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

The isolation, characterization, and identification of a microorganism isolated from gastrointestinal tracts of rabbits with mucoid enteritis are described. The isolated organism did not grow on standard media. This organism grew around colonies of Staphylococcus aureus and Lactobacillus desidiosus and around disks saturated with diphosphopyridin nucleotide (factor V) on brain heart infusion agar. The growth of this organism was also observed on media supplemented with beta-nicotinamide adenine dinucleotide. The organism appeared as gram-negative, pleomorphic rods or coccobacilli. It was positive for urease, oxidase, catalase, glycosidases, porphyrin, and indole, and it fermented glucose and sucrose. All of these characteristics suggest that the organism is a member of the genus Haemophilus. Because of its isolation from rabbits and differences in some characteristics from other species of this genus, the name Haemophilus paracuniculus is proposed for this organism.
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PMID:Characterization of a Haemophilus paracuniculus isolated from gastrointestinal tracts of rabbits with mucoid enteritis. 42 39

There has not previously been an objective comparison of medium formulations for the primary isolation of Haemophilus species. This study was undertaken to evaluate the components required for the optimal growth of large, easily identifiable colonies of these bacteria. We compared six medium bases and seven supplements for their ability to support the growth of 86 strains of Haemophilus influenzae and 17 strains of other species of Haemophilus. By using a growth index that combines colony size and the dilution factor, a formulation of GC agar base with 1% yeast autolysate and 5% sheep blood (chocolated) promoted the growth of large, easily recognizable colonies of H. influenzae and other Haemophilus species. This medium was designated GCYSB. The addition of hematin to supplements that supplied NAD (or factor V) to the medium was inhibitory to the growth of all of the Haemophilus species tested. In a clinical comparison of GCYSB with routinely used chocolate agar medium in two laboratories for the primary isolation of Haemophilus species, overall GCYSB promoted better growth of 124 strains of H. influenzae and H. parainfluenzae. GCYSB is easy to prepare and inexpensive compared with the ease of preparation and expense of other Haemophilus isolation media.
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PMID:Laboratory and clinical evaluations of media for the primary isolation of Haemophilus species. 150 Apr 94

The effect of a commercially available, chemically defined enrichment (Iso-VitaleX; BBL Microbiology Systems, Cockeysville, Md.) on the growth of 10 strains of Haemophilus somnus was studied. A 6- to 10-fold increase in growth, as measured turbidimetrically, was observed when Iso VitaleX was added to a basal medium of brain heart infusion broth to a final concentration of 1% (vol/vol). Thiamine pyrophosphate (cocarboxylase), a constituent component of Iso VitaleX, was found to be the only growth-promoting factor, and it could be used as a substitute for Iso VitaleX. An equimolar concentration (2.2 microM) of thiamine monophosphate promoted growth equal to that of thiamine pyrophosphate. Thiamine was nonstimulatory for all 10 strains tested. When alkaline thermal-treated brain heart infusion broth was used as the basal medium, 7 of the 10 strains had an absolute requirement for thiamine monophosphate or thiamine pyrophosphate. The three remaining strains showed minimal growth when thiamine was added to this basal medium; however, excellent growth was observed when thiamine monophosphate or thiamine pyrophosphate was utilized. Factor X (hemin) was found to further enhance the growth when concentrations of 5 to 10 micrograms/ml were coupled with thiamine pyrophosphate. No increase in growth was observed when factor V (nicotinamide adenine dinucleotide) was coupled with thiamine pyrophosphate. This is the first report of a growth factor requirement for H. somnus.
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PMID:Thiamine pyrophosphate (cocarboxylase) as a growth factor for Haemophilus somnus. 727 48

In this study, we identified and characterized a novel secreted protein, the extracellular serine protease EspP, which is encoded by the large plasmid of enterohaemorrhagic Escherichia coli (EHEC) O157:H7. The corresponding espP gene consists of a 3900 bp open reading frame that is able to encode a 1300-amino-acid protein. EspP is synthesized as a large precursor which is then processed at the N- and C-termini during secretion. It can be grouped into the autotransporter protein family. The deduced amino acid sequence of EspP showed homology to several secreted or surface-exposed proteins of pathogenic bacteria, in particular EspC of enteropathogenic E. coli and IgA1 proteases from Neisseria spp. and Haemophilus influenzae. Hybridization experiments and immunoblot analysis of clinical EHEC isolates showed that EspP is widespread among EHEC of the serogroup O157 and that it also exists in serogroup 026. A specific immune response against EspP was detected in sera from patients suffering from EHEC infections. Functional analysis showed that EspP is a protease capable of cleaving pepsin A and human coagulation factor V. Degradation of factor V could contribute to the mucosal haemorrhage observed in patients with haemorrhagic colitis.
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PMID:EspP, a novel extracellular serine protease of enterohaemorrhagic Escherichia coli O157:H7 cleaves human coagulation factor V. 919 4

Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks almost all the biosynthetic enzymes necessary for the de novo synthesis of that cofactor. Factor V can be provided as either nicotinamide adenosine dinucleotide (NAD), nicotinamide mononucleotide (NMN), or nicotinamide riboside (NR) in vitro, but little is known about the source or the mechanism of uptake of these substrates in vivo. As shown by us earlier, at least two gene products are involved in the uptake of NAD, the outer membrane lipoprotein e (P4), which has phosphatase activity and is encoded by hel, and a periplasmic NAD nucleotidase, encoded by nadN. It has also been observed that the latter gene product is essential for H. influenzae growth on media supplemented with NAD. In this report, we describe the functions and substrates of these two proteins as they act together in an NAD utilization pathway. Data are provided which indicate that NadN harbors not only NAD pyrophosphatase but also NMN 5'-nucleotidase activity. The e (P4) protein is also shown to have NMN 5'-nucleotidase activity, recognizing NMN as a substrate and releasing NR as its product. Insertion mutants of nadN or deletion and site-directed mutants of hel had attenuated growth and a reduced uptake phenotype when NMN served as substrate. A hel and nadN double mutant was only able to grow in the presence of NR, whereas no uptake of NMN was observed.
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PMID:NadN and e (P4) are essential for utilization of NAD and nicotinamide mononucleotide but not nicotinamide riboside in Haemophilus influenzae. 1139 61

Haemophilus influenzae has an absolute requirement for factor V because it lacks all the biosynthetic enzymes necessary for the de novo synthesis of NAD. Factor V can be provided as either nicotinamide adenosine dinucleotide (NAD), nicotinamide mono-nucleotide (NMN) or nicotinamide riboside (NR) in vitro, but little is known about the source or the mechanism of uptake for factor V in vivo. Recently, a hypothetical open reading frame (ORF), termed nadN, was identified to encode a gene product essential for H. influenzae growth on NAD. Here, we report its role in the virulent H. influenzae serotype b strain Eagan. Our results indicate that NadN of type b Eagan strains is involved in NAD uptake and in processing NAD to NR, which appears to be the substrate for an as yet unidentified cytoplasmic membrane NR transport system. Furthermore, we present data showing that H. influenzae type b nadN mutants are able to survive as well as Eagan, in vivo in the five-day-old infant rat model of human invasive disease. NAD pyrophosphatase and NMN 5'-nucleotidase activities were present in rat and human serum, implying that under infection conditions H. influenzae may obtain NR directly from its host.
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PMID:Is a NAD pyrophosphatase activity necessary for Haemophilus influenzae type b multiplication in the blood stream? 1155 62

This paper reports a case of Haemophilus segnis polymicrobial bacteraemia and a case of H. segnis monomicrobial bacteraemia identified by 16S ribosomal RNA gene sequencing. In the first case, a gram-negative aerobic coccobacillus was isolated with Streptococcus intermedius and S. sanguis from the blood culture of a 32-year-old intravenous drug addict with left thoracic empyema. In the second case, a gram-negative aerobic coccobacillus was isolated from the blood culture of an 82-year-old woman with Clostridium difficile colitis and septicaemic shock. Both gram-negative coccobacilli grew on chocolate agar as colonies of 1 mm in diameter after incubation for 24 h at 37 degress C in air with CO2 5%, but only to pinpoint sizes on blood agar under the same incubation conditions. Both strains were factor V-dependent, but not factor X-dependent. For the first isolate, the Vitek system (NHI) showed that it was 56% likely to be Actinobacillus actinomycetemcomitans and 40% Neisseria subflava; whereas the API system (NH) showed that it was 58% likely to be H. aphrophilus/paraphrophilus and 42% H. parainfluenzae. For the second isolate, the Vitek system (NHI) showed that it was 95% likely to be H. influenzae VIII; whereas the API system (NH) showed that it was 58% likely to be H. aphrophilus/paraphrophilus and 42% H. parainfluenzae. 16S rRNA gene sequencing showed that there were four base differences between isolate 1 and H. segnis and two base differences between isolate 2 and H. segnis, indicating that both isolates most closely resembled a strain of H. segnis. Only two cases of H. segnis bacteraemia were found in the English scientific literature, one in a case of infective endocarditis and the other in a case of pancreatic abscess. Including the present two cases, the overall mortality of H. segnis bacteraemia was 50%.
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PMID:Haemophilus segnis polymicrobial and monomicrobial bacteraemia identified by 16S ribosomal RNA gene sequencing. 1217 Dec 93

Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks all biosynthetic enzymes necessary for de novo synthesis of that cofactor. Therefore, growth in vitro requires the presence of NAD itself, NMN, or nicotinamide riboside (NR). To address uptake abilities of these compounds, we investigated outer membrane proteins. By analyzing ompP2 knockout mutants, we found that NAD and NMN uptake was prevented, whereas NR uptake was not. Through investigation of the properties of purified OmpP2 in artificial lipid membrane systems, the substrate specificity of OmpP2 for NAD and NMN was determined, with KS values of approximately 8 and 4mm, respectively, in 0.1 m KCl, whereas no interaction was detected for the nucleoside NR and other purine or pyrimidine nucleotide or nucleoside species. Based on our analysis, we assume that an intrinsic binding site within OmpP2 exists that facilitates diffusion of these compounds across the outer membrane, recognizing carbonyl and exposed phosphate groups. Because OmpP2 was formerly described as a general diffusion porin, an additional property of acting as a facilitator for nicotinamide-based nucleotide transport may have evolved to support and optimize utilization of the essential cofactor sources NAD and NMN in H. influenzae.
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PMID:Porin OmpP2 of Haemophilus influenzae shows specificity for nicotinamide-derived nucleotide substrates. 1269 15

Haemophilus species are an infrequent cause of subacute bacterial endocarditis. Of the Haemophilus species causing endocarditis, H. aphrophilus and H. parainfluenzae are more frequent causes of subacute bacterial endocarditis than H. influenzae. H. parainfluenzae requires growth factor V (nicotinamide adenine dinucleotide) and grows very slowly on routine culture media. H. parainfluenzae is a rare cause of "culture negative" endocarditis because it is a slow-growing organism. We present a case of a 42-year-old intravenous drug abuser with H. parainfluenzae mitral prosthetic valve endocarditis. To the best of our knowledge, this is the first case of mitral prosthetic valve endocarditis caused by H. parainfluenzae in an intravenous drug abuser.
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PMID:Haemophilus parainfluenzae mitral prosthetic valve endocarditis in an intravenous drug abuser. 1576 62

Haemophilus influenzae requires two growth factors, designated factor X (porphyrin) and factor V (NAD). Mammalian catalases contain both bound heme and NADPH. This study shows that catalase can supply both factors X and V to H. influenzae in vitro, thus representing a potential in vivo source of these essential growth factors.
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PMID:Catalase as a source of both X- and V-factor for Haemophilus influenzae. 1809 36


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