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Query: UMLS:C0032285 (pneumonia)
 54,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pasteurella multocida is a pathogenic Gram-negative bacterium that has been classified into three subspecies, five capsular serogroups and 16 serotypes. P. multocida serogroup A isolates are bovine nasopharyngeal commensals, bovine pathogens and common isolates from bovine respiratory disease (BRD), both enzootic calf pneumonia of young dairy calves and shipping fever of weaned, stressed beef cattle. P. multocida A:3 is the most common serotype isolated from BRD, and these isolates have limited heterogeneity based on outer membrane protein (OMP) profiles and ribotyping. Development of P. multocida-induced pneumonia is associated with environmental and stress factors such as shipping, co-mingling, and overcrowding as well as concurrent or predisposing viral or bacterial infections. Lung lesions consist of an acute to subacute bronchopneumonia that may or may not have an associated pleuritis. Numerous virulence or potential virulence factors have been described for bovine respiratory isolates including adherence and colonization factors, iron-regulated and acquisition proteins, extracellular enzymes such as neuraminidase, lipopolysaccharide, polysaccharide capsule and a variety of OMPs. Immunity of cattle against respiratory pasteurellosis is poorly understood; however, high serum antibodies to OMPs appear to be important for enhancing resistance to the bacterium. Currently available P. multocida vaccines for use in cattle are predominately traditional bacterins and a live streptomycin-dependent mutant. The field efficacy of these vaccines is not well documented in the literature.
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PMID:Pasteurella multocida and bovine respiratory disease. 1821 57

Viral influenza is a seasonal infection associated with significant morbidity and mortality. In the United States more than 35,000 deaths and 200,000 hospitalizations due to influenza occur annually, and the number is increasing. Children aged less than 1 year and adults aged more than 65 years, pregnant woman, and people of any age with comorbid illnesses are at highest risk. Annual vaccination is the cornerstone of prevention, but some older patients may derive less benefit from immunization than otherwise fit individuals. If started promptly, antiviral medications may reduce complications of acute influenza, but increasing resistance to amantadine and perhaps neuraminidase inhibitors underscores the need for novel prevention and treatment strategies. Pulmonary complications of influenza are most common and include primary influenza and secondary bacterial infection. Either may cause pneumonia, and each has a unique clinical presentation and pathologic basis. Staphylococcus aureus, including methicillin-resistant strains, is an important cause of secondary bacterial pneumonia with high mortality. During influenza season, treatment of pneumonia should include empiric coverage for this pathogen. Neuromuscular and cardiac complications are unusual but may manifest in persons of any age.
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PMID:Complications of viral influenza. 1837 80

Colonization of the airway by Streptococcus pneumoniae is typically asymptomatic; however, progression of bacteria beyond the oronasopharynx can cause diseases including otitis media and pneumonia. The mechanisms by which S. pneumoniae establishes and maintains colonization remain poorly understood. Both N-linked and O-linked glycans are abundant in the airway. Our previous research demonstrated that S. pneumoniae can sequentially deglycosylate N-linked glycans and suggested that this modification of sugar structures may aid in colonization. There is published evidence that S. pneumoniae expresses a secreted O-glycosidase that cleaves galactose beta1-3 N-acetylgalactosamine (Galbeta1-3GalNAc) from core-1 O-linked glycans; however, the biological function of this enzyme has not previously been determined. We established that the activity is not secreted but is instead surface associated in a sortase-dependent manner. Genome analysis revealed an open reading frame predicted to encode a sortase-dependent surface protein with sequence similarity to the O-glycosidase of Bifidobacterium longum. Deletion of this pneumococcal open reading frame confirmed that this gene encodes an O-glycosidase. Experiments using a model glycoconjugate demonstrated that this O-glycosidase, together with the neuraminidase NanA, is required for S. pneumoniae to cleave sialylated core-1 O-linked glycans. The ability of the O-glycosidase mutant to cleave this glycan structure was restored by both genetic complementation and the addition of O-glycosidase. The mutant showed a reduction in adherence to human airway epithelial cells and a significantly decreased ability to colonize the upper respiratory tract, suggesting that cleavage of core-1 O-linked glycans enhances the ability of S. pneumoniae to colonize the human airway.
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PMID:Identification of a pneumococcal glycosidase that modifies O-linked glycans. 1913 97

Influenza virus infection is a major respiratory infectious disease that generally induces pneumonia. The clinical manifestations of influenza virus infection and community-acquired pneumonia (CAP) differ between elderly persons and younger adults. To determine the clinical features of influenza-associated pneumonia, we studied 21 adult patients with influenza-associated pneumonia, as indicated by positive test results for influenza virus antigen. At presentation, the higher-age patients (> or =75 years; n=12) with influenza-associated pneumonia had lower body temperature than did the lower-age (<75 years) patients (n=9). Conversely, the laboratory data indicated significantly higher C-reactive protein (CRP) concentration in higher-age patients than that in lower-age patients. None of the 18 patients undergoing neuraminidase inhibitor therapy died, but two of three patients who did not receive this therapy died from complications of advanced pneumonia. In this study, vaccination did not appear to be an important factor for prevention of pneumonia. High-age patients with CAP have lower body temperature, raising the possibility that diagnosis and treatment may be delayed in these patients. Increased CRP levels in these patients at presentation, however, could contribute to early detection of this serious pulmonary complication.
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PMID:Influence of age on symptoms and laboratory findings at presentation in patients with influenza-associated pneumonia. 1915 Jan 40

Influenza is an infectious disease and can lead to life-threatening complications like pneumonia. The disease is caused by three types of RNA viruses called influenza types A, B and C, each consisting of eight negative single-stranded RNA-segments encoding 11 proteins. Current annual vaccines contain two type A strains and one type B strain and are capable of inducing strong antibody responses to both the surface glycoprotein hemagglutinin and the neuraminidase. While these vaccines are protective against vaccine viruses they are not effective against newly emerging viruses that contain antigenic variations known as antigenic drift and shift. In nature, environmental selection pressure generally plays a key role in selecting antigenic changes in the antigen determining spots of hemagglutinin, resulting in changes in the antigenicity of the virus. Recently, a new technology has been developed where influenza-specific IgG+ antibody-secreting plasma cells can be isolated and cloned directly from vaccinated humans and high affinity monoclonal antibodies can be produced within several weeks after vaccination. The new technology holds great promise for the development of effective passive antibody therapy to limit the spread of influenza viruses in a timely manner.
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PMID:Influenza virus antigenic variation, host antibody production and new approach to control epidemics. 1928 39

Streptococcus pneumoniae remains a major cause of bacteremia, pneumonia, and otitis media despite vaccines and effective antibiotics. The neuraminidase of S. pneumoniae, which catalyzes the release of terminal sialic acid residues from glycoconjugates, is involved in host colonization in animal models of infection and may provide a novel target for preventing pneumococcal infection. We demonstrate that the S. pneumoniae neuraminidase (NanA) cleaves sialic acid and show that it is involved in biofilm formation, suggesting an additional role in pathogenesis, and that it shares this property with the neuraminidase of Pseudomonas aeruginosa even though we show that the two enzymes are phylogenetically divergent. Using an in vitro model of biofilm formation incorporating human airway epithelial cells, we demonstrate that small-molecule inhibitors of NanA block biofilm formation and may provide a novel target for preventative therapy. This work highlights the role played by the neuraminidase in pathogenesis and represents an important step in drug development for prevention of colonization of the respiratory tract by this important pathogen.
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PMID:The NanA neuraminidase of Streptococcus pneumoniae is involved in biofilm formation. 1956 77

Streptococcus pneumoniae (the pneumococcus) is a major human pathogen and a leading cause of inflammatory infections such as pneumonia and otitis media. An important mechanism for host defense against S. pneumoniae is opsonophagocytic killing by neutrophils. To persist in the human host, the pneumococcus has developed strategies to evade opsonization and subsequent neutrophil-mediated killing. Utilizing a genomic approach, we identified NanA, the major pneumococcal neuraminidase, as a factor important for resistance to opsonophagocytic killing in ex vivo killing assays using human neutrophils. The effect of NanA was shown using both type 4 (TIGR4) and type 6A clinical isolates. NanA promotes this resistance by acting in conjunction with two other surface-associated exoglycosidases, BgaA, a beta-galactosidase, and StrH, an N-acetylglucosaminidase. Experiments using human serum showed that these exoglycosidases reduced deposition of complement component C3 on the pneumococcal surface, providing a mechanism for this resistance. Additionally, we have shown that antibodies in human serum do not contribute to this phenotype. These results demonstrate that deglycosylation of a human serum glycoconjugate(s) by the combined effects of NanA, BgaA, and StrH, is important for resistance to complement deposition and subsequent phagocytic killing of S. pneumoniae.
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PMID:Three surface exoglycosidases from Streptococcus pneumoniae, NanA, BgaA, and StrH, promote resistance to opsonophagocytic killing by human neutrophils. 2016 17

Influenza infection is annually responsible for significant morbidity and mortality, particularly among the very young and old. Recently updated guidelines recommend influenza vaccination of all children aged 6 months to 18 years; however, childhood vaccination remains underutilized. Furthermore, concerns over the reduced efficacy of vaccination in children have further heightened the need for effective treatment schemes. Antiviral therapies have emerged as attractive options in the battle against influenza infection. These agents include the adamantanes (amantadine and rimantadine) and neuraminidase inhibitors (zanamivir, oseltamivir, and peramivir). Broad-scale use of adamantane antivirals has been severely limited in recent years because of high resistance rates and their inability to cover influenza type B. Neuraminidase inhibitors cover influenza types A and B, and have been promulgated to first-line therapy because of historically low resistance rates and relatively infrequent side effects. Moreover, these agents are effective options in combating non-seasonal influenza strains, including H5N1 and pandemic 2009 H1N1. Oseltamivir may be particularly appealing for treating children since it is available in multiple oral dosage formulations, whereas commercially available zanamivir use is limited in young children because it requires inhalation. However, the emergence of resistance to oseltamivir among influenza A strains may limit its usefulness. Additional concerns with neuraminidase inhibitor use in pediatrics center around emerging reports, primarily from Japan, that have temporally linked oseltamivir to significant neuropsychiatric events in children of varying ages. Numerous novel antiviral agents are under development, but most are far from market approval. In addition to treating and preventing the initial burden of pediatric influenza infection, antiviral therapies may significantly reduce secondary bacterial infections (including pneumonia and otitis media), unnecessary antibiotic prescribing, and healthcare-associated costs.
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PMID:Antivirals for influenza: strategies for use in pediatrics. 2079 58

In Japan, about 20 million people were infected with pandemic (H1N1) 2009 virus between July 2009 and March 2010. About 60% of them were under 15 years, but only 38 pediatric deaths were reported. The reasons for hospitalization were respiratory and neurological complications. Children with pneumonia or encephalopathy were older than those with seasonal influenza. The time from onset to appear dyspnea in patients with lower respiratory complications was very short, and encephalopathy also appears very rapidly. It is very important to observe clinical course closely and to start neuraminidase inhibitor within 48 hours.
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PMID:[Pandemic (H1N1) 2009 in children]. 2084 41

The purpose of this study was to describe epidemiological, clinical and microbiological characteristics of confirmed novel influenza A (H1N1) infection, investigating factors associated with disease severity. We retrospectively selected patients seeking care for respiratory symptoms in two periods (May-August and September-November 2009) with different epidemiological characteristics. Only patients with confirmed pandemic influenza A (H1N1) were enrolled in this study. A total of 104 patients with H1N1 infection were evaluated, mostly referring classic influenza symptoms; in addition, diarrhea and vomiting were often referred. Clinical signs, symptoms and respiratory complications were different in the two periods. Of all patients, 18 (17%) had pneumonia. Patients older than 50 years showed a lower probability of pneumonia diagnosis when compared to children aged 0-13 (p = 0.049); a longer duration of symptoms before medical care was associated with a higher probability of pneumonia (p = 0.026). Phylogenetic analysis showed a low variability both in hemagglutinin and neuraminidase genes. In addition, no neuraminidase mutation associated with antiviral resistance was detected. A detailed description of respiratory diseases associated with H1N1 infection was provided and factors associated with its severity were investigated, thus contributing to the insight into epidemiological, clinical and microbiological knowledge of the disease.
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PMID:Clinical presentation, microbiological features and correlates of disease severity of 2009 pandemic influenza A (H1N1) infection. 2110 85


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