Type Of Es Research Articles

Genomic epidemiology of third-generation cephalosporin-resistant Escherichia coli from Argentinian pig and dairy farms reveals animal-specific patterns of co-resistance and resistance mechanisms.

Little is known about the ecology of critically important antibiotic resistance among bacteria with the potential to be opportunistic human pathogens (e.g., Escherichia coli) on South American farms. By studying 70 pig and dairy cattle farms in central-eastern Argentina, we identified that third-generation cephalosporin resistance (3GC-R) in E. coli was mediated by mechanisms seen more often in certain species and that 3GC-R pig E. coli were more likely to be co-resistant to florfenicol and amoxicillin/clavulanate. This suggests that on-farm antibiotic usage is key to selecting the types of E. coli present on these farms. 3GC-R E. coli and 3GC-R plasmids were diverse, suggestive of long-term circulation in this region. We identified the de novo mobilization of the resistance gene blaROB from pig pathogens into E. coli on a novel mobile genetic element, which shows the importance of surveying poorly studied regions for antibiotic resistance that might impact human health.

Transcriptional regulation in model organisms: recent progress and clinical implications.

In this review, we will summarize model organisms used by scientists in the laboratory, including Escherichia coli, yeast, Arabidopsis thaliana, nematodes, Drosophila, zebrafish, mice and other animals. We focus on the progress in research exploring different types of E. coli in the human body, and the specific molecular mechanisms by which they play a role in humans. First, we discuss the specific transcriptional regulation mechanism of E. coli in cell development, maturation, ageing and longevity, as well as tumorigenesis and development. Then, we discuss how the synthesis of some important substances in cells is regulated and how this affects biological behaviour. Understanding and applying these mechanisms, presumably, can greatly improve the quality of people's lives as well as increase their lifespan. For example, some E. coli can activate certain cells by secreting insulin-like growth factor-1, thus activating the inflammatory response of the body, while other E. coli can inactivate the immune response of the body by secreting toxic factors.

Equatorial E Region Electric Fields and Sporadic E Layer Responses to the Recovery Phase of the November 2004 Geomagnetic Storm

AbstractEquatorial E region electric fields (EEFs) inferred from coherent radar data, sporadic‐E (Es) layers observed from a digital ionosonde data, and modeling results are used to study the responses of the equatorial E region over São Luís (SLZ, 2.3°S, 44.2°W, ~−7° dip angle), Brazil, during the super storm of November 2004. The EEF is presented in terms of the zonal (Ey) and vertical (Ez) components in order to analyze the corresponding characteristics of different types of Es seen in ionograms and simulated with the E region ionospheric model. We bring out the variabilities of Ey and Ez components with storm time changes in the equatorial E region. In addition, some aspects of the electric fields and Es behavior in three cases of weak, very weak, and strong Type II occurrences during the recovery phase of the geomagnetic storm are discussed. The connection between the enhanced occurrence and suppressions of the Type II irregularities and the q‐type Es (Esq) controlled by electric fields, with the development or disruption of the blanketing sporadic E (Esb) layers produced by wind shear mechanism, is also presented. The mutual presence of Esq along with the Esb occurrences is a clear indicator of the secular drift of the magnetic equator and hence that of the equatorial electrojet (EEJ) over SLZ. The results show evidence about the EEJ and Es layer electrodynamics and coupling during geomagnetic disturbance time electric fields.

Differential Gene Expression of Three Mastitis-Causing Escherichia coli Strains Grown under Planktonic, Swimming, and Swarming Culture Conditions.

Bacterial motility is thought to play an important role in virulence. We have previously shown that proficient bacterial swimming and swarming in vitro is correlated with the persistent intramammary infection phenotype observed in cattle. However, little is known about the gene regulation differences important for different motility phenotypes in Escherichia coli. In this work, three E.coli strains that cause persistent bovine mastitis infections were grown in three media that promote different types of motility (planktonic, swimming, and swarming). Using whole-transcriptome RNA sequencing, we identified a total of 935 genes (~21% of the total genome) that were differentially expressed in comparisons of the various motility-promoting conditions. We found that approximately 7% of the differentially expressed genes were associated with iron regulation. We show that motility assays using iron or iron chelators confirmed the importance of iron regulation to the observed motility phenotypes. Because of the observation that E.coli strains that cause persistent infections are more motile, we contend that better understanding of the genes that are differentially expressed due to the type of motility will yield important information about how bacteria can become established within a host. Elucidating the mechanisms that regulate bacterial motility may provide new approaches in the development of intervention strategies as well as facilitate the discovery of novel diagnostics and therapeutics. IMPORTANCE Bacteria can exhibit various types of motility. It is known that different types of motilities can be associated with virulence. In this work, we compare gene expression levels in bacteria that were grown under conditions that promoted three different types of E.coli motility. Better understanding of the mechanisms of how bacteria can cause an infection is an important first step to better diagnostics and therapeutics.

Distribution of Strain Type and Antimicrobial Susceptibility of Escherichia coli Isolates Causing Meningitis in a Large Urban Setting in Brazil

The clinical management of meningitis caused by Escherichia coli is greatly complicated when the organism becomes resistant to broad-spectrum antibiotics. We sought to characterize the antimicrobial susceptibilities, sequence types (ST), and presence of known drug resistance genes of E. coli isolates that caused meningitis between 1996 and 2011 in Salvador, Brazil. We then compared these findings to those for E. coli isolates from community-acquired urinary tract infections (UTI) that occurred during the same time period and in the same city. We found that 19% of E. coli isolates from cases of meningitis and less than 1% of isolates from UTI were resistant to third-generation cephalosporins. The sequence types of E. coli isolates from cases of meningitis included ST131, ST69, ST405, and ST62, which were also found among isolates from UTI. Additionally, among the E. coli isolates that were resistant to third-generation cephalosporins, we found genes that encode the extended-spectrum beta-lactamases CTX-M-2, CTX-M-14, and CTX-M-15. These observations demonstrate that compared to E. coli strains isolated from cases of community-acquired UTI, those isolated from cases of meningitis are more resistant to third-generation cephalosporins, even though the same sequence types are shared between the two forms of extraintestinal infections.

Low‐latitude Es capable of controlling the onset of equatorial spread F

AbstractTo investigate their role on the occurrence of equatorial spread F (ESF), the low‐latitude E region in the evening hours has been characterized in terms of sporadic E (Es) activity based on ionosonde observations from Sriharikota, a low‐latitude station in India. While prior to the sunset, either Chapman type E layer, or Es, or a combination of the two was observed, after sunset, when observed, the E layer was exclusively Es. Es, however, could be either blanketing or nonblanketing type. Observations revealed that while the occurrence of ESF had a broad relationship with the type of Es, a detailed investigation suggested that (1) ESF occurred (did not occur) irrespective of Es type if the virtual height of the F layer base (h'F) was greater than ~360 km (less than ~290 km), and (2) ESF occurrence depended strongly on the type of Es if 290 km < h'F < 360 km. Model computation shows that low‐latitude Es can significantly influence the growth of the Rayleigh‐Taylor instability for the cases corresponding to category 2 by increasing the total field‐line integrated Pedersen conductivity, consistent with the observations. The results presented in this paper highlight under what circumstances the low‐latitude Es would play a critical role in the occurrence of ESF, which can be used to understand the day‐to‐day variability of ESF.

Specific Detection of Enteroaggregative Hemorrhagic Escherichia coli O104:H4 Strains by Use of the CRISPR Locus as a Target for a Diagnostic Real-Time PCR

In 2011, a large outbreak of an unusual bacterial strain occurred in Europe. This strain was characterized as a hybrid of an enteroaggregative Escherichia coli (EAEC) and a Shiga toxin-producing E. coli (STEC) strain of the serotype O104:H4. Here, we present a single PCR targeting the clustered regularly interspaced short palindromic repeats locus of E. coli O104:H4 (CRISPR(O104:H4)) for specific detection of EAEC STEC O104:H4 strains from different geographical locations and time periods. The specificity of the CRISPR(O104:H4) PCR was investigated using 1,321 E. coli strains, including reference strains for E. coli O serogroups O1 to O186 and flagellar (H) types H1 to H56. The assay was compared for specificity using PCR assays targeting different O104 antigen-encoding genes (wbwC(O104), wzx(O104), and wzy(O104)). The PCR assays reacted with all types of E. coli O104 strains (O104:H2, O104:H4, O104:H7, and O104:H21) and with E. coli O8 and O9 strains carrying the K9 capsular antigen and were therefore not specific for detection of the EAEC STEC O104:H4 type. A single PCR developed for the CRISPR(O104:H4) target was sufficient for specific identification and detection of the 48 tested EAEC STEC O104:H4 strains. The 35 E. coli O104 strains expressing H types other than H4 as well as 8 E. coli strains carrying a K9 capsular antigen tested all negative for the CRISPR(O104:H4) locus. Only 12 (0.94%) of the 1,273 non-O104:H4 E. coli strains (serotypes Ont:H2, O43:H2, O141:H2, and O174:H2) reacted positive in the CRISPR(O104:H4) PCR (99.06% specificity).

Typical Enteroaggregative and Atypical Enteropathogenic Types of Escherichia coli Are the Most Prevalent Diarrhea-Associated Pathotypes among Brazilian Children

A 1-year prospective study was carried out in two large urban centers of São Paulo State, Brazil, to determine the prevalences and roles of the different Escherichia coli pathotypes in children less than 5 years of age with diarrhea presenting to the emergency rooms of public hospitals or visiting private pediatricians' offices. Of the pathotypes sought, typical enteroaggregative and atypical enteropathogenic types of E. coli were isolated for 8.9% and 5.4% of 774 diarrhea cases, respectively, and were found to be dominant and significantly associated with diarrhea.

Investigation on Properties of Ionospheric Es Layer in Hainan Region

利用中国科学院空间科学与应用研究中心海南电离层观测站DPS-4电离层测高仪2002年3月至2005年2月的观测数据,对太阳活动下降期间海南地区上空发生的偶发E层(Es)的逐年变化和季节变化进行了统计分析.主要结果表明,在这3年中海南地区Es事件出现次数逐年增加;Esr,Esq出现最频繁,其次是Esr,而Esc和Esf出现次数较少,出现次数最少的是Esh;Es事件在夏季出现最为频繁,秋季和冬季次之,春季最为稀少;各季节不同类型Es事件的出现率也不同,其中Esl和Esq一般在各季节占主导地位,Esr其次,Esc,Esf和Esh出现次数较少,尤其是Esf在秋季几乎没有出现.这些结果对于进一步研究Es产生的物理机制提供了探测基础,同时对于电离层空间天气预报模型的建立也具有重要的意义.

Polar cap Sporadic-E: Part 1, Observations

Sporadic E (Es) is reasonably common in the central polar cap where some of the mechanisms that produce Es at lower latitudes should become inoperative. There is some occasional auroral Es but this is readily identifiable. The other types of Es that are observed have different properties in winter and summer. The characteristic winter type is a “height-spread”, short-lived layer that tends to occur in the middle and upper E region. The common summer type is in the form of a “thin”, long-lived layer in the lower E region. Both summer and winter types are associated with positive IMF B y . We explain the initial formation of Es by gravity waves that move ionization out of the lower F region into the E region and concentrate it at reversals of vertical gravity wave motion. These concentrations are seen in winter as transient Es layers. In summer, these transient layers persist and change into long-lived thin Es layers because of metallic ions that are maintained in an ionized state by charge exchange of neutral metal atoms with the ambient E region NO + and O 2 + ions produced by photo-ionization.

Growth phase-coupled changes of the ribosome profile in natural isolates and laboratory strains of Escherichia coli.

The growth phase-dependent change in sucrose density gradient centrifugation patterns of ribosomes was analyzed for both laboratory strains of Escherichia coli and natural isolates from the ECOR collection. All of the natural isolates examined formed 100S ribosome dimers in the stationary phase, and ribosome modulation factor (RMF) was associated with the ribosome dimers in the ECOR strains as in the laboratory strain W3110. The ribosome profile (70S monomers versus 100S dimers) follows a defined pattern over time during lengthy culture in both the laboratory strains and natural isolates. There are four discrete stages: (i) formation of 100S dimers in the early stationary phase; (ii) transient decrease in the dimer level; (iii) return of dimers to the maximum level; and (iv) dissociation of 100S dimers into 70S ribosomes, which are quickly degraded into subassemblies. The total time for this cycle of ribosome profile change, however, varied from strain to strain, resulting in apparent differences in the ribosome profiles when observed at a fixed time point. A correlation was noted in all strains between the decay of 100S ribosomes and the subsequent loss of cell viability. Two types of E. coli mutants defective in ribosome dimerization were identified, both of which were unable to survive for a prolonged period in stationary phase. The W3110 mutant, with a disrupted rmf gene, has a defect in ribosome dimerization because of lack of RMF, while strain Q13 is unable to form ribosome dimers due to a ribosomal defect in binding RMF.

A localized adherence-like pattern as a second pattern of adherence of classic enteropathogenic Escherichia coli to HEp-2 cells that is associated with infantile diarrhea.

Escherichia coli strains that cause nonbloody diarrhea in infants are known to present three distinct patterns of adherence to epithelial cells, namely, localized (LA), diffuse (DA), and aggregative (AA) adherence. Strains with LA (typical Enteropathogenic Escherichia coli [EPEC]) are well recognized as a cause of secretory diarrhea, but the role of strains with DA (DAEC) is controversial, and strains with AA (EAEC) have been more frequently related to persistent diarrhea whereas its relationship with acute diarrhea is not well defined. To determine the relationship of the different types of E. coli adherence patterns with acute diarrhea (lasting less than 14 days) and persistent diarrhea (lasting more than 14 days) in São Paulo, Brazil, we studied stool specimens from 40 infants under 1 year of age with diarrhea and 40 age-matched control infants without any gastrointestinal symptoms. Twenty-eight (35.0%) of eighty cases yielded adherent E. coli (HEp-2 cells). Strains with localized and aggregative adherence were associated with acute and persistent diarrhea. A total of 11.2% of the adherent strains were typical EPEC serotypes and hybridized with the enteroadherence factor probe; 5.0% were EAEC and hybridized with the EAEC probe. DAEC strains were isolated from 10.0% of patients and 7.5% of controls and did not hybridize with the two probes used (daaC and AIDA-I). Strains with a localized adherence-like pattern (atypical EPEC) were found significantly more frequently (P = 0.028) in cultures from children with diarrhea (17.5%) than in controls (2.5%).

Sequential sporadic-E layers at low latitudes in the Indian sector

Abstract. A study of the formation and movement of sequential Sporadic-E layers observed during the night-time hours at two Indian low-latitude stations, SHAR (dip 10°N) and Waltair (dip 20°N) shows that the layer are formed around 19:00 h. IST at altitudes of ~180 km. They descend to the normal E-region altitude of about 100 km in three to four hours and becomes blanketing type of Es before they disappear. However, the absence of these descending layers at an equatorial station, Trivandrum (dip 2°N) gives the experimental evidence for wind shear theory. The meridional neutral wind derived from the height variation of the F-layer showed significant poleward wind during the descent of these layers. Hence it is inferred that these layers are formed as a consequence of the convergence of plasma by the poleward wind and the equatorward propagating gravity waves (inferred from the height fluctuations of F-layer).Key words. Ionosphere (active experiments; equatorial ionosphere · ionospheric irregularities)

Sequential sporadic-E layers at low latitudes in the Indian sector

A study of the formation and movement of sequential Sporadic-E layers observed during the night-time hours at two Indian low-latitude stations, SHAR (dip 10°N) and Waltair (dip 20°N) shows that the layer are formed around 19:00 h. IST at altitudes of ~180 km. They descend to the normal E-region altitude of about 100 km in three to four hours and becomes blanketing type of Es before they disappear. However, the absence of these descending layers at an equatorial station, Trivandrum (dip 2°N) gives the experimental evidence for wind shear theory. The meridional neutral wind derived from the height variation of the F-layer showed significant poleward wind during the descent of these layers. Hence it is inferred that these layers are formed as a consequence of the convergence of plasma by the poleward wind and the equatorward propagating gravity waves (inferred from the height fluctuations of F-layer).Key words. Ionosphere (active experiments; equatorial ionosphere · ionospheric irregularities)

Ternary surface complexes by theE(%)-pH curve method

A new method for the study of ternary surface complexes at liquid-solid interface, theE(%) -pH curve method, was proposed. Four types ofE(%)-pH curves, namely, phenomenon of left-right shifts of S-shaped curve, V-shaped curve, monodirection shift curve and X-shaped curve, were discovered. Correspondingly, apart from type (I) ternary surface complex Open image in new window and type (II) ternary surface complex Open image in new window , a new type of ternary surface complex Open image in new window was discovered.

Distribution and abundance of giant sea anemones (Actiniaria) in subtropical eastern Australian waters

Five of the 10 known Indo-Pacific giant anemone species were recorded on subtidal reefs within the eastern Australian subtropics (26°37′S to 30°56′S) during surveys between 1993 and 1995. Giant anemones had a patchy distribution among the 30 localities sampled, and species richness did not display any latitudinal trends within this province. Spatial distribution patterns and abundance of anemones were assessed from total counts and from line-intercept and belt transects. Anemone abundance was significantly higher on reefs to the leeward of the prevailing swell than on more exposed sites, at Julian Rocks and North Solitary Island, northern NSW. Significant reductions in anemone cover were detected among years within shallow reefal sites at North Solitary Island, coinciding with two major storm events. The abundance of the widespread Entacmaea quadricolor at North Solitary Island was the highest reported worldwide. Significant differences were detected between two morphological types of E. quadricolor in terms of microhabitat type, oral disk size and spatial distribution patterns. Important factors influencing the distribution, abundance and spatial patterns of giant anemones over both large and localized spatial scales appear to be water temperature, wave disturbance and water depth.

Studies of Ternary Surface Complexes at Liquid–Solid Interfaces in Sea Water by theE(%)–pH Curve Method

A new method to study ternary surface complexes at liquid–solid interfaces, theE(%)–pH curve method, is proposed. Three types ofE(%)–pH curves, namely left–right shifts of S-shaped curves, V-shaped curves, and monodirectionally shifted curves, are postulated. Correspondingly, in addition to the Type I ternary surface complex [ii/home29/ap/collid/6g11/4244abss1.lay,l(4,0)] and the Type II ternary surface complex [ii/home29/ap/collid/6g11/4244abss2.lay,l(4,0)] a new type of ternary surface complex, [ii/home29/ap/collid/6g11/4244abss3.lay,l(4,0)] is proposed.

Long term trends in sporadic E layers and electric fields over Fortaleza, Brazil

Long term trends in the sporadic E‐layer occurrences and associated electric fields over the equatorial station, Fortaleza are analysed using 16 years (1975–1990) of ionosonde data. The secular drift of the magnetic equator and hence that of the equatorial electrojet current (EEJ) to northward of Fortaleza has resulted in marked long term changes in the occurrence characteristics of the different types of Es layers: the q‐type (arising from electrojet instability processes) and the 1, f, c and h types (resulting from wind/wind shear mechanisms). Systematic decrease in the occurrence rates of the q‐type Es, accompanied with increases in the remaining types of Es, was registered from 1975 to 1990, during which period the magnetic equator drifted to north of Fortaleza by ∼400km. The long term trend manifests competing roles of the equatorial electric field and wind systems, in the generation of the different types of Es layers as a function of the distance from the electrojet center. The F‐layer dynamo electric field is seen to exercise strong control of Es layer formation near sunset. Solar cycle variations, represented by the Fl0.7cm flux, seems to be present in elctrojet intensity and the lower thermospheric wind system.

Incidence and enterotoxigenicity of enterotoxigenic (Escherichia coli) from uncooked meat sausages

The incidence of enteropathogenicEscherichia coli was higher (33 to 50%) in uncooked chicken sausages than in pork sausages (10 to 43%). The toxigenic isolates in general were of O5 and O89 sero types ofE. coli. The amount of toxin produced varied in raw and boiled sausages as tested by ileal loop and rabbit skin permeability tests. The toxin production was invariably higher at 28°C or 37°C in raw and boiled sausages than at 45°C.

Aspects of colibacillosis in farm animals.

It has been known for a considerable time thatEscherichia coli, although a normal inhabitant of the intestinal tract, can also be associated with a variety of pathological conditions in man, farm animals and poultry.When Escherich (1885) isolated from the faeces of a newborn baby an organism which is now accepted asE. coli, he considered it to be a harmless saprophyte. Laruelle (1889) was the first to suggest the possible pathogenicity of this organism, while Jensen (1893) showed that it was the cause of white scour in calves. The development of reliable serological methods facilitated the differentiation of strains and numerous workers have demonstrated an association between certain serological types ofE. coliand various disease conditions in animals. Enteric diseases in young animals are an important cause of mortality and economic loss to the farming community.