scholarly journals Interaction between the Microbial Community and Invading Escherichia coli O157:H7 in Soils from Vegetable Fields

2013 ◽  
Vol 80 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Zhiyuan Yao ◽  
Haizhen Wang ◽  
Laosheng Wu ◽  
Jianjun Wu ◽  
Philip C. Brookes ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Microbial Community ◽  
Soil Microbial Community ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Principal Component ◽  
Content Type ◽  
E Coli ◽  
Soil Microbial ◽  
The Impact

ABSTRACTThe survival ofEscherichia coliO157:H7 in soils can contaminate vegetables, fruits, drinking water, etc. However, data on the impact ofE. coliO157:H7 on soil microbial communities are limited. In this study, we monitored the changes in the indigenous microbial community by using the phospholipid fatty acid (PLFA) method to investigate the interaction of the soil microbial community withE. coliO157:H7 in soils. Simple correlation analysis showed that the survival ofE. coliO157:H7 in the test soils was negatively correlated with the ratio of Gram-negative (G−) to Gram-positive (G+) bacterial PLFAs (G−/G+ratio). In particular, levels of 14 PLFAs were negatively correlated with the survival time ofE. coliO157:H7. The contents of actinomycetous and fungal PLFAs in the test soils declined significantly (P, <0.05) after 25 days of incubation withE. coliO157:H7. The G−/G+ratio declined slightly, while the ratio of bacterial to fungal PLFAs (B/F ratio) and the ratio of normal saturated PLFAs to monounsaturated PLFAs (S/M ratio) increased, afterE. coliO157:H7 inoculation. Principal component analysis results further indicated that invasion byE. coliO157:H7 had some effects on the soil microbial community. Our data revealed that the toxicity ofE. coliO157:H7 presents not only in its pathogenicity but also in its effect on soil microecology. Hence, close attention should be paid to the survival ofE. coliO157:H7 and its potential for contaminating soils.

Impact of Humics and Plants on Microbial Community and Petroleum Hydrocarbon Degradation in Contaminated Soil

2013 ◽  
Vol 726-731 ◽  
pp. 131-140
Author(s):  
Hai Hua Jiao ◽  
Kai Wang ◽  
Jian Gang Pan ◽  
De Cai Jin ◽  
Zhan Bin Huang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Microbial Community ◽  
Petroleum Hydrocarbon ◽  
Phospholipid Fatty Acid ◽  
Principal Component ◽  
Total Petroleum Hydrocarbon ◽  
Crop Species ◽  
Functional Activities ◽  
Soil Microbial ◽  
Gram Positive Bacteria

A greenhouse pot experiment, in which 3 different crops (wheat, cabbage, spinach) were cultivated in soil with and without humics (HS), was conducted to evaluate the effect of HS on soil microbiological properties. Phospholipid fatty acid (PLFA) profiles were analyzed to reveal the microbial community structure. As a measure of the functional activity of soil microbial community, the ratio of degraded to total petroleum hydrocarbon in soil was estimated. The results indicated that HS had an important effect on the soil microbial community and its functional activities. First, the principal component analysis (PCA) of the PLFA signatures revealed marked changes between soil with HS and without HS. In addition, the total amount and the profile of PLFA were significantly different between the untreated and HS-amended soils. Using PLFA patterns as a biomarker, it was found that gram-positive bacteria (G+) were more sensitive to HS than gram-negative bacteria (G-), and the biomass of G+ was higher in soil with HS than in that without HS. Second, the crop could stimulate the growth of soil microorganisms; however, the differences depended clearly on the crop species. The G+ and G- biomass was increased in spinach soil containing HS, but was decreased in wheat and cabbage soils. The population of fungi was increased in wheat and spinach soils containing HS, but was decreased in cabbage soil. The population of actinomycetes was increased in cabbage soil, but was decreased in wheat and spinach soils containing HS. Third, the ratio of degraded to total petroleum hydrocarbon was also affected by the HS treatment. It was slightly increased in soil with HS treatment, but a significant change depended on the crop species. In general, fatty acids ranged from C13 to C19. In total, 25 different PLFAs were identified, including saturated (SAT), monounsaturated (MUFA), branched (BR), and polyunsaturated (PUFA) species. There was a clear difference in the PLFA composition between soils with and without HS.

scholarly journals Comparison of Drivers of Soil Microbial Communities Developed in Karst Ecosystems with Shallow and Deep Soil Depths

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 173
Author(s):  
Huiling Guan ◽  
Jiangwen Fan ◽  
Haiyan Zhang ◽  
Warwick Harris
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Soil Depth ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Deep Soil ◽  
Soil System ◽  
Soil Microbial ◽  
Total Soil ◽  
Karst Ecosystems

Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities.

scholarly journals Streptomycin-Induced Inflammation Enhances Escherichia coli Gut Colonization Through Nitrate Respiration

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Alanna M. Spees ◽  
Tamding Wangdi ◽  
Christopher A. Lopez ◽  
Dawn D. Kingsbury ◽  
Mariana N. Xavier ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Microbial Community ◽  
Intestinal Inflammation ◽  
Anaerobic Bacteria ◽  
Nitrate Respiration ◽  
Colonization Resistance ◽  
Content Type ◽  
E Coli ◽  
Gut Colonization ◽  
Facultative Anaerobic Bacteria

ABSTRACTTreatment with streptomycin enhances the growth of human commensalEscherichia coliisolates in the mouse intestine, suggesting that the resident microbial community (microbiota) can inhibit the growth of invading microbes, a phenomenon known as “colonization resistance.” However, the precise mechanisms by which streptomycin treatment lowers colonization resistance remain obscure. Here we show that streptomycin treatment rendered mice more susceptible to the development of chemically induced colitis, raising the possibility that the antibiotic might lower colonization resistance by changing mucosal immune responses rather than by preventing microbe-microbe interactions. Investigation of the underlying mechanism revealed a mild inflammatory infiltrate in the cecal mucosa of streptomycin-treated mice, which was accompanied by elevated expression ofNos2, the gene that encodes inducible nitric oxide synthase. In turn, this inflammatory response enhanced the luminal growth ofE. coliby nitrate respiration in aNos2-dependent fashion. These data identify low-level intestinal inflammation as one of the factors responsible for the loss of resistance toE. colicolonization after streptomycin treatment.IMPORTANCEOur intestine is host to a complex microbial community that confers benefits by educating the immune system and providing niche protection. Perturbation of intestinal communities by streptomycin treatment lowers “colonization resistance” through unknown mechanisms. Here we show that streptomycin increases the inflammatory tone of the intestinal mucosa, thereby making the bowel more susceptible to dextran sulfate sodium treatment and boosting theNos2-dependent growth of commensalEscherichia coliby nitrate respiration. These data point to the generation of alternative electron acceptors as a by-product of the inflammatory host response as an important factor responsible for lowering resistance to colonization by facultative anaerobic bacteria such asE. coli.

scholarly journals Impact of Extended-Spectrum β-Lactamase Production on Treatment Outcomes of Acute Pyelonephritis Caused by Escherichia coli in Patients without Health Care-Associated Risk Factors

2015 ◽  
Vol 59 (4) ◽  
pp. 1962-1968 ◽  
Author(s):  
Sun Hee Park ◽  
Su-Mi Choi ◽  
Dong-Gun Lee ◽  
Sung-Yeon Cho ◽  
Hyo-Jin Lee ◽  
...  
Keyword(s):  
Risk Factors ◽  
Escherichia Coli ◽  
Health Care ◽  
Treatment Outcomes ◽  
Acute Pyelonephritis ◽  
Esbl Production ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
The Impact

ABSTRACTExtended-spectrum β-lactamase-producingEscherichia coli(ESBL-EC) is increasingly identified as a cause of acute pyelonephritis (APN) among patients without recent health care contact, i.e., community-associated APN. This case-control study compared 75 cases of community-associated ESBL-EC APN (CA-ESBL) to 225 controls of community-associated non-ESBL-EC APN (CA-non-ESBL) to identify the risk factors for ESBL-EC acquisition and investigate the impact of ESBL on the treatment outcomes of community-associated APN (CA-APN) caused byE. coliat a Korean hospital during 2007 to 2013. The baseline characteristics were similar between the cases and controls; the risk factors for ESBL-EC were age (>55 years), antibiotic use within the previous year, and diabetes with recurrent APN. The severity of illness did not differ between CA-ESBL and CA-non-ESBL (Acute Physiology and Chronic Health Evaluation [APACHE] II scores [mean ± standard deviation], 7.7 ± 5.9 versus 6.4 ± 5.3;P= 0.071). The proportions of clinical (odds ratio [OR], 1.76; 95% confidence interval [CI], 0.57 to 5.38;P= 0.323) and microbiological (OR, 1.16; 95% CI, 0.51 to 2.65;P= 0.730) cures were similar, although the CA-ESBL APN patients were less likely to receive appropriate antibiotics within 48 h. A multivariable Cox proportional hazards analysis of the prognostic factors for CA-APN caused byE. colishowed that ESBL production was not a significant factor for clinical (hazard ratio [HR], 0.39; 95% CI, 0.12 to 1.30;P= 0.126) or microbiological (HR, 0.49; 95% CI, 0.21 to 1.12;P= 0.091) failure. The estimates did not change after incorporating weights calculated using propensity scores for acquiring ESBL-EC. Therefore, ESBL production did not negatively affect treatment outcomes among patients with community-associatedE. coliAPN.

scholarly journals STRUKTUR KOMUNITAS MIKROBA TANAH DAN IMPLIKASINYA DALAM MEWUJUDKAN SISTEM PERTANIAN BERKELANJUTAN

el–Hayah ◽  
2012 ◽  
Vol 1 (4) ◽  
Author(s):  
Prihastuti Prihastuti
Keyword(s):  
Microbial Community ◽  
Microbial Diversity ◽  
Microbial Communities ◽  
Soil Microbial Community ◽  
Soil Microbial Communities ◽  
Organic Soil ◽  
Plant Type ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Wide Range

<p>Soils are made up of organic and an organic material. The organic soil component contains all the living creatures in the soil and the dead ones in various stages of decomposition.  Biological activity in soil helps to recycle nutrients, decompose organic matter making nutrient available for plant uptake, stabilize humus, and form soil particles.<br />The extent of the diversity of microbial in soil is seen to be critical to the maintenance of soil health and quality, as a wide range of microbial is involved in important soil functions.  That ecologically managed soils have a greater quantity and diversity of soil microbial. The two main drivers of soil microbial community structure, i.e., plant type and soil type, are thought to exert their function in a complex manner. The fact that in some situations the soil and in others the plant type is the key factor determining soil microbial diversity is related to their complexity of the microbial interactions in soil, including interactions between microbial and soil and microbial and plants. <br />The basic premise of organic soil stewardship is that all plant nutrients are present in the soil by maintaining a biologically active soil environment. The diversity of microbial communities has on ecological function and resilience to disturbances in soil ecosystems. Relationships are often observed between the extent of microbial diversity in soil, soil and plant quality and ecosystem sustainability. Agricultural management can be directed toward maximizing the quality of the soil microbial community in terms of disease suppression, if it is possible to shift soil microbial communities.</p><p>Keywords: structure, microbial, implication, sustainable agriculture<br /><br /></p>

scholarly journals Impact of UV and Peracetic Acid Disinfection on the Prevalence of Virulence and Antimicrobial Resistance Genes in Uropathogenic Escherichia coli in Wastewater Effluents

2014 ◽  
Vol 80 (12) ◽  
pp. 3656-3666 ◽  
Author(s):  
Basanta Kumar Biswal ◽  
Ramzi Khairallah ◽  
Kareem Bibi ◽  
Alberto Mazza ◽  
Ronald Gehr ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Peracetic Acid ◽  
Content Type ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
Municipal Wastewaters ◽  
The Impact

ABSTRACTWastewater discharges may increase the populations of pathogens, includingEscherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenicEscherichia coli(UPEC), the most abundantE. colipathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766E. coliisolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm2and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters.

scholarly journals In VivoTransmission of an IncA/C Plasmid in Escherichia coli Depends on Tetracycline Concentration, and Acquisition of the Plasmid Results in a Variable Cost of Fitness

2015 ◽  
Vol 81 (10) ◽  
pp. 3561-3570 ◽  
Author(s):  
Timothy J. Johnson ◽  
Randall S. Singer ◽  
Richard E. Isaacson ◽  
Jessica L. Danzeisen ◽  
Kevin Lang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Dose ◽  
Broad Host Range ◽  
Antibiotic Administration ◽  
Dose Administration ◽  
Content Type ◽  
E Coli ◽  
The Impact ◽  
Selection Of

ABSTRACTIncA/C plasmids are broad-host-range plasmids enabling multidrug resistance that have emerged worldwide among bacterial pathogens of humans and animals. Although antibiotic usage is suspected to be a driving force in the emergence of such strains, few studies have examined the impact of different types of antibiotic administration on the selection of plasmid-containing multidrug resistant isolates. In this study, chlortetracycline treatment at different concentrations in pig feed was examined for its impact on selection and dissemination of an IncA/C plasmid introduced orally via a commensalEscherichia colihost. Continuous low-dose administration of chlortetracycline at 50 g per ton had no observable impact on the proportions of IncA/C plasmid-containingE. colifrom pig feces over the course of 35 days. In contrast, high-dose administration of chlortetracycline at 350 g per ton significantly increased IncA/C plasmid-containingE. coliin pig feces (P< 0.001) and increased movement of the IncA/C plasmid to other indigenousE. colihosts. There was no evidence of conjugal transfer of the IncA/C plasmid to bacterial species other thanE. coli.In vitrocompetition assays demonstrated that bacterial host background substantially impacted the cost of IncA/C plasmid carriage inE. coliandSalmonella.In vitrotransfer and selection experiments demonstrated that tetracycline at 32 μg/ml was necessary to enhance IncA/C plasmid conjugative transfer, while subinhibitory concentrations of tetracyclinein vitrostrongly selected for IncA/C plasmid-containingE. coli. Together, these experiments improve our knowledge on the impact of differing concentrations of tetracycline on the selection of IncA/C-type plasmids.

Distinct assembly processes and determinants of soil microbial communities between farmland and grassland in arid and semiarid areas

2021 ◽  
Author(s):  
Aiai Xu ◽  
Jie Liu ◽  
Zhiying Guo ◽  
Changkun Wang ◽  
Kai Pan ◽  
...  
Keyword(s):  
Microbial Community ◽  
Variable Selection ◽  
Microbial Communities ◽  
Soil Microbial Community ◽  
Environmental Gradient ◽  
Soil Microbial Communities ◽  
Soil Microbial ◽  
Semiarid Areas ◽  
Arid And Semiarid Areas ◽  
Arid And Semiarid

It is critical to identify the assembly processes and determinants of soil microbial communities to better predict soil microbial responses to environmental change in arid and semiarid areas. Here, soils from 16 grassland-only, 9 paired grassland and farmland, and 16 farmland-only sites were collected across the central Inner Mongolia Plateau covering a steep environmental gradient. Through analyzing the paired samples, we discovered that land uses had strong effects on soil microbial communities, but weak effects on their assembly processes. For all samples, although no environmental variables were significantly correlated with the net relatedness index (NRI), both the nearest taxon index (NTI) and the β-nearest taxon index (βNTI) were most related to mean annual precipitation (MAP). With the increase of MAP, soil microbial taxa at the tips of the phylogenetic tree were more clustered, and the contribution of determinism increased. Determinism (48.6%), especially variable selection (46.3%), and stochasticity (51.4%) were almost equal in farmland, while stochasticity (75.0%) was dominant in grassland. Additionally, Mantel tests and redundancy analyses (RDA) revealed that the main determinants of soil microbial community structure were MAP in grassland, but mean annual temperature (MAT) in farmland. MAP and MAT were also good predictors of the community composition (the top 200 dominant OTUs) in grassland and farmland, respectively. Collectively, in arid and semiarid areas, soil microbial communities were more sensitive to environmental change in farmland than in grassland, and unlike the major impact of MAP on grassland microbial communities, MAT was the primary driver of farmland microbial communities. Importance As one of the most diverse organisms, soil microbes play indispensable roles in many ecological processes in arid and semiarid areas with limited macrofaunal and plant diversity, yet the mechanisms underpinning soil microbial community are not fully understood. In this study, soil microbial communities were investigated along a 500 km transect covering a steep environmental gradient across farmland and grassland in the areas. The results showed that precipitation was the main factor mediating the assembly processes. Determinism was more influential in farmland, and variable selection of farmland was twice that of grassland. Temperature mainly drove farmland microbial communities, while precipitation mainly affected grassland microbial communities. These findings provide new information about the assembly processes and determinants of soil microbial communities in arid and semiarid areas, consequently improving the predictability of the community dynamics, which have implications for sustaining soil microbial diversity and ecosystem functioning, particularly under global climate change conditions.

The Impact of Reclaimed Water Irrigation on Soil Microbial Community Structure

2014 ◽  
Vol 955-959 ◽  
pp. 3635-3639 ◽  
Author(s):  
Ji Hua Wang ◽  
Xue Gong ◽  
Jian Fei Guan ◽  
Hui Yan Xing
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Soil Microbial Community ◽  
Soil Column ◽  
Reclaimed Water ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
The Impact ◽  
Reclaimed Water Irrigation

The reclaimed water treated in a Harbin recycled water plant has been taken as a target of research, by using microbial traditional culture method and tablet coated counting method, discussing the influence of the reclaimed water irrigation on soil microbial community structure through the method of short-term indoor simulated soil column irrigation. The results shows that the reclaimed water irrigation can significantly increase the quantity of bacteria and actinomycetes in the surface 0-20 cm layer soil, but it has little affect on 20-40 cm and 40-60 cm layer soil. Microbial community structure and diversity were changed relatively with the irrigation of reclaimed water, which embodied the increase or decrease of dominant and subdominant groups, the disappearance of non-dominant groups sensitive to reclaimed water, the appear or disappear of the other part of the occasional groups.

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