Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of potential pathogens to acquire iron in a host is an important determinant of both their virulence and the nature of the infection produced. Virulent gram-negative bacteria are capable of acquiring sufficient iron from the host because their virulence (for chick embryos) is unaffected by exogenous iron. Avirulent mutants which are apparently limited in their ability to acquire iron could be isolated from the virulent strains. The lethality of these mutants was significantly enhanced by exogenous iron. Reduction of the relatively high serum iron saturation of chick embryos (to levels more closely approximating those in man) by pretreatment with iron-binding proteins or endotoxin inhibits the lethality of some virulent bacteria. Those bacteria whose virulence was reduced include the Shigella, Vibrio cholerae and strains of Neisseria gonorrhoeae, all of which are nondisseminating pathogens in the normal human host. Pathogens which produce septicemic and disseminating infections such as Neisseria meningitidis, Haemophilus influenzae type B, Escherichia coli possessing K-1 antigen, Pseudomonas aeruginosa and Salmonella typhimurium and disseminating strains of N. gonorrhoeae were, in general, unaffected by reduced serum iron saturation. These disseminating bacteria appeared to produce greater quantities of compounds (siderophores) which stimulated microbial growth in low-iron media than did the nondisseminating pathogens. Thus, the gram-negative bacteria tested can be divided into four major classes according to their responses to modifications in iron levels in the chick embryo model and these results correlate with the nature of the infections which they typically produce in man.
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PMID:The critical role of iron in host-bacterial interactions. 65 5

The mutated gene in JG16, a Haemophilus influenzae strain deficient in competence-induced DNA binding and uptake, was cloned and the wild-type allele was sequenced. The gene was shown by Northern analysis to be constitutively expressed on a 1.7-kilobase transcript. The gene product was identified as a 20.6-kDa protein targeted to the periplasm. The protein contains the sequence Cys-Pro-His-Cys (CPHC) and is highly similar to two other periplasmic CPHC motif-containing proteins: DsbA, an Escherichia coli protein (45% identity, 87% homology) and TcpG, a Vibrio cholerae protein (32% identity, 74% homology). Both DsbA and TcpG promote disulfide bond formation in periplasmic proteins, are required for pilus biogenesis, and, like thioredoxin, are capable of reducing insulin in vitro. The Haemophilus protein was shown to complement an E. coli mutation in DsbA and was named Por (periplasmic oxidoreductase). In JG16 the competence-dependent redistribution of inner membrane proteins did not occur. These findings suggest that Por is required for the correct assembly and/or folding of one or more disulfide-containing cell envelope protein involved either in competence development or in the DNA-binding and -uptake machinery.
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PMID:A periplasmic protein disulfide oxidoreductase is required for transformation of Haemophilus influenzae Rd. 143 13

Freeze-substitution was performed on strains of Escherichia coli, Pasteurella multocida, Campylobacter fetus, Vibrio cholerae, Pseudomonas aeruginosa, Pseudomonas putida, Aeromonas salmonicida, Proteus mirabilis, Haemophilus pleuropneumoniae, Caulobacter crescentus, and Leptothrix discophora with a substitution medium composed of 2% osmium tetroxide and 2% uranyl acetate in anhydrous acetone. A thick periplasmic gel ranging from 10.6 to 14.3 nm in width was displayed in E. coli K-12, K30, and His 1 (a K-12 derivative containing the K30 capsule genes), P. multocida, C. fetus, P. putida, A. salmonicida, H. pleuropneumoniae, and P. mirabilis. The other bacteria possessed translucent periplasms in which a thinner peptidoglycan layer was seen. Capsular polysaccharide, evident as electron-dense fibers radiating outward perpendicular to the cell surface, was observed on E. coli K30 and His 1 and P. mirabilis cells. A more random arrangement of fibers forming a netlike structure was apparent surrounding cells of H. pleuropneumoniae. For the first time a capsule, distinct from the sheath, was observed on L. discophora. In all instances, capsular polysaccharide was visualized in the absence of stabilizing agents such as homologous antisera or ruthenium red. Other distinct envelope structures were observed external to the outer membrane including the sheath of L. discophora and the S layers of A. salmonicida A450 and C. crescentus CB15A. We believe that the freeze-substitution technique presents a more accurate image of the structural organization of these cells and that it has revealed complex ultrastructural relationships between cell envelope constituents previously difficult to visualize by more conventional means of preparation.
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PMID:Freeze-substitution of gram-negative eubacteria: general cell morphology and envelope profiles. 199 83

With the exception of a few consistent pathogens--Pasteurella multocida strains of bovine hemorrhagic septicemia and fowl cholera, Actinobacillus (Haemophilus) pleuropneumoniae, Haemophilus aegyptius and Haemophilus paragallinarum--members of the family Pasteurellaceae are commensal parasites on mucous membranes of vertebrate animals. Many have pathogenic potential, which becomes manifest under conditions of immunodeficiency and stress. Pathogenesis (except in porcine atrophic rhinitis) depends on mobilization of inflammatory responses probably in large part by endotoxin with contributions from protein toxins, which interfere with leukocyte activity and, by their cytotoxicity, cause exacerbation of the inflammatory reaction. Disease patterns include pneumonic/septicemic, upper respiratory and local/traumatic. Acquired resistance is chiefly antibody-dependent, and, with current and emerging biotechnical resources, stands a good chance of being artificially achievable for many important diseases attributed to Pasteurellaceae.
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PMID:Our understanding of the Pasteurellaceae. 219 10

Two cases of infectious coryza in meat chickens are reported. The first case involved 6-week-old broiler chickens in which only Haemophilus paragallinarum was isolated. The second case involved 11-week-old roaster chickens in which H. paragallinarum and Mycoplasma synoviae were isolated. Both farms were in close proximity to layer-chicken farms where infectious coryza had been previously diagnosed. In both cases, only certain houses on the farm were affected, and mortality in these houses increased slightly. At processing, the condemnation rates for affected houses were considerably higher than rates for unaffected houses. Condemnations for affected houses were mostly due to airsacculitis. A dissecting fibronopurulent cellulitis was a prominent lesion in the second case. This lesion could lead to confusion with chronic fowl cholera and swollen-head syndrome.
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PMID:Infectious coryza in meat chickens in the San Joaquin Valley of California. 228 6

Two commercial enzyme-linked immunosorbent assay (ELISA) kits, seven serum plate agglutination (SPA) antigens, and the hemagglutination-inhibition (HI) test for antibodies to Mycoplasma gallisepticum (MG) were compared for sensitivity and specificity using known MG-positive and MG-negative sera from leghorn chickens. All SPA antigens proved to be highly sensitive when testing MG-positive sera. Laboratory-prepared SPA antigens yielded fewer positive reactions when testing MG-negative sera than commercial SPA antigens. Both MG ELISA kits showed high rates of positive reactions when testing sera from birds given commercial M. synoviae bacterin, fowl coryza (Haemophilus paragallinarum) bacterin, inactivated infectious bursal disease virus vaccine, and to a lesser extent fowl cholera (Pasteurella multocida) bacterin. Immunization with Frey's medium with 12% swine serum-in-oil or Staphylococcus aureus-in-oil resulted in sera which yielded numerous positive ELISA reactions. During the first 1 to 3 weeks, antibodies induced by experimental infection with MG were better detected by the SPA test than by the ELISAs and the HI test, thus confirming the SPA test's importance in Mycoplasma diagnostic serology. The HI test can serve to confirm positive SPA results.
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PMID:Evaluation of the specificity and sensitivity of two commercial enzyme-linked immunosorbent assay kits, the serum plate agglutination test, and the hemagglutination-inhibition test for antibodies formed in response to Mycoplasma gallisepticum. 304 57

In developing countries, where economic development is lacking and literacy rates are low, priority must be given to primary health care and to the establishmend of sustainable health care delivery systems. The World Health Organization's Expanded Program of Immunization was designed with the goal of immunizing all children against measles, pertussis, tetanus, poliomyelitis, tuberculosis, and diphtheria by 1990. A second function of the immunization program is to establish a health care delivery system. Today 50% of infants receive 3 doses of diptheria/pertussis/tetanus and polio vaccines, and 70% receive at least 1 dose. Measles kills 2 million children every year. The standard strain of attenuated vaccine is given at 9 months, and 1 dose protects 95% of children for life. Tetanus kills 800,000 infants every year. The vaccine must be refrigerated, and 2 doses are essential. Tuberculosis kills 2 million children under 5 every year. The attenuated BCG vaccine should be given at birth, and a single dose confers some protection. Diphtheria is most common among poor, urban children in termperate climates, and 3 doses of toxoid at monthly intervals are recommended. Poliomyelitis paralyzes 250,000 children a year. 4 doses of live attenuated Sabin vaccine are recommended. The vaccine is very sensitive to heat. Other vaccines in use or being developed include yellow fever, meningococcus, Japanese B encephalitis, rubella, hepatitis B, cholera, rotavirus, pneumonococcus, and Haemophilus influezae. 2 problems that confront the delivery of health services, including immunization, are lack of funds and lack of access to susceptible populations. Approaches to the lack of funds problem include fee for service, taxation, beter management of existing resources, reallocation of health resources, and increased funding from donor nations. Approaches to the problem of access include vaccination whenever children come into contact with a health facility for any reason, channeling by members of the community, involvement of traditional healers and birth attendants, outreach services, mass campaigns, pulse technics, and financial incentives.
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PMID:Vaccination strategies in developing countries. 305 59

The antibacterial activity of ofloxacin, a new fluoroquinolone, was evaluated against a wide range of clinical bacterial isolates and compared with that of nalidixic acid, norfloxacin, enoxacin, pefloxacin and ciprofloxacin by determination of minimum inhibitory concentrations (MICs). Ofloxacin was very active against nalidixic acid-susceptible isolates of the Enterobacteriaceae (MIC less than or equal to 0.12 mg/l) and was also active against strains resistant to nalidixic acid (MIC less than or equal to 2 mg/l). The activity was similar to norfloxacin, enoxacin and pefloxacin but some four-fold less than that of ciprofloxacin. All of the fluoroquinolones were highly active against Vibrio cholerae (MIC less than or equal to 0.015 mg/l), V. parahaemolyticus (MIC less than or equal to 0.12 mg/l) Aeromonas hydrophila (MIC less than or equal to 0.03 mg/l), Plesiomonas shigelloides (MIC less than or equal to 0.015 mg/l), Campylobacter jejuni (MIC less than or equal to 0.5 mg/l), Neisseria spp., Haemophilus influenzae, H. ducreyi, Bordetella pertussis and Legionella pneumophila (MIC less than or equal to 0.06 mg/l for all species). Ofloxacin, ciprofloxacin and pefloxacin (MIC less than or equal to 1, 2 and 2 mg/l, respectively) showed similar activity against Staphylococcus spp. and were somewhat more active than enoxacin (MIC less than or equal to 4 mg/l) and norfloxacin (MIC less than or equal to 8 mg/l). Ofloxacin was moderately active against beta-haemolytic Streptococcus spp. (MIC less than or equal to 2 mg/l), Corynebacterium diphtheriae (MIC less than or equal to 1 mg/l) and Cory. jeikeium (MIC less than or equal to 2 mg/l) and somewhat less active against alpha- and non-haemolytic Streptococcus spp., Str. pneumoniae and Listeria monocytogenes (MIC less than or equal to 4 mg/l for all species) and Str. faecalis (MIC less than or equal to 8 mg/l). The activity of ofloxacin, against these species, was similar to ciprofloxacin and four to eight times greater than norfloxacin, enoxacin and pefloxacin. Ofloxacin, and all of the fluoroquinolones, were less active against anaerobic than aerobic bacteria. Clostridium perfringens (MIC less than or equal to 1 mg/l) was more susceptible to ofloxacin than were other anaerobic species and Cl. difficile (MIC less than or equal to 16 mg/l) was more resistant. Ofloxacin was the most active compound tested against Chlamydia trachomatis SA2f (MIC less than or equal to 0.5 mg/l) with only ciprofloxacin (MIC less than or equal to 1 mg/l) approaching similar activity.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The comparative in-vitro activity of ofloxacin. 318 68

The in vitro activity of nine fluoroquinolones has been determined by agar dilution method against 1100 clinical isolates of different microorganisms: 412 Enterobacteriaceae, 93 non-fermenters, 398 enteropathogens, 140 Gram-positive cocci, 31 Haemophilus and 26 gonococci. The bactericidal activity tested in broth against different representative isolates was generally similar to the inhibitory concentration. Killing kinetics studied in different isolates of Enterobacteriaceae, in Pseudomonas aeruginosa, Vibrio cholerae, Staphylococcus aureus and Streptococcus faecalis showed a very rapid bactericidal effect, after 2 to 8 h of contact, in all species except in Streptococcus faecalis.
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PMID:In vitro activity and mode of action of fluoroquinolones. 343 48

Cefotaxime and its desacetoxymethyl derivative, ceftizoxime (previously known as FK749), are both extremely active against a wide spectrum of bacteria. In the present comparative study, the activity of ceftizoxime exceeded that of cefotaxime by a factor of four or more for strains of Klebsiella, Enterobacter, Providencia, Serratia, and Bacteroides; the only species for which the activity of cefotaxime exceeded that of ceftizoxime by a factor of four was Vibrio cholerae. Against other species, the activity of the two drugs was roughly comparable. Both showed outstanding activity against Haemophilus influenzae and Neisseria gonorrhoeae. Comparative turbidimetric and morphological studies revealed that ceftizoxime was able to induce spheroplast formation and rapid lysis in Escherichia coli strains at lower concentrations than cefotaxime. This difference was not found, however, when E. coli strains resistant to ampicillin by an intrinsic (nonenzymic) mechanism were tested.
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PMID:Comparative in vitro activities of cefotaxime and ceftizoxime (FK749): new cephalosporins with exceptional potency. 625 29


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