The Experts below are selected from a list of 31296 Experts worldwide ranked by ideXlab platform
Xin Fan - One of the best experts on this subject based on the ideXlab platform.
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glycerophosphorylcholine regulates Haemophilus influenzae glpq gene expression
Fems Microbiology Letters, 2015Co-Authors: Enas Alrousan, Xin FanAbstract:An important virulence strategy adopted by Haemophilus influenzae to establish a niche on the mucosal surface of the host is the phosphorylcholine (ChoP) decoration of its lipopolysaccharides, which promotes adherence to the host cells. Haemophilus influenzae is able to use glycerophosphorylcholine (GPC) from host for ChoP synthesis. Utilization of GPC requires glpQ, which encodes a glycerophosphodiester phosphodiesterase enzyme. In this study, we investigate the transcriptional regulation of glpQ gene using real-time PCR and transcriptional fusion of H. influenzae glpQ promoter to the Escherichia coli lacZ reporter gene. The glpQ promoter activities were examined under environmental conditions including changes in temperature, oxygen, high salt and minimal growth medium. Our data showed that under room temperature and anaerobic conditions, the glpQ gene expression levels were significantly higher than under other growth conditions. In addition, the glpQ gene expression levels were upregulated in the presence of GPC. These results suggest that H. influenzae may upregulate glpQ expression in response to different environments it encounters during infection, from the airway surfaces (room temperature) to deep tissues (anaerobic). Upregulation of glpQ by GPC may allow efficient use of abundant GPC from mammalian cells by H. influenzae as a source of nutrient and for ChoP decoration of lipopolysaccharide that facilitates bacterial adhesion to host cells and growth during infection.
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research l etter pathogens pathogenicity glycerophosphorylcholine regulates Haemophilus influenzae glpq gene expression
2015Co-Authors: Enas Alrousan, Xin FanAbstract:An important virulence strategy adopted by Haemophilus influenzae to establish a niche on the mucosal surface of the host is the phosphorylcholine (ChoP) decoration of its lipopolysaccharides, which promotes adherence to the host cells. Haemophilus influenzae is able to use glycerophosphorylcholine (GPC) from host for ChoP synthesis. Utilization of GPC requires glpQ, which encodes a glycerophosphodiester phosphodiesterase enzyme. In this study, we investigate the transcriptional regulation of glpQ gene using real-time PCR and transcriptional fusion of H. influenzae glpQ promoter to the Escherichia coli lacZ reporter gene. The glpQ promoter activities were examined under environmental conditions including changes in temperature, oxygen, high salt and minimal growth medium. Our data showed that under room temperature and anaerobic conditions, the glpQ gene expression levels were significantly higher than under other growth conditions. In addition, the glpQ gene expression levels were upregulated in the presence of GPC. These results suggest that H. influenzae may upregulate glpQ expression in response to different environments it encounters during infection, from the airway surfaces (room temperature) to deep tissues (anaerobic). Upregulation of glpQ by GPC may allow efficient use of abundant GPC from mammalian cells byH. influenzae as a source of nutrient and for ChoP decoration of lipopolysaccharide that facilitates bacterial adhesion to host cells and growth during infection.
Janet R. Gilsdorf - One of the best experts on this subject based on the ideXlab platform.
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high genetic diversity of nontypeable Haemophilus influenzae isolates from two children attending a day care center
Journal of Clinical Microbiology, 2008Co-Authors: Nathan C Lacross, Carl F Marrs, Mayuri Patel, Sara A Sandstedt, Janet R. GilsdorfAbstract:Twenty-one nontypeable Haemophilus influenzae (NTHi) isolates from the throats of two healthy children were genotyped by multilocus sequence typing. Nine unique sequence types (STs) were identified. These STs were scattered throughout the phylogenetic tree of reported NTHi STs, demonstrating the high level of NTHi diversity found in colonized children.
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diversity and sharing of Haemophilus influenzae strains colonizing healthy children attending day care centers
Pediatric Infectious Disease Journal, 2004Co-Authors: Rand S Farjo, Carl F Marrs, Mayuri Patel, Betsy Foxman, Lixin Zhang, Melinda M Pettigrew, Sandra I Mccoy, Janet R. GilsdorfAbstract:Background.Children attending day-care centers (DCCs) are at risk for Haemophilus influenzae nasopharyngeal colonization and acute otitis media. The degree to which a given strain circulates within a day-care center and the heterogeneity of strains among DCCs in a geographic area are not well-charac
Jens Jorgen Christensen - One of the best experts on this subject based on the ideXlab platform.
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nontypable Haemophilus influenzae septicemia and urinary tract infection associated with renal stone disease
The Open Microbiology Journal, 2018Co-Authors: Marianne Staerk, Sara Tolouee, Jens Jorgen ChristensenAbstract:Introduction Haemophilus influenzae commonly causes upper respiratory tract infections and has only rarely been reported etiology of urinary tract infections. Since the introduction of the Haemophilus influenzae b (Hib) vaccine, non-typable Haemophilus species now cause the majority of invasive disease in Europe. Case report We report a case of an adult man with non-typable Haemophilus influenzae septicemia, urinary tract infection and bilateral renal stone disease. The patient presented with right sided flank pain and a CT scan showed bilateral renal stones and a right sided ureteral stone causing obstruction. Results and discussion Haemophilus influenzae was identified in blood and urine and despite a tendency of increasing antibiotic resistance among Haemophilus influenzae, our strain was susceptible to all antibiotics tested. Treatment consisted of 3 days of intravenous cefuroxime, insertion of a right sided JJ ureteric stent and 5 days of peroral ciprofloxacin after discharge. Physicians and microbiologists should be aware of Haemophilus influenzae as a possible urinary tract pathogen, especially when urinary tract abnormalities are present, and take the risk of antibiotic resistance into consideration at initial treatment.
Enas Alrousan - One of the best experts on this subject based on the ideXlab platform.
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glycerophosphorylcholine regulates Haemophilus influenzae glpq gene expression
Fems Microbiology Letters, 2015Co-Authors: Enas Alrousan, Xin FanAbstract:An important virulence strategy adopted by Haemophilus influenzae to establish a niche on the mucosal surface of the host is the phosphorylcholine (ChoP) decoration of its lipopolysaccharides, which promotes adherence to the host cells. Haemophilus influenzae is able to use glycerophosphorylcholine (GPC) from host for ChoP synthesis. Utilization of GPC requires glpQ, which encodes a glycerophosphodiester phosphodiesterase enzyme. In this study, we investigate the transcriptional regulation of glpQ gene using real-time PCR and transcriptional fusion of H. influenzae glpQ promoter to the Escherichia coli lacZ reporter gene. The glpQ promoter activities were examined under environmental conditions including changes in temperature, oxygen, high salt and minimal growth medium. Our data showed that under room temperature and anaerobic conditions, the glpQ gene expression levels were significantly higher than under other growth conditions. In addition, the glpQ gene expression levels were upregulated in the presence of GPC. These results suggest that H. influenzae may upregulate glpQ expression in response to different environments it encounters during infection, from the airway surfaces (room temperature) to deep tissues (anaerobic). Upregulation of glpQ by GPC may allow efficient use of abundant GPC from mammalian cells by H. influenzae as a source of nutrient and for ChoP decoration of lipopolysaccharide that facilitates bacterial adhesion to host cells and growth during infection.
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research l etter pathogens pathogenicity glycerophosphorylcholine regulates Haemophilus influenzae glpq gene expression
2015Co-Authors: Enas Alrousan, Xin FanAbstract:An important virulence strategy adopted by Haemophilus influenzae to establish a niche on the mucosal surface of the host is the phosphorylcholine (ChoP) decoration of its lipopolysaccharides, which promotes adherence to the host cells. Haemophilus influenzae is able to use glycerophosphorylcholine (GPC) from host for ChoP synthesis. Utilization of GPC requires glpQ, which encodes a glycerophosphodiester phosphodiesterase enzyme. In this study, we investigate the transcriptional regulation of glpQ gene using real-time PCR and transcriptional fusion of H. influenzae glpQ promoter to the Escherichia coli lacZ reporter gene. The glpQ promoter activities were examined under environmental conditions including changes in temperature, oxygen, high salt and minimal growth medium. Our data showed that under room temperature and anaerobic conditions, the glpQ gene expression levels were significantly higher than under other growth conditions. In addition, the glpQ gene expression levels were upregulated in the presence of GPC. These results suggest that H. influenzae may upregulate glpQ expression in response to different environments it encounters during infection, from the airway surfaces (room temperature) to deep tissues (anaerobic). Upregulation of glpQ by GPC may allow efficient use of abundant GPC from mammalian cells byH. influenzae as a source of nutrient and for ChoP decoration of lipopolysaccharide that facilitates bacterial adhesion to host cells and growth during infection.
Michael R Jacobs - One of the best experts on this subject based on the ideXlab platform.
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antimicrobial resistance in Haemophilus influenzae
Clinical Microbiology Reviews, 2007Co-Authors: S G Tristram, Michael R Jacobs, Peter C AppelbaumAbstract:Haemophilus influenzae is a major community-acquired pathogen causing significant morbidity and mortality worldwide. Meningitis and bacteremia due to type b strains occur in areas where the protein-conjugated type b vaccine is not in use, whereas nontypeable strains are major causes of otitis media, sinusitis, acute exacerbations of chronic bronchitis, and pneumonia. Antibiotic resistance in this organism is more diverse and widespread than is commonly appreciated. Intrinsic efflux resistance mechanisms limit the activity of the macrolides, azalides, and ketolides. β-Lactamase production is highly prevalent worldwide and is associated with resistance to ampicillin and amoxicillin. Strains with alterations in penicillin binding proteins, particularly PBP3 (β-lactamase negative ampicillin resistant and β-lactamase positive amoxicillin-clavulanate resistant), are increasing in prevalence, particularly in Japan, with increasing resistance to ampicillin, amoxicillin, amoxicillin-clavulanate, and many cephalosporins, limiting the efficacy of expanded-spectrum cephalosporins against meningitis and of many oral cephalosporins against other diseases. Most strains remain susceptible to the carbapenems, which are not affected by penicillin binding protein changes, and the quinolones. The activity of many oral agents is limited by pharmacokinetics achieved with administration by this route, and the susceptibility of isolates based on pharmacokinetic and pharmacodynamic parameters is reviewed.
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Haemophilus influenzae a significant pathogen in acute otitis media
Pediatric Infectious Disease Journal, 2004Co-Authors: Eugene Leibovitz, Michael R Jacobs, Ron DaganAbstract:Haemophilus influenzae is a major pathogen in acute otitis media (AOM) causing disease that is not clinically distinguishable from that caused by Streptococcus pneumoniae. AOM caused by H. influenzae is particularly associated with older age and recurrent disease. Antibiotics differ in their ability to eradicate H. influenzae from the middle ear space. In the United States, widespread pneumococcal vaccination has increased the importance of H. influenzae as a major therapeutic challenge in the treatment of AOM.
