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

The percentage of beta-lactamase producing Haemophilus influenzae strains from patients with meningitis in The Netherlands increased from 0% in 1975/1976 to 4.6% in 1985/1986 (n = 1559). Twenty-three isolates resistant to ampicillin, penicillin, chloramphenicol, rifampicin and/or tetracycline were subtyped to determine if one resistant strain was spreading. (Sub)typing was performed by capsular typing, analysis of the major outer membrane protein patterns on sodium dodecylsulfate gels (SDS-PAGE subtypes), lipopolysaccharide serotyping and biotyping. The (sub)types of the resistant strains were similar to those of sensitive strains, thus indicating that antibiotic resistant strains develop at random.
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PMID:Comparison of antibiotic resistant and sensitive strains of Haemophilus influenzae type b in The Netherlands by outer-membrane protein subtyping. 313 38

Envelope proteins of Haemophilus pleuropneumoniae were extracted by 3 methods and analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Three major envelope proteins (45,000 Mr, 41,000 Mr, 31,500 Mr) were distinguished in sonicated cell envelopes together with minor proteins. Using selective solubilisation with sodium lauryl sarcosinate or Triton X-100, outer membrane proteins were distinguished from those of the cytoplasmic membrane. Extraction into LiCl produced a similar profile, but the 41,000 Mr and 31,500 Mr bands were present in reduced amounts. Extraction into saline at 60 degrees C produced a grossly different pattern, with a major band at 20,000 Mr. All 3 major envelope proteins were shown to be heat-modifiable, and the 31,500 Mr band was found to be the non-heat-modified form of a 43,000 Mr protein, which showed similar properties to the Protein d of H. influenzae which is related to the OmpA protein of E. coli K-12. The 45,000 Mr major protein was also weakly associated with the peptidoglycan in SDS/Triton at low temperature.
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PMID:Preparation and characterisation of envelope proteins from Haemophilus pleuropneumoniae. 332 48

After three serial passages of Haemophilus influenzae type b strain Fuju in rats, we recovered a variant, which differed in colonial morphology, serum sensitivity, and lipopolysaccharide configuration from the parent strain. The parent organism (Fuju) appeared iridescent and transparent on Levinthal agar, and the rat-passaged variant (rat3 Fuju) appeared iridescent and opaque. The transparent, parent strain Fuju was sensitive to the complement-mediated bactericidal activity of normal rat serum, and the opaque, rat-passaged strain rat3 Fuju was serum resistant. Serum killing of the serum-sensitive strain appeared to be mediated by the classic complement pathway. Both serum-resistant and serum-sensitive strains were killed equally well by immune rat and human serum. These two strains did not differ in the amount of capsular polysaccharide that they elaborated nor in their major outer membrane protein patterns on SDS-PAGE. Lipopolysaccharide isolated from these two strains demonstrated different electrophoretic mobility patterns. Furthermore, the organisms showed different reactivities with two monoclonal antibodies directed against determinants of Hib lipopolysaccharide. Thus, the difference in susceptibility to complement-mediated bactericidal activity of normal rat serum displayed by these two strains is associated with their phenotypes, appears to be unrelated to differences in major outer membrane proteins or in the amounts of capsular polysaccharide elaborated, and is associated with differences in surface lipopolysaccharides.
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PMID:Susceptibility of phenotypic variants of Haemophilus influenzae type b to serum bactericidal activity: relation to surface lipopolysaccharide. 348 71

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of lipopolysaccharide (LPS) was performed to assess the usefulness of this technique for the epidemiologic analysis of Haemophilus influenzae type b isolates. LPS samples were prepared from isolates which had been passaged either in vitro or in infant rats. Preparations from paired isolates from a number of epidemiologically related clinical situations also were examined. The gel patterns of LPS prepared on different occasions from an individual isolate were stable. However, the LPS gel patterns changed in 5 of 14 (36%) of the passaged isolates, and differences in gel patterns also were observed among epidemiologically related isolates. The variability in LPS electrophoretic patterns of individual isolates indicated that this technique is not useful for the epidemiologic analysis of H. influenzae type b disease.
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PMID:Lipopolysaccharide gel profiles of Haemophilus influenzae type b are not stable epidemiologic markers. 348 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.
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PMID:Composition of the lipopolysaccharide from different capsular serotype strains of Haemophilus influenzae. 349 80

The incidence and mechanisms of ampicillin resistance (MIC greater than 1 mg/l) were investigated in 105 clinical isolates of Haemophilus influenzae collected in Edinburgh during 1983/4. Fifteen (14.3%) ampicillin-resistant strains were identified and these were non-serotypable and comprised six biotypes. Isoelectric focusing and beta-lactamase-inhibition studies demonstrated that production of the TEM-1 beta-lactamase was the principal mechanism of resistance in nine (60%) strains. Radiolabelling revealed that one beta-lactamase-positive strain also had an unusual penicillin-binding protein (PBP) profit. No beta-lactamase activity was detected in the other six (40%) ampicillin-resistant strains. Two beta-lactamase-negative ampicillin-resistant strains had atypical PBP profiles. SDS-PAGE analysis showed that four beta-lactamase-negative ampicillin-resistant strains, including one with altered PBPs, exhibited outer membrane protein profiles which differed from those of sensitive strains of the same biotype. The ampicillin-resistance mechanism of the remaining strain could not be determined. Thus, several resistance mechanisms, either acting individually or in combination, are implicated in ampicillin resistance in H. influenzae.
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PMID:Ampicillin resistance in Haemophilus influenzae: identification of resistance mechanisms. 350 21

The ability of convalescent serum to passively protect calves against Haemophilus somnus-induced pneumonia was studied. Preimmune and convalescent serum were obtained from calves before or after recovery from experimental chronic H. somnus pneumonia. Passive protection was assessed in another group of calves by intrabronchial inoculation of H. somnus that had been incubated with preimmune or convalescent serum. Each calf was inoculated with each treatment in alternating caudal lung lobes. Twenty-four hours after inoculation almost no pneumonia was present in lungs inoculated with bacteria incubated with convalescent serum, whereas severe pneumonia was present in lungs inoculated with bacteria incubated with preimmune serum. Quantitation of calf pneumonia in both treatment groups indicated a significantly different protective capacity between convalescent serum and preimmune serum (P less than 0.0005). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Western blotting of purified H. somnus lipopolysaccharide resulted in intense reactivity with convalescent serum, but no reactivity was detected with preimmune serum. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis of H. somnus outer membrane-enriched fractions, Western blots with convalescent serum gave intense reactions against H. somnus outer membrane antigens with apparent molecular masses of 78 and 40 kilodaltons and weaker reactions with 60-, 34-, 31-, 29-, 18-, and 15-kilodalton outer membrane antigens. No reactivity was detected with preimmune serum. Antibodies eluted from H. somnus after adsorption of convalescent serum reacted almost identically to unadsorbed convalescent serum in Western blots against bacterial outer membrane-enriched fractions. Thus, most of the antigens recognized by convalescent serum are likely to be on the bacterial surface and accessible to antibody. Surface antigens recognized by protective convalescent serum are candidate antigens for a subunit vaccine against H. somnus pneumonia.
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PMID:Protective ability and specificity of convalescent serum from calves with Haemophilus somnus pneumonia. 357 Apr 72

Chloramphenicol resistance in Haemophilus influenzae occurs most frequently via plasmid-mediated chloramphenicol acetyltransferase production. We studied four strains with high-level chloramphenicol resistance (MIC greater than 20 micrograms/ml) which did not have detectable chloramphenicol acetyltransferase activity. The chloramphenicol resistance determinant was transformed into a chloramphenicol-susceptible laboratory H. influenzae strain from each of the four wild-type strains, enabling isogenic comparisons. By thin-layer chromatography and a bioassay, there was no evidence of non-chloramphenicol acetyltransferase modification of chloramphenicol. In vitro protein synthesis in the presence of chloramphenicol was equivalently inhibited in the chloramphenicol-resistant transformants and in the susceptible recipient. Chloramphenicol uptake by these strains during logarithmic growth was compared by high-pressure liquid chromatographic quantitation; at chloramphenicol concentrations of 5, 10, and 20 micrograms/ml the four transformants showed a decreased rate of uptake of chloramphenicol compared with the isogenic chloramphenicol-susceptible recipient. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of outer membrane proteins revealed a markedly diminished 40-kilodalton protein in the resistant transformants. We propose that the mechanism of chloramphenicol resistance in these strains is a relative permeability barrier due to the loss of an outer membrane protein.
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PMID:A permeability barrier as a mechanism of chloramphenicol resistance in Haemophilus influenzae. 387 25

Major outer membrane antigens, proteins, and lipopolysaccharides (LPSs), from nontypable Haemophilus influenzae were characterized and examined as targets for complement-dependent human bactericidal antibodies. Outer membranes from two nontypable H. influenzae isolates that caused otitis media and pneumonia (middle ear and transtracheal aspirates) were prepared by shearing organisms in EDTA. These membranes were compared with membranes prepared independently by spheroplasting and lysozyme treatment of whole cells and found to have: similar sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of the proteins; identical densities (rho = 1.22 g/cm3); and minimal d-lactose dehydrogenase activity indicating purity from cytoplasmic membranes. Outer membranes were solubilized in an LPS-disaggregating buffer and proteins were separated from LPS by molecular sieve chromatography. The SDS-PAGE patterns of outer membrane proteins (OMPs) from the two strains differed in the major band although other prominent bands appeared similar in molecular weight. LPS prepared by hot phenol water extraction of each of the strains contained 45% (pneumonia isolate) and 60% (otitis isolate) lipid (wt/wt), 49% and 50% carbohydrate (wt/wt), respectively, and less than 1%, 3-deoxy-manno octulosonic acid. Immunoglobulin M (IgM) purified from normal human serum (NHS) plus complement was bactericidal for both strains. Purified immunoglobulin G (IgG) from NHS killed the middle ear isolate and immune convalescent IgM from the serum of the patient with pneumonia killed his isolate. NHS or convalescent serum were absorbed with OMPs and LPS (0.6-110 micrograms) from each of the strains and immune specific inhibition of bactericidal antibody activity by each antigen was determined. OMPs from the pulmonary isolate inhibited bactericidal antibody activity directed against the isolate in both NHS (1.5 microgram of antigen) and immune serum (0.75 microgram of antigen). OMPs (60 micrograms) from the ear isolate also inhibited bactericidal activity in the respective immune serum. LPSs exhibited minimal inhibition (greater than 110 micrograms). Three human sera (two normal, one immune) were selectively depleted of 80% of antibody activity against OMPs (measured by enzyme-linked immunosorbent assay) by affinity chromatography using OMPs from the pulmonary isolate coupled to a solid phase. These OMP antibody-depleted sera also showed an 88% reduction of bactericidal activity against this strain. Immunopurified antibody against OMPs eluted from the solid phase was bactericidal.
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PMID:Characterization of antigens from nontypable Haemophilus influenzae recognized by human bactericidal antibodies. Role of Haemophilus outer membrane proteins. 387 75

The whole-cell proteins of 105 clinical isolates of Haemophilus ducreyi from several geographic sources (North America, Africa, Asia, and Europe) were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein profiles were reproducible and unaffected by repeated subculturing or age of culture. At least seven different subtypes were determined by proteins in the molecular weight range of 24,000-50,000. These proteins are located in the outer membrane of the cell, as determined by SDS-PAGE of the sarcosinate-insoluble membrane preparations of these strains. Thirteen isolates from a Winnipeg, Manitoba, Canada, outbreak of chancroid had identical patterns, suggesting a common origin. Although H ducreyi shares a number of proteins in common with other Haemophilus species, the protein profiles appear to be species specific. Heterogeneity in the protein composition of H ducreyi has provided a basis for subtyping, which could be of value in future epidemiologic studies.
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PMID:Characterization of cell proteins of Haemophilus ducreyi by polyacrylamide gel electrophoresis. 660 92


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