Comparative antimicrobial susceptibility of aerobic and facultative bacteria from community-acquired bacteremia to ertapenem in Taiwan

<p>Abstract</p> <p>Background</p> <p>Ertapenem is a once-a-day carbapenem and has excellent activity against many gram-positive and gram-negative aerobic, facultative, and anaerobic bacteria. The susceptibility of isolates of community-acquired bacteremia to ertapenem has not been reported yet. The present study assesses the in vitro activity of ertapenem against aerobic and facultative bacterial pathogens isolated from patients with community-acquired bacteremia by determining and comparing the MICs of cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin. The prevalence of extended broad spectrum β-lactamases (ESBL) producing strains of community-acquired bacteremia and their susceptibility to these antibiotics are investigated.</p> <p>Methods</p> <p>Aerobic and facultative bacteria isolated from blood obtained from hospitalized patients with community-acquired bacteremia within 48 hours of admission between August 1, 2004 and September 30, 2004 in Chang Gung Memorial Hospital at Keelung, Taiwan, were identified using standard procedures. Antimicrobial susceptibility was evaluated by Etest according to the standard guidelines provided by the manufacturer and document M100-S16 Performance Standards of the Clinical Laboratory of Standard Institute. Antimicrobial agents including cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin were used against the bacterial isolates to test their MICs as determined by Etest. For <it>Staphylococcus aureus </it>isolates, MICs of oxacillin were also tested by Etest to differentiate oxacillin-sensitive and oxacillin-resistant <it>S. aureus</it>.</p> <p>Results</p> <p>Ertapenem was highly active in vitro against many aerobic and facultative bacterial pathogens commonly recovered from patients with community-acquired bacteremia (128/159, 80.5 %). Ertapenem had more potent activity than ceftriaxone, piperacillin-tazobactam, or ciprofloxacin against oxacillin-susceptible <it>S</it>. <it>aureus </it>(17/17, 100%)and was more active than any of these agents against <it>enterobacteriaceae </it>(82/82, 100%).</p> <p>Conclusion</p> <p>Based on the microbiology pattern of community-acquired bacteremia, initial empiric treatment that requires coverage of a broad spectrum of both gram-negative and gram-positive aerobic bacteria, such as ertapenem, may be justified in moderately severe cases of community-acquired bacteremia in non-immunocompromised hosts.</p

Evidence for Circadian Regulation of Starch and Sucrose Synthesis in Sugar Beet Leaves

Starch accumulation and sucrose synthesis and export were measured in leaves of sugar beet (Beta vulgaris L.) during a period of prolonged irradiance in which illumination was extended beyond the usual 14-hour day period. During much of the 14-hour day period, approximately 50% of the newly fixed carbon was distributed to sucrose, about 40% to starch, and less than 10% to hexose. Beginning about 2 hours before the end of the usual light period, the portion of newly fixed carbon allocated to sucrose gradually increased, and correspondingly less carbon went to starch. By the time the transition ended, about 4 hours into the extension of the light period, nearly 90% of newly fixed carbon was incorporated into sucrose and little or none into starch. Most of the additional sucrose was exported. Gradual cessation of starch accumulation was not the result of a futile cycle of simultaneous starch synthesis and degradation. Neither was it the result of a Dec.rease in the extractable activity of adenosine diphosphoglucose pyrophosphorylase or phosphoglucose isomerase, enzymes important in starch synthesis. Nor was there a notable change in control metabolites considered to be important in regulating starch synthesis. Starch accumulation appeared to Dec.rease markedly because of an endogenous circadian shift in carbon allocation, which occurred in preparation for the usual night period and which diverted carbon from the chloroplast to the cytosol and sucrose synthesis

Fast signature computation algorithm for LFSR and MISR

A multiple-input signature register (MISR) computation algorithm for fast signature simulation is proposed. Based on the table look-up linear compaction algorithm and the modularity property of a single-input signature register (SISR), some new accelerating schemes - partial-input look-up tables and flying-state look-up tables - are developed to boost the signature computation speed. Mathematical analysis and simulation results show that this algorithm has an order of magnitude speedup without extra memory requirement compared with the original linear compaction algorithm. Though this algorithm is derived for SISR, a simple conversion scheme exists that can convert internal-EXOR MISR to SISR. Consequently, fast MISR signature computation can be done.link_to_subscribed_fulltex

MISR computation algorithm for fast signature simulation

A fast multiple input signature register (MISR) computation algorithm for signature simulation is proposed. Based on the linear compaction algorithm the modularity property of a single input signature register (SISR), and the sparsity of the error-domain input, some new accelerating schemes - partial input look-up tables and reverse zero-checking policy - are developed to boost the signature computation speed. Mathematical analysis and simulation results show that this algorithm has an order of magnitude speedup without extra memory requirement compared with the linear compaction algorithm. Though originally derived for SISR, this algorithm is applicable to MISR by a simple conversion procedure or a bit-adjusting scheme with little effort. Consequently, a very fast MISR signature simulation can be achieved.link_to_subscribed_fulltex

Efficient multifrequency analysis of fault diagnosis in analog circuits based on large change sensitivity computation

A fast multiple input signature register (MISR) computation algorithm for signature simulation is proposed. Based on the linear compaction algorithm the modularity property of a single input signature register (SISR), and the sparsity of the error-domain input, some new accelerating schemes - partial input look-up tables and reverse zero-checking policy - are developed to boost the signature computation speed. Mathematical analysis and simulation results show that this algorithm has an order of magnitude speedup without extra memory requirement compared with the linear compaction algorithm. Though originally derived for SISR, this algorithm is applicable to MISR by a simple conversion procedure or a bit-adjusting scheme with little effort. Consequently, a very fast MISR signature simulation can be achieved.link_to_subscribed_fulltex

Opportunities for Nanomedicine in Clostridioides difficile Infection

Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI

CXCL1 Regulation in Human Pulmonary Epithelial Cells by Tumor Necrosis Factor

Background/Aims: The chemokine CXCL1 has been reported to be expressed in lung airway epithelium and non-small cell lung cancer biopsy specimens. In this study, we investigated the effects of TNF-α, an abundant cytokine detected in inflammation and various cancers, on CXCL1 release by human A549 lung carcinoma epithelial cells. Methods: CXCL1 expression was determined by ELISA and RT-PCR. TNF-α signaling was examined by western blotting. Monocyte migration was assayed by a Transwell migration system. Results: TNF-α stimulated CXCL1 release and mRNA expression, and this release was inhibited by inhibitors of JNK, p38 MAPK, PI-3K/Akt and AP-1 transcription factor. TNF-α treatment was followed by JNK, p38 MAPK and PI3K/Akt activation. However, only the JNK inhibitor could reduce the CXCL1 mRNA level, suggesting that JNK is required mainly for CXCL1 mRNA synthesis, whereas p38 MAPK and PI-3K/Akt might be responsible for CXCL1 secretion. Dexamethasone (dex) and TGF-β reduced CXCL1 secretion, with dex upregulating the expression of MAP kinase phosphatase-1 and TGF-β causing smad2/3 activation and nuclear translocation. A functional analysis showed that the released CXCL1 enhanced monocyte migration and could be abolished by a CXCL1 neutralizing antibody and CXCR antagonist. Conclusion: We demonstrate that TNF-α induces CXCL1 expression through the JNK, p38 MAPK and PI-3K/Akt signaling pathways in human pulmonary epithelial cells