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 antibacterial activity of the recently developed cephems cefixime and cefetamet-pivoxyl was evaluated in 408 gram-positive and gram-negative rods, all isolated recently from clinical specimens, and compared to that of other orally active agents such as ampicillin, amoxycillin + clavulanic acid, cefaclor, cefuroxime-axetil and to ceftriaxone. With regard to ampicillin-resistant Enterobacteriaceae ceftriaxone proved to be the most active agent, followed by cefixime and cefetamet, whereas cefuroxime was less active. Cefaclor and amoxycillin + claculanic acid were active against ampicillin-resistant Escherichia coli, Klebsiella pneumoniae, and Proteus ssp. isolates. All beta-lactam compounds exhibited poor activity against Acinetobacter anitratus isolates, but were highly active against Haemophilus influenzae with the exception of cefaclor. Both cefixime and cefetamet were poorly active against Staphylococcus aureus, but highly active against beta-hemolytic streptococci. Moreover, both compounds remained unaffected by the production of plasmid-mediated beta-lactamases such as the TEM or OXA enzymes. Resistance to both agents was observed in Enterobacteriaceae that produced large amounts of chromosomally mediated enzymes; their affinity to the class I enzyme from Enterobacter cloacae was somewhat lower than that of other third-generation cephalosporins. However, in contrast with these agents breakdown of cefixime and cefetamet by a class IIIa enzyme form Proteus vulgaris was marginal. In methicillin-resistant S. aureus isolates there was a complete cross-resistance between all beta-lactam compounds included in this study.
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PMID:Comparable evaluation of orally active beta-lactam compounds in ampicillin-resistant gram-positive and gram-negative rods: role of beta-lactamases on resistance. 326 45

LY163892 is a new orally absorbed carbacephem. It inhibited Streptococcus pyogenes and Str. pneumoniae at less than or equal to 1 mg/l, but was less active against group B streptococci and groups C, F, G and bovis streptococci with MICs of 1 to 2 mg/l for most but as high as 8 mg/l for some isolates. MIC90 of methicillin-susceptible Staphylococcus aureus was 8 mg/l, but greater than 128 mg/l for methicillin-resistant staphylococci. LY163892 had activity similar to cefaclor and cephalexin with MIC90 values of 16 mg/l for Escherichia coli, 8 mg/l for Klebsiella pneumoniae, Proteus mirabilis, Yersinia enterocolitica, but was more active against Haemophilus influenzae, and Branhamella catarrhalis. It had no activity against Enterobacter, Providencia, Serratia, and Pseudomonas and Bacteroides spp. LY163892 was more rapidly lytic than cephalexin. It was hydrolyzed by a number of plasmid and chromosomal beta-lactamases. For TEM-1, the Km = 354.7 microM, Vmax = 2.5 microMoles/min/mg of protein, P99 Km = 24.3 microM, Vmax = 28.9 microM/min/micrograms of protein, Staph. aureus PC Km = 47.4 microM, Vmax = 2.7 microMoles/min/mg of protein. Overall it had beta-lactamase stability similar to cefaclor, less than cephalexin, and markedly less than cefuroxime.
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PMID:In-vitro activity and beta-lactamase stability of LY163892. 326 52

Tigemonam is an orally administered monobactam. At less than or equal to 1 microgram/ml it inhibited the majority of strains of Escherichia coli, Klebsiella spp., Enterobacter aerogenes, Citrobacter diversus, Proteus spp., Providencia spp., Aeromonas hydrophila, Salmonella spp., Shigella spp., Serratia marcescens, and Yersinia enterocolitica. At less than or equal to 0.25 microgram/ml it inhibited Haemophilus spp., Neisseria spp., and Branhamella catarrhalis. It did not inhibit Pseudomonas spp. or Acinetobacter spp. Tigemonam was more active than cephalexin and amoxicillin-clavulanate and inhibited many members of the family Enterobacteriaceae resistant to trimethoprim-sulfamethoxazole and gentamicin. Some Enterobacter cloacae and Citrobacter freundii strains resistant to aminothiazole iminomethoxy cephalosporins and aztreonam were resistant to tigemonam. The MIC for 90% of hemolytic streptococci of groups A, B, and C and for Streptococcus pneumoniae was 16 micrograms/ml, but the MIC for 90% of enterococci, Listeria spp., Bacteroides spp., and viridans group streptococci was greater than 64 micrograms/ml. Tigemonam was not hydrolyzed by the common plasmid beta-lactamases such as TEM-1 and SHV-1 or by the chromosomal beta-lactamases of Enterobacter, Morganella, Pseudomonas, and Bacteroides spp. Tigemonam inhibited beta-lactamases of E. cloacae and Pseudomonas aeruginosa but did not induce beta-lactamases. The growth medium had a minimal effect on the in vitro activity of tigemonam, and there was a close agreement between the MICs and MBCs.
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PMID:Tigemonam, an oral monobactam. 327 6

The in-vitro activity of BMY 28142, an iminomethoxy, aminothiazolyl cephalosporin containing a methyl pyrrolidinio C-3 was compared with that of cefotaxime, ceftazidime, aztreonam, imipenem and tobramycin against various bacteria. BMY 28142 was the most active agent tested against the Enterobacteriaceae inhibiting 90% at less than or equal to 1 mg/l. The in-vitro activity of BMY 28142 was equal to or superior to cefotaxime against the highly susceptible members of the Enterobacteriaceae and several-fold superior to ceftazidime and aztreonam. BMY 28142 inhibited many Enterobacter cloacae, Citrobacter freundii and Serratia marcescens resistant to cefotaxime, ceftazidime and aztreonam. BMY 28142 was more active than imipenem against Proteus, Providencia and Morganella species. Ceftazidime and imipenem were more active than BMY 28142 against Pseudomonas aeruginosa, but it inhibited piperacillin and tobramycin-resistant isolates. BMY 28142 inhibited beta-lactamase producing Haemophilus influenzae and Neisseria gonorrhoeae. BMY 28142 was more active than ceftazidime against streptococcal and staphylococcal species, but it did not inhibit or kill most methicillin-resistant Staphylococcus aureus. BMY 28142 did not inhibit most Bacteroides species. BMY 28142 was not hydrolyzed by common plasmid and chromosomal beta-lactamases, but it bound poorly to Enterobacter beta-lactamase, was a poor inhibitor of the TEM plasmid beta-lactamase and was a poor inducer of beta-lactamases.
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PMID:The activity of BMY 28142 a new broad spectrum beta-lactamase stable cephalosporin. 348 62

The most common cause of ampicillin resistance in Haemophilus influenzae type b is production of TEM-1 beta-lactamase; however, a novel enzyme with a similar substrate profile but a quite different isoelectric point has also been described. This beta-lactamase, designated ROB-1, has not been found previously in any other organism. In a survey of 46 ampicillin-resistant H. influenzae type b isolates, we found a second human isolate that produces ROB-1 and discovered that ampicillin-resistant isolates of the porcine pathogen Haemophilus pleuropneumoniae also produced ROB-1. In both Haemophilus species ROB-1 production was determined by plasmids that had considerable DNA sequence homology. However, the ROB-1 and TEM-1 beta-lactamase genes were not related. Our findings suggest that this form of ampicillin resistance has an animal reservoir and that conditions fostering its prevalence in animal strains may play a role in the spread of resistance to human pathogens.
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PMID:An animal source for the ROB-1 beta-lactamase of Haemophilus influenzae type b. 348 84

Available data indicate that the most common beta-lactamase produced by Branhamella catarrhalis is plasmid mediated. The same enzyme occurs in Moraxella nonliquefaciens, a commensal in the upper respiratory tract. The ability to produce the enzyme, which is known as BRO-1, can be transferred by conjugation from M. nonliquefaciens to B. catarrhalis. Since the first beta-lactamase-producing strains of B. catarrhalis appeared in 1977, the frequency of beta-lactamase production has increased rapidly; figures as high as 76% have been reported. The plasmid-mediated beta-lactamase TEM-1 occurs in several species of the genus Haemophilus. While the frequency of beta-lactamase production in H. influenzae is reported to be 10-15%, the incidence is significantly higher in non-pathogenic Haemophilus species. Both phenoxymethyl-penicillin and ampicillin promote the occurrence of beta-lactamase-producing strains, but the selective pressure exerted by ampicillin seems to be more pronounced. It may be possible to reduce the ecological effects of the penicillins by avoiding overdiagnosis of the most common bacterial infections of the respiratory tract, and by shortening the courses of antibiotic treatment.
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PMID:Upper respiratory tract infections. Ecological and therapeutic aspects of beta-lactamase production with special reference to Branhamella catarrhalis. 348 90

In order to determine the recovery rate of species of the genera Haemophilus and Moraxella (including subgenus Branhamella) from the upper respiratory tract and the incidence of beta-lactamase production within these genera, cultures were made of nose and throat swab specimens and adenoid tissue in 50 children undergoing adenoidectomy. Haemophilus influenzae was isolated from 92% of the children. All children harboured strains of Haemophilus spp. and in 46%, at least one strain produced the TEM-1 beta-lactamase. Branhamella catarrhalis and/or Moraxella nonliquefaciens were isolated from 82% of the children and strains producing the BRO-1 beta-lactamase from 34%. Overall, TEM-1 and/or BRO-1 producing strains were recovered from 60% of the investigated patients. The beta-lactamase production was found to be transferable by conjugation within the respective genera. It is suggested that the apathogenic species may be a source of transferable determinants mediating beta-lactamase production in the upper respiratory tract.
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PMID:Beta-lactamase production in the upper respiratory tract flora. 349 Sep 74

The in vitro activity of amoxicillin in the presence of clavulanic acid against clinical isolates of Haemophilus influenzae and Branhamella catarrhalis was assessed in comparison with ampicillin, amoxicillin, cefaclor and erythromycin. The isolates were selected so as to yield equal numbers of beta-lactamase producing and non-beta-lactamase producing strains of the two species. MICs obtained by agar dilution indicated that amoxicillin in the presence of clavulanic acid was the most active of the drugs tested. Clavulanic acid potentiated the activity of amoxicillin against beta-lactamase-producing strains of both Haemophilus influenzae and Branhamella catarrhalis. Further studies on a few strains of each species revealed that the beta-lactamase of Haemophilus influenzae (TEM-1) rapidly inactivated ampicillin and slowly inactivated cefaclor but not cefuroxime. The Branhamella catarrhalis enzyme rapidly inactivated cefaclor, ampicillin and to some extent cefuroxime. Clavulanic acid afforded protection against the beta-lactamase action of both species when beta-lactam antibiotics were added to bacterial cultures.
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PMID:In vitro activity of amoxicillin plus clavulanic acid against Haemophilus influenzae and Branhamella catarrhalis. 349 74

Three Haemophilus parainfluenzae strains isolated from the urogenital tract harbored a beta-lactamase-coding 3.2-megadalton plasmid identical, by restriction endonuclease digestion and hybridization with radioactive and biotin-labeled probes specific for the TEM-1 beta-lactamase and TnA sequences, to the 3.2-megadalton "African-type" plasmid found in Neisseria gonorrhoeae.
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PMID:Isolation and molecular characterization of beta-lactamase-producing Haemophilus parainfluenzae from the genital tract. 349 10

A total of 114 strains of Haemophilus influenza were characterized with respect to beta-lactamase production and ampicillin MIC. Of this total, 41 strains produced a TEM-type beta-lactamase, and ampicillin MICs for these strains were greater than or equal to 2.0 microgram/ml. It was found that 54 strains lacked TEM-type beta-lactamase activity, and ampicillin MICs for them were less than or equal to 0.5 microgram/ml. The remaining 19 strains were beta-lactamase negative, but ampicillin MICs were greater than or equal to 2.0 micrograms/ml. Disk diffusion susceptibility tests were performed with two media, i.e., Mueller-Hinton agar containing 1.0% hemoglobin and 1.0% IsoVitaleX supplement (CHOC-MHA) and enriched chocolate agar (CHOC), by using disks containing 10 and 2 micrograms of ampicillin. If strains of H. influenzae for which ampicillin MICs were greater than or equal to 2.0 micrograms/ml were considered resistant, while strains for which MICs were less than or equal to 0.5 microgram/ml were considered susceptible, the following zone diameter interpretive criteria were identified as indicating ampicillin susceptibility: CHOC-MHA (10-micrograms disks), greater than or equal to 20 mm; CHOC-MHA (2-micrograms disks), greater than or equal to 17 mm; CHOC (10-micrograms disks), greater than or equal to 25 mm; and CHOC (2-micrograms disks), greater than or equal to 20 mm. In all cases, zones of inhibition less than those listed above would be interpreted as indicating resistance. Each of these four combinations was found to be essentially equivalent in identifying susceptible and resistant strains of H. influenzae, irrespective of beta-lactamase production.
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PMID:Ampicillin disk diffusion susceptibility testing of Haemophilus influenzae. 349 38


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