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 antibody response to bacteria of the so-called HACEK group, i.e. Haemophilus spp., Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens and Kingella kingae, was measured in sera of six patients with endocarditis. The corresponding isolates from their blood cultures were identified by conventional methods, including reactions for nitrate reduction and catalase as well as acid production from sugars. Crude antigens were prepared by glycine extraction and sonification of the blood culture isolates, and used to determine titers by complement fixation. A patient with Haemophilus parainfluenzae bacteremia received a short course of antibiotic therapy, and relapsed with spondylitis and endocarditis 5 months later. Titers of sera against his own isolate rose from 1:40 to 1:320 and fell to 1:40 after therapy within one year. A patient with C. hominis endocarditis had a similarly prolonged course. The complement fixation titer against his own isolate was already 1:240 before antibiotics were administered. Another patient with C. hominis endocarditis presented a titer of 1:320 2 weeks after the diagnosis. These three patients revealed C-reactive protein values over 50 mg/l in the first serum sample. Decrease of both antibody titers and C-reactive protein values correlated with clinical improvement. Two patients with prosthetic valve replacement 5 months earlier developed C. hominis and K. kingae endocarditis, respectively. At admission, C-reactive protein values were 64 and 82, respectively, and therapy was instituted immediately. The first sera were received 3 and 6 weeks, respectively, after isolation of the corresponding blood culture isolates and revealed already low titers, i. e. 1:80 and 1:60, respectively. A woman with A. actinomycetemcomitans endocarditis received immediate therapy and did not develop titers against her own isolate. CRP was 100 at admission and remained over 50 5 weeks later. We conclude that the complement fixation assay with individual antigen preparations was easy to perform and allowed monitoring of the antibody response in 5 of 6 HACEK endocarditis cases under therapy, but the usefulness of this method to find culture-negative HACEK endocarditis needs to be established.
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PMID:Antibody response in six HACEK endocarditis cases under therapy. 967 92

Transposon mutagenesis in bacteria generally requires efficient delivery of a transposon suicide vector to allow the selection of relatively infrequent transposition events. We have developed an IS903-based transposon mutagenesis system for diverse gram-negative bacteria that is not limited by transfer efficiency. The transposon, IS903phikan, carries a cryptic kan gene, which can be expressed only after successful transposition. This allows the stable introduction of the transposon delivery vector into the host. Generation of insertion mutants is then limited only by the frequency of transposition. IS903phikan was placed on an IncQ plasmid vector with the transposase gene located outside the transposon and expressed from isopropyl-beta-D-thiogalactopyranoside (IPTG)-inducible promoters. After transposase induction, IS903phikan insertion mutants were readily selected in Escherichia coli by their resistance to kanamycin. We used IS903phikan to isolate three catalase-deficient mutants of the periodontal pathogen Actinobacillus actinomycetemcomitans from a library of random insertions. The mutants display increased sensitivity to hydrogen peroxide, and all have IS903phikan insertions within an open reading frame whose predicted product is closely related to other bacterial catalases. Nucleotide sequence analysis of the catalase gene (designated katA) and flanking intergenic regions also revealed several occurrences of an 11-bp sequence that is closely related to the core DNA uptake signal sequence for natural transformation of Haemophilus influenzae. Our results demonstrate the utility of the IS903phikan mutagenesis system for the study of A. actinomycetemcomitans. Because IS903phikan is carried on a mobilizable, broad-host-range IncQ plasmid, this system is potentially useful in a variety of bacterial species.
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PMID:Direct selection of IS903 transposon insertions by use of a broad-host-range vector: isolation of catalase-deficient mutants of Actinobacillus actinomycetemcomitans. 1057 34

An inverse correlation between colonization of the human nasopharynx by Streptococcus pneumoniae and Haemophilus influenzae, both common upper respiratory pathogens, has been reported. Studies were undertaken to determine if either of these organisms produces substances which inhibit growth of the other. Culture supernatants from S. pneumoniae inhibited growth of H. influenzae, whereas culture supernatants from H. influenzae had no effect on the growth of S. pneumoniae. Moreover, coculture of S. pneumoniae and H. influenzae led to a rapid decrease in viable counts of H. influenzae. The addition of purified catalase prevented killing of H. influenzae in coculture experiments, suggesting that hydrogen peroxide may be responsible for this bactericidal activity. H. influenzae was killed by concentrations of hydrogen peroxide similar to that produced by S. pneumoniae. Hydrogen peroxide is produced by the pneumococcus through the action of pyruvate oxidase (SpxB) under conditions of aerobic growth. Both an spxB mutant and a naturally occurring variant of S. pneumoniae, which is downregulated in SpxB expression, were unable to kill H. influenzae. A catalase-reversible inhibitory effect of S. pneumoniae on the growth of the respiratory tract pathogens Moraxella catarrhalis and Neisseria meningitidis was also observed. Elevated hydrogen peroxide production, therefore, may be a means by which S. pneumoniae is able to inhibit a variety of competing organisms in the aerobic environment of the upper respiratory tract.
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PMID:Inhibitory and bactericidal effects of hydrogen peroxide production by Streptococcus pneumoniae on other inhabitants of the upper respiratory tract. 1085 13

Plasmid profile analyses were performed for 113 strains of atypical Aeromonas salmonicida and the reference strain A. salmonicida subsp. salmonicida ATCC 14174. The atypical A. salmonicida strains comprised 98 strains obtained from fish originating from 54 farms and 2 lakes in Norway, 10 strains from Canada (2), Denmark (2), Finland (1), Iceland (1) and Sweden (4), the reference strains NCMB 1109 and ATCC 15711 (Haemophilus piscium) of A. salmonicida subsp. achromogenes, and the type cultures A. salmonicida subsp. achromogenes NCMB 1110, A. salmonicida subsp. masoucida ATCC 27013 and A. salmonicida subsp. smithia CCM 4103. A total of 95 strains of atypical A. salmonicida were separated into 7 groups (I to VII) based on the plasmid profiles. Eighteen strains of atypical A. salmonicida had no common plasmid profile. The type strain NCMB 1110 and the reference strain NCMB 1109 were included in group IV, and the type strain ATCC 27013 in group V, but the other reference and type strains had plasmid profiles different from all the other strains. An epidemiological link was documented between strains collected from different farms/localities in each of groups I, III, V and VII. Physiological and biochemical characterizations were performed for 93 of the strains to investigate phenotypic differences between the plasmid groups. Group VII strains and 3 strains with no common plasmid profile differed from the other groups in being catalase-negative. Differences in phenotypic characteristics were shown between the plasmid groups. However, significant variations in reactions for several phenotypic characteristics also occurred within each of the groups I to VII. The present study indicates that plasmid profiling may give useful epidemiological information during outbreaks of atypical A. salmonicida infections in fish. Additional comprehensive phenotypic characterisation is of limited value since the phenotypic characteristics in each plasmid group are not uniform.
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PMID:Grouping by plasmid profiles of atypical Aeromonas salmonicida isolated from fish, with special reference to salmonid fish. 1095 Jan 78

Nicotinamide adenine dinucleotide (NAD)-dependent Pasteurellaceae other than Actinobacillus pleuropneumoniae and Haemophilus parasuis are frequently isolated from the respiratory tract of pigs. The taxonomic classification and relevance for pathogenicity of these bacteria deserves further attention. In the present study, 107 of these NAD-dependent isolates from the porcine respiratory tract, primarily from lungs with pathological changes, were investigated. On the basis of phenotypic criteria, such as haemolysis, urease, catalase, and indole formation as well as other fermentative activities, 50 of the isolates were assigned to Actinobacillus minor, 36 isolates to Actinobacillus porcinus and 21 isolates to Actinobacillus indolicus. However, many isolates among the three species showed fermentative activities differing from those of the respective type strain of the species. Serotyping on the basis of heat-stable polysaccharide antigens and 16 rDNA sequencing also revealed substantial heterogeneity within each of the three species although they clustered together in three distinct groups in the phylogenetic analysis. These three groups of NAD-dependent bacteria are different from, or in a borderline position, to the existing species or genera within the family Pasteurellaceae. A considerable number of isolates of these three groups were isolated in pure cultures from pneumonic lungs. Consequently, it will be necessary to critically review the opinion, that these NAD-dependent Pasteurellaceae are only "agents colonizing the mucosa". Further, taxonomic examinations of the strains within these three groups are indispensable to testing isolates for their virulence in gnotobiotic pigs.
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PMID:Phenotypic and genetic characterization of NAD-dependent Pasteurellaceae from the respiratory tract of pigs and their possible pathogenetic importance. 1139 Jan 8

Chronic granulomatous disease (CGD) is a rare inherited disorder in which phagocytes are incapable of generating bactericidal-reactive oxygen derivatives. Typically these patients are susceptible to life-threatening infections with catalase-producing organisms. Haemophilus species, particularly H. paraphrophilus, are not associated with CGD infections, because these organisms rarely if ever produce catalase. Haemophilus species are part of the indigenous oral microbial flora and, other than H. influenzae, are rarely recognized as pathogens. They are fastidious and require additional growth factors and capnophilic culture conditions for optimal growth and identification. Here we describe three cases of infection with non-H. influenzae (NHI) Haemophilus species in CGD patients. These organisms were catalase-negative and therefore not expected to be virulent in CGD patients, but they were also H(2)O(2) production-negative, thereby negating the putative loss of virulence of being catalase-negative. These are the first reports of NHI Haemophilus species in CGD and reinforce the critical need for careful microbiologic evaluation of infections in CGD patients.
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PMID:Infections with Haemophilus species in chronic granulomatous disease: insights into the interaction of bacterial catalase and H2O2 production. 1270 9

Glutathione is an abundant and ubiquitous low-molecular-weight thiol that may play a role in many cellular processes, including protection against the deleterious effects of reactive oxygen species. We address here the role of glutathione in protection against hydrogen peroxide (H2O2) in Haemophilus influenzae and show that glutathione and catalase provide overlapping defense systems. H. influenzae is naturally glutathione deficient and imports glutathione from the growth medium. Mutant H. influenzae lacking catalase and cultured in glutathione-deficient minimal medium is completely devoid of H2O2 scavenging activity and, accordingly, substantial amounts of H2O2 accumulate in the growth medium. H. influenzae generates H2O2 at rates similar to those reported for Escherichia coli, but the toxicity of this harmful metabolite is averted by glutathione-based H2O2 removal, which appears to be the primary system for protection against H2O2 endogenously generated during aerobic respiration. When H2O2 concentrations exceed low micromolar levels, the hktE gene-encoded catalase becomes the predominant scavenger. The requirement for glutathione in protection against oxidative stress is analogous to that in higher and lower eukaryotes but is unlike the situation in other bacteria in which glutathione is dispensable for aerobic growth during both normal and oxidative stress conditions.
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PMID:Glutathione and catalase provide overlapping defenses for protection against respiration-generated hydrogen peroxide in Haemophilus influenzae. 1294 8

White, David C. (The Rockefeller Institute, New York, N. Y.) Cytochrome and catalase patterns during growth of Haemophilus parainfluenzae. J. Bacteriol. 83:851-859. 1962.-By following the cytochrome and catalase concentrations during the growth cycle and under various growth conditions in Haemophilus parainfluenzae, a rapid increase in the cytochrome oxidases and a large increase in cytochrome c(1) concentration can be demonstrated between log-phase and stationary-phase cells and between vigorously aerated and anaerobic growth conditions. The three cytochrome oxidases develop differentially under various growth conditions. The principal oxidase formed in vigorously aerated cultures is cytochrome o. With limited aeration, maximal development of cytochrome a(2) occurs; with anaerobically grown cells, there is a marked increase in the concentration of cytochrome a(1). With the rapid increase in cytochrome c(1) concentration, soluble, nonenzymatically reducible cytochrome c(1) is also formed, which remains in the bacterial cell sap. From these data it is postulated that the electron-transport system is assembled from individual components which can be modified by the growth conditions. The cytochrome c(1) may be synthesized in the cell sap and then incorporated into the electron-transport system.
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PMID:Cytochrome and catalase patterns during growth of Haemophilus parainfluenzae. 1400 6

The chimeric peroxidase PGdx of Haemophilus influenzae Rd belongs to a recently identified family of thiol peroxidases capable of reducing hydrogen peroxide as well as alkylhydroperoxides by means of glutathione redox cycling. In the present study, we constructed a H. influenzae Rd strain, deficient in its PGdx encoding gene (open reading frame HI0572). The mutant was shown by disk inhibition and liquid culture growth assays to exhibit increased susceptibility to organic hydroperoxides. The hampered growth was restored by complementing the interrupted gene on the genome with a replicating plasmid bearing an intact copy of the gene, hereby rejecting the possible influences of polar effects. Elevated levels of hydrogen peroxide scavenging activity, due to the catalase HktE, were measured in the absence of a functional pgdx gene rendering the mutant more resilient against hydrogen peroxide. On the other hand, after initiation of the stationary phase, aerobic cultures of the pgdx mutant were practically devoid of living cells, whereas wild-type counterparts retained viability. This observed feature was alleviated by complementation with the functional gene or with the addition of catalase.
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PMID:Physiological characterization of Haemophilus influenzae Rd deficient in its glutathione-dependent peroxidase PGdx. 1470 67

Although Haemophilus somnus causes septicemia and vasculitis in cattle, relatively little is known about how H. somnus affects endothelial cells in vitro. We previously reported that H. somnus lipooligosaccharide (LOS)-induced activation of caspases-3, -8 and -9, and apoptosis of bovine pulmonary artery endothelial cells (BPAEC) in vitro. Previous reports indicate that the generation of reactive oxygen species (ROS) or reactive nitrogen intermediates (RNI) can contribute to the induction of apoptosis. In the present study, we sought to determine whether ROS and RNI are involved in LOS-mediated apoptosis of BPAEC. We found that H. somnus LOS induced the generation of ROS in BPAEC, which was blocked by pretreatment with membrane permeable ROS scavengers, such as dimethylsulfoxide (DMSO) and allopurinol (AP). Addition of DMSO or AP significantly reduced H. somnus LOS-mediated caspase-3 activation. Addition of membrane impermeable ROS scavengers (e.g. catalase and superoxide dismutase), failed to block LOS-mediated caspase-3 activation, suggesting a role for intracellular generation of ROS in LOS-induced apoptosis of BPAEC. Addition of N(G)-nitro-L-arginine methyl ester (L-NAME) or aminoguanidine, which are selective inhibitors of nitric oxide synthase, blocked NO release and significantly reduced caspase-3 activation in LOS treated BPAEC. These data suggest H. somnus LOS triggers endogenous ROS and RNI production by endothelial cells, which contributes to apoptosis.
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PMID:Reactive oxygen and nitrogen intermediates contribute to Haemophilus somnus lipooligosaccharide-mediated apoptosis of bovine endothelial cells. 1474 Nov 39


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