnosed with Nocardia infection based on microscopic and culture characteristics were selected. Antibacterial susceptibility tests were performed and Nocardia speciation was performed using MLSA and phylogenetic tree analysis of the 16 s rRNA gene and the gyrB, hsp65 and secA1 genes.Results. A total of 43 culture-proven patients were identified during the study period. All isolates were 100 % sensitive to amikacin and 98 % resistant to ceftazidime. Fluoroquinolone sensitivity was observed in the range of 58 to 72 %. Year-wise analysis of antibiotic resistance patterns revealed there was a significant increase in resistance to fluoroquinolones. Twenty-two isolates were stored and six different species were identified. Nocardia farcinica (n=10) was found to be the most predominant, followed by Nocardia cyriacigeorgica (n=4), Nocardia otitidiscaviarum (n=3), Nocardia amikacinitolerans (n=2), Nocardia puris (n=2) and Nocardia higoensis (n=1).Conclusions. N. farcinica is the major pathogen, and this is the first report to identify N. otitidiscaviarum, N. amikacinitolerans and N. higoensis as causing endophthalmitis. Overall, visual outcomes were mostly poor even after aggressive management.


Asunto(s)
Endoftalmitis/diagnóstico , Endoftalmitis/microbiología , Tipificación de Secuencias Multilocus , Nocardiosis/diagnóstico , Nocardiosis/microbiología , Nocardia/clasificación , Nocardia/genética , Antibacterianos/farmacología , Resistencia a Antineoplásicos , Endoftalmitis/tratamiento farmacológico , Genes Bacterianos , Genes Esenciales , Humanos , Nocardia/efectos de los fármacos , Nocardiosis/tratamiento farmacológico , Filogenia , ARN Ribosómico 16S/genética
14.
J Environ Manage ; 266: 110581, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32310121

RESUMEN

Green tea residues (GTRs) are byproducts of tea production and processing, and this type of agricultural waste retains nutritious components. This study investigated the co-composting of GTRs with swine manure, as well as the effects of GTRs on antibiotic resistance genes (ARGs) and the bacterial community during co-composting. The temperature and C/N ratio indicate compost was mature after processing. The addition of GTRs effectively promoted the reduction in the abundances of most targeted ARGs (tet and sul genes), mobile genetic element (MGE; intI1), and metal resistance genes (MRGs; pcoA and tcrB). Redundancy analysis (RDA) showed that GTRs can reduce the abundance of MRGs and ARGs by reducing the bioavailability of heavy metals. Network analysis shows that Firmicutes and Actinobacteria were the main hosts of ARGs and ARGs, MGEs, and MRGs shared the same potential host bacteria. Adding GTRs during composting may reduce ARGs transmission through horizontal gene transfer (HGT). GTRs affected the bacterial community, thereby influencing the variations in the ARG profiles and reducing the potential risk associated with the compost product.


Asunto(s)
Compostaje , Animales , Antibacterianos , Bacterias , Farmacorresistencia Microbiana , Genes Bacterianos , Estiércol , Porcinos ,
15.
Chemosphere ; 252: 126476, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32229364

RESUMEN

Emerging contaminants such as antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) are becoming a global environmental problem. In this study, the glow discharge plasma (GDP) was applied for degrading antibiotic resistant Escherichia coli (E. coli) with resistance genes (tetA, tetR, aphA) and transposase gene (tnpA) in 0.9% sterile saline. The results showed that GDP was able to inactivate the antibiotic resistant E. coli and remove the ARGs and reduce the risk of gene transfer. The levels of E. coli determined by 16S rRNA decreased by approximately 4.7 logs with 15 min of discharge treatment. Propidium monoazide - quantitative polymerase chain reaction (PMA-qPCR) tests demonstrated that the cellular structure of 4.8 more logs E. coli was destroyed in 15 min. The reduction of tetA, tetR, aphA, tnpA genes was increased to 5.8, 5.4, 5.3 and 5.5 logs with 30 min discharge treatment, respectively. The removal of ARGs from high salinity wastewater was also investigated. The total abundance of ARGs was reduced by 3.9 logs in 30 min. Scavenging tests indicated that hydroxyl radicals (·OH) was the most probable agents for bacteria inactivation and ARGs degradation. In addition, the active chlorine (Cl· and Cl2) which formed during the discharge may also contribute to the inactivation and degradation.


Asunto(s)
Farmacorresistencia Bacteriana/genética , Escherichia coli/genética , Purificación del Agua/métodos , Antibacterianos , Bacterias/genética , Cloro , Genes Bacterianos , ARN Ribosómico 16S , Aguas Residuales/microbiología
16.
Parasit Vectors ; 13(1): 200, 2020 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-32306993

RESUMEN

BACKGROUND: Approximately 30% of children worldwide are infected with gastrointestinal parasites. Depending on the species, parasites can disrupt intestinal bacterial microbiota affecting essential vitamin biosynthesis. METHODS: Stool samples were collected from 37 asymptomatic children from a previous cross-sectional Argentinian study. A multi-parallel real-time quantitative PCR was implemented for Ascaris lumbricoides, Ancylostoma duodenale, Necator americanus, Strongyloides stercoralis, Trichuris trichiura, Cryptosporidium spp., Entamoeba histolytica and Giardia duodenalis. In addition, whole-genome sequencing analysis was conducted for bacterial microbiota on all samples and analyzed using Livermore Metagenomic Analysis Toolkit and DIAMOND software. Separate analyses were carried out for uninfected, Giardia-only, Giardia + helminth co-infections, and helminth-only groups. RESULTS: For Giardia-only infected children compared to uninfected children, DNA sequencing data showed a decrease in microbiota biodiversity that correlated with increasing Giardia burden and was statistically significant using Shannon's alpha diversity (Giardia-only > 1 fg/µl 2.346; non-infected group 3.253, P = 0.0317). An increase in diversity was observed for helminth-only infections with a decrease in diversity for Giardia + helminth co-infections (P = 0.00178). In Giardia-only infections, microbiome taxonomy changed from Firmicutes towards increasing proportions of Prevotella, with the degree of change related to the intensity of infection compared to uninfected (P = 0.0317). The abundance of Prevotella bacteria was decreased in the helminths-only group but increased for Giardia + helminth co-infections (P = 0.0262). Metagenomic analysis determined cobalamin synthesis was decreased in the Giardia > 1 fg/µl group compared to both the Giardia < 1 fg/µl and the uninfected group (P = 0.0369). Giardia + helminth group also had a decrease in cobalamin CbiM genes from helminth-only infections (P = 0.000754). CONCLUSION: The study results may provide evidence for an effect of parasitic infections enabling the permissive growth of anaerobic bacteria such as Prevotella, suggesting an altered capacity of vitamin B12 (cobalamin) biosynthesis and potential impact on growth and development in children .


Asunto(s)
Coinfección , Microbioma Gastrointestinal/genética , Intestinos , Parásitos/genética , Vitamina B 12/genética , Animales , Niño , Preescolar , Coinfección/microbiología , Coinfección/parasitología , Estudios Transversales , ADN de Helmintos , ADN Protozoario , Femenino , Genes Bacterianos , Giardia lamblia/clasificación , Giardia lamblia/genética , Giardia lamblia/aislamiento & purificación , Helmintos/clasificación , Helmintos/genética , Helmintos/aislamiento & purificación , Humanos , Intestinos/microbiología , Intestinos/parasitología , Masculino , Metagenómica , Parásitos/clasificación , Parásitos/aislamiento & purificación , Proyectos Piloto , Reacción en Cadena en Tiempo Real de la Polimerasa , Vitamina B 12/metabolismo , Secuenciación Completa del Genoma
17.
Gene ; 748: 144704, 2020 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-32339624

RESUMEN

Resistance to antibiotics have created havoc around the globe due to the emergence of multi-drug resistant (MDR) pathogenic bacterial strains. To decipher this problem, a detailed understanding of the antimicrobial resistance (AMR) genes and their resistant mechanisms are obligatory. The present study is mainly focused on an opportunistic, nosocomial bacterial strain Enterococcus faecalis V583, which possess acquired exogenous AMR genes portraying resistance against Chloramphenicol, Tetracycline, Vancomycin, Linezolid, Ampicillin and other antibiotics. An interaction network of eight AMR genes along with 40 functional partners have been constructed and analysed. Functional enrichment analysis highlighted 20, 21 and 22 genes having significant roles in Cellular Component (CC), Molecular Functions (MF) and Biological Process (BP) respectively. Clustering analysis resulted in four densely interconnected clusters (C1-C4) which were associated with three AMR mechanisms that include the alteration in drug target (pbps, mur and van genes), complete replacement/bypass of target sites (van genes) and ATP Binding Cassette (ABC) transporter efflux pump mechanisms (msrA, EF_1680, EF_1682 and pbps). Our results showed that the genes responsible for ß-lactams resistance (pbp1A, 1C, 2A, 2B); glycopeptide resistance (ddl, vanBHBRBSBWXYB); Erythromycin, Macrolides, Lincosamide and Streptogramin-B (MLSB) resistance (msrA, EF_1680, EF_1682) along with mur genes (murABBCDEFG) played an important role in MDR mechanisms. Network analysis has shown the genes mraY, pbpC, murE, murG and murD possessed 26, 24, 23, 22 and 22 interactions respectively. With more number of direct interactions, these genes can be considered as hub genes that could be exploited as potential drug targets for new drug discovery.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Enterococcus faecalis/efectos de los fármacos , Redes Reguladoras de Genes , Enterococcus faecalis/genética , Genes Bacterianos
18.
Int J Syst Evol Microbiol ; 70(5): 3049-3054, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32242797

RESUMEN

A short rod-shaped, Gram-stain-negative strain that can degrade multiple polymers was isolated from forest soil in China and designated as DSWY01T. The results of 16S rRNA gene sequence analysis showed that this isolate shared high similarities with Pseudomonas alcaliphila NBRC 102411T (99.3 %), Pseudomonas mendocina NBRC 14162T (99.2%) and Pseudomonas oleovorans NBRC 13583T (99.0%). The results of phylogenetic analysis based on 16S rRNA gene sequence and multilocus sequence analysis (recA, gyrB, nuoD, glnS and rpoD) indicated that strain DSWY01T belongs to the genus Pseudomonas and is a member of the P. oleovorans group in an independent branch. The average nucleotide identity and digital DNA-DNA hybridization between the genome of strain DSWY01T and the genomes of other species (ANIb 77.72-89.65 %; GGDC 15.50-31.10 %) showed that the isolate represents a novel species. The DNA G+C content of strain DSWY01T was 63.67 mol%, and the major cellular fatty acids (>15 %) were a mixture of C18 : 1ω7c/C18 : 1ω6c and C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and two unidentified lipids, and the major quinone was CQ-10. The morphological, physiological and biochemical characteristics of the isolate were then compared with those of reference type strains. The isolate differed considerably from its closest relatives and is representative of a novel species of Pseudomonas, for which the name Pseudomonas hydrolytica sp. nov. is proposed. The type strain is DSWY01T (=DSM 106702T=CCTCC AB 2018053T).


Asunto(s)
Filogenia , Pseudomonas/clasificación , Microbiología del Suelo , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Bosques , Genes Bacterianos , Tipificación de Secuencias Multilocus , Hibridación de Ácido Nucleico , Fosfolípidos/química , Polímeros , Pseudomonas/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Ubiquinona/análogos & derivados , Ubiquinona/química
19.
Int J Syst Evol Microbiol ; 70(5): 3111-3116, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32250236

RESUMEN

Two Gram-stain-positive, rod-shaped, non-motile, non-spore-forming, catalase-negative bacteria, designated strains SG162T and NK01, were isolated from Japanese rice grain silage and total mixed ration silage, respectively. They were initially identified as Lactobacillus buchneri based on the 16S rRNA gene sequence similarities. However, the two strains were separated into a distinct clade from L. buchneri DSM 20057T (=JCM 1115T) through whole-genome sequence-based characterization, forming an infraspecific subgroup together with strains CD034 and S42, whose genomic sequences were available in the public sequence database. Strains within the subgroup shared 99.4-99.7 % average nucleotide identity (ANI) and 97.5-99.0 % digital DNA-DNA hybridization (dDDH) with each other, albeit 96.9-97.0 % ANI and 76.0-76.6 % dDDH against DSM 20057T. Strains SG162T and NK01 could utilize more substrates as sole carbon sources than DSM 20057T, potentially owing to the abundance of genes involved in carbon metabolism, especially the Entner-Doudoroff pathway. The inability of γ-aminobutyric acid (GABA) production was evidenced by the lack of glutamate decarboxylase and glutamate/GABA antiporter genes in the new subgroup strains. Strain SG162T grew at 10-45 °C (optimum, 30 °C), pH 3.5-8.0, and 0-8 % (w/v) NaCl. Its genomic DNA G+C content was 44.1 mol%. The predominant fatty acids were C16 : 0, C19 : 0 cyclo ω8c, and summed feature 8. On the basis of the polyphasic characterization findings, strains SG162T and NK01 represent a novel subspecies of L. buchneri, for which the name Lactobacillus buchneri subsp. silagei subsp. nov. is proposed. The type strain is SG162T (=JCM 32599T=DSM 107969T), and strains CD034 and S42 are also transferred to L. buchneri subsp. silagei.


Asunto(s)
Lactobacillus/clasificación , Oryza/microbiología , Filogenia , Ensilaje/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Grano Comestible/microbiología , Ácidos Grasos/química , Genes Bacterianos , Japón , Lactobacillus/aislamiento & purificación , Hibridación de Ácido Nucleico , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
20.
Chemosphere ; 253: 126697, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32298915

RESUMEN

The emergence and spread of antibiotic resistance are major threats to ecosystems and human health. Transoceanic channels (e.g., ship ballast water) can transfer harmful aquatic organisms across geographically isolated waters. However, the occurrence of antibiotic resistance genes (ARGs) in ship ballast water and their relationship with microbial communities and environmental factors remain unknown. In this study, ballast water from 28 vessels sailing to Shanghai and Jiangyin (China) were collected, and the ARGs in these water samples were investigated. Considerable levels of ARGs and integrase of the class-I integrons (intI1) were detected in all ballast water samples. sul1 and tetQ were the most and least abundant ARGs in ballast water samples, respectively. The ARGs were strongly correlated with those of the 16S rRNA and intI1 genes. Ballast water exchange can reduce the absolute abundance of some kinds of ARGs while increasing the relative abundance of several ARGs (e.g., mefA, mexF, strB, sul1, and tetQ). Moreover, the bacterial hosts of ARGs were generally different in the unexchanged ballast water (UEBW) and exchanged ballast water (EBW). In particular, Leisingera and unclassified_Erythrobacteraceae were the main ARGs-associated genera in the EBW, while Pseudohongiella, Cycloclasticus, OM43_clade, norank_f_Rhodospirillaceae, and norank_f_Rhodobacteraceae were the dominant ARGs hosts in the UEBW. Overall, ship ballast water is an effective moving carrier for the global transference of ARGs, and its sufficient management is required for mitigating ARGs propagation across oceans.


Asunto(s)
Farmacorresistencia Microbiana/genética , Genes Bacterianos , Navíos , Eliminación de Residuos Líquidos/métodos , Bacterias/efectos de los fármacos , China , Ecosistema , Integrones/genética , Océanos y Mares , ARN Ribosómico 16S/genética , Abastecimiento de Agua
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA