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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biochemical properties of 39 strains of Haemophilus avium from chickens were determined. All the strains produced acid from fructose, galactose, glucose and mannose but not from lactose. Variable reactions were found for arabinose, maltose, mannitol, sorbitol, trehalose and xylose. No strains showed urease activity or produced indole, while beta-galactosidase and/or ornithine decarboxylase activity was present in some strains. This variability allowed the recognition of 15 biochemical biovars including some not previously recognized in H. avium. Only 25 (64%) of the H. avium strains could be assigned to the three species (Pasteurella avium, P. volantium and Pasteurella species A) recently proposed to replace H. avium.
J Gen Microbiol 1988 Oct
PMID:Biochemical properties of catalase-positive avian haemophili. 315 Dec 6

The organisms cultured and their antibiotic sensitivities, together with clinical details, were obtained from all the available bacteriology requestlresult forms from a rural practice over a six-year period. The 3022 bacteriology specimens analysed yielded 997 potential pathogens. The main infections studied were those of the urinary tract, the upper respiratory tract and the skin and soft tissue. In spite of the fact that trimethoprim alone had never been used in the practice, 29% of urinary tract pathogens were resistant to this drug. Ninety-six per cent of isolates of Haemophilus influenzae were sensitive to ampicillin. The overall results suggest that most infectious disease in rural general practice can be managed with a limited and inexpensive antibiotic regimen. Such a regimen is described.
J R Coll Gen Pract 1988 Mar
PMID:The bacteriology of a rural general practice: a retrospective six-year study. 320 78

Haemophilus somnus expresses two types of receptors that bind to the Fc region of bovine IgG, IgA and IgM. In this study, the relationship between these two types of Fc receptors is characterized. The high molecular mass receptors (350, 270 and 120 kDa) were secreted into the culture medium and were also in the insoluble protein fraction of the culture medium. The 41 kDa Fc receptor, which is a major outer-membrane protein, was only present in the insoluble protein fraction. Peptide mapping of the two types of Fc receptors suggests that the 41 kDa receptor is related to the high molecular mass receptor complex. Disulphide linkage is unlikely to be the mechanism of association of the 41 kDa receptor with the high molecular mass receptors since reducing agents had no effect on separating the individual receptors. Although the 41 kDa receptor is a major protein in the outer membrane of H. somnus, it does not react with convalescent bovine sera in Western blots. In contrast, convalescent bovine sera reacts intensely with the high molecular mass receptors in Western blots.
J Gen Microbiol 1988 Jul
PMID:Characterization of two Haemophilus somnus Fc receptors. 324 93

The utilization of exogenous nicotinamide adenine dinucleotide (NAD) by Haemophilus parainfluenzae was studied in suspensions of whole cells using radiolabelled NAD, nicotinamide mononucleotide (NMN), and nicotinamide ribonucleoside (NR). The utilization of these compounds by H. parainfluenzae has the following characteristics. (1) NAD is not taken up intact, but rather is degraded to NMN or NR prior to internalization. (2) Uptake is carrier-mediated and energy-dependent with saturation kinetics. (3) There is specificity for the beta-configuration of the glycopyridine linkage. (4) An intact carboxamide groups is required on the pyridine ring. The intracellular metabolism of NAD was studied in crude cell extracts and in whole cells using carbonyl-14C-labelled NR, NMN, NAD, nicotinamide, and nicotinic acid as substrates in separate experiments. A synthetic pathway from NR through NMN to NAD that requires Mg2+ and ATP was demonstrated. Nicotinamide was found as an end-product of NAD degradation. Nicotinic acid mononucleotide and nicotinic acid adenine dinucleotide were not found as intermediates. The NAD synthetic pathway in H. parainfluenzae differs from the Preiss-Handler pathway and the pyridine nucleotide cycles described in other bacteria.
J Gen Microbiol 1988 Oct
PMID:Utilization and metabolism of NAD by Haemophilus parainfluenzae. 325 36

Twenty-five Haemophilus parainfluenzae strains were characterized for lipopolysaccharide (LPS) profiles, outer membrane protein profiles, serum sensitivity, plasmid profiles and DNA homology. Seventeen strains produced low-Mr LPS that did not contain O-sidechains, while the remaining eight strains contained ladder-like LPS suggestive of O-repeated units. This is the first time in the genus Haemophilus that LPS with O-repeated groups has been described. The strains producing the different types of LPS could not be distinguished from each other in outer membrane protein profiles or the other characteristics examined.
J Gen Microbiol 1986 Mar
PMID:Characterization of Haemophilus parainfluenzae strains with low-Mr or ladder-like lipopolysaccharides. 348 70

The small plasmid pAT4 transformed at characteristically low frequencies those competent Haemophilus influenzae Rd strains that had no DNA homology with this plasmid. Transformation was increased up to 100 times, however, when the recipient cells were exposed to 30% glycerol before plating for transformants. Expression of plasmid resistance markers was then immediate. Ultraviolet irradiation experiments indicated that this large increase was due to release by the glycerol of double-stranded plasmid molecules, presumably from transformasomes. Several other plasmids exhibited the same phenomenon. Dimethylsulfoxide also stimulated plasmid transformation but lysolecithin and high concentrations of NaCl or glucose were ineffective. Glycerol did not increase the efficiency of transformation by either chromosomal DNA or linearized plasmid DNA.
Mol Gen Genet 1986 May
PMID:Effect of glycerol on plasmid transfer in genetically competent Haemophilus influenzae. 348 89

Outer membrane proteins (OMPs) were prepared from 20 previously established subtypes of Haemophilus influenzae type b. Proteins were separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (11% acrylamide). Each lane in the gels contained two internal molecular weight standards. One central lane contained a range of molecular weight standards, which were used to calculate a molecular weight curve for each gel. Migration distances of the OMPs were determined with a soft laser-scanning densitometer, and the distances were normalized by using the mean migration distances of the internal standards. The protein patterns of all subtypes were compared by a recently described method (B.D. Plikaytis, G.M. Carlone, and B.B. Plikaytis, J. Gen. Microbiol. 132:2653-2660, 1986). All subtypes could be differentiated by this method. The ability to store and compare numerous OMP patterns from different isolates of H. influenzae type b, separated with a single homogeneous polyacrylamide gel, will facilitate the continued development of a subtyping system based on these proteins.
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PMID:Separation of Haemophilus influenzae type b subtypes by numerical analysis. 349 45

Penicillin-binding protein (PBP) alterations have been associated with non-beta-lactamase-mediated ampicillin resistance in Haemophilus influenzae. We evaluated the PBP profiles of several ampicillin-susceptible and -resistant clinical isolates of H. influenzae to determine how consistently the described alterations occurred, and to document the reproducibility of the PBP profiles for this species. The MIC of ampicillin ranged from 0.06 to 0.13 microgram ml-1 for the susceptible isolates at an inoculum of 100,000 c.f.u. when tested by broth dilution, and was 0.5 microgram ml-1 for all four isolates when tested by agar dilution. The MIC for the resistant isolates ranged from 4 to 8 micrograms ml-1 when tested by broth dilution, and from 1.5 to 16 micrograms ml-1 when tested by agar dilution. At least eight distinct PBPs with molecular masses ranging from 27 to 90 kDa were detected both in cell membrane preparations and whole cell (in vivo) binding assays done on cells in the exponential growth phase. PBP variability was evident both in the ampicillin-susceptible and -resistant isolates; however, much greater variability existed within the four resistant strains. The differences in PBP patterns included (1) electrophoretic mobility, (2) binding capacity for the antibiotic and (3) the presence of additional PBPs in two of the resistant isolates. However, decreased binding capacity was consistently demonstrated in PBP 5 (56 kDa) of all of the resistant isolates. Saturation curves with both penicillin and ampicillin indicated that PBP 5 had decreased affinity for the antibiotics.(ABSTRACT TRUNCATED AT 250 WORDS)
J Gen Microbiol 1986 Oct
PMID:Ampicillin resistance and penicillin-binding proteins of Haemophilus influenzae. 349 5

Lipopolysaccharide (LPS) from all six serotype strains of Haemophilus influenzae was similar in composition. The oligosaccharide, of each LPS, was composed of glucose, galactose, heptose and 2-keto-3-deoxyoctonic acid. The lipid A was composed of glucosamine, phosphate and the fatty acids 14:0 and 3-OH 14:0. Each LPS also contained ethanolamine and ethanolamine phosphate, and the oligosaccharides from two strains additionally contained small amounts of glucosamine. Although the LPS was similar in composition, different serotypes had quantitative differences, especially in the galactose content, which correlated with the antigenic specificity of their homologous antisera and with their mobility on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). A survey by SDS-PAGE showed that LPS from strains of the serotypes a, c and d was characteristically of lower Mr than the LPS from most (80%) serotype b strains.
J Gen Microbiol 1987 Jun
PMID:Composition of the lipopolysaccharide from different capsular serotype strains of Haemophilus influenzae. 349 80

Studies on the pathogenesis of Haemophilus influenzae b infection have used bacteria grown in vitro which are relatively serum-sensitive (using serum devoid of anticapsular antibody) compared to organisms taken from infected hosts. We compared the virulence of relatively serum-sensitive and serum-factor induced serum-resistant H. influenzae b by inoculating rats with organisms having one or the other phenotype. The serum-resistant phenotype was more virulent following intraperitoneal or intravenous inoculation; however, there was no difference in the incidence of colonization or bacteraemia following intranasal inoculation. Furthermore, organisms colonizing the pharynx of rats had the serum-resistant phenotype. Thus, different phenotypes of the same strain of H. influenzae b differed in virulence following parenteral, but not intranasal, inoculation of bacteria. This could be explained by a change from serum-sensitive to serum-resistant phenotype shortly after entering the nasopharynx. The phenotype of micro-organisms grown in vitro may differ from organisms in infected individuals and these differences may be of critical importance in studies of immunity to infection and the pathogenesis of infection.
J Gen Microbiol 1985 Mar
PMID:The effect of serum-factor induced resistance to somatic antibodies on the virulence of Haemophilus influenzae type b. 387 28


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