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 molecular nature of two beta-lactamase-specifying plasmids isolated from two separate ampicillin-resistant Haemophilus influenzae type b strains was examined. A 30 X 10(6)-dalton (30-Mdal) plasmid (RSF007) had a copy number of approximately 3 per chromosomal equivalent and a mole fraction guanine plus cytosine content of 0.39. By heteroduplex analysis the 30-Mdal plasmid was found to contain the entire ampicillin translocation DNA segment (TnA) found on R factors of enteric origin. A 3.0-Mdal plasmid (RSF0885) was found as a multicopy pool of approximately 28 copies per chromosomal equivalent, had a mole fraction guanine plus cytosine content of 0.40, and contained only about one-third of the transposable TnA sequence. RSF007 and RSF0885 appeared to be unrelated plasmids in that they share base sequence homology only within the confines of the TnA segment. The 3.0-Mdal Haemophilus plasmid was used to transform E. coli to ampicillin resistance but was found to be unstable in this host in the absence of antibiotic. The possibility that R-plasmids arose in Haemophilus by the translocation of TnA from a donor R-factor onto an indigenous H. influenzae plasmid is discussed.
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PMID:Molecular nature of two beta-lactamase-specifying plasmids isolated from Haemophilus influenzae type b. 77 Apr 29

A plasmid containing a 13.3-kb insert (pER194) was isolated from an EcoRI genomic library of Haemophilus influenzae on the basis of its ability to increase the transformability of the transformation-deficient mutants Com-78 and Com-101. The plasmid failed to increase the transformability of the Rec-1 and Rec-2 mutants, indicating that the mutations producing the Com-78 and Com-101 phenotypes are distinct from those giving rise to the Rec-1 and Rec-2 phenotypes. The physical mapping of the cloned fragment on the H. influenzae chromosome was found to be consistent with the genetic mapping of the Com-101 trait. A 2.8-kb EcoRI-BglII subfragment, representing one end of the 13.3-kb clone, was found to increase the transformation frequency of the Com-78 and Com-101 mutants when supplied in trans, indicating that the subfragment carries one or more loci required for chromosomal transformation. The corresponding region of the Com-101 chromosome was determined by hybridization analysis to contain a 0.3-kb insertion, suggesting that the Com-101 strain may contain an insertion mutation at this locus. A 3.0-kb EcoRI-MluI subfragment, representing the other end of the 13.3-kb EcoRI fragment, was found to increase the transformation frequency of the Com-101 mutant but not of the Com-78 mutant, suggesting that the Com-101 phenotype results from a complex genotype involving mutations at two or more transformation-related loci. This conclusion is consistent with data indicating that the Com-101 trait can be genetically separated into at least two components.
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PMID:Molecular cloning of two linked loci that increase the transformability of transformation-deficient mutants of Haemophilus influenzae. 164 18

Following the administration of a standardized questionnaire, 62 adult patients with chronic bronchitis were enrolled into a double-blind controlled trial of an oral killed Haemophilus influenzae vaccine in the highlands of Papua New Guinea. A 3-day course of vaccine or placebo was given monthly for 3 consecutive months. Participants were monitored weekly over 12 months for acute exacerbations; early morning sputum specimens were collected monthly and during acute exacerbations. Density of colonization by H. influenzae and H. parainfluenzae was determined by standard quantitative and semiquantitative techniques, and the latter method (quadrant score) was used to determine the density of growth of pneumococci. A total of 30 patients received vaccine and 32 placebo. The incidence rate of acute bronchitis in the vaccine group (0.011 episodes/person-weeks) was significantly lower than that in the placebo group (0.021 episodes/person-weeks), but there was no difference between the two groups in the incidence rates of more severe disease. Vaccine efficacy was maximal at times of peak incidence of disease. There was no evidence of a decline in vaccine efficacy for acute bronchitis over the 12-month follow-up period. The number of viable H. influenzae in the sputum declined in both vaccine and placebo groups over the 12-month follow-up period. The average concentration of H. influenzae in the vaccine group fell below that in the placebo group within 1 to 2 months after first immunization and remained so for 12 months, although the difference between the two groups narrowed during the follow-up period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reduction in the incidence of acute bronchitis by an oral Haemophilus influenzae vaccine in patients with chronic bronchitis in the highlands of Papua New Guinea. 185 55

A 3 1/2 year old girl presented with failure to thrive and a five month history of diarrhoea and recurrent cough. The results of sweat sodium tests suggested a diagnosis of cystic fibrosis; but atypical organisms were found (Haemophilus influenzae, Candida albicans, but no Staphylococcus aureus), she failed to respond to treatment, and her sweat sodium concentrations fell in response to fludrocortisone. She also had hyperglobulinaemia, neutropenia, and reduced numbers of T4 lymphocytes, which prompted the performance of a test for antibody to human immunodeficiency virus (HIV). This proved positive, and she was treated with co-trimoxazole, zidovudine, and human immunoglobulin. Both parents and two siblings were also positive for HIV, though all had normal sweat sodium concentrations. Children with symptoms suggestive of cystic fibrosis but who also show atypical features, as in this case, should have their HIV state checked.
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PMID:Abnormal sweat electrolytes in symptomatic human immunodeficiency virus infection in a child. 312 Oct 56

A 3-year-old child with Haemophilus influenzae endocarditis and aortic route abscesses presented with sudden cardiovascular collapse. During resuscitation, the child was noted to be in complete heart block. Transcutaneous pacing was instituted three times, and ventricular dysrhythmias were associated with each pacing attempt. When pacing was discontinued, the patient spontaneously reverted to complete heart block without ventricular ectopy. An emergency thoracotomy revealed rupture of the aortic route, and the patient died during surgery. Transcutaneous pacing may precipitate serious dysrhythmias; appropriate precautions are recommended.
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PMID:Ventricular tachycardia related to transcutaneous pacing. 334 22

A 3-kb fragment of Haemophilus haemolyticus DNA which carries the HhaII restriction (r) and modification (m) genes has been cloned into the PstI site of pBR322 (Mann et al., 1978). When propagated in Escherichia coli, it was observed that spontaneous insertions of IS5 inactivated the restriction gene, producing r- mutants at a frequency of 10(-6). Electron microscopy, restriction-site mapping and sequence analysis of two r- plasmids have demonstrated the presence of IS5 at a single target site in both possible orientations. The complete nucleotide sequence of IS5 has been determined. It is 1195 bp long and has inverted terminal repeats of 16 bp. The target site for IS5 in this plasmid is 5'-CTAG. Approx. ten copies of IS5 were found to be present at about the same locations on the E. coli chromosome in various K-12 strains, using Southern hybridization analysis.
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PMID:The nucleotide sequence of IS5 from Escherichia coli. 626 59

A 3-day regimen of azithromycin (500 mg once daily) and a 10-day regimen of co-amoxiclav (625 mg three times daily) were compared in a double-blind study of 67 patients with acute infectious exacerbations of chronic bronchitis (AIECBs, n = 54), acute bronchitis (n = 7), or pneumonia (n = 6). In patients treated with azithromycin, satisfactory clinical responses (cure or improvement) were seen in 24/28 (86%) patients with AIECBs, 2/4 (50%) with acute bronchitis and 2/2 (100%) with pneumonia. Responses were satisfactory in 24/26 (92%), 4/4 (100%) and 4/4 (100%) patients, respectively, receiving co-amoxiclav. Streptococcus pneumoniae and Haemophilus influenzae were the commonest pathogens isolated at baseline. At the end of treatment, baseline pathogens were eradicated in 9/10 microbiologically-assessable patients treated with azithromycin and in 10/10 treated with co-amoxiclav. Adverse events related or possibly related to treatment occurred in five patients in each treatment group; the majority of these events affected the gastrointestinal system. One patient in each treatment group discontinued therapy because of adverse events. The study, therefore, demonstrates that 500 mg azithromycin administered once daily for 3 days is as efficacious and well tolerated as co-amoxiclav given three times daily for 10 days in the domiciliary treatment of adults with acute lower respiratory tract infections.
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PMID:Once-daily, 3-day azithromycin versus a three-times-daily, 10-day course of co-amoxiclav in the treatment of adults with lower respiratory tract infections: results of a randomized, double-blind comparative study. 881 50

The azalide antibacterial agent azithromycin is a semisynthetic acid-stable erythromycin derivative with an expanded spectrum of activity and improved tissue pharmacokinetic characteristics relative to erythromycin. The drug is noted for its activity against some Gram-negative organisms associated with respiratory tract infections, particularly Haemophilus influenzae. Azithromycin has similar activity to other macrolides against Streptococcus pneumoniae and Moraxella catarrhalis, and is active against atypical pathogens such as Legionella pneumophila, Chlamydia pneumoniae and Mycoplasma pneumoniae. Once-daily administration of azithromycin is made possible by the long elimination half-life of the drug from tissue. Azithromycin is rapidly and highly concentrated in a number of cell types after absorption, including leucocytes, monocytes and macrophages. It undergoes extensive distribution into tissue, from where it is subsequently eliminated slowly. A 3-day oral regimen of once-daily azithromycin has been shown to be as effective as 5- to 10-day courses of other more frequently administered antibacterial agents [such as erythromycin, amoxicillin-clavulanic acid and phenoxymethylpenicillin (penicillin V)] in patients with acute exacerbations of chronic bronchitis, pneumonia, sinusitis, pharyngitis, tonsillitis and otitis media. Adverse effects of azithromycin are mainly gastrointestinal in nature and occur less frequently than with erythromycin. Azithromycin is likely to prove most useful as a 3-day regimen in the empirical management of respiratory tract infections in the community. Its ease of administration and 3-day duration of therapy, together with its good gastrointestinal tolerability, should optimise patient compliance (the highest level of which is achieved with once-daily regimens). Azithromycin is also likely to be useful in the hospital setting, particularly for outpatients and for those unable to tolerate erythromycin.
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PMID:Azithromycin. A review of its pharmacological properties and use as 3-day therapy in respiratory tract infections. 888 83

Haemophilus influenzae type b, a causative agent of bacterial sepsis and meningitis in young children, contains a single superoxide dismutase (SOD), a cytoplasmic MnSOD. To study the role of this enzyme, a chromosomal sodA::lacZ mutant (M-2) was constructed. M-2 had an increased sensitivity towards oxygen and the redox-active agent paraquat. A 3.4-fold increase in sodA-lacZ expression was found in M-2 grown with oxygen supply rates between 3 and 36 mmol of O2/liter/h. In similar experiments with the wild type, assaying SodA activity, a 3.1-fold increase was found. Both the wild type and M-2 grew best at the lowest oxygen supply rate tested, consistent with the notion that H. influenzae prefers a more anaerobic environment. In the infant rat model of infection, the ability of M-2 to colonize the nasopharynx was found to be impaired, but its ability to cause invasive disease was unaffected. This suggests that after invasion, the growth disadvantage imposed by a SodA- phenotype is not limiting.
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PMID:Role of bacterial Mn-cofactored superoxide dismutase in oxidative stress responses, nasopharyngeal colonization, and sustained bacteremia caused by Haemophilus influenzae type b. 919 39

A 3.9 kb Haemophilus influenzae genomic DNA fragment was cloned in plasmid pUC9 that partially complemented the ultraviolet light sensitivity (UVs) of Escherichia coli uvrC mutant hosts. This fragment also complemented the UVs of H. influenzae uvr-1 (DB112) and uvr-2 (DB116) mutants. It genetically transformed the latter mutants to wild type UV resistance. The nucleotide (nt) sequence of this fragment revealed 3 open reading frames (ORFs). ORF2, now designated uvr-1+ (1746 nt), shows significant similarity in both the nt and amino acid (aa) composition to 7 complete proven or putative uvrC gene sequences. Computer analysis of the DNA sequence revealed several possible regulatory motifs 5' to uvr-1+, including a putative LexA-binding site as an inverted SOS box, located within the 3' region of ORF1, (extensive homology to the E. coli CMP-KDO synthetase gene), upstream of uvr-1+. Further computer analysis has also predicted that the four putative active site amino acids, located in the C-terminal half of each protein, are each situated in an area of secondary structure that are highly conserved.
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PMID:Structure of the Haemophilus influenzae uvr-1+ gene: homology with other uvrC-like genes and characterization of the Haemophilus influenzae uvr-1 and uvr-2 mutations. 927 62


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