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)

Recent experimental work has shown that a so-called PAE (postantibiotic effect, i.e. persistent suppression of regrowth after short exposure of bacteria to the study drug in vitro) is a feature of most current antibiotics. However, marked quantitative differences were found between different types of antibiotics and also between Gram-positive and Gram-negative organisms studied. A PAE has not yet been demonstrated for roxithromycin, a new macrolide antibiotic. Therefore, we compared the PAE of roxithromycin, erythromycin, and clindamycin against laboratory strains and clinical isolates of Staphylococcus aureus, Streptococcus pyogenes, Str. pneumoniae, and Haemophilus influenzae in vitro. Identical multiples of the MIC and identical exposure times resulted in similar PAEs for the three study drugs tested. Good correlations could be found between the area under the in-vitro concentration-vs-time curve (AUC) and PAEs. The longest PAE of 9.6 h was observed after exposure of Str. pneumoniae to 1.9 mg/l of roxithromycin for 6 h.
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PMID:Postantibiotic effect of roxithromycin, erythromycin, and clindamycin against selected gram-positive bacteria and Haemophilus influenzae. 350 26

Ertapenem is a new 1-beta-methyl carbapenem, stable to dehydropeptidase, which binds preferable to penicillin-binding proteins (PBP) 2 and 3. Ertapenem has a broad antibacterial spectrum with MIC90 values < 0.5 mg/l for penicillin-susceptible Streptococcus pneumoniae, Streptococcus pyogenes, methicillin-sensitive Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Escherichia coli, Citrobacter spp., Klebsiella spp., Serratia spp., Proteus spp., Clostridium perfringens, Fusobacterium spp. Peptostreptococcus spp. and anaerobic Streptococcus spp. Ertapenem exhibits a bactericidal mode of action as shown by time-killing curves and exhibits a short PAE of 1.4 - 2.6 h against the Gram-positive strains but no PAE against Gram-negative strains. In an infection model in mice, it has been shown that ertapenem and imipenem were highly efficacious at a level of 2 mg/kg in bacterial clearance in comparison to ceftriaxone, cefepime, ceftazidime, cefazolin, cefonicid, cefotaxime and meropenem. In comparison to other available carbapenems, ertapenem has a long half-life of 4.5 h and is developed as a single daily dose carbapenem. The protein binding is dose-dependent and is estimated to 94% at concentrations under 100 mg/l and approximately 85% at 300 mg/l. Cmax after a dose of 1 g in healthy volunteers has been estimated to 190 mg/l. Given the pharmacokinetic/pharmacodynamic data, it may be predicted that ertapenem will have an effect on most Gram-positive and Gram-negative bacteria with the exception of Pseudomonas aeruginosa, Enterococcus spp. and Acinetobacter spp. For pathogens with a MIC of 0.5 mg/l, the estimated T > MIC will be 50% (of 24 h) and for pathogens with a MIC of 1 mg/l 31%. For anaerobic bacteria with MIC values between 1-2 mg/l, the T > MIC may not be sufficient for bacterial eradication. However, clinical trials have to confirm this hypothesis.
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PMID:Ertapenem: a new carbapenem. 1177 42

Thiamphenicol is a derivative of chloramphenicol characterized by a spectrum comparable to that of the parent compound against multiresistant pathogens but showing satisfactory tolerability. The in vitro activity of thiamphenicol and of 11 comparative drugs against 397 recently isolated antibiotic-resistant and/or invasive pneumococci and 52 multiply-resistant MRSA including 2 VISA strains was determined. Bactericidal activity against Haemophilus influenzae and the post-antibiotic effect on Streptococcus pneumoniae, H. influenzae, Staphylococcus aureus and Escherichia coli were also assessed. Against invasive pneumococci, thiamphenicol and chloramphenicol were the most potent non-beta-lactam molecules together with vancomycin and rifampin. Against high-level penicillin-resistant strains phenicol activities were superior to those of cefotaxime, ceftriaxone and imipenem. Against MRSA thiamphenicol and chloramphenicol were second only to the glycopetides and also inhibited the VISA strains. Thiamphenicol showed a significant PAE (0.33 to 2.9h) on all pathogens studied and a powerful bactericidal effect against beta-lactamase-positive and -negative H. influenzae. These results indicate a good in vitro activity of thiamphenicol against difficult-to-treat multiply resistant pathogens.
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PMID:In vitro activity of thiamphenicol against multiresistant Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus in Italy. 1258 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