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  • 1
    Online Resource
    Online Resource
    cyAbrB Transcriptional Regulators as Safety Devices To Inhibit Heterocyst Differentiation in Anabaena sp. Strain PCC 7120
    American Society for Microbiology ; 2019
    In:  Journal of Bacteriology Vol. 201, No. 17 ( 2019-09)
    Details
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 201, No. 17 ( 2019-09)
    Abstract: Cyanobacteria are monophyletic organisms that perform oxygenic photosynthesis. While they exhibit great diversity, they have a common set of genes. However, the essentiality of them for viability has hampered the elucidation of their functions. One example of these genes is cyabrB1 (also known as calA in Anabaena sp. strain PCC 7120), encoding a transcriptional regulator. In the present study, we investigated the function of calA/cyabrB1 in the heterocyst-forming cyanobacterium Anabaena sp. PCC 7120 through CRISPR interference, a method that we recently utilized for the photosynthetic production of a useful chemical in this strain. Conditional knockdown of calA/cyabrB1 in the presence of nitrate resulted in the formation of heterocysts. Two genes, hetP and hepA , which are required for heterocyst formation, were upregulated by calA/cyabrB1 knockdown in the presence of combined nitrogen sources. These genes are known to be induced by HetR, a master regulator of heterocyst formation. hetR was not induced by calA/cyabrB1 knockdown. hetP and hepA were repressed by direct binding of CalA/cyAbrB1 to their promoter regions in a HetR-independent manner. In addition, the overexpression of calA/cyabrB1 abolished heterocyst formation upon nitrogen depletion. Also, knockout of calB / cyabrB2 (a paralogue gene of calA/cyabrB1 ), in addition to knockdown of calA/cyabrB1 , enhanced heterocyst formation in the presence of nitrate, suggesting functional redundancy of cyAbrB proteins. We propose that a balance between amounts of HetR and CalA/cyAbrB1 is a key factor influencing heterocyst differentiation during nitrogen stepdown. We concluded that cyAbrB proteins are essential safety devices that inhibit heterocyst differentiation. IMPORTANCE Spore formation in Bacillus subtilis and Streptomyces has been extensively studied as models of prokaryotic nonterminal cell differentiation. In these organisms, many cells/hyphae differentiate simultaneously, which is governed by a network in which one regulator stands at the top. Differentiation of heterocysts in Anabaena sp. strain PCC 7120 is unique because it is terminal, and only 5 to 10% of vegetative cells differentiate into heterocysts. In this study, we identified CalA/cyAbrB1 as a repressor of two genes that are essential for heterocyst formation independently of HetR, a master activator for heterocyst differentiation. This finding is reasonable for unique cell differentiation of Anabaena because CalA/cyAbrB1 could suppress heterocyst differentiation tightly in vegetative cells, while only cells in which HetR is overexpressed could differentiate into heterocysts.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    URL: Article
    DOI: 10.1128/JB.00244-19
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2019
    detail.hit.zdb_id: 1481988-0
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  • 2
    Online Resource
    Online Resource
    Antifungal Susceptibilities of Aspergillus fumigatus Clinical Isolates Obtained in Nagasaki, Japan
    American Society for Microbiology ; 2012
    In:  Antimicrobial Agents and Chemotherapy Vol. 56, No. 1 ( 2012-01), p. 584-587
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 56, No. 1 ( 2012-01), p. 584-587
    Abstract: We investigated the triazole, amphotericin B, and micafungin susceptibilities of 196 A. fumigatus clinical isolates in Nagasaki, Japan. The percentages of non-wild-type (non-WT) isolates for which MICs of itraconazole, posaconazole, and voriconazole were above the ECV were 7.1%, 2.6%, and 4.1%, respectively. A G54 mutation in cyp51A was detected in 64.2% (9/14 isolates) and 100% (5/5 isolates) of non-WT isolates for itraconazole and posaconazole, respectively. Amphotericin B MICs of ≥2 μg/ml and micafungin minimum effective concentrations (MECs) of ≥16 μg/ml were recorded for two and one isolates, respectively.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.05394-11
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2012
    detail.hit.zdb_id: 1496156-8
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  • 3
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    Online Resource
    Factors Associated with Breakthrough Fungemia Caused by Candida , Trichosporon , or Fusarium Species in Patients with Hematological Disorders
    American Society for Microbiology ; 2022
    In:  Antimicrobial Agents and Chemotherapy Vol. 66, No. 3 ( 2022-03-15)
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 66, No. 3 ( 2022-03-15)
    Abstract: Limited data are available on breakthrough fungemia, defined as fungemia that develops on administration of antifungal agents, in patients with hematological disorders. We reviewed the medical and microbiological records of adult patients with hematological diseases who had breakthrough fungemia between January 2008 and July 2019 at Toranomon Hospital and Toranomon Hospital Kajigaya in Japan. A total of 121 cases of breakthrough fungemia were identified. Of the 121 involved patients, 83, 11, 5, and 22 were receiving micafungin, voriconazole, itraconazole, and liposomal amphotericin B, respectively, when the breakthrough occurred. Of the 121 causative breakthrough fungal strains, 96 were Candida species, and the rest were 13 cases of Trichosporon species, 7 of Fusarium species, 2 of Rhodotorula mucilaginosa , and 1 each of Cryptococcus neoformans , Exophiala dermatitidis , and Magnusiomyces capitatus . The crude 14-day mortality rate of breakthrough fungemia was 36%. Significant independent factors associated with the crude 14-day mortality rate were age of ≥60 years ( P =  0.011), chronic renal failure ( P =  0.0087), septic shock ( P  〈   0.0001), steroid administration ( P =  0.0085), and liposomal amphotericin B breakthrough fungemia ( P =  0.0011). An absolute neutrophil count of 〉 500/μL was significantly more common in candidemia in the multivariate analysis ( P = 0.0065), neutropenia and nonallogeneic hematopoietic stem cell transplants were significantly more common in Trichosporon fungemia ( P =  0.036 and P =  0.033, respectively), and voriconazole breakthrough fungemia and neutropenia were significantly more common in Fusarium fungemia ( P =  0.016 and P =  0.016, respectively). The epidemiological and clinical characteristics of breakthrough fungemia of patients with hematological disorders were demonstrated. Some useful factors to predict candidemia, Trichosporon fungemia, and Fusarium fungemia were identified.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/aac.02081-21
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2022
    detail.hit.zdb_id: 1496156-8
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  • 4
    Online Resource
    Online Resource
    In Vivo Efficacy of Daptomycin against Methicillin-Resistant Staphylococcus aureus in a Mouse Model of Hematogenous Pulmonary Infection
    American Society for Microbiology ; 2013
    In:  Antimicrobial Agents and Chemotherapy Vol. 57, No. 6 ( 2013-06), p. 2841-2844
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 57, No. 6 ( 2013-06), p. 2841-2844
    Abstract: Daptomycin is inactivated by pulmonary surfactant, but its effectiveness in hematogenous pulmonary infection has been poorly studied. The potential therapeutic application was evaluated in a methicillin-resistant Staphylococcus aureus (MRSA) hematogenous pulmonary infection mouse model. Compared with control results, daptomycin improved survival ( P 〈 0.001) and decreased the number of abscesses and bacteria in the lungs ( P 〈 0.01). Daptomycin may be an effective therapeutic option for MRSA hematogenous pulmonary infection.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.02331-12
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2013
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
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  • 5
    Online Resource
    Online Resource
    Azithromycin Attenuates Lung Inflammation in a Mouse Model of Ventilator-Associated Pneumonia by Multidrug-Resistant Acinetobacter baumannii
    American Society for Microbiology ; 2013
    In:  Antimicrobial Agents and Chemotherapy Vol. 57, No. 8 ( 2013-08), p. 3883-3888
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 57, No. 8 ( 2013-08), p. 3883-3888
    Abstract: Acinetobacter baumannii is one of the main pathogens that cause ventilator-associated pneumonia (VAP) and is associated with a high rate of mortality. Little is known about the efficacy of macrolides against A. baumannii . In order to confirm the efficacy of azithromycin (AZM) against VAP caused by multidrug-resistant A. baumannii (MDRAB), we used a mouse model that mimics VAP by placement of a plastic tube in the bronchus. AZM (10 and 100 mg/kg of body weight) was administered subcutaneously every 24 h beginning at 3 h after inoculation. Phosphate-buffered saline was administered as the control. Survival was evaluated over 7 days. At 48 h postinfection, mice were sacrificed and the numbers of viable bacteria in lungs and bronchoalveolar lavage fluid were compared. Histopathological analysis of lung specimens was also performed. The treatment groups displayed significantly longer survival than the control group ( P 〈 0.05). AZM did not have an antimicrobial effect. Histopathological examination of lung specimens indicated that the progression of lung inflammation was prevented in the AZM-treated groups. Furthermore, total cell and neutrophil counts, as well as cytokine levels, in bronchoalveolar lavage fluid were significantly decreased ( P 〈 0.05) in the AZM-treated groups. AZM may have a role for the treatment of VAP with MDRAB because of its anti-inflammatory effects.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.00457-13
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2013
    detail.hit.zdb_id: 1496156-8
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  • 6
    Online Resource
    Online Resource
    Analyses of Current-Generating Mechanisms of Shewanella loihica PV-4 and Shewanella oneidensis MR-1 in Microbial Fuel Cells
    American Society for Microbiology ; 2009
    In:  Applied and Environmental Microbiology Vol. 75, No. 24 ( 2009-12-15), p. 7674-7681
    Details
    In: Applied and Environmental Microbiology, American Society for Microbiology, Vol. 75, No. 24 ( 2009-12-15), p. 7674-7681
    Abstract: Although members of the genus Shewanella have common features (e.g., the presence of decaheme c -type cytochromes [ c -cyts]), they are widely variable in genetic and physiological features. The present study compared the current-generating ability of S. loihica PV-4 in microbial fuel cells (MFCs) with that of well-characterized S. oneidensis MR-1 and examined the roles of c -cyts in extracellular electron transfer. We found that strains PV-4 and MR-1 exhibited notable differences in current-generating mechanisms. While the MR-1 MFCs maintained a constant current density over time, the PV-4 MFCs continued to increase in current density and finally surpassed the MR-1 MFCs. Coulombic efficiencies reached 26% in the PV-4 MFC but 16% in the MR-1 MFCs. Although both organisms produced quinone-like compounds, anode exchange experiments showed that anode-attached cells of PV-4 produced sevenfold more current than planktonic cells in the same chamber, while planktonic cells of MR-1 produced twice the current of the anode-attached cells. Examination of the genome sequence indicated that PV-4 has more c -cyt genes in the metal reductase-containing locus than MR-1. Mutational analysis revealed that PV-4 relied predominantly on a homologue of the decaheme c -cyt MtrC in MR-1 for current generation, even though it also possesses two homologues of the decaheme c -cyt OmcA in MR-1. These results suggest that current generation in a PV-4 MFC is in large part accomplished by anode-attached cells, in which the MtrC homologue constitutes the main path of electrons toward the anode.
    Type of Medium: Online Resource
    ISSN: 0099-2240 , 1098-5336
    URL: Article
    DOI: 10.1128/AEM.01142-09
    RVK:
    WA 15000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2009
    detail.hit.zdb_id: 223011-2
    detail.hit.zdb_id: 1478346-0
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  • 7
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    Online Resource
    Melting Curve Analysis for Rapid Detection of Topoisomerase Gene Mutations in Haemophilus influenzae
    American Society for Microbiology ; 2009
    In:  Journal of Clinical Microbiology Vol. 47, No. 3 ( 2009-03), p. 781-784
    Details
    In: Journal of Clinical Microbiology, American Society for Microbiology, Vol. 47, No. 3 ( 2009-03), p. 781-784
    Abstract: We established a real-time PCR assay with melting curve analysis to rapidly genotype quinolone resistance-determining regions (QRDRs) of gyrase A and topoisomerase IV genes in Haemophilus influenzae . This assay is a useful tool for the detection of fluoroquinolone resistance and for the early detection of preexisting QRDR mutations.
    Type of Medium: Online Resource
    ISSN: 0095-1137 , 1098-660X
    URL: Article
    DOI: 10.1128/JCM.01645-08
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2009
    detail.hit.zdb_id: 1498353-9
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  • 8
    Online Resource
    Online Resource
    In Vitro Activity and Clinical Efficacy of Faropenem against Third-Generation Cephalosporin-Resistant Escherichia coli and Klebsiella pneumoniae
    American Society for Microbiology ; 2022
    In:  Antimicrobial Agents and Chemotherapy Vol. 66, No. 6 ( 2022-06-21)
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 66, No. 6 ( 2022-06-21)
    Abstract: Faropenem (FRPM) is active against extended-spectrum β-lactamase (ESBL)-producing Enterobacterales , but evidence for its efficacy is lacking. This study determined the correlation between the susceptibility by disk diffusion method and the MIC of FRPM for third-generation cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae , and the effectiveness of FRPM for the treatment of urinary tract infection (UTI) caused by these two bacteria in a retrospective cohort analysis. Of the 48 third-generation cephalosporin-resistant clinical isolates tested, 44 isolates produced ESBL, and 8 isolates produced AmpC, including 4 isolates produced both ESBL and AmpC. Thirty-seven isolates had an FRPM MIC of ≤1 mg/L, and seven had an FRPM MIC of 2 mg/L. An FRPM MIC of 〉 2 mg/L was observed with four isolates. In a retrospective cohort analysis, 63 patients with UTI treated with FRPM were identified. All isolates of ESBL-producing E. coli ( n  = 54) and K. pneumoniae ( n  = 9) treated with FRPM showed disk diffusion zone diameters larger than 16.0 mm (estimated MIC, 2.2 mg/L). All patients completed the scheduled treatment courses with FRPM, but 28- and 90-day relapses happened in 10 patients (16%) and 16 patients (25%), respectively. No significant risk factors for the 28- and 90-day relapses were found. FRPM can be used according to disk diffusion susceptibility testing in UTI. Further investigations are necessary to assess the clinical breakpoint of FRPM for ESBL-producing Enterobacterales and the candidates most likely to benefit from using FRPM.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/aac.00125-22
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2022
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
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  • 9
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    Online Resource
    Efficacy of AiiM, an N -Acylhomoserine Lactonase, against Pseudomonas aeruginosa in a Mouse Model of Acute Pneumonia
    American Society for Microbiology ; 2013
    In:  Antimicrobial Agents and Chemotherapy Vol. 57, No. 8 ( 2013-08), p. 3653-3658
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 57, No. 8 ( 2013-08), p. 3653-3658
    Abstract: Quorum sensing (QS) in Pseudomonas aeruginosa regulates the production of many virulence factors and plays an important role in the pathogenesis of P. aeruginosa infection. N -acyl homoserine lactones (AHL) are major QS signal molecules. Recently, a novel AHL-lactonase enzyme, AiiM, has been identified. The aim of this study was to evaluate the effect of AiiM on the virulence of P. aeruginosa in a mouse model of acute pneumonia. We developed a P. aeruginosa PAO1 strain harboring an AiiM-expressing plasmid. The production of several virulence factors by the AiiM-expressing strain was examined. Mice were intratracheally infected with an AiiM-expressing PAO1 strain. Lung histopathology, bacterial burden, and bronchoalveolar lavage (BAL) fluid were assessed at 24 h postinfection. AiiM expression in PAO1 reduced production of AHL-mediated virulence factors and attenuated cytotoxicity against human lung epithelial cells. In a mouse model of acute pneumonia, AiiM expression reduced lung injury and greatly improved the survival rates. The levels of proinflammatory cytokines and myeloperoxidase activity in BAL fluid were significantly lower in mice infected with AiiM-expressing PAO1. Thus, AiiM can strongly attenuate P. aeruginosa virulence in a mammalian model and is a potential candidate for use as a therapeutic agent against P. aeruginosa infection.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.00456-13
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2013
    detail.hit.zdb_id: 1496156-8
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    SSG: 15,3
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  • 10
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    Online Resource
    Immunomodulatory Effect of Linezolid on Methicillin-Resistant Staphylococcus aureus Supernatant-Induced MUC5AC Overexpression in Human Airway Epithelial Cells
    American Society for Microbiology ; 2014
    In:  Antimicrobial Agents and Chemotherapy Vol. 58, No. 7 ( 2014-07), p. 4131-4137
    Details
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 58, No. 7 ( 2014-07), p. 4131-4137
    Abstract: Linezolid is the first member of the oxazolidinones and is active against drug-resistant Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA). Additionally, linezolid shows an immunomodulatory effect, such as inhibition of inflammatory cytokine production. In this study, we examined the effect of linezolid on MRSA-induced MUC5AC overexpression in airway epithelial cells. In this study, an MRSA supernatant was used to avoid the direct effect of linezolid on MRSA. MUC5AC protein production was significantly increased with a 40-fold dilution of MRSA supernatant. At the mRNA level, MUC5AC gene expression was significantly increased 6 and 9 h after stimulation. In an inhibition study, linezolid significantly reduced MRSA-induced MUC5AC protein and mRNA overexpression at concentrations of 5 and 20 μg/ml, which were the same as the trough and peak concentrations in human epithelial lining fluid. In an analysis of cell signaling, among the mitogen-activated protein kinase inhibitors, only the extracellular signal-regulated protein kinase 1/2 (ERK1/2) inhibitor reduced the MUC5AC protein production to the same level as that of the control; on Western blot analysis, only ERK1/2 was phosphorylated by the MRSA supernatant. In addition, the ERK1/2 phosphorylation was inhibited by linezolid. MUC5AC and MUC5B are the major barrier that traps inhaled microbial organisms, particulates, and foreign irritants. However, in patients with chronic respiratory diseases, pathogen-induced MUC5AC overexpression causes many problems, and control of the overexpression is important. Thus, this study revealed that linezolid showed a direct immunomodulatory effect in airway epithelial cells.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    URL: Article
    DOI: 10.1128/AAC.02811-13
    RVK:
    XA 24552
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2014
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
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