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Query: UNIPROT:O75191 (H. influenzae)
 4,961 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A micromethod utilizing paper discs impregnated with different substrates (Minitek-system) permits differentiation of Haemophilus and their biotypes. Differentiation of biotypes presents an assured advantage: it is the only technic for an exact study of non typable H. influenzae strains and NAD-dependent Haemophilus strains. It is also a complement for study of capsulated H. influenzae. In an epidemiological aspect, this differentiation shows a evident predominance of biotypes I and II for H. influenzae and H. para-influenzae. Except that biotype I includes the larger number of serotypable strains, different serotypes are distributed in the five biotypes of H. influenzae. Likewise none relation has been found between biotypes and antibiotypes.
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PMID:[Utilization of a micromethod for the differentiation of Haemophilus biotypes. Relations with serotypes and antibiotypes (author's transl)]. 39 66

There has not previously been an objective comparison of medium formulations for the primary isolation of Haemophilus species. This study was undertaken to evaluate the components required for the optimal growth of large, easily identifiable colonies of these bacteria. We compared six medium bases and seven supplements for their ability to support the growth of 86 strains of Haemophilus influenzae and 17 strains of other species of Haemophilus. By using a growth index that combines colony size and the dilution factor, a formulation of GC agar base with 1% yeast autolysate and 5% sheep blood (chocolated) promoted the growth of large, easily recognizable colonies of H. influenzae and other Haemophilus species. This medium was designated GCYSB. The addition of hematin to supplements that supplied NAD (or factor V) to the medium was inhibitory to the growth of all of the Haemophilus species tested. In a clinical comparison of GCYSB with routinely used chocolate agar medium in two laboratories for the primary isolation of Haemophilus species, overall GCYSB promoted better growth of 124 strains of H. influenzae and H. parainfluenzae. GCYSB is easy to prepare and inexpensive compared with the ease of preparation and expense of other Haemophilus isolation media.
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PMID:Laboratory and clinical evaluations of media for the primary isolation of Haemophilus species. 150 Apr 94

The location of the genes coding for NAD independence in four unusual clinical isolates of Haemophilus parainfluenzae was determined by transferring these genes to plasmid-free Haemophilus influenzae Rd by transformation and analysing transformants for the presence of plasmids by agarose gel electrophoresis. All NAD-independent transformants were found to carry a single plasmid species. The plasmids, originally harboured by the four H. parainfluenzae isolates recovered from unrelated sources, were of the same size (5.25 kb). Spontaneous reversion to NAD dependence occurred with a low frequency (0.1 to 0.2% of the progeny of a single clone) in both H. parainfluenzae and H. influenzae Rd. The revertants had lost this small plasmid. Mitomycin C exhibited a plasmid 'curing' effect with a frequency of 'curing' of between 1 and 6% of the surviving clones. It was concluded that the genes conferring NAD independence were located on the small 5.25 kb plasmid.
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PMID:Plasmid-mediated NAD independence in Haemophilus parainfluenzae. 177 Mar 56

Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs. These compounds and several other nicotinamide riboside analogs were evaluated for their ability to support the growth of H. influenzae and for their ability to block the uptake of [carbonyl-14C]nicotinamide riboside by H. influenzae. 3-Aminopyridine riboside blocked the uptake of [carbonyl-14C]nicotinamide riboside and inhibited the growth of H. influenzae when NAD, nicotinamide mononucleotide, or nicotinamide riboside served as the V factor. The antibacterial activity of 3-aminopyridine riboside was found to be specific for H. influenzae but had no effect on the growth of Staphylococcus aureus or Escherichia coli. In additional experiments by reversed-phase high-performance liquid chromatography, it was determined that whole cells of H. influenzae degrade 3-aminopyridine adenine dinucleotide to 3-aminopyridine riboside, which is then internalized. Inside the cell, 3-aminopyridine riboside has the ability to interfere with the growth of H. influenzae by an undetermined mechanism.
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PMID:In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae. 214

Previous studies of Haemophilus influenzae documented the importance of several pyridine nucleotide-dependent enzymes in processing extracellular NAD and NMN to satisfy the V-factor growth requirement of the organism. The substrate specificities of two of these enzymes. NMN:ATP adenylyltransferase and NAD kinase, were investigated following partial purification. The ability of the transferase to utilize 3-acetylpyridine mononucleotide and 3-aminopyridine mononucleotide as substrates for the synthesis of the corresponding dinucleotides was demonstrated. The NAD kinase was observed to accept 3-acetylpyridine adenine dinucleotide as a substrate but failed to utilize 3-aminopyridine adenine dinucleotide. The mononucleotides of 3-acetylpyridine and 3-aminopyridine were shown to be as effective as the corresponding dinucleotides in the support of growth and inhibition of growth of H. influenzae, respectively. Inhibition of growth of H. influenzae by submicromolar 3-aminopyridine adenine dinucleotide was shown to occur because 3-aminopyridine mononucleotide was produced from it in reactions catalysed by the H. influenzae periplasmic nucleotide pyrophosphatase. The presence of an additional important pyridine nucleotide-dependent enzyme, NMN glycohydrolase, is also reported.
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PMID:Studies of NAD kinase and NMN:ATP adenylyltransferase in Haemophilus influenzae. 216 21

Haemophilus influenzae D(-)-lactate dehydrogenase (D(-)-lactate:NAD oxidoreductase; EC 1.1.1.28) was purified to electrophoretic homogeneity using salt fractionation, hydrophobic and dye affinity chromatography. The enzyme was purified 2100-fold with a 14% recovery and a final specific activity of 300 units/mg protein. The enzyme was demonstrated to be a tetramer of Mr 135,000. The enzyme catalyzed the reduction of pyruvate to give exclusively D(-)-lactate using NADH as coenzyme. The reaction catalyzed was essentially unidirectional, with the oxidation of D-lactate in the presence of NAD proceeding at less than 0.2% the rate of pyruvate reduction. Kinetic parameters for the reduction of pyruvate were determined for NADH and four structural analogs of the coenzyme. Coenzyme-competitive inhibition by adenosine derivatives indicated the presence of regions in the coenzyme binding site interacting with the adenosine and pyrophosphate moieties of the coenzyme. The purified enzyme was sensitive to oxidation and was effectively inactivated by sulfhydryl reagents. Conversion of D-lactate to pyruvate catalyzed by a membrane-bound D-lactate oxidase was demonstrated in cell-free extracts of H. influenzae.
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PMID:Purification and characterization of Haemophilus influenzae D-lactate dehydrogenase. 230 73

There is poor correlation between the MICs and zone sizes obtained for erythromycin against Haemophilus influenzae. The effect of two media, Mueller-Hinton medium supplemented with 3% lysed horse blood and 10 micrograms of NAD per ml (MHA + LYHB) and Mueller-Hinton agar supplemented with 1% bovine hemoglobin and 1% IsoVitaleX (MHA + HGB), on the MICs and zone sizes of erythromycin against H. influenzae was determined. The effect of three different methods for inoculum preparation on the susceptibility of H. influenzae was also determined. The MICs were independent of the method of inoculum preparation, but the zone sizes were smaller if the inoculum was carefully adjusted to contain approximately 10(8) CFU/ml. MICs were higher and zone sizes were smaller when MHA + HGB was used instead of MHA + LYHB. Good correlation was found when MHA + LYHB was used for determining the MIC and MHA + HGB was used for determining susceptibility by the disk method. When the inoculum was adjusted to match a McFarland 0.5 standard, the viable counts had to be approximately 10(8) CFU/ml for good correlation between MICs and zone sizes. A-56268, a new macrolide antibiotic, was tested against H. influenzae, and its MICs and tentative breakpoints against this organism were determined. The MICs obtained by various methods were correlated with in vivo efficacy by using a mouse septicemia model. MICs obtained on MHA + HGB or MHA + LYHB incubated without a 5% CO2 atmosphere showed the best correlation with in vivo efficacy.
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PMID:Susceptibility testing of macrolide antibiotics against Haemophilus influenzae and correlation of in vitro results with in vivo efficacy in a mouse septicemia model. 295 54

Four separate laboratories performed antimicrobial susceptibility tests with 40 Haemophilus influenzae isolates, each tested in triplicate. Erythromycin and a new macrolide, clarithromycin (A-56268; TE-031), were tested by the disk diffusion method, by the agar dilution procedure in two different media, and by broth microdilution tests in four different media. Erythromycin MICs for 90% of the strains were 16 micrograms/ml in Mueller-Hinton broth with 3% lysed horse blood and NAD, 4.0 micrograms/ml in hemophilus test medium, and 2.0 micrograms/ml in supplemented Schaedler broth or in the fastidious broth medium from Beckman Instruments, Inc. Clarithromycin MICs were generally 1 doubling dilution greater than erythromycin MICs in each of the media. Erythromycin disk tests corresponded best with MICs determined in the fastidious broth medium. In that same medium, clarithromycin MICs were about 1 doubling dilution greater than what would be expected from the results of disk tests. Because there were fewer growth failures, hemophilus test medium is recommended for microdilution tests with H. influenzae. Incubation of all tests for a full 24 h without an increased CO2 atmosphere was needed to achieve maximal precision of the tests. Interlaboratory and intralaboratory reproducibility of all tests was satisfactory.
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PMID:Variability of clarithromycin and erythromycin susceptibility tests with Haemophilus influenzae in four different broth media and correlation with the standard disk diffusion test. 297 73

Both Neisseria meningitidis and Haemophilus influenzae are important isolates recovered in blood cultures from septicemic children. Sodium polyanetholsulfonate is present in most blood culture media and can inhibit the growth of certain bacteria, including N. meningitidis. The addition of gelatin to blood culture media neutralizes this inhibition. The growth of H. influenzae is enhanced by specific growth factors such as hemin and NAD. The addition of gelatin and V-factor-analog (a proprietary supplement for enhancing the growth of H. influenzae) might have a positive effect on the yield and on the speed of detection of septicemia in children. To evaluate this possibility, we did 4,565 paired comparisons of blood cultured in BACTEC 6B (aerobic) medium with and without the addition of both 1.2% gelatin and V-factor-analog. More aerobic and facultative bacteria grew in the 6B than in the 6B-gelatin-V-factor-analog medium (P less than 0.01). Only seven isolates of Neisseria spp. were recovered during this study period, with the 6B medium performing as well as the supplemented medium. When microorganisms grew in both bottles, they did so at the same time except for H. influenzae and Candida albicans. H. influenzae was recovered earlier from the 6B-gelatin-V-factor-analog bottle (P less than 0.01), with a mean time to detection of 8.5 h compared with 15.9 h for the 6B bottle. C. albicans was recovered earlier from the 6B bottle (P less than 0.02), with a mean time to detection of 34.9 h compared with 71.6 h for the 6B-gelatin-V-factor-analog bottle. We conclude that the 6B medium in its present formulation is superior to bB supplemented with gelatin and V-factor-analog.
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PMID:Controlled evaluation of blood culture medium containing gelatin and V-factor-analog for detection of septicemia in children. 336 69

A broth system was developed for rapid identification of the requirement for X factor (hemin), or V factor (NAD), or both for growth of Haemophilus species. This system was compared to growth around paper discs/strips impregnated with factors X and/or V. The broth system consisted of three tubes, each containing brain-heart infusion broth supplemented with V factor, X factor, or both. Each tube was inoculated with a saline suspension of an Haemophilus isolate, and the broths were shaken for aeration at 37 degrees C. Under these conditions turbidity or clumping was usually evident after 4-5 hr only in the broth(s) containing the required supplement(s). A few strains requiring only V factor required overnight incubation. One hundred fifty-six Haemophilus isolates were tested for growth around supplemented discs/strips or in supplemented broths: 129 were H. influenzae/aegypticus, 25 were of various species that required only V factor, and 2 were H. aphrophilus. Ten of 89 H. influenzae isolates from the respiratory tract were misidentified by satellitism. All isolates were correctly identified by growth in supplemented broths. The cost of the broth assay was about 60 cents/test, whereas the satellite assay cost about 120 cents/test. Serotyping and antibiotic sensitivity testing could be performed directly from the broth culture. Determination of X and/or V requirement by Haemophilus species with supplemented broths was sensitive, rapid, and inexpensive.
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PMID:Rapid determination of X/V growth requirements of Haemophilus species in broth. 349 13


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