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

A simple micromethod in a liquid medium using the API-ATB system was developed for testing the susceptibility of Haemophilus to antibiotics. To evaluate this method, 50 strains, including 12 beta-lactamase producers, were studied. Results were compared to those obtained using MIC determination in a liquid medium (reference) and an agar diffusion method (routine). For all three techniques, a Mueller-Hinton medium enriched in hemoglobin and NAD was used, and cultures were incubated at 37 degrees C for 24 hours in normal atmosphere. Influence of the inoculum on results was evaluated using the API-ATB method for all antibiotics and MIC determination for ampicillin; the optimal inoculum was found to be 8.10(5) CFU/ml. Beta-lactamase was looked for using the chromogen cephalosporin test associated with the API-ATB system. Values of MICs for the various antibiotics were consistent with previous reports. Paired comparison of techniques showed a 5.3% disagreement rate between API-ATB and MIC, with only 0.5% major discrepancies; in contrast, the disagreement rate exceeded 10% when disk diffusion was compared with the two other techniques. We conclude to the reliability and reproducibility of the API-ATB method which seems capable of improving current routine evaluations of the susceptibility of Haemophilus to antibiotics.
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PMID:[Evaluation of the sensitivity of Haemophilus to antibiotics by the modified API-ATB system]. 391 Nov 54

The uptake of homologous DNA by Haemophilus influenzae was studied as a function of the proton motive force in completely competent cultures in the pH range of 6 to 8. The composition and magnitude of the proton motive force were varied by using the ionophores valinomycin and nigericin (in the presence of various potassium ion concentrations) and by using protonophores. No interaction of the ionophores with the DNA transformation system itself was observed. Either component of the proton motive force, the electrical potential or the pH gradient, can drive the uptake of DNA, and the extent of the uptake of DNA is ultimately determined by the total proton motive force. The transformation frequency increases with the proton motive force, which reaches a maximum value at around -130 mV. These results are consistent with an electrogenic proton-DNA symport mechanism, but direct evidence for such a system is not available. The proton motive force was followed during competence development of H. influenzae at pH 8. In the initial phase (up to 50 min), the proton motive force remained constant at about -90 mV, whereas the transformation frequency rose steeply. In the second phase, the proton motive force increased. The transformation frequency in this phase increased with the proton motive force, as in completely competent cultures. These observations and the observed inhibition by NAD of both the proton motive force and the transformation frequency indicate that structural components of the competent state are formed in the initial phase of competence development, whereas the second phase is characterized by an increase of the proton motive force.
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PMID:Role of the electrochemical proton gradient in genetic transformation of Haemophilus influenzae. 632 40

A total of 307 lungs obtained from a slaughterhouse were cultured by a dilution technique for the isolation of Haemophilus spp. The technique consisted of performing serial (10-fold) dilutions of the tissue samples to a dilution of 10(-5). Two selective media were used. L broth consisted of a basal brain heart infusion broth containing 5% horse serum, 5% yeast extract, and 100 micrograms of NAD and 0.5 microgram of lincomycin per ml. L-B broth was identical to L broth, except 1.5 microgram of bacitracin per ml was included. The broths were incubated overnight and then plated onto blood agar. A total of 83 (27%) isolates were obtained, and both media proved to be necessary, as a proportion of isolates grew in one of the media employed but not in the other. Of the isolates, 66.3% were urease positive and most of these (98%) were classified as "minor group" strains. Urease-negative strains (27.7%) were classified as Haemophilus parasuis.
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PMID:Dilution technique for isolation of Haemophilus from swine lungs collected at slaughter. 635 Mar 43

Thirty Haemophilus strains and six Actinobacillus strains, all of porcine origin, were examined for their biochemical reactivity on API 20E and API ZYM test strips using dense cell suspensions (supplemented with NAD as appropriate) as strip inocula. When combined with a test for V-factor dependency, the use of both strips allowed adequate differentiation of closely related organisms. Numerical taxonomic analysis of the data demonstrated that the majority of the haemophili and actinobacilli studied could be placed in one of four major clusters; these clusters contained, respectively, the H. pleuropneumoniae--A. pleuropneumoniae strains, the H. parasuis strains, strains belonging to Haemophilus taxon "minor group," and strains belonging to an unusual group of mannitol-positive, urease-negative haemophili. A representative of Haemophilus species taxon C and an unusual Actinobacillus isolate appeared to be comparatively unrelated to organisms in the four major clusters. Although it may, on occasion, be difficult to place an unusual isolate in any one particular group, owing to the uncertain taxonomy of some of these organisms, it is concluded that API test strips can serve as useful tools for the characterization and differentiation of porcine haemophili and actinobacilli.
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PMID:Porcine haemophili and actinobacilli: characterization by means of API test strips and possible taxonomic implications. 650 90

The mean generation time of Haemophilus influenzae in simulated blood cultures is 103 to 107 min. With 0.56 to 0.58 doublings per h, even large inocula of 256 cells per ml reach only 2 X 10(6) cells per ml and produce no visible evidence of growth after 24 h of incubation. Hemin and NAD added to simulated blood cultures triple the rate of growth of H. influenzae, so that even small inocula produce visible turbidity after overnight incubation. With a mean generation time of 36 min, a single cell of H. influenzae in simulated blood culture supplemented with hemin and NAD undergoes 30 doublings in 18 h, producing 2(30) (1.07 X 10(9] cells and visible turbidity.
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PMID:Growth of Haemophilus influenzae in simulated blood cultures supplemented with hemin and NAD. 660 36

Fragility of rabbit erythrocytes in agar plates results in gradual release of their NAD and NADP contents into the medium. Due to high NADase and negligible NADPase activity of rabbit red blood cell stroma at neutral pH, the NAD released into the medium is hydrolyzed and NADP remains intact. Thus, rabbit erythrocytes and their lysates support the growth of NAD(P)-requiring Haemophilus by serving as a source of NADP. Stability of sheep erythrocytes in agar plates results in retention of their NAD and NADP contents and consequently in inhibition of growth of NAD(P)-requiring Haemophilus. The highly active NAD- and NADP-splitting enzyme(s) of sheep red blood cell stroma prevent(s) the growth of Haemophilus on sheep blood lysates through inactivation of both NAD and NADP which are released into the medium.
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PMID:Nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate splitting enzyme(s) of sheep and rabbit erythrocytes: their effect on the growth of Haemophilus. 711 35

A modified selective medium supplemented with N-acetyl-D-glucosamine (NAG), hemin, and NAD plus two cefsulodin disks, for primary isolation of nonencapsulated Haemophilus influenzae from sputum of patients with cystic fibrosis, is described. Isolation of H. influenzae from this medium, designated NAG medium, was compared with recovery by standard media and immunochemical detection of H. influenzae with monoclonal antibody 8BD9. The H. influenzae recovery rate increased from 31% with standard media to 42% with NAG medium. H. influenzae was detected by immunoperoxidase staining in 54% of the sputum specimens. The results of this study demonstrate that NAG medium improves H. influenzae recovery, although immunoperoxidase staining is superior for detection of H. influenzae from sputum of cystic fibrosis patients.
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PMID:N-acetyl-D-glucosamine medium improves recovery of Haemophilus influenzae from sputa of patients with cystic fibrosis. 768 56

Several agar media (Mueller-Hinton agar, MHA; diagnostic sensitivity test agar, DSTA; Schaedler agar, SchA; Todd-Hewitt agar with added yeast extract, THYA; Wilkins-Chalgren agar, WCA) were compared using the Bauer-Kirby agar disk diffusion test against six nonfastidious quality control strains: Staphylococcus aureus ATCC 25923 and ATCC 29213, Escherichia coli ATCC 25922 and ATCC 35218, Pseudomonas aeruginosa ATCC 27853, and Enterococcus faecalis ATCC 29212. MHA, DSTA, and THYA yielded essentially comparable inhibition zones. However, WCA and SchA antagonized cotrimoxazole and aminoglycoside antibiotics; furthermore, SchA antagonized polymyxin B, and both WCA and SchA antagonized imipenem against the P. aeruginosa strain, but not against the E. coli strains. Sheep blood-MHA (Bl-MHA), WCA, THYA, and DSTA were examined with Streptococcus pyogenes ATCC 19615, Streptococcus agalactiae ATCC 13813, and Streptococcus pneumoniae ATCC 6306. In comparison with Bl-MHA, both WCA and THYA yielded comparable inhibition zones against S. pyogenes; DSTA afforded suboptimal growth. DSTA yielded larger inhibition zones with the majority of antimicrobial drugs against S. agalactiae, whereas WCA and THYA enhanced the activity of oxacillin and penicillin G against this strain. S. pneumoniae strain ATCC 6306 grew well on Bl-MHA, yielded suboptimal growth on WCA and faint growth on THYA, and failed to grow on DSTA. Chocolate-supplemented sheep blood-MHA (CHOC-MHA) was compared with Haemophilus test medium (HTM), WCA with added NAD, and THYA with added hematin and NAD against Haemophilus influenzae strains ATCC 35056 and ATCC 49247. The activities of doxycycline and rifampin were enhanced against both strains by HTM, WCA+NAD, and THYA+hematin+NAD. Only WCA+NAD antagonized cotrimoxazole against both H. influenzae strains, an effect due to thymidine; however, HTM antagonized cotrimoxazole against S. aureus ATCC 25923 and E. coli ATCC 25922. It was concluded that Bl-MHA performed best for beta-hemolytic streptococci quality control strains. Likewise, CHOC-MHA was optimal for the two H. influenzae strains used in this comparative agar disk diffusion study.
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PMID:Agar disk diffusion (Bauer-Kirby) tests with various fastidious and nonfastidious reference (ATCC) strains: comparison of several agar media. 784 20

The results of this study show that goat blood as a culture medium supplement is as supportive as horse blood for the isolation and identification of Haemophilus influenzae and Streptococcus pneumoniae from clinical material. Care is required in the preparation of goat blood chocolate agar to ensure that a thermolabile growth inhibitor of NAD-dependent Haemophilus species is eliminated.
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PMID:Comparison of goat and horse blood as culture medium supplements for isolation and identification of Haemophilus influenzae and Streptococcus pneumoniae from upper respiratory tract secretions. 785 93

NAD dependent members of the family Pasteurellaceae were cultured from the nasal cavity, surface and cut surface of the tonsils, and from the apical and caudal lobes of the lungs of 303 slaughterhouse pigs from 5 different herds in order to obtain information on the ecology of these bacteria. The specimens were plated on two different selective agar media using a special dilution technique that resulted in a good separation of individual colonies. Bacteriological results were compared with serological and pathological findings. The bacteriological examination demonstrated that NAD dependent Pasteurellaceae belonging to the taxa previously described could be isolated from the surface and cut surface of the tonsils, and from lungs with and without gross pathologic lesions. Haemophilus parasuis was detected mainly from the nasal cavity, and Actinobacillus pleuropneumoniae mainly from the surface and cut surface of the tonsils (42%). From two herds, 19% and 24% respectively of the animals without antibodies against A. pleuropneumoniae serotypes 1 and 2 harboured the bacteria mainly in the tonsils. This may reflect a very recent infection or may suggest that A. pleuropneumoniae can colonize the tonsils without inducing a serologic reaction. Serological and bacteriological evidence of more than one serotype in the same herd indicates that natural infection with one serotype does not necessarily protect against another.
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PMID:Optimalization of the detection of NAD dependent Pasteurellaceae from the respiratory tract of slaughterhouse pigs. 827 73


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