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

Two hundred clinical isolates of Haemophilus influenzae were tested for tolerance (MBC/MIC greater than or equal to 32) to ampicillin and cefotaxime by broth dilution tests. Of 200 strains, 9 were tolerant to ampicillin, and 10 were tolerant to cefotaxime. Tolerant organisms were identified in both systemic and nonsystemic infections and among different biotypes and serotypes of H. influenzae. These tolerant isolates were compared with nontolerant isolates by broth dilution and killing curves with log-phase and stationary-phase inocula. Both tolerant and nontolerant bacteria in log phase were killed more rapidly by antibiotics than bacteria in stationary-phase growth. When tested against 11 different beta-lactams, several patterns of tolerance were observed. Six of the ten strains were tolerant to aztreonam, four were tolerant to cefuroxime, three were tolerant to cefamandole, and two were tolerant to cefoxitin. Strain H130 was tolerant to all beta-lactam antibiotics studied. None of the 10 tolerant H. influenzae isolates were tolerant to chloramphenicol, rifampin, tobramycin, ciprofloxacin, enoxacin, and trimethoprim-sulfamethoxazole. Although the clinical significance of tolerance is not determined, this study suggests that the bactericidal activity (MBC) of beta-lactam antibiotics against H. influenzae should be determined in cases of severe infections in which clinical response is slow or unsatisfactory.
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PMID:Tolerance of Haemophilus influenzae to beta-lactam antibiotics. 387 60

The susceptibility of 554 recent clinical isolates and known resistant bacterial strains to the new monocyclic beta-lactam Ro 17-2301 were studied and compared to that to other beta-lactams (including aztreonam and temocillin) and gentamicin. Ro 17-2301 had a high degree of activity against the Enterobacteriaceae (MIC90 less than or equal to 0.25 mg/l) being similar or slightly more active than aztreonam and ceftazidime. Strains of Acinetobacter spp. (MIC90 16 mg/l). Haemophilus influenzae strains (including beta-lactamase producers) were more susceptible (MIC90 0.5 mg/l) than those of Neisseria gonorrhoeae (MIC90 4 mg/l); against these latter two groups of isolates aztreonam was more active (MIC90 0.12 mg/l). Both aztreonam and Ro 17-2301 had little activity against Gram-positive cocci with the exception of Streptococcus pneumoniae for which the MIC90 of RO 17-2301 was 16 mg/l. Ro 17-2301 had modest activity against Bacteroides fragilis. The MBC of Ro 17-2301 was very similar to the MIC and the addition of human serum had little effect on the amount of the compound. The mean serum protein binding was 26.3%. A study of the penicillin binding protein affinity of Ro 17-2301 in a strain of Escherichia coli showed PBP 3 to be the primary target. The morphological response to exposure to Ro 17-2301 was filamentation followed by lysis after prolonged exposure.
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PMID:The in-vitro activity of Ro 17-2301, a new monobactam, compared with other antimicrobial agents. 398 Mar 9

The in vitro activity of cefoperazone (CPZ) and cefotiam (CTM) was compared to other available cephalosporins. Using an agar dilution procedure both CTM and CPZ were more active against the Enterobacteriaceae tested than cefoxitin, cefuroxime and cefazolin; CTM being slightly more active than CPZ, in particular against Klebsiella spp Haemophilus influenzae were more susceptible to CPZ. CTM had no activity against Pseudomonas aeruginosa but CPZ exhibited considerable activity (mode MIC 4 mg/l). Against Bacteroides fragilis CPZ had a similar activity to cefuroxime, but CTM was less active. CTM was about twice as active as CPZ against Staphylococcus aureus, cefazolin being the most active agent tested. The MBC was about twice the MIC for each compound and the presence of 75% serum had only a modest effect on the MIC and MBC. The protein binding of CPZ was 94% and CTM 62%.
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PMID:Cefoperazone and cefotiam--two new cephalosporins: an in-vitro comparison. 645 75

The in-vitro activity of cefotetan, a recently developed cephamycin, was investigated under various experimental conditions. The compound showed moderate activity against Staphylococcus aureus and Streptococcus pyogenes, no activity against Pseudomonas aeruginosa and Streptococcus faecalis, but a high activity against Enterobacteriaceae, including beta-lactamase-producing strains. Haemophilus influenzae also was fairly susceptible. The MBC was usually equal to or two- or fourfold higher than MIC. Medium composition, pH and inoculum size had minimal influence on its activity. About 50% of recent clinical isolates of Bacteroides fragilis were susceptible to cefotetan, but some were highly resistant. Killing curves of cefotetan against different bacterial strains indicated that it was rapidly bactericidal at concentrations equal to MIC or two- to fourfold higher. However, some strains showed regrowth after initial inhibition. Combination of cefotetan with aminoglycosides, or with cefazolin, cefotaxime, moxalactam or piperacillin resulted either in synergy, addition or indifference according to the bacterial strain and the nature of the combination. Antagonism was never observed. Human serum protein binding varied from 75 to 86% according to the assay method. Binding with horse serum protein was about 28%.
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PMID:In-vitro antibacterial activity of cefotetan. 657 25

The in vitro activity of fludalanine ( MK641 ) combined with pentizidone ( MK642 ) so as to give a fludalanine /D-cycloserine ratio of 1:1 was compared with the activities of ampicillin, ticarcillin, cefuroxime, ceftazidime, and trimethoprim against 452 recent isolates and known beta-lactam- and trimethoprim-resistant strains. In addition, the in vitro activity of fludalanine - pentizidone on four different media, including a defined medium ( DFN -2), was studied. The MIC of fludalanine - pentizidone against 90% of Escherichia coli, Klebsiella spp., Enterobacter spp., Providencia stuartii, Haemophilus influenzae, Neisseria gonorrhoeae, Staphylococcus aureus, and fecal streptococci was 4 micrograms or less per ml on DFN -2, and activity was somewhat reduced on the other media. Proteus spp. and Pseudomonas aeruginosa (90% MIC, less than or equal to 64 micrograms/ml) and Bacteroides spp. (90% MIC, 16 micrograms/ml) were less susceptible. Generally, fludalanine - pentizidone was less active than ceftazidime and comparable in activity to cefuroxime. beta-Lactamase-producing and trimethoprim-resistant strains tended to be susceptible to fludalanine - pentidizone . In the absence of human serum, the MBC of fludalanine - pentizidone was similar to the MIC. In the presence of increasing concentrations of human serum, there tended to be a greater difference between the MIC and MBC.
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PMID:In vitro activity of fludalanine combined with pentizidone compared with those of other agents. 661 Mar 89

The choice of antibiotics in bacterial meningitis must integrate several parameters. i) The bacterial epidemiology of community acquired meningitis: Haemophilus influenzae (Hi) Neisseria meningitidis (Nm), Streptococcus pneumoniae (Sp) represents more than 95% of cases; ii) The increase of antibiotic bacterial resistance, particularly preoccupying for Sp; iii) The microbiological properties and pharmacokinetics of antibiotics, especially their penetration in CSF: the concentrations achieved must be several times higher than the MBC. In fact, CSF is not favourable to the antibiotic activity; iv) The results of clinical comparative trials; v) The contribution of animal models to the knowledge of meningitis physiopathology. Third generation cephalosporins (cefotaxime, ceftriaxone) satisfy this objective for Hi, Nm, and penicillin sensitive strains of Sp. For penicillin resistant Sp, no treatment can achieve antibiotic CSF concentrations higher than ten times the MBC. An increase in dosage of cephalosporins, the use of an other regimen (Vancomycin or imipenem) and antibiotic association (rifamycin, fosfomycin) are needed.
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PMID:[Antibiotherapy as first choice in infectious meningitis]. 839 91

Quinupristin/dalfopristin is a new streptogramin combination that occurs at a natural ratio and formulation of 30:70. Rapid metabolism of the dalfopristin component to RP 12536 in vivo puts in question the validity of in vitro test of spectrum with the parent combination. In studies of quinupristin with both dalfopristin and RP 12536, a wide range of ratios (30:70, 50:50, 70:30) were tested by reference MIC and MBC tests. No significant potency differences were observed between combination ratios or metabolic components when testing 256 bacterial strains. Quinupristin/dalfopristin or quinupristin/RP 12536 remained active, by bactericidal action against many staphylococci and Streptococcus ssp. Enterococcus faecium strains were susceptible (MIC90, 2 micrograms/ml; static effect only) to the streptogramin, but E. faecalis, Pasteurella multocida, Pediococcus ssp., Haemophilus influenzae, and Bacteroides fragilis were generally less susceptible (MIC90, > or = 8 micrograms/ml). The log phase inoculum was preferred for MBC and kill-curve tests with this combination. The 30:70 ratio in vitro susceptibility test of quinupristin/dalfopristin as used to date, seems to predict the potency and spectrum of this streptogramin accurately and all clinically important in vivo ratios of the injectable form or its major metabolites. Quinupristin/dalfopristin should be further investigated for clinical use against emerging resistant Gram-positive infections, especially penicillin-resistant streptococci and glycopeptide-resistant E. faecium that exhibit susceptibility in this investigation.
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PMID:Antimicrobial characteristics of quinupristin/dalfopristin (Synercid at 30:70 ratio) compared to alternative ratios for in vitro testing. 915 9

The in vitro activity of FK041, a new orally active cephem antibiotic, against a wide variety of clinical isolates of bacteria was investigated and compared with those of cefdinir (CFDN) and cefditoren (CDTR). FK041 exhibited broad spectrum activity against reference strains of Gram-positive and Gram-negative aerobes and anaerobes. FK041 was active against clinical isolates of Gram-positive organisms except Enterococcus faecalis with MIC90s less than 1.56 microg/ml. FK041 was more active than CFDN and CDTR against Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus agalactiae and was comparable to CFDN and CDTR against Streptococcus pyogenes and Streptococcus pneumoniae. FK041 had no activity against methicillin-resistant staphylococci, like CFDN and CDTR. FK041 showed moderate activity against penicillin-resistant S. pneumoniae with an MIC range of 0.05 approximately 3.13 microg/ml, and was superior to CFDN but inferior to CDTR. Against clinical isolates of many Gram-negative organisms such as Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis, FK041 had good activity comparable or superior to those of CFDN and CDTR. However, it was inferior to CDTR in activity against Moraxella catarrhalis, Haemophilus influenzae, Morganella morganii, and Serratia marcescens, and was inactive against Pseudomonas aeruginosa. With FK041 a small difference between MIC and MBC against S. aureus, E. coli, K. pneumoniae, and H. influenzae was found, indicating that its action is bactericidal against these species. FK041 was stable to group 2beta-lactamase hydrolysis but was unstable to group 1beta-lactamase hydrolysis. The stability of FK041 to these enzymes was similar to those of CFDN and CDTR. FK041 showed high affinity for the main penicillin-binding proteins (PBPs) of S. aureus (PBP 3, 2, and 1) and E. coli (PBP 3, 4, lbs, 2, and 1a).
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PMID:In vitro antibacterial activity of FK041, a new orally active cephalosporin. 1051 45

Recent macrolide derivatives, roxithromycin, azithromycin and clarithromycin show more favourable pharmacokinetic characteristics in comparison to old ones and some differences in antibacterial activity. With the aim of improving our understanding of some aspects of their action against respiratory pathogens, we determined the MICs and MBCs of Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Moraxella catarrhalis and Haemophilus influenzae. Azithromycin was the most active agent against Haemophilus influenzae and Moraxella catarrhalis, while clarithromycin was more active against Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus with MICs similar to those of erythromycin. The bactericidal activity of all tested derivatives was weak against Staphylococcus aureus (MBC/MIC ratio approximately 16) and against Moraxella catarrhalis (MBC/MIC ratio, 8-16), but good against Staphylococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae (MBC/MIC ratio, 2-4). The determination of killing curves in the presence of 2 MIC and 10 MIC of azithromycin, clarithromycin and roxithromycin confirmed their weak bactericidal activity against Staphylococcus aureus and Moraxella catarrhalis as well as their effective activity against Streptococcus pyogenes and Streptococcus pneumoniae. Azithromycin showed the highest bactericidal activity against Haemophilus influenzae. As expected, the three derivatives produced a quite prolonged PAE when exposed to 5 MIC for 1 h, ranging between 2-4 h. The bactericidal activity and the prolonged PAE of new macrolides for the most common respiratory pathogens should assure a good clinical activity in respiratory infections including those sustained by Haemophilus influenzae, which is less susceptible to erythromycin and other old macrolides.
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PMID:Comparative antimicrobial activity and post-antibiotic effect of azithromycin, clarithromycin and roxithromycin against some respiratory pathogens. 1861 54

We have compared the in-vitro bacteriostatic and bactericidal activity of ceftazidime against cephalothin-resistant Gram-negative bacteria, Haemophilus influenzae and Gram-positive bacteria. Comparison was made with cefaperazone, cefuroxime, moxalactam, cefotaxime, cefamandole, cefoxitin, cephalothin, cefazolin, azlocillin, carbenicillin, ticarcillin, ampicillin and oxacillin. In general ceftazidime was one of the most active compounds with low MIC and MBC values.
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PMID:The in-vitro activity of ceftazidime: comparison with other beta-lactam antibiotics. 1980 70


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