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 in vitro activity of sparfloxacin (CI-978; AT-4140) was compared with those of other antimicrobial agents against isolates of staphylococci, enterococci, and various respiratory tract pathogens. Sparfloxacin was the most active drug tested against staphylococci (MIC for 90% of the strains tested [MIC90], 0.125 micrograms/ml) and enterococci (MIC90, 1.0 microgram/ml). It was also active against Haemophilus influenzae (MIC90, less than or equal to 0.06 microgram/ml), Moraxella (Branhamella) catarrhalis (MIC90, 0.125 microgram/ml), Streptococcus pneumoniae (MIC90, 0.5 microgram/ml), and Streptococcus pyogenes (MIC90, 1.0 microgram/ml).
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PMID:Comparative in vitro activities of sparfloxacin (CI-978; AT-4140) and other antimicrobial agents against staphylococci, enterococci, and respiratory tract pathogens. 212 51

Imipenem proved highly active against Enterobacteriaceae: the different bacterial groups exhibited similar mode MICs (0.12 to 0.25 micrograms/ml), except for Serratia (0.25-0.5 micrograms/ml), Proteus mirabilis (0.5 micrograms/ml), indole-positive Proteus (2 micrograms/ml) and Providencia (1 mu/ml). The MICs of cefotaxime-resistant strains (cephalosporinase hyperproducing or very broad spectrum betalactamase producing) were within the susceptibility range. Imipenem also exhibited satisfactory activity against Pseudomonas aeruginosa (mode MIC 1-2 micrograms/ml), although resistant strains by decrease of permeability were observed, and against Acinetobacter (mode MIC 0.25-0.5 micrograms/ml). The MICs ranged from 0.03 to 4 micrograms/ml (mode MIC 0.5) for Haemophilus and from 0.25 to 1 micrograms/ml for Neisseria gonorrhoeae, regardless of the betalactamase producing status. The MICs for N. meningitidis were less than 0.06 micrograms/ml. Methicillin-susceptible staphylococci had low MICs ranging from 0.008 to 0.5 micrograms/ml (mode MIC 0.016). The MICs for methicillin-resistant strains varied widely from 0.016 to 64 micrograms/ml and were higher after incubation at 30 degrees C. Streptococci and pneumococci were highly susceptible (usually 0.008 to 0.03 micrograms/ml). The MICs for enterococci varied from 0.12 to 32 micrograms/ml (mode MIC 1-2). With the exception of Clostridium difficile, anaerobic bacteria were inhibited by concentrations lower than 1 (mode MIC 0.06 for C. Perfringens and 0.03 for Bacteroides fragilis).
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PMID:[In vitro activity of imipenem against hospital bacteria]. 213 36

This study was set up to establish the regression curve for clarithromycin inhibition zone diameters (disks 15 micrograms) and MIC to create a strain distribution plot, in order to allow accurate interpretation of the disk diffusion method for testing susceptibility to clarithromycin. 430 bacterial strains were studied in three university hospital. Clarithromycin was active against erythromycin sensitive Staphylococcus aureus and coagulase negative Staphylococci at concentrations of 0.12 to 0.25 microgram/ml (mode 0.25). Erythromycin resistant strains were also resistant to clarithromycin. Enterococci could be divided into two populations, one resistant (MIC greater than 128 micrograms/ml) and the other with MIC of 0.06 to 2 (mode 0.25). This was also the case for Streptococci and Pneumococci with MIC lower for susceptible strains (mode 0.03 to 0.06). Clarithromycin was active on Haemophilus at concentrations of 4 to 64 micrograms/ml (mode 16); MICs for beta-lactamase producing strains were comparable to those of strains not producing. MICs for Neisseria were 0.12 to 16 and for B. catarrhalis 0.016 to 0.5. MIC were 0.5 and 1 (mode 1) for Clostridium perfringens; Bacteroides fragilis strains were inhibited by 0.12 to 8 micrograms/ml (mode 0.5-1). So, antibacterial activity of C was similar to that of E; it was sometimes slightly superior, particularly on Gram positive cocci. For MIC breakpoints of 1 and 4 micrograms/ml, zone size breakpoints should be 23 and 17 mm and for 2 and 8 micrograms/ml, 20 and 15 mm.
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PMID:[In vitro antibacterial activity of clarithromycin, a new macrolide antibiotic, and regression curve]. 214 74

The in-vitro activities of azithromycin and erythromycin were compared against 689 clinical isolates, including Gram-positive cocci, Haemophilus influenzae, and anaerobes. Of the 100 methicillin-susceptible isolates of Staphylococcus aureus tested, 77% were susceptible to 1 mg/l azithromycin and 0.5 mg/l erythromycin, whereas 22% were resistant to 32 mg/l of both compounds. All methicillin-resistant S. aureus isolates were highly resistant to both macrolides (MIC greater than 64 mg/l). Coagulase-negative staphylococci showed a wide range of susceptibilities to both compounds; MIC50 values for azithromycin and erythromycin for all isolates were 0.5 and 0.25 mg/l, respectively. With the exception of enterococci, both macrolides showed similar activity against streptococci; MIC90 values for both group A and group B streptococci were 0.03 and 0.06 mg/l for erythromycin and azithromycin, respectively. Azithromycin was less active than erythromycin against enterococci, with mode MICs of 4.0 and 1.0 mg/l, respectively; about 20% of isolates were highly resistant to both compounds. Azithromycin was substantially more active than erythromycin against H. influenzae; 41% of isolates were inhibited by 0.5 mg/l azithromycin and all isolates were inhibited by 2 mg/l. The MIC90 for erythromycin was 8 mg/l; 36% of isolates required concentrations of greater than or equal to 4 mg/l for inhibition. The anaerobic bacteria tested showed similar susceptibility to both azithromycin and erythromycin.
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PMID:Comparative in-vitro activity of azithromycin and erythromycin against Gram-positive cocci, Haemophilus influenzae and anaerobes. 215 33

Macrolide antibiotics, commonly used in upper and lower respiratory tract infections, are inconsistently active against Haemophilus influenzae. The new azalide, azithromycin, was compared with erythromycin and roxithromycin against this pathogen. Azithromycin (MIC range 0.06-1 mg/l) was four to eight times more potent than erythromycin (MIC range 0.5-8 mg/l) and roxithromycin (MIC range 0.5-16 mg/l). At 1 mg/l, 100% of the strains of H. influenzae were inhibited by azithromycin compared with 16% with erythromycin and 5% with roxithromycin. Azithromycin exhibited a rapid bactericidal effect, with a 99.9% kill at 4 h. The MBC was equal to or up to four-times greater than the MIC.
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PMID:Bacteriostatic and bactericidal activity of azithromycin against Haemophilus influenzae. 215 34

Measurement of killing kinetics of azithromycin against strains of Streptococcus pneumoniae and Klebsiella pneumoniae in vitro showed that it had a limited bactericidal activity (greater than 90% kill) for the first eight hours of incubation, but developed complete bactericidal activity (greater than 99.9% kill) by 24 h incubation. Since high and sustained tissue levels of azithromycin occur in animals and humans, it was proposed that it might produce a bactericidal effect in vivo. This was demonstrated in a lung infection model in mice, designed to mimic the in-vitro killing studies. A 25 mg/kg dose of azithromycin given 24 h before intranasal challenge reduced the recoverable Str. pneumoniae population by greater than 99.9%, in comparison with untreated controls. Erythromycin did not produce a bactericidal effect at 100 mg/kg, and roxithromycin only reduced the viable count by 96%, at a dose of 50 mg/kg. Against a K. pneumoniae lung infection, a 50 mg/kg dose of azithromycin reduced the bacterial count by 99%. The bactericidal effect was correlated with lung tissue concentrations of azithromycin. In a proliferating Escherichia coli paper disc infection model, extravascular fluid concentrations of azithromycin were correlated with a 99.9% reduction in bacterial count, while corresponding serum concentrations were always less than the MIC. Dosing with azithromycin eradicated Haemophilus influenzae from the bulla (middle ear) of gerbils, as was not the case with erythromycin and roxithromycin. This effect was correlated with the antibiotic concentration in bulla lavage.
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PMID:Relationship of high tissue concentrations of azithromycin to bactericidal activity and efficacy in vivo. 215 42

The aim of this study was to evaluate whether pre-exposure of bacteria to a subinhibitory concentration (sub-MIC) of loracarbef (LY 163892) or daptomycin (LY 146032) could modify bacterial susceptibility to serum bactericidal activity and to phagocytosis and killing by murine peritoneal macrophages and by human polymorphonuclear leucocytes. Escherichia coli, Haemophilus influenzae type b and Staphylococcus aureus grown in the presence of one quarter the MIC of loracarbef, and S. aureus exposed to one quarter the MIC of daptomycin were phagocytosed and killed in numbers significantly higher than non-exposed bacteria. Pre-exposure to loracarbef resulted in increased susceptibility of E. coli and H. influenzae type b to the bactericidal activity of antiserum, but exposure to loracarbef or daptomycin did not modify serum sensitivity of S. aureus. Loracarbef treatment and antiserum enhanced phagocytosis and killing of E. coli and H. influenzae type b to a greater extent than either antibiotic treatment or antiserum alone. These data indicate that loracarbef and daptomycin at sub-MIC enhance the susceptibility of bacterial pathogens to cellular and host defence mechanisms.
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PMID:Influence of subinhibitory concentrations of loracarbef (LY 163892) and daptomycin (LY 146032) on bacterial phagocytosis, killing and serum sensitivity. 217 52

The in vitro activity of ceftriaxone, ampicillin and chloramphenicol was studied at a reference laboratory against the isolates of the first 33 patients enrolled in a pediatric Swiss Multicenter Meningitis Study. The predictive value of the MIC data of 31 of the strains was further corroborated by two sets of bacterial killing curves in broth supplemented with 2 g/l of albumin. Ceftriaxone had the lowest geometric mean MIC values against all groups of isolates except for ampicillin against Streptococcus agalactiae. The bactericidal activity of ceftriaxone and that of ampicillin, alone and in combination with chloramphenicol, was compared at six times the respective MICs and at pharmacologically readily achievable concentrations in cerebrospinal fluid. The bactericidal power of ceftriaxone at six times the MIC was as good or better than that of ampicillin alone or in combination against Neisseria meningitidis and Streptococcus pneumoniae despite the very low drug concentrations of ceftriaxone compared to that of the competitors; and it was barely lower at six times the MIC and at 1 mg/l (a level that is readily surpassed in CSF at the 24 h trough level after a single daily dose of ceftriaxone of 100 mg/kg (neonates 50 mg/kg) than that of ampicillin and chloramphenicol at much higher concentrations against Haemophilus influenzae type b.
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PMID:Short course single daily ceftriaxone monotherapy for acute bacterial meningitis in children: results of a Swiss multicenter study. Part II: Bacteriological results. 218 57

The in vitro activity of LJC10,627, a new carbapenem, was compared with those of imipenem and ceftazidime. LJC10,627 had broad-spectrum activity against gram-positive and gram-negative clinical isolates. The MICs of this compound for 90% of members of the family Enterobacteriaceae tested (MIC90s), including strains resistant to ceftazidime, ranged from 0.1 to 25 micrograms/ml. LJC10,627 inhibited Pseudomonas aeruginosa at an MIC90 of 3.13 micrograms/ml; it thus was twofold more active than imipenem. This compound inhibited Haemophilus, Neisseria, and Branhamella species at MIC90s of 3.13, 0.1, and 0.1 micrograms/ml, respectively. LJC10,627 was two- to fourfold less active than imipenem against methicillin-susceptible Staphylococcus aureus and Staphylococcus epidermidis at MIC90s of 0.1 and 0.39 microgram/ml. However, the compound was found to be twofold more active than imipenem against Bacteroides fragilis at an MIC90 of 1.56 microgram/ml. LJC10,627 was very stable to various beta-lactamases except for Xanthomonas maltophilia oxyiminocephalosporinase type II. LJC10,627 was minimally hydrolyzed by swine renal dehydropeptidase I; its residual activity was 93.0% after 2 h. Killing kinetics of this compound for Escherichia coli and Pseudomonas aeruginosa showed that bactericidal action occurred at concentrations above the MIC (0.05 and 0.39 microgram/ml, respectively). LJC10,627 had a high affinity for penicillin-binding proteins 2, 4, and 1B(s) of Escherichia coli and Pseudomonas aeruginosa and penicillin-binding proteins 1 and 4 of Staphylococcus aureus.
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PMID:In vitro activity of LJC10,627, a new carbapenem antibiotic with high stability to dehydropeptidase I. 220 13

We compared results of MIC and disk susceptibility tests on Haemophilus test medium (HTM) and those on comparative media. Ampicillin MICs were determined with seven ampicillin-resistant, non-beta-lactamase-producing (AmprNBLP) isolates by using HTM and supplemented brain heart infusion (sBHI) agar. Ampicillin and amoxicillin-clavulanate disk tests with 16 AmprNBLP strains, 18 ampicillin-susceptible (Amps) isolates, and 17 ampicillin-resistant, beta-lactamase-producing (AmprBLP) strains were performed by using five media: laboratory-prepared HTM (PHTM), commercial HTM (CHTM), sBHI, enriched chocolate agar, and Mueller-Hinton chocolate agar. We observed that five of seven and three of seven AmprNBLP strains were misclassified as susceptible with PHTM (MIC, less than 2 micrograms/ml) with inocula of 10(3) and 10(5) CFU, respectively, but were resistant with sBHI (MIC, greater than or equal to 2 micrograms/ml). Whereas Mueller-Hinton chocolate agar and enriched chocolate agar plates supported the growth of all 51 strains by the disk tests, 37% (19 of 51) and 8% (4 of 51) of strains did not grow on PHTM and CHTM, respectively. Lack of growth on PHTM was observed for all three phenotypes; 7 of 18 Amps, 4 of 17 AmprBLP, and 8 of 16 AmprNBLP strains did not grow. The four strains that did not grow on CHTM were all AmprNBLP isolates. Zone sizes were significantly larger on PHTM than on the other media. Of the strains that were evaluable by the new National Committee for Clinical Laboratory Standards guidelines with either PHTM or CHTM, all Amps strains were classified as susceptible. Among the AmprBLP strains, CHTM correctly identified all as resistant, whereas PHTM detected two isolates to be intermediate. Among the AmprNBLP strains, CHTM and PHTM misclassified four (33%) and five (62%) isolates, respectively, as susceptible; an additional isolate was identified as intermediate on both media. We conclude that there is strain-dependent growth on HTM, that adoption of this medium for routine Haemophilus susceptibility testing is problematic due to this growth variability, and that detection of AmprNBLP isolates would be unreliable.
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PMID:Problems with current recommendations for susceptibility testing of Haemophilus influenzae. 222 55


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