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A retrospective study was conducted at two medical centers in Taiwan to evaluate the clinical characteristics, outcomes, and risk factors for mortality among patients treated with a carbapenem for bacteremia caused by extended-spectrum-beta-lactamase (ESBL)-producing organisms. A total of 251 patients with bacteremia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates treated by a carbapenem were identified. Among these ESBL-producing isolates, rates of susceptibility to ertapenem (MICs ≤ 0.25 μg/ml) were 83.8% and 76.4%, respectively; those to meropenem were 100% and 99.3%, respectively; and those to imipenem were 100% and 97.9%, respectively. There were no significant differences in the critical illness rate (P = 0.1) or sepsis-related mortality rate (P = 0.2) for patients with bacteremia caused by ESBL-producing K. pneumoniae (140 isolates, 55.8%) and E. coli (111 isolates, 44.2%). Multivariate analysis of variables related to sepsis-related mortality revealed that the presence of severe sepsis (odds ratio [OR], 15.9; 95% confidence interval [CI], 5.84 to 43.34; P < 0.001), hospital-onset bacteremia (OR, 4.65; 95% CI, 1.42 to 15.24; P = 0.01), and ertapenem-nonsusceptible isolates (OR, 5.12; 95% CI, 2.04 to 12.88; P = 0.001) were independent risk factors. The patients receiving inappropriate therapy had a higher sepsis-related mortality than those with appropriate therapy (P = 0.002), irrespective of ertapenem, imipenem, or meropenem therapy. Infections due to the ertapenem-susceptible isolates (MICs ≤ 0.25 μg/ml) were associated with a more favorable outcome than those due to ertapenem-nonsusceptible isolates (MICs > 0.25 μg/ml), if treated by a carbapenem. However, the mortality for patients with bacteremic episodes due to isolates with MICs of ≤ 0.5 μg/ml was similar to the mortality for those whose isolates had MICs of >0.5 μg/ml (P = 0.8). Such a finding supports the rationale of the current CLSI 2011 criteria for carbapenems for Enterobacteriaceae.

Background: The purpose of this study is to delineate clinical characteristics of urosepsis caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK) in different clinical settings, with an emphasis on community-acquired infections., Methods: A retrospective study was conducted at two medical centers in Taiwan. From May 2002 to August 2007, clinical data of adults with urosepsis caused by ESBL-EK were collected. Patients were categorized into three groups according to the place of acquisition. Baseline characteristics, microbiological data and clinical outcomes were compared., Results: Ninety-three cases of ESBL-EK urosepsis were included. Their mean age was 69.4 years, and 48.4% were men. Eleven (11.8%), 41 (44.1%), and 41 (44.1%) patients were categorized as having community-acquired, healthcare-associated, and hospital-acquired infections, respectively. Cases of ESBL-EK urosepsis from different settings shared similar characteristics in terms of age, gender, comorbidity and resistance profiles of bacterial strains. Of the bacterial isolates, 75% and 38.7% were resistant to fluoroquinolones and aminoglycosides, respectively. Cases of community-acquired urosepsis had a lower disease severity than those acquired in healthcare facilities or hospitals. Of note, there was no case fatality in 11 cases of community-acquired urosepsis and, in contrast, a crude mortality rate of 41.5% was found among adults with hospital-acquired urosepsis (p < 0.001)., Conclusion: A limited number of adults with community-acquired urosepsis caused by ESBL-EK in the present study had a favorable outcome. Nonetheless, clinicians should be cautious of the emergence of urinary tract infections caused by ESBL-producers in the community setting., (Copyright © 2011. Published by Elsevier B.V.)

Background: Clinical information about bacteremia due to extended-spectrum β-lactamase (ESBL)-producing pathogens in cancer patients was limited. The study was aimed to identify the clinical manifestations and risk factors for mortality in ESBL-producer bacteremia in cancer patients., Methods: A retrospective study of bacteremia caused by ESBL-producing Escherichia coli or Klebsiella pneumoniae in adults with cancer in National Cheng Kung University Hospital and National Taiwan University Hospital from July 2002 to August 2007 was conducted. Clinical characteristics, initial manifestations, and antimicrobial therapy were analyzed for their association with crude mortality at 14 days after bacteremia onset., Results: A total 113 episodes of bacteremia caused by E coli (59.3%), K pneumoniae (39.8%) or both (0.9%) were included. Patients with hematological malignancy were younger (55 ± 22 vs. 69 ± 14 years, p < 0.003) and had less co-morbidity, but were more likely to have neutropenia (73.1% vs. 4.6%, p < 0.001) than those with solid tumor. By the univariate analysis in 113 episodes of ESBL-producer bacteremia, several risk factors, including pneumonia or soft-tissue infection as the bacteremia source, initial manifestations with high Pitt bacteremia scores, shock, respiratory failure or severe sepsis, and inappropriate definitive therapy were associated with 14-day crude mortality. By multivariate analysis, only pneumonia [adjusted odds ratio (AOR), 5.2; 95% confident interval (CI), 1.3-21.0; p = 0.021], severe sepsis (AOR, 24.3; 95% CI, 5.6-105.0; p < 0.001), and inappropriate definitive therapy (AOR, 11.3; 95% CI, 1.7-72.8; p = 0.011) were independently associated with a fatal outcome., Conclusion: The presence of neutropenia or underlying hematological malignancy in cancer patients with ESBL-producer bacteremia was not associated with an increase in the mortality rate. Appropriate definitive antimicrobial therapy will be beneficial in improving clinical outcome., (Copyright © 2011. Published by Elsevier B.V.)

For 244 patients with bacteremia due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli or Klebsiella pneumoniae treated by ertapenem (73, 29.9%) or either imipenem or meropenem (171, 70.1%), the therapeutic efficacy was evaluated. Ertapenem therapy was effective for patients with ESBL-producing E. coli or K. pneumoniae bacteremia in terms of mortality and microbiological responses, as compared with imipenem or meropenem., (Copyright © 2011 Elsevier Inc. All rights reserved.)

We report the mixotrophic growth of Escherichia coli based on recombinant 2-oxoglutarate:ferredoxin oxidoreductase (OGOR) to assimilate CO2 using malate as an auxiliary carbon source and hydrogen as an energy source. We employ a long-term (~184 days) two-stage adaptive evolution to convert heterotrophic E. coli into mixotrophic E. coli. In the first stage of evolution with serine, diauxic growth emerges as a prominent feature. At the end of the second stage of evolution with malate, the strain exhibits mixotrophy with CO2 as an essential substrate for growth. We expect this work will open new possibilities in the utilization of OGOR for microbial CO2 assimilation and future hydrogen-based electro-microbial conversion. [ABSTRACT FROM AUTHOR]