Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0032285 (pneumonia)
 54,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mannheimia haemolytica (previously known as Pasteurella haemolytica) is a weakly hemolytic, gram-negative coccobacillus that is an opportunistic pathogen of cattle, sheep and other ruminants. In stressed, immunocompromised animals, the organism causes a fibrinous, necrotic pneumonia, commonly called "shipping fever". In the United States, economic losses due to shipping fever pneumonia surpass the combined cost of all other diseases of cattle. M. haemolytica, which is a member of the family Pasteurelleaceae, includes twelve serotypes (A1, A2, A5-A9, A12-14, A16 and A17) based on capsular antigen typing. Worldwide, serotypes A1 and A2 predominate, though all serotypes can cause disease. Serotype A1 causes pasteurellosis in cattle and has been the subject extensive study, while serotype A2 causes disease in sheep and is less-well characterized. Potential virulence factors of M. haemolytica have been identified and characterized by gene cloning and DNA sequence analysis. These factors include a ruminant-specific leukotoxin, an anti-phagocytic capsule, lipopolysaccharide, iron-regulated outer membrane proteins, lipoproteins, a sialoglycoprotease, a neuraminidase and two potential immunoglobulin proteases. Unlike the well-characterized leukotoxin, little is known about the expression of these other virulence factors. Attempts to dissect the mechanisms of M. haemolytica pathogenesis have been hindered by the lack of a robust genetic system for mutation of the organism, though new tools for genetic manipulation of M. haemolytica have been developed. Expression plasmids and operon fusion plasmids have been created and a series of antibiotic resistance cassettes useful for site-specific recombination have been constructed. It is anticipated that use of these tools for gene expression and mutagenesis, in combination with the soon to be released genomic sequence of a serotype A1 organism, will aid in understanding the molecular mechanisms of pathogenesis of M. haemolytica and will help to drive development of new vaccines to prevent shipping fever.
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PMID:Molecular genetic analysis of virulence in Mannheimia (pasteurella) haemolytica. 1153 7

Haemophilus somnus isolates from cases of thrombotic meningoencephalitis, pneumonia, and other disease sites are capable of undergoing a high rate of phase variation in the oligosaccharide component of their lipooligosaccharides (LOS). In contrast, the LOS of commensal strains isolated from the normal reproductive tract phase vary little or not at all. In addition, the LOS of H. somnus shares conserved epitopes with LOS from Neisseria gonorrhoeae, Haemophilus influenzae, and other species that can incorporate sialic acid into their LOS. We now report that growth of disease isolates of H. somnus with CMP-N-acetylneuraminic acid (CMP-NeuAc) or NeuAc added to the medium resulted in incorporation of NeuAc into the LOS. However, NeuAc was not incorporated into the LOS of commensal isolates and one disease isolate following growth in medium containing CMP-NeuAc or NeuAc. Sialylated LOS was detected by an increase in the molecular size or an increase in the amount of the largest-molecular-size LOS electrophoretic bands, which disappeared following treatment with neuraminidase. Sialylated LOS could also be detected by reactivity with Limax flavus agglutinin lectin, which is specific for sialylated species, by dot blot assay; this reactivity was also reversed by neuraminidase treatment. H. somnus strain 2336 LOS was found to contain some sialic acid when grown in medium lacking CMP-NeuAc or NeuAc, although supplementation enhanced NeuAc incorporation. In contrast strain 738, an LOS phase variant of strain 2336, was less extensively sialylated when the growth medium was supplemented with CMP-NeuAc or NeuAc, as determined by electrophoretic profiles and electrospray mass spectrometry. The sialyltransferase of H. somnus strain 738 was confirmed to preferentially sialylate the Gal(beta)-(1-3)-GlcNAc component of the lacto-N-tetraose structure by capillary electrophoresis assay. Enhanced sialylation of the strain 2336 LOS inhibited the binding of monoclonal antibodies to LOS by enzyme immunoassay and Western blotting. Furthermore, sialylation of the LOS enhanced the resistance of H. somnus to the bactericidal action of antiserum to LOS. Sialylation and increased resistance to killing by normal serum also occurred in a deletion mutant that was deficient in the terminal Gal-GlcNAc disaccharide. LOS sialylation may therefore be an important virulence mechanism to protect H. somnus against the host immune system.
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PMID:Incorporation of N-acetylneuraminic acid into Haemophilus somnus lipooligosaccharide (LOS): enhancement of resistance to serum and reduction of LOS antibody binding. 1218 31

Influenza illness is an important cause of severe morbidity and mortality in the population. Oseltamivir, the first oral neuraminidase inhibitor, has proven efficacy. In children of 1 year and older (weight-dependent dosing: 30 mg, 45 mg, 60 mg or 75 mg BID for 5 days) and adults (75 mg BID for 5 days), oseltamivir reduces the duration and severity of acute influenza. Furthermore, it decreases the incidence of secondary complications such as otitis media, bronchitis, pneumonia and sinusitis. Oseltamivir has been shown to prevent influenza when given for long-term prophylaxis or for post-exposure prophylaxis. Because oseltamivir blocks the neuraminidase, an enzyme crucial to influenza virion liberation from the host cell, it is only effective during the replication phase. Clinical benefits are only seen, when oseltamivir is applied within 48 h after onset of symptoms, and clinical efficacy in acute influenza is highly dependent on the beginning of treatment. Treatment within 12 h after onset of symptoms reduces the duration of illness by an additional 74.6 h, and treatment within 24 hours an additional 53.9 h compared to the benefit seen with an intervention at 48 h. In conclusion, clinical efficacy of oseltamivir can be maximized by early start of treatment. Resistance of influenza virus against oseltamivir has rarely been observed and seems to be of no clinical relevance due to reduced transmissibility and pathogenicity of mutants. Oseltamivir is generally well tolerated. About 10% of the patients complain of transient upper gastrointestinal events, which resolved within 1-2 days, and which could be reduced when the medication was taken with a light snack.
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PMID:Early therapy with the neuraminidase inhibitor oseltamivir maximizes its efficacy in influenza treatment. 1245 53

Influenza vaccination is estimated to be 50-68% efficacious in preventing pneumonia, hospitalisation or death in nursing home residents. Large culture-proven outbreaks may occur despite high resident vaccination rates. There is, therefore, a significant role for concurrent administration of influenza vaccination and antiviral therapy. The use of antiviral treatment and chemoprophylaxis requires community reporting of viral isolates, and contingency plans for rapid case identification and application of antiviral therapy. Clinicians must react quickly to control a highly infectious seasonal pathogen that may strike as an explosive outbreak. This situation is unique in geriatric practice. Current antiviral treatment should be administered within 48 hours of symptom onset, and is more efficacious if administered within 12 hours. In the case of an explosive institutional outbreak, a 1-day delay in prophylaxis may allow infection of many residents with a potentially fatal illness. Influenza must be differentiated from other respiratory viruses or syndromes. Grouped rapid diagnostic tests can aid laboratory confirmation. Antiviral agents include the M(2) inhibitors, amantadine and rimantadine, active against influenza A, and the neuraminidase inhibitors, zanamivir and oseltamivir, active against influenza A and B. In our experience, influenza B illness is as severe as influenza A. All agents have similar efficacy as treatment and prophylaxis against sensitive strains. When M(2) inhibitors are used simultaneously within an enclosed space (i.e. household or nursing home) as both treatment and prophylaxis, resistant strains may emerge that limit prophylactic efficacy. When M(2) inhibitors are administered to suspected cases (residents or staff) in institutions, precautions against secretion are especially important to diminish the risk of transmission of resistant virus. Rimantadine has been shown to have significantly fewer CNS adverse events compared with amantadine. Amantadine and oseltamivir require dosage adjustment in those with renal impairment. Oseltamivir, rimantadine and amantadine are administered by mouth, while zanamivir is administered by oral inhalation in a lactose powder. The labelling advises caution in the use of zanamivir in those with underlying airway disease. Pooled analysis of studies in patients given zanamivir indicate that individuals over the age of 50 years (at high risk for complications) and those severely symptomatic at presentation, tend to benefit most from early treatment. Neuraminidase inhibitors also diminish the need for antibacterials to treat secondary complications. An institutional programme to control influenza should include vaccination, and contingency plans for clinical surveillance, specimen processing and the rapid application of antiviral treatment and prophylaxis.
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PMID:Influenza vaccination and antiviral therapy: is there a role for concurrent administration in the institutionalised elderly? 1257 97

Haemophilus parasuis, which causes polyserositis, polysynovitis, meningitis, septicemia, and pneumonia in pigs, has emerged as an increasing problem in modern swine production systems. Co-factors for and the pathogenesis of H. parasuis disease are not defined. One of the potential virulence factors of H. parasuis is its neuraminidase (sialidase). While purifying the H. parasuis neuraminidase from the membrane fraction, we developed a protocol to renature enzymatic activity after enzyme preparations were resolved electrophorectically in denaturing polyacrylamide gels. The H. parasuis neuraminidase co-resolved with recombinant neuraminidase of Vibrio cholera; thus its apparent molecular mass is 82 kilodalton (kDa). The H. parasuis neuraminidase was associated with the membrane fraction and the purification protocol removed over 99% of the H. parasuis cell protein while retaining over 90% of the neuraminidase activity. Purified protein will provide another avenue to clone the neuraminidase gene that has been refractory to cloning and the protocol will be a means to purify recombinant protein.
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PMID:Purification and renaturation of membrane neuraminidase from Haemophilus parasuis. 1259 Dec 9

A lethal synergism exists between influenza virus and Streptococcus pneumoniae, accounting for excess mortality during influenza epidemics. Using a model of viral-bacterial synergism, we assessed the role that the influenza virus neuraminidase (NA) has in priming mice for pneumococcal infection. Administration of the selective NA inhibitor oseltamivir improved survival, independent of viral replication and morbidity from influenza. Both pathologic examination of the lungs and live imaging of pneumonic lesions, using a bioluminescent pneumococcus, suggested that the effect of NA inhibition was to limit the extent of pneumococcal pneumonia during early infection. Adherence assays and immunohistochemical staining for sialic acids in lungs from infected mice demonstrated that the influenza virus NA potentiates development of pneumonia by stripping sialic acid from the lung, thus exposing receptors for pneumococcal adherence. Selective NA inhibitors may be useful clinically to interrupt this novel mechanism of synergism and to prevent excess mortality from secondary bacterial pneumonia.
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PMID:Role of neuraminidase in lethal synergism between influenza virus and Streptococcus pneumoniae. 2175 27

Respiratory viruses (RVs) frequently cause severe respiratory disease in bone marrrow transplant (BMT) recipients. To evaluate the frequency of RV, nasal washes were collected year-round from BMT recipients with symptoms of upper respiratory tract infection (URI). Direct immunofluorescence assay was performed for respiratory syncytial virus (RSV), influenza (Flu) A and B, adenovirus and parainfluenza (Paraflu) virus. Patients with RSV pneumonia or with upper RSV infection, but considered at high risk for developing RSV pneumonia received aerosolized ribavirin. Oseltamivir was given to patients with influenza. A total of 179 patients had 392 episodes of URI. In all, 68 (38%) tested positive: RSV was detected in 18 patients (26.4%), Flu B in 17 (25%), Flu A in 11 (16.2%) and Paraflu in 7 (10.3%). A total of 14 patients (20.6%) had multiple RV infections or coinfection. RSV pneumonia developed in 55.5% of the patients with RSV-URI. One of the 15 patients (6.6%) with RSV pneumonia died. Influenza pneumonia was diagnosed in three patients (7.3%). RSV and influenza infections peaked in fall-winter and winter-spring months, respectively. We observed decreased rates of influenza and parainfluenza pneumonia and low mortality because of RSV pneumonia. The role of antiviral interventions such as aerosolized ribavirin and new neuraminidase inhibitors remains to be defined in randomized trials.
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PMID:Low mortality rates related to respiratory virus infections after bone marrow transplantation. 1269 10

Influenza is a serious disease for the elderly. Although influenza causes a high fever in the elderly similar to that of healthy adults, the cough lasts longer but frequency and degree of sore throat and coryza are lower in the elderly. A characteristic of influenza in the elderly is a high frequency of pneumonia complications. Decreased serum albumin level is a good indicator of the risk of post-influenza pneumonia. Rapid diagnosis kits have contributed to better diagnosis of influenza in clinical practice. In addition to amantadine, newly developed neuraminidase inhibitors are available for treatment of influenza. These drugs can mitigate various symptoms efficiently and hasten recovery. To treat influenza in the elderly, not only are prophylaxis and treatment of pneumonia important, but management of the general health condition is essential.
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PMID:[Clinical characteristic of the elderly in influenza infection]. 1461 33

The incidence of lower respiratory tract infection (LRTI) in women of child-bearing age is approximately 64 per 1000 population. The spectrum of illness ranges from acute bronchitis, which is very common, through influenza virus infection and exacerbations of underlying lung disease, to pneumonia, which, fortunately is uncommon (<1.5% LRTI), but can be severe. Acute bronchitis is generally mild, self-limiting and usually does not require antibacterial therapy. Influenza virus infection in pregnant women has been recently related to increased hospitalization for acute cardiorespiratory conditions. At present, the safety of the newer neuraminidase inhibitors for the treatment of influenza virus infection has not been established in pregnancy and they are not routinely recommended. In influenza virus infection complicated by pneumonia, antibacterial agents active against Staphylococcus aureus and Streptococcus pneumoniae superinfection should be used. There are few data on infective complications of asthma or COPD in pregnancy. The latter is rare, as patients with COPD are usually male and aged over 45 years. Management is the same as for nonpregnant patients. The incidence and mortality of pneumonia in pregnancy is similar to that in nonpregnant patients. Infants born to pregnant patients with pneumonia have been found to be born earlier and weigh less than controls. Risk factors for the development of pneumonia include anemia, asthma and use of antepartum corticosteroids and tocolytic agents. Based on the few available studies, the main pathogens causing pneumonia are S. pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae and viruses. Beta-Lactam and macrolide antibiotics therefore remain the antibiotics of choice in terms of both pathogen coverage and safety in pregnancy. In HIV-infected pregnant patients, recurrent bacterial pneumonia, but not Pneumocystis carinii pneumonia (PCP), is more common than in nonpregnant patients. Trimethoprim/sulfamethoxazole (cotrimoxazole) has not definitely been associated with adverse clinical outcomes despite theoretical risks. Currently it is still the treatment of choice in PCP, where mortality remains high. In conclusion, there are few data specifically related to pregnant women with different types of LRTI. Where data are available, no significant differences compared with nonpregnant patients have been identified. In considering the use of any therapeutic agent or investigation in pregnant patients with LRTI, safety aspects must be carefully weighed against potential benefit. Otherwise, management strategies should not differ from those for nonpregnant patients. Further research in this area is warranted.
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PMID:Treatment of community-acquired lower respiratory tract infections during pregnancy. 1472 4

Influenza virus infection accounts for significant morbidity, mortality, and healthcare expenditures among persons worldwide. Approximately 20,000 to 40,000 people in the US die each year as a result of influenza. Individuals most susceptible to adverse outcomes include the elderly and those with asthma, chronic obstructive pulmonary disease (COPD), heart disease, renal failure, malignancy, or immunosuppression. Prior to the AIDS epidemic, underlying respiratory disease was the greatest risk factor for influenza-related hospitalization ranking third to heart disease and malignancy for risk of mortality. Although the influenza vaccine can help prevent pneumonia and hospitalization, it is limited by less than ideal immunization rates and the possibility of viral antigenic shifts that render the vaccine ineffective. Pharmacologic interventions play an important role in the management of influenza virus infection by shortening the duration of symptoms. The advent of the neuraminidase inhibitors (NAIs) zanamivir and oseltamivir has significantly affected the treatment of influenza. Unlike NAIs, the older therapeutic options amantadine and rimantadine may cause significant central nervous system adverse effects. In addition, amantadine and rimantadine are not active against influenza B viruses, whereas NAIs are active against both influenza A and B. Post-marketing surveillance of the NAIs has revealed that bronchospasm may occur in patients with underlying respiratory disease treated with the NAI zanamivir. Recent data suggest zanamivir is effective in patients with underlying respiratory disease, but the data are insufficient to elucidate the true risk of bronchospasm. Based on post-marketing reports, zanamivir should be used with caution in patients with asthma or COPD. Although oseltamivir has not been associated with any significant respiratory adverse effects, no data exist on the safety and efficacy of this NAI in patients with underlying respiratory disease.
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PMID:Neuraminidase inhibitors in patients with underlying airways disease. 1472 62


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