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)

Pyridinium-2-azo-p-dimethylaniline chromophore was evaluated as a test tube, filter paper and spectrophotometric assay for detection of beta-lactamases from gram-positive and gram-negative organisms. Although useful for detection of TEM beta-lactamases in Haemophilus influenzae and Neisseria gonorrhoeae, it was a poor agent for detecting TEM, OXA and PSE enzymes in Enterobacteriaceae. It also proved poor for detecting cephalosporinases in Pseudomonas aeruginosa and Enterobacteriaceae, and penicillinases in Staphylococcus aureus when compared to nitrocefin. As a spectrophotometric substrate it was equivalent to nitrocefin and cephaloridine with various beta-lactamases.
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PMID:Pyridinium 2-azo-p-dimethylaniline chromophore, a chromogenic reagent for beta-lactamase testing compared to nitrocefin. 633 17

Ampicillin resistance in Haemophilus influenzae is most often due to the plasmid-mediated production of TEM beta-lactamase. We studied four strains with high-level ampicillin resistance (MIC of 32 micrograms/ml with an inoculum of 10(5) CFU on solid media) which did not produce detectable beta-lactamase activity with two different detection methods. Two of the four strains contained extrachromosomal DNA by agarose gel electrophoresis. Conjugation failed to transfer ampicillin resistance; in contrast, transformation yielded ampicillin-resistant transformants in three of the four strains. These transformants did not contain detectable extrachromosomal DNA. In addition, mobilization of the resistance determinant by transformation to, or conjugation with, recombination-deficient strains was unsuccessful. DNA-DNA hybridization experiments revealed no homology of the DNA of these strains with two R plasmids (one coding for ampicillin resistance, the other for chloramphenicol and tetracycline resistance). We conclude that the genetic basis of the non-beta-lactamase ampicillin resistance in these strains appears to be chromosomally mediated. We investigated the mechanism of resistance in these strains. Enzymatic modification of penicillin was not detected by autoradiography of a thin-layer chromatogram of cell sonic extracts of three ampicillin-resistant transformant strains incubated with [14C]penicillin. To assess changes in permeability of the cell envelope, a plasmid coding for beta-lactamase was conjugated into these strains, and the hydrolysis of penicillin by intact cells and cell sonic extracts was compared. Only one of three transformant strains had significantly diminished permeability. Outer membrane proteins of these strains analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed apparent differences in comparison with the isogenic ampicillin-susceptible recipient strain. Autofluorography of a sodium dodecyl sulfate-polyacrylamide gel electrophoresis of Sarkosyl-solubilized crude membrane (the putative inner membranes) from these ampicillin-resistant transformant strains incubated with [3H]penicillin compared with the isogenic ampicillin-susceptible recipient strain revealed reduced binding to PBP 3 and 6, 3 and 4, or 4. In addition, affinity binding studies revealed decreased affinity of PBP 4 for ampicillin of all four transformants tested. We conclude that the major mechanism of resistance in these strains is altered penicillin-binding proteins; however, other mechanisms, including permeability, may also play a role.
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PMID:Characterization of non-beta-lactamase-mediated ampicillin resistance in Haemophilus influenzae. 633 8

A rapid, simple assay for screening large numbers of Escherichia coli colonies for production of certain plasmid-mediated beta-lactamases (including TEM-1, TEM-2, HMS-1, SHV-1, OXA-1, PSE-1, PSE-4, and CEP-2) is described. The technique, a modification of the method of Slack et al. for detection of beta-lactamase in limited numbers of Haemophilus influenzae clinical isolates (Lancet ii:906, 1977), uses filter paper impregnated with benzylpenicillin and a pH indicator dye (bromocresol purple) that changes color in the presence of beta-lactamase activity. The test paper is briefly applied to an agar surface containing bacterial colonies which are subsequently scored individually on the paper by color: yellow indicates the presence of beta-lactamase, dark green its absence, and variegation (yellow and dark green) a mixed population. Concordance of the results of this assay with those of replica plating for antibiotic resistance was over 99%. Hundreds of colonies per plate can be scored quickly and remain viable for further evaluation. The assay appears to be useful for studies of the stability of plasmids encoding beta-lactamases and in cloning with vectors such as pBR322 in which insertion of DNA fragments can be detected by inactivation of the beta-lactamase gene. Whenever the assay is to be used, results should always be confirmed initially by another method, such as replica plating, because the test paper assay does not detect three beta-lactamases (OXA-2, OXA-3, and PSE-2) and also would miss intrinsic penicillin resistance.
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PMID:Rapid method for screening large numbers of Escherichia coli colonies for production of plasmid-mediated beta-lactamases. 634 Jun 5

Resistance to beta-lactams may be difficult to recognize. This is due to the difficulty in detecting these resistances, when the routine tests performed in diagnostic laboratories are interpreted in the usual manner. Since failure to recognize this type of resistance may have serious consequences for the patient, it is essential that it be detected when present. For the detection of methicillin resistance of Staphylococcus aureus a standardized method using either a medium containing 5% NaCl or a low incubation temperature is advocated. Methicillin resistance of S. epidermidis can only be recognized reliably by means of a quantitative test and incubation for 42-48 h. Resistance of Haemophilus influenzae to ampicillin may be intrinsic or it may be caused by a TEM beta-lactamase; a beta-lactamase test should be used to detect the latter type of resistance. Inducible cephalosporinase may be responsible for the rapid development of resistance of some bacterial species to cefamandole, even during therapy. If a stable beta-lactamase production is attained by mutation, resistance to other beta-lactams will usually be present as well. Routine induction tests should be performed for all isolates of species of Enterobacter, Serratia, Citrobacter and Proteus, indole-positive. The same type of 'hidden' resistance may be present in Pseudomonas aeruginosa, with regard to cefotaxime and other third-generation cephalosporins. Beta-lactamase-positive Neisseria gonorrhoeae can easily be recognized by a beta-lactamase test. In addition, the results of diffusion tests allow one to distinguish between beta-lactamase-positive and beta-lactamase-negative strains. Recognition of those strains of N. gonorrhoeae having a decreased susceptibility to penicillin is only possible when well-standardized quantitative tests are used.
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PMID:Recognition and clinical significance of mechanisms of bacterial resistance to beta-lactams. 644 23

The activity in vitro of the new parenteral penicillin, temocillin, was determined by an agar dilution technique at two inocula against 201 recent clinical isolates and also against reference strains that produced characterized beta-lactamases. Ampicillin, ticarcillin, latamoxef (moxalactam) and cefoxitin were used as comparative agents. Temocillin showed no useful activity against Pseudomonas aeruginosa or the Bacteroides fragilis group but was highly active against the Enterobacteriaceae, inhibiting all isolates (Serratia marcescens excepted) at less than or equal to 8 mg/l. The MIC50 and MIC90 were usually within one dilution and results with both inoculum sizes were similar. Temocillin also had good activity against Haemophilus influenzae and beta-lactamase producing strains were as susceptible as non-beta-lactamase producers. Neither for the Enterobacteriaceae nor for H. influenzae did a 1000-fold increase in inoculum result in a greater than two-fold increase in MIC. The above results implied excellent stability to beta-lactamases and this was borne out by the activity of temocillin against strains containing chromosomal cephalosporinases, the 'broad-spectrum' Class IV enzyme and the plasmid mediated enzymes TEM-1, OXA-1 and SHV-1. The protein binding of temocillin was found to be 87%.
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PMID:Comparative in-vitro activity of temocillin (BRL 17421), a new penicillin. 660 23

HR810 (Hoechst-Roussel Pharmaceuticals Inc., Somerville, N.J.) is a new, cyclical-pyridinium cephalosporin that appeared superior to numerous comparison drugs against 658 strains of aerobic and facultative anaerobic bacteria. Seventeen Enterobacteriaceae spp. were tested by broth microdilution methods, and the 50% MICs (MIC50S) and 90% MICs (MIC90s) were 0.03 to 0.12 and 0.03 to 2.0 micrograms/ml, respectively. Only one strain had an MIC greater than 8.0 micrograms/ml (99.6% is considered susceptible). HR810 inhibited 98% of Pseudomonas aeruginosa isolates at less than or equal to 16 micrograms/ml, and the MIC90 for Acinetobacter spp. was 4.0 micrograms/ml. It was also very active against Pseudomonas spp. and Staphylococcus aureus (MIC90, 0.5 micrograms/ml) but marginally active against methicillin-resistant staphylococcal strains (MIC90, 16 micrograms/ml) and enterococcus (MIC90, 32 micrograms/ml). Non-enterococcal streptococci had MIC50s ranging from 0.008 micrograms/ml for Streptococcus pyogenes to 0.12 micrograms/ml for pneumococci. All MICs of HR810 against Haemophilus and Neisseria spp. were less than or equal to 0.03 micrograms/ml (MIC50, 0.002 to 0.008 micrograms/ml). HR810 poorly inhibited beta-lactamases and was very stable against 11 tested beta-lactamases of plasmid (TEM, OXA, SHV-1, and PSE) and chromosomal (K1, K14, P99) types.
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PMID:In vitro evaluation of HR810, a new wide-spectrum aminothiazolyl alpha-methoxyimino cephalosporin. 661 Nov 35

Penicillinase-producing Neisseria gonorrhoeae strains were isolated in the Netherlands with increasing frequency during the period of 1976 to 1979. About 3% of the gonococci isolated in the first half of 1979 produced penicillinase. In contrast to the period of 1976 to 1977, most penicillinase-producing N. gonorrhoeae infections during the period of 1978 to 1979 were contracted in the Netherlands. The results of genetic and molecular studies on 80 penicillinase-producing N. gonorrhoeae strains were similar to earlier observations of others: resistance plasmids of only two sizes, 4.5 and 3.3 megadaltons (Md), occurred in penicillinase-producing N. gonorrhoeae strains, and these encoded for the TEM-1 enzyme. The 4.5-Md plasmid could be transferred to Escherichia coli when it coexisted with a plasmid of 24 Md. The latter plasmid was present in the vast majority of the strains carrying the 4.5-Md plasmid. One strain carried a cryptic 7.5-Md plasmid in addition to the commonly found 2.5-Md plasmid. Two penicillinase-producing strains of Haemophilus parainfluenzae isolated were found to carry a 3.3-Md plasmid species which was indistinguishable from the 3.3-Md gonococcal resistance plasmids. No plasmid deoxyribonucleic acid was found in two strains of penicillinase-producing Branhamella catarrhalis, and these strains produced a penicillinase different from the TEM-1 enzyme.
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PMID:Penicillinase-producing Neisseria gonorrhoeae in the Netherlands: epidemiology and genetic and molecular characterization of their plasmids. 677 87

A 4.4-megadalton penicillinase plasmid, pWD2, from Neisseria gonorrhoeae was transformed into Escherichia coli. pWD2 was efficiently mobilized by IncP plasmids in E. coli but not by Flac, R1drd-19, or R64drd-11. pWD2 could be isolated as a DNA-protein relaxation complex with properties similar to the well characterized ColE1 complex. The host range of pWD2 was shown to include gonococci, Enterobacteriaceae, and Hemophilus influenzae, but not Acinetobacter calcoaceticus or Pseudomonas aeruginosa. These findings suggest that P-group plasmids could have played a role in the dissemination of the TEM beta-lactamase to pathogenic gram-negative bacteria.
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PMID:Transfer of the gonococcal penicillinase plasmid: mobilization in Escherichia coli by IncP plasmids and isolation as a DNA-protein relaxation complex. 680 Oct 22

BRL 17421, a novel beta-lactam antibiotic, was tested in vitro against fastidious gram-negative bacteria and compared with amoxicillin and amoxicillin plus clavulanic acid. The compound showed good activity against Haemophilus influenzae (range of minimal inhibitory concentrations, 0.2 to 1 microgram/ml), Neisseria gonorrhoeae (0.007 to 0.5 microgram/ml), and Branhamella catarrhalis (0.03 to 0.1 microgram/ml). BRL 17421 exhibited excellent stability against the TEM-type beta-lactamase of H. influenzae and N. gonorrhoeae, and its activity was little affected by inoculum size. Minimal lethal concentrations of BRL 17421 for 10(7) colony-forming units of H. influenzae ranged between 0.5 and 4 micrograms/ml.
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PMID:In vitro activity of BRL 17421 against Haemophilus influenzae, Neisseria gonorrhoeae, and Branhamella catarrhalis. 680 22

Carriage of ampicillin-resistant (Ampr) Haemophilus parainfluenzae has become frequent among children in our community, although carriage of Ampr Haemophilus influenzae remains uncommon. In this study we characterized the mechanism of ampicillin resistance in 27 representative isolates of H. parainfluenzae. As determined by isoelectric focusing, each isolate had a TEM-1 beta-lactamase; substrate profiles assessed for enzymes from 10 strains were also consistent with TEM-1 enzyme. Agarose gel electrophoresis revealed a plasmid of 23 to 34 megadaltons in each isolate and a small plasmid (less than or equal to 4 megadaltons) in 14 isolates. Transfer of ampicillin resistance to H. influenzae Rd was achieved during membrane mating with 14 of 15 donors. The transconjugants exhibited high-level ampicillin resistance (greater than or equal to 50 micrograms/ml), which was stable despite serial passage of isolates on antibiotic-free media. The transconjugants tested retained fertility. Cryptic plasmids were discovered in 7 of 25 antibiotic-susceptible H. parainfluenzae isolates. Our data suggest that H. parainfluenzae may play an important role in the exchange of Ampr genes among throat bacteria.
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PMID:Characterization of ampicillin-resistant Haemophilus parainfluenzae. 698 Jun 26


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