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

Mutants of Actinobacillus pleuropneumoniae strain HK 361 (serotype 2) were isolated which were deficient in type II (Ca2(+)-dependent) haemolysin activity (Hly-). Some of the Hly- mutants secreted a potent, heat-labile extracellular cytotoxic activity against porcine alveolar macrophages. Comparison of cell-free culture supernatant from the parent strain and some Hly- mutants by SDS-PAGE and immunoblotting revealed the loss of a major extracellular polypeptide of 109 kDa. Two Hly- mutants which in addition failed to secrete a 120 kDa polypeptide produced no extracellular cytotoxic activity, suggesting that the 120 kDa protein was the cytotoxin. Antiserum raised to the culture supernatant from a Hly- mutant lacking the 109 kDa polypeptide recognized the 120 kDa band, but not the 109 kDa band, in immunoblots and neutralized the cytotoxic activity, but not the haemolytic activity, of A. pleuropneumoniae. The 120 kDa polypeptide and extracellular cytotoxic activity were widespread among A. pleuropneumoniae strains, but absent from related bacterial pathogens of the pig: Actinobacillus suis, Haemophilus parasuis and Pasteurella multocida. A clear correlation was found between the presence of the 120 kDa polypeptide and cytotoxic activity in culture supernatants. The cytotoxic activity of all the strains tested was neutralized by antibody to the Hly- extracellular material and by convalescent pig serum. It is proposed that the 120 kDa polypeptide represents the cytotoxin of A. pleuropneumoniae, that it is distinct from the haemolysin, and that it be termed pleurotoxin.
J Gen Microbiol 1991 Mar
PMID:The cytotoxin of Actinobacillus pleuropneumoniae (pleurotoxin) is distinct from the haemolysin and is associated with a 120 kDa polypeptide. 203 78

Chemotaxonomic data for strains of Actinobacillus, Haemophilus and Pasteurella spp. were analysed using three multivariate statistical strategies: principal components, partial least squares discriminant, and soft independent modelling of class analogy. The species comprised Actinobacillus actinomycetemcomitans. Haemophilus aphrophilus, H. paraphrophilus, H. influenzae, Pasteurella multocida, P. haemolytica and P. ureae. Strains were characterized by cell sugar and fatty acid composition, lysis kinetics during EDTA and EDTA plus lysozyme treatment, and methylene blue reduction. In total 23 quantitative variables were compiled from chemotaxonomic analyses of 25 strains. A. actinomycetemcomitans and H. aphrophilus formed distinct classes which differed from those of H. paraphrophilus, H. influenzae and Pasteurella spp. All characterization variables, except those describing fatty acid content, contributed significantly to inter-species discrimination.
J Gen Microbiol 1990 Mar
PMID:Multivariate analysis of quantitative chemical and enzymic characterization data in classification of Actinobacillus, Haemophilus and Pasteurella spp. 211 66

The specificity by which Haemophilus species acquired iron from transferrin (TF) was investigated. In a plate bioassay H. influenzae used iron bound to human, bovine and rabbit TFs but not mouse, rat, dog, horse, guinea-pig, pig or ovo- TFs or human and bovine lactoferrins. In contrast, H. pleuropneumoniae used iron only from pig TF whilst H. parainfluenzae was unable to utilize iron bound to any of the human or animal TFs tested. The inhibition of growth imposed on H. influenzae type b strain Eagan by the addition of the synthetic iron chelator EDDA to the culture medium was reversed by 30% iron-saturated human TF added directly to the medium but not when the TF was contained inside a dialysis bag. Dot-blotting of whole cells revealed that human TF bound to the surface of bacteria cultured in iron-restricted but not in iron-plentiful media. Incubation of whole bacterial cells in the presence of the proteolytic enzyme trypsin also abolished TF-binding activity, suggesting that the TF receptor was a protein. In competition dot blotting experiments, human and bovine but not rabbit, dog, mouse or guinea-pig TFs blocked the binding of a horseradish peroxidase--human TF conjugate. SDS-PAGE and Western blotting of outer membranes revealed the presence of a TF-binding protein of approximately 72 kDa. These results suggest that the acquisition of TF-bound iron by H. influenzae type b probably involves a direct interaction with an outer-membrane protein which shows some TF-species specificity.
J Gen Microbiol 1990 May
PMID:Siderophore-independent acquisition of transferrin-bound iron by Haemophilus influenzae type b. 214 16

The ability of Haemophilus influenzae, H. parainfluenzae and H. paraphrophilus to utilize iron complexes, iron-proteins and exogenous microbial siderophores was evaluated. In a plate bioassay, all three species used not only ferric nitrate but also the iron chelates ferric citrate, ferric nitrilotriacetate and ferric 2,3-dihydroxybenzoate. Each Haemophilus species examined also used haemin, haemoglobin and haem-albumin as iron sources although only H. influenzae could acquire iron from transferrin or from haemoglobin complexed with haptoglobin. None of the haemophili obtained iron from ferritin or lactoferrin or from the microbial siderophores aerobactin or desferrioxamine B. However, the phenolate siderophore enterobactin supplied iron to both H. parainfluenzae and H. paraphrophilus, and DNA isolated from both organisms hybridized with a DNA probe prepared from the Escherichia coli ferric enterobactin receptor gene fepA. In addition, a monospecific polyclonal antiserum raised against the E. coli 81 kDa ferric enterobactin receptor (FepA) recognized an iron-repressible outer membrane protein (OMP) in H. parainfluenzae of between 80 and 82 kDa (depending on the strain). This anti-FepA serum did not cross-react with any of the OMPs of H. paraphrophilus or H. influenzae. The OMPs of each Haemophilus species were also probed with antisera raised against the 74 kDa Cir or 74 kDa IutA (aerobactin receptor) proteins of E. coli. Apart from one H. parainfluenzae strain (NCTC 10665), in which an OMP of about 80 kDa cross-reacted with the anti-IutA sera, no cross-reactivity was observed between Cir, IutA and the OMPs of H. influenzae, H. parainfluenzae or H. paraphrophilus.(ABSTRACT TRUNCATED AT 250 WORDS)
J Gen Microbiol 1990 Dec
PMID:Utilization of enterobactin and other exogenous iron sources by Haemophilus influenzae, H. parainfluenzae and H. paraphrophilus. 215 Apr 14

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.
J Gen Microbiol 1990 Mar
PMID:Studies of NAD kinase and NMN:ATP adenylyltransferase in Haemophilus influenzae. 216 21

A collection of 117 strains of Haemophilus influenzae, including 112 non-typable isolates recovered predominantly in the USA and France from genital, obstetric and neonatal sources, was characterized by the electrophoretic mobilities of 10 metabolic enzymes. Eighty-six distinctive multilocus chromosomal genotypes (electrophoretic types, ETs) were distinguished on the basis of allele profiles at the enzyme loci. Isolates of five allied biotype IV ETs were highly divergent from all other strains and hybridization of chromosomal DNA revealed that they undoubtedly represent a previously unrecognized species of Haemophilus. Isolates representing these ETs were recovered predominantly from obstetric infections and serious neonatal diseases and apparently possess specific tropism for the genital tract. Strains of these five ETs were present in samples from both the USA and France, but only in the USA did they cause bacteraemia and meningitis, an occurrence which probably reflects differences in patient management between the two countries. Although strains assigned to H. influenzae (sensu stricto) were strongly polymorphic in multilocus enzyme genotype, 69% of isolates recovered from patients with meningitis and/or septicaemia were assigned to only two clone families, a result suggesting that some serologically nontypable strains of H. influenzae originating from the genital tract are unusually virulent.
J Gen Microbiol 1990 Jul
PMID:Urogenital, maternal and neonatal isolates of Haemophilus influenzae: identification of unusually virulent serologically non-typable clone families and evidence for a new Haemophilus species. 223 Jul 14

Genetic relationships among isolates assigned to Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus and H. paraphrophilus were determined by analysis of electrophoretically demonstrable allelic variation in 14 structural genes encoding metabolic enzymes. Among the 51 isolates analysed there were 25 electrophoretic types (ETs), among which mean genetic diversity per locus was 0.753. Cluster analysis of ETs demonstrated one well-defined group of 11 ETs representing solely the genotypes of all 17 isolates assigned to A. actinomycetemcomitans. The remaining 14 ETs represented the genotypes of the 34 isolates of H. aphrophilus and H. paraphrophilus. With the exception of ATCC 13252, all strains of H. aphrophilus were closely related, whereas strains assigned to H. paraphrophilus included distantly related lineages, some of which were similar to those of H. aphrophilus and should be assigned to this species. Thus, the study showed that there is no significant overall genetic similarity between A. actinomycetemcomitans and the two Haemophilus spp.
J Gen Microbiol 1990 Oct
PMID:Differentiation between Actinobacillus (Haemophilus) actinomycetemcomitans, Haemophilus aphrophilus and Haemophilus paraphrophilus by multilocus enzyme electrophoresis. 226 78

Four, NAD-independent, clinical isolates of Haemophilus parainfluenzae were recovered from a genital ulcer, a purulent skin lesion, a sputum specimen and a throat swab respectively. With the exception of NAD requirement, the strains exhibited the biochemical characteristics of H. parainfluenzae biotype II. The genetic relationship between these isolates and a standard strain of H. parainfluenzae was determined by testing transforming activities of two chromosomal markers, streptomycin resistance and nalidixic acid resistance. The clinical isolates were efficient donors and recipients in transformation. In addition, we demonstrated transfer of the genes conferring NAD independence to typical, NAD-requiring H. parainfluenzae and Haemophilus influenzae strains.
J Gen Microbiol 1990 Jun
PMID:Naturally occurring NAD-independent Haemophilus parainfluenzae. 238 41

Porins are pore-forming outer-membrane proteins which serve as a non-specific pathway for the entry of hydrophilic molecules into Gram-negative bacteria. We studied four strains of Haemophilus influenzae that had decreased permeability to chloramphenicol associated with diminished quantities of a 40 kDa major outer-membrane protein. Isogenic pairs of organisms containing and lacking this protein were compared. The latter strains grew more slowly and were less permeable to sucrose and raffinose. They were also more resistant to multiple hydrophilic antibiotics than an isogenic strain containing the 40 kDa protein and were less permeable to penicillin G and chloramphenicol. We conclude that the 40 kDa outer-membrane protein functions as a porin in H. influenzae.
J Gen Microbiol 1987 May
PMID:A major outer-membrane protein functions as a porin in Haemophilus influenzae. 244 11

The taxonomy of the family Pasteurellaceae has remained controversial despite investigations of biochemistry, serology, and nucleic acid relatedness. In an attempt to resolve some of this confusion, we have partially sequenced the 16S rRNAs of seven members of the family, representing all three genera. The sequences were aligned, similarity scores calculated, and single, average and complete linkage cluster analysis of the resulting distance matrix performed. In this way, an evolutionary branching pattern of these closely related species was reconstructed, and the approximate phylogenetic position of the family determined. Actinobacillus (Haemophilus) actinomycetemcomitans clustered with Haemophilus instead of Actinobacillus, supporting transfer of this species to the genus Haemophilus. Thus cluster analysis of phylogenetic relatedness was found to be particularly useful for studying closely related organisms, and could be performed using a microcomputer.
J Gen Microbiol 1988 Jul
PMID:Comparison of 16S rRNA sequences from the family Pasteurellaceae: phylogenetic relatedness by cluster analysis. 246 75


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