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 distribution of serogroups among 156 strains of beta-hemolyzing streptococci from clinical material was as follows: A - 64.1%, B - 3.2%, C - 11.5%, D - 0.6%, F- 6.4%, G - 14.1% (Table 1). Serogroup A was found in pus specimens in 84%, in throat swabs in 67%, and in sputum specimens (x2 greater than 6.64) in only 23% of strains; among clinical diagnoses (Table 2), distribution of this group was as follows: scarlet fever 100%, infected wounds 83%, and otorhinolaryngological diseases less than 70% of strains. From 54% of specimens received, other organisms were isolated in addition to beta-hemolyzing streptococci, In Table 3, the distribution of serogroups (x2 greater than 1) in cases of single and mixed infections is shown for the most frequent types of material received. Combinations of the individual serogroups with concomitant bacteria, above all Staphylococcus aureus, a number of enterobacteria, and Haemophilus influenzae can be seen from Table 4. Staph. aureus was found preferentially in combination with group A streptococci (x2 greater then 6.64). The proportion of mixed infections among specimens of the most important types of material was varying (Table 5): 82% of sputum specimens, 46%of throat swabs, and 39% of pus specimens. As concomitant organisms, especially Haem. influenzae, Staph. aureus (in throat swabs and pus specimens), and enterobacteria were found. With scarlet fever, Staph. aureus was present in as much as 60% of all cases. Ampicillin-resistant strains were isolated among the various concomitant organisms from 22% of all materials and 45% of all sputum specimens.
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PMID:[Mixed infections by hemolyzing streptococci in clinical material (author's transl)]. 127 97

We sought to determine whether chloramphenicol would worsen or mitigate the anemia associated with Haemophilus influenzae type b meningitis if administered in doses which produce 'therapeutic' serum concentrations. Seventy-four cases of H. influenzae meningitis were stratified by chloramphenicol cumulative doses (mg/kg body weight) of less than 300 and greater than 300. There was no significant difference in the decrease in blood hemoglobin concentration or in the increase in the FEP:Heme ratio between the two study groups. Plasma iron and transferrin saturation values indicated iron deficiency at days 1 and 5 of hospitalization; by day 10 mean values were within the normal range. These data suggest that H. influenzae type b meningitis, not chloramphenicol therapy in the presence of monitoring is causing the observed anemia.
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PMID:Anemia during Haemophilus influenzae type b meningitis: lack of an effect of chloramphenicol. 276 22

MICs of meropenem were determined for a wide range of common bacteria of clinical importance. For Enterobacteriaceae, Aeromonas spp., Haemophilus influenzae, Branhamella catarrhalis, Neisseria gonorrhoeae, Gardnerella vaginalis, Campylobacter coli/jejuni, beta-haemolytic streptococci and anaerobes other than Clostridium difficile, MICs were almost always within the range 0.002-0.5 mg/l. The activity of meropenem for these organisms was always greater than that of imipenem and piperacillin, and was similar to that of ceftazidime and cefotaxime except that strains resistant to these latter, and to piperacillin, were usually sensitive to imipenem and meropenem. Meropenem was also active against most non-fermentative Gram-negative bacilli, with MICs in the range 0.12-4 mg/l but Pseudomonas (Xanthomonas) maltophilia was often resistant, as it was to all the other drugs tested. Staphylococci, Strreptococcus pneumoniae and other alpha-haemolytic streptococci were usually more sensitive to imipenem than to meropenem, but even methicillin-resistant staphylococci were sensitive to both drugs (MICs less than 4 mg/l). Enterococci were also less sensitive to meropenem than to imipenem, and Enterococcus faecium was invariably highly resistant to all the drugs tested except ciprofloxacin, which had marginal activity. Results for Ps. maltophilia and Haem. influenzae were affected by media used for sensitivity testing.
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PMID:Comparative in-vitro activity of meropenem on clinical isolates from the United Kingdom. 280 14

The mechanisms for acquisition of iron by Haemophilus influenzae and their role in pathogenesis are not known. Heme and nonheme sources of iron were evaluated for their effect on growth of type b and nontypable strains of H. influenzae in an iron-restricted, defined medium. All 13 strains acquired iron from heme, hemoglobin, hemoglobin-haptoglobin, and heme-hemopexin. Among nonheme sources of protein-bound iron, growth of H. influenzae was enhanced by partially saturated human transferrin but not by lactoferrin or ferritin. Purified ferrienterochelin and ferridesferrioxamine failed to provide iron to H. influenzae, and the supernatants of H. influenzae E1a grown in iron-restricted medium failed to enhance iron-restricted growth of siderophore-dependent strains of Escherichia coli, Salmonella typhimurium, and Arthrobacter terregens. Marked alterations in the profile of outer membrane proteins of H. influenzae were observed when the level of free iron was varied between 1 microM and 1 mM. Catechols were not detected in the supernatants of strain E1a; however, iron-related hydroxamate production was detected by two biochemical assays. We conclude that the sources of iron for H. influenzae are diverse. The significance of hydroxamate production and iron-related outer membrane proteins to H. influenzae iron acquisition is not yet clear.
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PMID:Iron acquisition by Haemophilus influenzae. 296 10

The results of 2439 blood cultures that were taken in an acute children's hospital over a two-year period were reviewed. Three hundred and twenty-two organisms were cultured from 310 patients. One hundred and thirty-five (5.5%) isolates were considered to be pathogenic and 187 (7.7%) isolates were considered to be contaminants. Coagulase-positive staphylococci and enteric Gram-negative organisms were the isolates of which the significance was most difficult to determine. Community-acquired bacteraemia that affected children of less than five years of age was caused by Haemophilus influenzae in 65% of cases. Staphylococcus aureus was the major pathogen in older children. In 20% of cases, antimicrobial agents were commenced or changed after blood culture results. Delayed or inappropriate therapy was significantly more common in patients without an apparent focus of infection. The results of our study suggest that narrow spectrum antimicrobial agents can be used as appropriate empiric therapy for unlocalized infections in previously-well children. In children of between three months and five years of age, treatment should be directed against Haem. influenzae and Streptococcus pneumoniae, and in children of over five years of age, antistaphylococcal therapy should also be included.
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PMID:Blood cultures in hospitalized children. 350 Mar 92

Heme can serve Haemophilus influenzae as a source of both essential porphyrin and iron. In extracellular mammalian body fluids neither free heme nor free iron is available, since they are tightly bound to hemopexin and transferrin, respectively. Since H. influenzae grows in the presence of iron-transferrin and heme-hemopexin and is known to express a saturable receptor for transferrin, we investigated the process by which this pathogen acquired heme from hemopexin for use as an iron source. The ability of human and rabbit hemopexin to donate heme as a source of iron to H. influenzae type b strains was demonstrated by plate bioassays. With a dot enzyme assay with biotinylated hemopexin as ligand, H. influenzae bound heme-hemopexin and apo-hemopexin following growth in iron-restricted, but not in iron-sufficient, medium. Competitive binding studies with heme-hemopexin and apo-hemopexin demonstrated saturability of binding. Neither heme, protoporphyrin IX, hemoglobin, nor transferrin blocked the binding of hemopexin to whole cells, demonstrating the specificity of binding. Treatment of whole H. influenzae cells with trypsin abolished binding. Taken together, these observations suggest that H. influenzae type b expresses an outer membrane protein(s) which acts as a receptor for hemopexin and which is regulated by the availability of iron in the growth medium. In iron-restricted media, H. influenzae 706705 and DL42 did not express the 100-kDa hemopexin-binding protein previously reported (M.S. Hanson, S.E. Pelzel, J. Latimer, U. Muller-Eberhard, and E.J. Hansen, Proc. Natl. Acad. Sci. USA 89:1973-1977, 1992). The putative iron-regulated hemopexin receptor was solubilized from cell envelopes of H. influenzae 706705, DL42, and Eagan with the detergent CHAPS (3-[(3-cholamidopropyl)-dimethyl-ammonio]-1-propanesulfonate) and isolated by affinity chromatography on heme-hemopexin-Sepharose 4B. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the proteins bound to the affinity resin revealed three proteins of 29, 38, and 57 kDa, of which the 57- and 29-kDa proteins bound hemopexin after Western blotting (immunoblotting). A monoclonal antibody to the 57-kDa hemopexin-binding protein of 706705 recognized a 57-kDa protein on Western blots of the cell envelope proteins of 706705, DL42, and Eagan; no reaction was observed with the 100-kDa hemopexin-binding protein of DL42. These data suggest that some H. influenzae strains possess at least two hemopexin receptors, the expression of which is determined by the prevailing growth environment.
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PMID:Identification and characterization of an iron-regulated hemopexin receptor in Haemophilus influenzae type b. 826 49

Heme uptake is a common means of iron and porphyrin acquisition by many pathogenic bacteria. The genus Haemophilus includes several important pathogenic bacterial species that characteristically require hemin-, protoporphyrin-, or heme-substituted proteins as essential growth factors under aerobic conditions. However, the mechanism of heme transport is not understood for Haemophilus. We have cloned a DNA fragment from H. influenzae that allows an Escherichia coli hemA mutant to employ exogenous hemin or protoporphyrin IX as sole sources of porphyrin. DNA sequencing of the cloned DNA fragment suggested that a previously characterized gene (hel) encoding an antigenic, outer membrane lipoprotein e(P4) was responsible for the complementation activity. Construction of hel insertion mutations in strain H. influenzae Rd demonstrated that hel is essential for growth under aerobic conditions but not under anaerobic conditions. The aerobic growth defect of hel mutants could be reversed by providing exogenous hemin in the presence of outer membrane. The analysis of hybrids between e(P4) and beta-lactamase demonstrated that a domain of e(P4) near its NH2' terminus was required for its function in hemin use. Within this domain is a short amino acid sequence that displays similarity to H. influenzae hemin binding protein HbpA, hemin-binding motifs present in eukaryotic transcription activator heme-activated protein, and the heme containing proteins hemoglobin (alpha-chain) and cytochrome C3, suggesting that this region may be involved in hemin binding and/or transport.
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PMID:Lipoprotein e(P4) is essential for hemin uptake by Haemophilus influenzae. 862 73

Etiologic agents of meningitis were prospectively investigated among patients admitted to Usman Danfodio University Teaching Hospital, Sokoto. Of 1097 cerebrospinal fluid (CSF) samples submitted to the microbiology laboratory from various wards of the hospital, 289 (26%) were microscopically, culturally and/or serologically proven to be bacterial meningitis. The etiologic spectrum was as follows: Neisseria meningitidis (61%), Streptococcus pneumoniae (18%), Haemophilus influenzae (10%), Staphylococcus aureus (6%), Coliform bacilli (3%), Escherichia coli (0.7%), Mycobacterium tuberculosis (0.7%), Listeria monocytogenes (0.4%), Flavobacterium meningosepticum (0.4%) and Pseudomonas putrifasciens (0.4%). Bacterial meningitis was most prevalent (195 or 68%) among children aged 1-9 y, while adults and neonates were least affected. Coliform bacilli caused five of eight neonatal cases. Males were more frequently affected than females (chi2 = 12.50; p < 0.05). Culture and microscopy were comparatively less efficient than the search for bacterial antigens, especially in the diagnosis of Haemophilus meningitis. Antimicrobial susceptibility of N. meningitidis to ampicillin and benzyl penicillin reduced progressively over the years (F = 406.98; p < 0.001). Nineteen (11%) of the isolates (5 Meningococci, 7 Staph. aureus, 1 Haem. influenza and 6 others) showed simultaneous resistance to chloramphenicol, ampicillin and benzyl penicillin.
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PMID:Etiologic spectrum and pattern of antimicrobial drug susceptibility in bacterial meningitis in Sokoto, Nigeria. 1097 35

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

Haemophilus influenzae requires an exogenous heme source for aerobic growth in vitro. Hemoglobin or hemoglobin-haptoglobin satisfies this requirement. Heme acquisition from hemoglobin-haptoglobin is mediated by proteins encoded by hgp genes. Both Hgps and additional proteins, including those encoded by the hxu operon, provide independent pathways for hemoglobin utilization. Recently we showed that deletion of the set of three hgp genes from a nontypeable strain (86-028NP) of H. influenzae attenuated virulence in the chinchilla otitis media model of noninvasive disease. The present study was undertaken to investigate the role of the hgp genes in virulence of the wild-type serotype b clinical isolate HI689 in the infant rat model of hematogenous meningitis, an established model of invasive disease requiring aerobic growth. Bacteremia of high titer and long duration (>14 days) and histopathologically confirmed meningitis occurred in >95% of infant rats challenged at 5 days of age with strain HI689. While mutations disrupting either the Hgp- or Hxu-mediated pathway of heme acquisition had no effect on virulence in infant rats, an isogenic mutant deficient for both pathways was unable to sustain bacteremia or produce meningitis. In contrast, mutations disrupting either pathway decreased the limited ability of H. influenzae to initiate and sustain bacteremia in weanling rats. Biochemical and growth studies also indicated that infant rat plasma contains multiple heme sources that change with age. Taken together, these data indicate that both the hgp genes and the hxuC gene are virulence determinants in the rat model of human invasive disease.
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PMID:Complex role of hemoglobin and hemoglobin-haptoglobin binding proteins in Haemophilus influenzae virulence in the infant rat model of invasive infection. 1696 15


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