SciCombinator

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Concept: Escherichia

144

We aimed to investigate the prevalence of extended-spectrum β-lactamases (ESBL)-producing Escherichia coli (E. coli) in Beijing Tongren hospital and find the relationship between colonization and infection. The clinical data of 650 inpatients included between March 2012 and July 2012 were retrospectively reviewed. The prevalence of ESBL-producing E. coli among inpatients was 25.7% (167/650), with the highest of 50.0% in rheumatology ward and lowest of 10.0% in intensive care unit. Hospital stay more than 2 years, usage of antibiotics less than 3 months, and use of glucocorticoids or immunosuppressive were found to be significantly associated with ESBL carriage (P < 0.05). Totally, 76 sequence types (ST) were revealed by MLST. ST38 (n = 12, 7.2%) was the most common type, followed by ST10 (n = 10, 6.0%), ST131 and ST167 (n = 9, 5.4%). Among the faecal carriers, only one patient suffered infection, which was resulted by a ST38 strain. In conclusion, in Beijing Tongren hospital, the prevalence of ESBL-producing E. coli was not high. The risk factors for ESBL carriage were hospitalization and usage of antibiotics, glucocorticoids and immunosuppressive. ST38, ST10, ST131 and ST167 were the prominent genotypes, but almost 50.0% ST were dispersedly distributed.

Concepts: Bacteria, Hospital, Antibiotic resistance, Escherichia coli, Enterobacteriaceae, Escherichia, Proteobacteria, Beta-lactamase

55

The volumetric heating values of today’s biofuels are too low to power energy-intensive aircraft, rockets, and missiles. Recently, pinene dimers were shown to have a volumetric heating value similar to that of the tactical fuel JP-10. To provide a sustainable source of pinene, we engineered Escherichia coli for pinene production. We combinatorially expressed three pinene synthases (PS) and three geranyl diphosphate synthases (GPPS), with the best combination achieving ∼28 mg/L of pinene. We speculated that pinene toxicity was limiting production; however, toxicity should not be limiting at current titers. Because GPPS is inhibited by geranyl diphosphate (GPP) and to increase flux through the pathway, we combinatorially constructed GPPS-PS protein fusions. The Abies grandis GPPS-PS fusion produced 32 mg/L of pinene, a 6-fold improvement over the highest titer previously reported in engineered E. coli. Finally, we investigated the pinene isomer ratio of our pinene-producing microbe and discovered that the isomer profile is determined not only by the identity of the PS used but also by the identity of the GPPS with which the PS is paired. We demonstrated that the GPP concentration available to PS for cyclization alters the pinene isomer ratio.

Concepts: Protein, Bacteria, Antibiotic resistance, Escherichia coli, Biotechnology, Enterobacteriaceae, Escherichia, Proteobacteria

51

For 2013-2014, we prospectively identified US adults with flank pain, temperature >38.0°C, and a diagnosis of acute pyelonephritis, confirmed by culture. Cultures from 453 (86.9%) of 521 patients grew Escherichia coli. Among E. coli isolates from 272 patients with uncomplicated pyelonephritis and 181 with complicated pyelonephritis, prevalence of fluoroquinolone resistance across study sites was 6.3% (range by site 0.0%-23.1%) and 19.9% (0.0%-50.0%), respectively; prevalence of extended-spectrum β-lactamase (ESBL) production was 2.6% (0.0%-8.3%) and 12.2% (0.0%-17.2%), respectively. Ten (34.5%) of 29 patients with ESBL infection reported no exposure to antimicrobial drugs, healthcare, or travel. Of the 29 patients with ESBL infection and 53 with fluoroquinolone-resistant infection, 22 (75.9%) and 24 (45.3%), respectively, were initially treated with in vitro inactive antimicrobial drugs. Prevalence of fluoroquinolone resistance exceeds treatment guideline thresholds for alternative antimicrobial drug strategies, and community-acquired ESBL-producing E. coli infection has emerged in some US communities.

Concepts: Urinary tract infection, Antibiotic resistance, Escherichia coli, Enterobacteriaceae, Escherichia, Proteobacteria, Beta-lactamase, Pyelonephritis

48

The literature on hand washing, while extensive, often contains conflicting data, and key variables are only superficially studied or not studied at all. Some hand washing recommendations are made without scientific support, and agreement between recommendations is limited. The influence of key variables such as soap volume, lather time, water temperature, and product formulation on hand washing efficacy was investigated in the present study. Baseline conditions were 1 mL of a bland (nonantimicrobial) soap, a 5-s lather time, and 38°C (100°F) water temperature. A nonpathogenic strain of Escherichia coli (ATCC 11229) was the challenge microorganism. Twenty volunteers (10 men and 10 women) participated in the study, and each test condition had 20 replicates. An antimicrobial soap formulation (1% chloroxylenol) was not significantly more effective than the bland soap for removing E. coli under a variety of test conditions. Overall, the mean reduction was 1.94 log CFU (range, 1.83 to 2.10 log CFU) with the antimicrobial soap and 2.22 log CFU (range, 1.91 to 2.54 log CFU) with the bland soap. Overall, lather time significantly influenced efficacy in one scenario, in which a 0.5-log greater reduction was observed after 20 s with bland soap compared with the baseline wash (P = 0.020). Water temperature as high as 38°C (100°F) and as low as 15°C (60°F) did not have a significant effect on the reduction of bacteria during hand washing; however, the energy usage differed between these temperatures. No significant differences were observed in mean log reductions experienced by men and women (both 2.08 log CFU; P = 0.988). A large part of the variability in the data was associated with the behaviors of the volunteers. Understanding what behaviors and human factors most influence hand washing may help researchers find techniques to optimize the effectiveness of hand washing.

Concepts: Bacteria, Effectiveness, Escherichia coli, Thermodynamics, Enterobacteriaceae, Escherichia coli O157:H7, Escherichia, Proteobacteria

42

Among 390 Escherichia coli and Klebsiella pneumoniae clinical isolates collected during 2014-2015 displaying colistin MIC values ≥4 μg/ml, 19 (4.9%) carried mcr-1 These isolates were all E. coli collected in ten countries, including the United States. Most isolates were susceptible to cephalosporins and were all susceptible to carbapenems, amikacin, tigecyline and ceftazidime-avibactam among other agents. Data from this global surveillance program expand the knowledge on the occurrence of mcr-1-carrying isolates.

Concepts: United States, Escherichia coli, Enterobacteriaceae, Escherichia, Proteobacteria, Beta-lactamase, Enterobacteria, Cephalosporin

28

A retrospective study was conducted at a Taiwanese medical center to characterize bloodstream infections caused by IMP-8 metallo-β-lactamase (MBL)-producing Enterobacteriaceae isolates and to assess the need for laboratory detection of IMP producers. We analyzed 37 patients infected with IMP-8 producers (two Escherichia coli, nine Klebsiella pneumoniae, 25 Enterobacter cloacae, and one Citrobacter freundii) and 107 patients infected with non-IMP-8 producers (eight E. coli, 26 K. pneumoniae, 70 E. cloacae, and three C. freundii) that were interpreted as carbapenem-nonsusceptible based on the updated Clinical and Laboratory Standards Institute (CLSI) 2010 guidelines. Only 18 (48.6 %) of the IMP-8 producers were regarded as potential carbapenemase producers based on the CLSI 2012 guidelines. The production of extended-spectrum β-lactamases (ESBLs) was more common in the MBL group (73.0 %) than in the non-MBL group (41.1 %). There were no significant differences in carbapenem susceptibilities, clinical characteristics, carbapenem use for empirical and definitive treatment, and mortality rates between the two groups. Eighteen IMP-8 producers could be deemed as resistant to all carbapenems [minimum inhibitory concentration (MIC) of any carbapenem ≥2 μg/mL]; patients with these isolates had a lower, but non-significant, 28-day mortality rate (27.8 %) than patients infected with non-MBL producers having similar carbapenem MICs (39.0 %) (p = 0.41). A multivariate analysis revealed severity of acute illness as the single independent variable associated with both 7-day and 28-day mortality rates (p < 0.01) for infections caused by Enterobacteriaceae with decreased carbapenem susceptibilities. Our findings suggest that the clinical detection of IMP-producing Enterobacteriaceae is not required even when the "old" CLSI criteria are used.

Concepts: Escherichia coli, Phage therapy, Enterobacteriaceae, Escherichia, Gram negative bacteria, Enterobacteria, Klebsiella pneumoniae, Klebsiella

27

Shigella species are so closely related to Escherichia coli that routine matrix-assisted laser desorption/ionization - time of flight mass spectrometry (MALDI-TOF MS) cannot reliably differentiate them. Biochemical and serological methods are typically used to distinguish these species; however “inactive” isolates of E. coli are biochemically very similar to Shigella species and thus pose a greater diagnostic challenge. We used ClinProTools (Bruker Daltonics) software to discover MALDI-TOF MS biomarker peaks and generate classification models based on the genetic algorithm to differentiate between Shigella species and E. coli. Sixty-six Shigella spp. and 72 E. coli were used to generate and test classification models, and the optimal models contained 15 biomarker peaks for genus-level classification and 12 peaks for species-level classification. We were able to identify 90% of E. coli and Shigella clinical isolates correctly to species. Only 3% of tested isolates were misidentified. This novel MALDI-TOF MS approach allows laboratories to streamline the identification of E. coli and Shigella species.

Concepts: Mass spectrometry, Escherichia coli, Enterobacteriaceae, Escherichia, Proteobacteria, Matrix-assisted laser desorption/ionization, Shigella, Bruker

26

The presence of the highly toxic furfural and hydroxymethylfurfural (HMF) in the hydrolysate of lignocellulosic biomass prompted the investigation of the E. coli ΔacrR regulatory mutant for higher tolerance to these compounds, to facilitate the production of biofuels, biochemicals and furthur biocatalytic conversions. In comparison with the parental strain, the regulatory mutant with the upregulated efflux pump AcrAB-TolC produced moderately better growth and higher tolerance to concentrations of furfural and HMF between 1 to 2 g l(-1) This article is protected by copyright. All rights reserved.

Concepts: Antibiotic resistance, Escherichia coli, Enterobacteriaceae, Escherichia, Proteobacteria, All rights reserved, Copyright, Hydroxymethylfurfural

26

A microfluidic chip is developed to selectively isolate magnetically tagged cells from heterogeneous suspensions, the track-etched magnetic micropore (TEMPO) filter. The TEMPO consists of an ion track-etched polycarbonate membrane coated with soft magnetic film (Ni20 Fe80 ). In the presence of an applied field, provided by a small external magnet, the filter becomes magnetized and strong magnetic traps are created along the edges of the micro-pores. In contrast to conventional microfluidics, fluid flows vertically through the porous membrane allowing large flow rates while keeping the capture rate high and the chip compact. By utilizing track-etching instead of conventional semiconductor fabrication, TEMPOs can be fabricated with microscale pores over large areas A > 1 cm(2) at little cost (< 5 C| cm(-) (2) ). To demonstrate the utility of this platform, a TEMPO with 5 μm pore size is used to selectively and rapidly isolate immunomagnetically targeted Escherichia coli from heterogeneous suspensions, demonstrating enrichment of ζ > 500 at a flow rate of Φ = 5 mL h(-1) . Furthermore, the large density of micropores (ρ = 10(6) cm(-2) ) allows the TEMPO to sort E. coli from unprocessed environmental and clinical samples, as the blockage of a few pores does not significantly change the behavior of the device.

Concepts: Fluid dynamics, Magnet, Escherichia coli, Magnetism, Enterobacteriaceae, Escherichia, Microfluidics, Lab-on-a-chip

24

The emergence and worldwide spread of carbapenemase-producing Enterobacteriaceae is of great concern to public health. The aim of this study was to investigate the occurrence of carbapenemase-producing Escherichia coli in companion animals in Algeria. Two hundred fecal samples were obtained from healthy and diseased dogs and cats in one veterinary office and private owners in Bejaia city, Algeria, during November 2014 to March 2015. Isolates were screened by polymerase chain reaction for the presence of carbapenemase, acquired plasmidic AmpC (pAmpC) and extended-spectrum beta-lactamase genes. Five carbapenemase-producing E. coli isolates were detected including four OXA-48-producing isolates and one isolate producing NDM-5. Coexpression of ESBL and pAmpC genes was observed in these isolates. Phylogenetic grouping revealed that these isolates belonged to A and D phylogroups. The results of this study show that carbapenemase-producing E. coli spread to the companion animals in Algeria.

Concepts: DNA, Gut flora, Polymerase chain reaction, Molecular biology, Escherichia coli, Enterobacteriaceae, Escherichia, Beta-lactamase