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)

Three hundred and five strains of Haemophilus (129 H. influenzae, 55 H. parainfluenzae, 97 H. parahaemolyticus, 5 H. haemolyticus, 10 H. paraphrophilus and 9 H. paraphrohaemolyticus) isolated from pathological material over the year 1976, were systematically tested for beta-lactamase production. Only 2 strains of H. parainfluenzae produced this enzyme. Both were able to transfer ampicillin resistance to Escherichia coli K12. All strains but the two beta-lactamase producers were susceptible to penicillin G, ampicillin and cephalotin. However, the correct interpretation of the susceptibility tests needed the microscopic observation of prints of the inhibition zones surrounding the disks: all sensitive strains presented a hazy growth around the disks which corresponded to the presence of spheroplasts; this phenomenon was not observed with the 2 beta-lactamase producing strains of H. parainfluenzae which grew up to the disks but presented a typical bacillary form.
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PMID:[Ampicillin-resistant "Haemophilus": their detection and occurrence in Brussels area (author's transl)]. 31 52

From June 1973 to July 1976, 742 strains of Haemophilus influenzae and parainfluenzae, isolated from clinical specimens, were routinely tested for in vitro sensitivity to twelve antibiotics: penicillin, ampicillin, cephalothin, streptomycin, kanamycin, gentamicin, chloramphenicol, tetracyclin, minocyclin, erythromycin, sulfamethoxazol, trimethoprim. 61 strains were found resistant to one or more of these antibiotics (ampicillin, kanamycin, chloramphenicol and tetracyclin). The MICs of 23 antibiotics were determined by the agar dilution method on most of the resistant strains and on 60 sensitive strains isolated during the same period and considered as control. 21 strains transferred their resistance determinants into E. coli K12; 23 plasmids were obtained isolated from these strains: 2 strains contained two different plasmids. 90% of the transconjugants were stable after repeated subcultures.
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PMID:[Drug sensitivity of Haemophilus sp. and transfer of resistance into E. coli (author's transl)]. 32 13

Kanamycin resistance was transferred by conjugation from a Haemophilus influenzae strain into Escherichia coli K12, and between E. coli K12 strains in subsequent transfers. Covalently closed molecules of DNA were isolated by sedimentation analysis of the DNA of the resistant E. coli K12 strains. These facts support the hypothesis that kanamycin resistance is mediated by a transferable plasmid in this strain of H. influenzae.
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PMID:A transferable kanamycin resistance plasmid isolated from Haemophilus influenzae. 110 77

Transposon Tn916 was shown to be capable of direct conjugative transfer in broth and membrane matings between strains of Escherichia coli K12 and between E. coli K12 and Haemophilus influenzae type b. Only Tn916 was transferred, but Tn916 donor ability was not itself inheritable by the recipients and seemed to be associated with the presence of Tn916 on a non-conjugative pBR322-derived vector in the original donor strain. Transfer of Tn916 by conjugation was found to be an efficient method for producing insertion mutations in the chromosome of recipient cells. Although such insertions were unstable when the cells were grown under non-selective conditions, it was possible to show that over 40% of the isolated Tn916 insertions in the chromosome of E. coli K12 were in gene(s) concerned with histidine biosynthesis, implying that there is a partial hot-spot for Tn916 insertion on the E. coli K12 chromosome. When a strain of H. influenzae type b was used as a recipient, out of approximately 1500 transconjugants tested, two mutants were isolated with insertions in genes controlling the expression of iron-regulated transferrin-binding proteins. These mutants constitutively produced major 76 kDa and minor 90 kDa proteins which bound transferrin, even when grown under iron-sufficient conditions. Tn916 insertion mutagenesis, following transfer by conjugation, is a convenient method for isolating mutations in genes concerned with iron acquisition by this important human pathogen.
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PMID:Tn916 insertion mutagenesis in Escherichia coli and Haemophilus influenzae type b following conjugative transfer. 131 5

The minimum inhibitory concentration (MIC) of cefdinir (CI-983, FK-482), cephalexin cefuroxime, cefixime and ceftazidime were determined against clinical isolates. Cefdinir was as effective as cefixime against Haemophilus and Moraxella (Branhamella) strains and both were more effective than cefuroxime. Against streptococci, cefdinir was much more effective than cefixime and had similar efficacy to cefuroxime. Against staphylococci, cefdinir had the lowest MIC50 of all of the drugs tested. The efficacy of these antibiotics was tested against Escherichia coli K12 strains harbouring 16 of the new extended-spectrum plasmid-mediated beta-lactamases, and cefdinir was more effective than ampicillin, cephalexin, cefuroxime, ceftazidime and aztreonam.
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PMID:The sensitivity of clinical bacteria isolated in Scotland to the oral cephalosporin, cefdinir. 147 61

The in-vitro activity of cefpodoxime was studied in 529 clinical isolates and compared with the activity of other oral beta-lactams. Amongst the Enterobacteriaceae cefpodoxime was very active (MIC90 less than or equal to 1 mg/l--other than genera commonly possessing chromosomal beta-lactamases). Against these strains cefpodoxime was comparable in activity to cefixime and about eight-fold more active than cefuroxime and 8-16-fold more active than cefaclor and cephalexin. Staphylococcus aureus strains were moderately susceptible (MIC90 4 mg/l) to cefpodoxime in comparison with cefixime (16 mg/l). The respiratory pathogens, Haemophilus influenzae, Streptococcus pneumoniae and Branhamella catarrhalis were susceptible to less than or equal to 0.5 mg/l cefpodoxime. An increase in inoculum from 10(4) to 10(6) cfu had little effect upon activity. Studies in beta-lactamase hydrolysis of cefpodoxime showed it to be stable to TEM-1, SHV-1 and BRO-1 enzymes but with high affinity for the P99 enzyme. The primary target of cefpodoxime is PBP3 (I50 1 mg/l) in Escherichia coli K12. The protein binding of the agent to human serum was 14.3-18.3% at 1 and 5 mg/l respectively.
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PMID:The in-vitro activity of cefpodoxime: a comparison with other oral cephalosporins. 235 24

The polymerase chain reaction (PCR) offers a sensitive and specific way of detecting microbial DNA in clinical samples. The aims of the present study were to develop an assay, based on a single-tube, nested PCR, for identifying Brucella in samples of human blood and then to explore the use of this test in diagnosis. The primers chosen were derived from IS711, the insertion sequence gene found in all species of Brucella. The assay amplified a 52-bp final product which was detected colorimetrically. The PCR was sensitive and specific, giving positive reactions with 14 strains of Brucella from five species. The lower limit of detection in vitro was 30 organisms. There were no false-positive reactions either with a range of bacteria known to evoke serological cross-reactions with Brucella (Vibrio cholerae, Yersinia enterocolitica, Serratia marcescens, Haemophilus influenzae, Pseudomonas aeruginosa and Escherichia coli K12) or with organisms producing similar clinical syndromes (Mycobacterium tuberculosis and Salmonella typhi). The results of a preliminary field trial of the assay in Kuwait indicate that the assay may be a valuable technique in the diagnosis of human brucellosis, meriting further study with larger numbers of cases. All 28 subjects with brucellosis (diagnosed on the basis of typical clinical features and confirmed by positive serology and, in three cases, by positive blood cultures) were PCR-positive whereas 28 healthy controls and 28 patients with febrile illness attributable to infections other than brucellosis were PCR-negative.
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PMID:Single-tube, nested PCR for the diagnosis of human brucellosis in Kuwait. 1217 21

We present a computational method for operon prediction based on a comparative genomics approach. A group of consecutive genes is considered as a candidate operon if both their gene sequences and functions are conserved across several phylogenetically related genomes. In addition, various supporting data for operons are also collected through the application of public domain computer programs, and used in our prediction method. These include the prediction of conserved gene functions, promoter motifs and terminators. An apparent advantage of our approach over other operon prediction methods is that it does not require many experimental data (such as gene expression data and pathway data) as input. This feature makes it applicable to many newly sequenced genomes that do not have extensive experimental information. In order to validate our prediction, we have tested the method on Escherichia coli K12, in which operon structures have been extensively studied, through a comparative analysis against Haemophilus influenzae Rd and Salmonella typhimurium LT2. Our method successfully predicted most of the 237 known operons. After this initial validation, we then applied the method to a newly sequenced and annotated microbial genome, Synechococcus sp. WH8102, through a comparative genome analysis with two other cyanobacterial genomes, Prochlorococcus marinus sp. MED4 and P.marinus sp. MIT9313. Our results are consistent with previously reported results and statistics on operons in the literature.
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PMID:Operon prediction by comparative genomics: an application to the Synechococcus sp. WH8102 genome. 1509 77

Heme, a major iron source, is transported through the outer membrane of Gram-negative bacteria by specific heme/hemoprotein receptors and through the inner membrane by heme-specific, periplasmic, binding protein-dependent, ATP-binding cassette permeases. Escherichia coli K12 does not use exogenous heme, and no heme uptake genes have been identified. Nevertheless, a recombinant E. coli strain expressing just one foreign heme outer membrane receptor can use exogenous heme as an iron source. This result suggests either that heme might be able to cross the cytoplasmic membrane in the absence of specific carrier or that there is a functional inner membrane heme transporter. Here, we show that to use heme iron E. coli requires the dipeptide inner membrane ATP-binding cassette transporter (DppBCDF) and either of two periplasmic binding proteins: MppA, the L-alanyl-gamma-D-glutamyl-meso-diaminopimelate binding protein, or DppA, the dipeptide binding protein. Thus, wild-type E. coli has a peptide/heme permease despite being unable to use exogenous heme. DppA, which shares sequence similarity with the Haemophilus influenzae heme-binding protein HbpA, and MppA are functional heme-binding proteins. Peptides compete with heme for binding both "in vitro" and "in vivo."
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PMID:The housekeeping dipeptide permease is the Escherichia coli heme transporter and functions with two optional peptide binding proteins. 1690 47

In previous work, our laboratory generated novel chimeric lipopolysaccharides (LPS) in Escherichia coli transformed with a plasmid containing exogenous lipooligosaccharide synthesis genes (lsg) from Haemophilus influenzae. Analysis of these novel oligosaccharide-LPS chimeras allowed characterization of the carbohydrate structures generated by several putative glycosyltransferase genes within the lsg locus. Here, we adapted this strategy to construct a modular approach to study the synthetic properties of individual glycosyltransferases expressed alone and in combinations. To this end, a set of expression vectors containing one to four putative glycosyltransferase genes from the lsg locus, lsgC-F, were transformed into E. coli K12 (XL-1) which is defective in LPS O-antigen biosynthesis. This strategy relied on the inclusion of the H. influenzae gene product lsgG in every plasmid construct, which partially rescues the E. coli LPS biosynthesis defect by priming uridine diphosphate-undecaprenyl in the WecA-dependent O-antigen synthetic pathway with N-acetyl-glucosamine (GlcNAc). This GlcNAc-undecaprenyl then served as an acceptor substrate for further carbohydrate extension by transformed glycosyltransferases. The resultant LPS-linked chimeric glycans were isolated from their E. coli constructs and characterized by mass spectrometry, methylation analysis and enzyme-linked immunosorbent assays. These structural data allowed the specificity of various glycosyltransferases to be unambiguously assigned to individual genes. LsgF was found to transfer a galactose (Gal) to terminal GlcNAc. LsgE was found to transfer GlcNAc to Gal-GlcNAc, and both LsgF and LsgD were found to transfer Gal to GlcNAc-Gal-GlcNAc but with differing linkage specificities. This method can be generalized and readily adapted to study the substrate specificity of other putative or uncharacterized glycosyltransferases.
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PMID:Utilizing the O-antigen lipopolysaccharide biosynthesis pathway in Escherichia coli to interrogate the substrate specificities of exogenous glycosyltransferase genes in a combinatorial approach. 2020 62


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