Antistaphylococcal activity of oritavancin and its synergistic effect in combination with other antimicrobial agents.

Oritavancin exhibited in vitro activity against 169 strains of vancomycin-susceptible, methicillin-resistant Staphylococcus aureus (MRSA) with MICs ranging from 0.03 to 1 μg/ml and against vancomycin-intermediate MRSA (VISA; n = 29), heterogeneous vancomycin-intermediate MRSA (hVISA; n = 5), and vancomycin-resistant MRSA (n = 5) strains, with MICs ranging from 0.12 to 4 μg/ml.

Augmented breaths ('sighs') are suppressed by morphine in a dose-dependent fashion via naloxone-sensitive pathways in adult rats.

Morphine treatment can eliminate augmented breaths (ABs; 'sighs') during spontaneous breathing. In the present study, unanesthetized rats were studied to: (1) determine the involvement of naloxone-sensitive receptor pathways, and (2) establish the dose-response relationship of this side effect. At a dosage of 5mg/kg (2-10mg/kg is recommended range for analgesia) morphine eliminated ABs from the breathing rhythm across nearly 100 min post-administration (vs.

Activity of telavancin compared to other agents against coagulase-negative staphylococci with different resistotypes by time kill.

Among 10 coagulase-negative staphylococci, telavancin, quinupristin/dalfopristin, and tigecycline were the most potent antimicrobials. Telavancin exhibited bactericidal effect to 9 strains out of 10 tested at 4× MIC after 24 h of exposure similar to those of vancomycin and daptomycin. By contrast, linezolid was mainly bacteriostatic and teicoplanin was bactericidal to 7 strains tested at 4× MIC after 24 h.

In vitro activity of fusidic acid (CEM-102, sodium fusidate) against Staphylococcus aureus isolates from cystic fibrosis patients and its effect on the activities of tobramycin and amikacin against Pseudomonas aeruginosa and Burkholderia cepacia.

We tested the MICs of fusidic acid (CEM-102) plus other agents against 40 methicillin-resistant Staphylococcus aureus (MRSA) isolates from cystic fibrosis patients and the activities of fusidic acid with or without tobramycin or amikacin against Pseudomonas aeruginosa, MRSA, and Burkholderia cepacia isolates from cystic fibrosis patients in a 24-h time-kill study. Fusidic acid was potent (MICs, 0.125 to 0.

Activity of ACHN-490 tested alone and in combination with other agents against Pseudomonas aeruginosa.

ACHN-490 was tested alone and in combination with cefepime, doripenem, imipenem, or piperacillin-tazobactam in a synergy time-kill analysis against 25 Pseudomonas aeruginosa strains with different resistance phenotypes. Each combination was synergistic against most isolates at 24 h, and antagonism was not observed. Combinations of ACHN-490 with cefepime, doripenem, imipenem, or piperacillin-tazobactam yielded synergies in ≥70% and ≥80% of strains at 6 and 12 h, respectively, and in ≥68% at 24 h.

Time-kill activity of the streptogramin NXL 103 against Gram-positive and -negative bacteria.

Against 33 Gram-positive and -negative bacteria, NXL 103 MICs were 0.03 to 1 μg/ml. NXL 103 was bactericidal by 12 h at 2 × MIC against all 5 pneumococci and at 2 × MIC after 24 h against all 5 group A and B β-hemolytic streptococci.

Activity of doripenem with and without levofloxacin, amikacin, and colistin against Pseudomonas aeruginosa and Acinetobacter baumannii.

At 24 h, sub-MIC doripenem and levofloxacin showed synergy against 21 of 25 Pseudomonas aeruginosa strains, sub-MIC doripenem and amikacin against 22 isolates, and sub-MIC doripenem and colistin against 19 isolates. Of 25 Acinetobacter baumannii strains, sub-MIC doripenem and levofloxacin showed synergy against 11 strains at 24 h, sub-MIC doripenem and amikacin against 24 strains, and sub-MIC doripenem and colistin against all isolates.

Antistaphylococcal activities of telavancin tested alone and in combination by time-kill assay.

Synergy time-kill studies against 40 methicillin-resistant Staphylococcus aureus (MRSA) strains of differing resistance phenotypes were conducted. Subinhibitory concentrations of telavancin were combined with sub-MIC concentrations of other antimicrobial agents that might be used in combination with telavancin to provide Gram-negative coverage. The highest incidence of synergy was found after 24 h with gentamicin (90% of strains), followed by ceftriaxone (88%), rifampin and meropenem (each 65%), cefepime (45%), and ciprofloxacin (38%) for combinations tested at or below the intermediate breakpoint for each agent.

Comparative study of the mutant prevention concentrations of moxifloxacin, levofloxacin, and gemifloxacin against pneumococci.

We tested the propensity of three quinolones to select for resistant Streptococcus pneumoniae mutants by determining the mutant prevention concentration (MPC) against 100 clinical strains, some of which harbored mutations in type II topoisomerases. Compared with levofloxacin and gemifloxacin, moxifloxacin had the lowest number of strains with MPCs above the susceptibility breakpoint (P<0.001), thus representing a lower selective pressure for proliferation of resistant mutants.

Activity of telavancin against staphylococci and enterococci determined by MIC and resistance selection studies.

This study used CLSI broth microdilution to test the activity of telavancin and comparator antimicrobial agents against 67 methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) isolates. Twenty-six vancomycin-intermediate S. aureus (VISA) strains were among the isolates tested; all strains were susceptible to telavancin at < or = 1 microg/ml, whereas 12/26 (46%) of these isolates were nonsusceptible to daptomycin at the same concentration.

Activity of meropenem with and without ciprofloxacin and colistin against Pseudomonas aeruginosa and Acinetobacter baumannii.

Time-kill synergy studies showed that at 24 h, subinhibitory meropenem and ciprofloxacin concentrations of 0.06 to 128 and 0.03 to 32 microg/ml, respectively, showed synergy against 34/51 Pseudomonas aeruginosa strains; subinhibitory concentrations of meropenem (0.

Multistep resistance selection and postantibiotic-effect studies of the antipneumococcal activity of LBM415 compared to other agents.

LBM415 is a peptide deformylase inhibitor active against gram-positive bacterial species and some gram-negative species. In multiselection studies, LBM415 had low MICs against all Streptococcus pneumoniae strains tested, regardless of their genotype, and selected resistant clones after 14 to 50 days. MIC increases correlated with changes mostly in the 70GXGXAAXQ77 motif in peptide deformylase.

Effects of various media on the activity of NXL103 (formerly XRP 2868), a new oral streptogramin, against Haemophilus influenzae.

The activity of NXL103 against 108 strains of Haemophilus influenzae was tested using Haemophilus test media (HTM) obtained from various sources. With the exception of those obtained with stored HTM, MICs did not differ significantly, with MIC(50) and MIC(90) values of 0.5 and 0.

Activity of LBM415 compared to those of 11 other agents against Haemophilus species.

When tested against 254 Haemophilus influenzae strains, LBM415, a peptide deformylase inhibitor, gave MIC50 and MIC90 values of 2.0 microg/ml and 8.0 microg/ml, respectively.

Antipneumococcal activity of DW-224a, a new quinolone, compared to those of eight other agents.

DW-224a is a new broad-spectrum quinolone with excellent antipneumococcal activity. Agar dilution MIC was used to test the activity of DW-224a compared to those of penicillin, ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin, gemifloxacin, amoxicillin-clavulanate, cefuroxime, and azithromycin against 353 quinolone-susceptible pneumococci. The MICs of 29 quinolone-resistant pneumococci with defined quinolone resistance mechanisms against seven quinolones and an efflux mechanism were also tested.

Activity of retapamulin against Streptococcus pyogenes and Staphylococcus aureus evaluated by agar dilution, microdilution, E-test, and disk diffusion methodologies.

The in vitro activity of retapamulin against 106 Staphylococcus aureus isolates and 109 Streptococcus pyogenes isolates was evaluated by the agar dilution, broth microdilution, E-test, and disk diffusion methodologies. Where possible, the tests were performed by using the CLSI methodology. The results of agar dilution, broth microdilution, and E-test (all with incubation in ambient air) for S.

Activities of tizoxanide and nitazoxanide compared to those of five other thiazolides and three other agents against anaerobic species.

Agar dilution was used, and MICs of metronidazole, tizoxanide, nitazoxanide, denitrotizoxanide, RM 4803, RM 4807, RM 4809, RM 4819, amoxicillin-clavulanate, and clindamycin were measured against 412 anaerobes. Nitazoxanide, tizoxanide, RM 4807, and RM 4809 were active against all groups, except for gram-positive non-spore-forming rods with 50% minimum inhibitory concentrations (when the latter were excluded) of 1 to 2 microg/ml and 90% minimum inhibitory concentrations of 4 to 8 microg/ml, respectively. Metronidazole MICs were usually lower against all groups except clostridia.

Activities of two novel macrolides, GW 773546 and GW 708408, compared with those of telithromycin, erythromycin, azithromycin, and clarithromycin against Haemophilus influenzae.

The MIC at which 50% of strains are inhibited (MIC(50)) and the MIC(90) of GW 773546, a novel macrolide, were 1.0 and 2.0 microg/ml, respectively, for 223 beta-lactamase-positive, beta-lactamase-negative, and beta-lactamase-negative ampicillin-resistant Haemophilus influenzae strains.

Antipneumococcal activities of two novel macrolides, GW 773546 and GW 708408, compared with those of erythromycin, azithromycin, clarithromycin, clindamycin, and telithromycin.

The MICs of GW 773546, GW 708408, and telithromycin for 164 macrolide-susceptible and 161 macrolide-resistant pneumococci were low. The MICs of GW 773546, GW 708408, and telithromycin for macrolide-resistant strains were similar, irrespective of the resistance genotypes of the strains. Clindamycin was active against all macrolide-resistant strains except those with erm(B) and one strain with a 23S rRNA mutation.

Antistaphylococcal activity of CB-181963 (CAB-175), an experimental parenteral cephalosporin.

Among 265 methicillin-susceptible and -resistant staphylococci, CB-181963 (CAB-175) had a 50% minimum inhibitory concentration of 2 microg/ml and a 90% minimum inhibitory concentration of 4 microg/ml. All strains except two vancomycin-resistant S. aureus and 5 vancomycin-intermediate S.

Antipneumococcal activity of LBM415, a new peptide deformylase inhibitor, compared with those of other agents.

The MICs of LBM415, a new peptide diformylase inhibitor, were evaluated and ranged from 0.03 to 4.0 microg/ml for 300 pneumococci, irrespective of their beta-lactam, macrolide, and quinolone susceptibilities.

Susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis to 17 oral antimicrobial agents based on pharmacodynamic parameters: 1998-2001 U S Surveillance Study.

Pharmacokinetic/pharmacodynamic parameters were used to interpret susceptibility data for the oral agents tested in a clinically meaningful way. Among S pneumoniae isolates, >99% were susceptible to respiratory fluoroquinolones, 91.6% to amoxicillin, 92.

Activities of a new oral streptogramin, XRP 2868, compared to those of other agents against Streptococcus pneumoniae and haemophilus species.

MIC methodology was used to test the antibacterial activity of XRP 2868, a new oral combination of two semisynthetic streptogramins, RPR 132552A and RPR 202868, compared to activities of other antibacterial agents against pneumococci, Haemophilus influenzae, and Haemophilus parainfluenzae. For 261 pneumococci, XRP 2868 and pristinamycin MICs were similar, irrespective of penicillin G and erythromycin A susceptibilities (MIC at which 50% of isolates were inhibited [MIC(50)], 0.25 micro g/ml; MIC(90), 0.

Bactericidal activity of daptomycin against Streptococcus pneumoniae compared with eight other antimicrobials.

A spectrum of pneumococci with varying susceptibilities to beta-lactams, macrolides and quinolones was tested for susceptibility to nine antibiotics, including the novel lipopeptide daptomycin. Daptomycin was active against all strains (MIC range View Article and Find Full Text PDF

Incidence, epidemiology, and characteristics of quinolone-nonsusceptible Streptococcus pneumoniae in Croatia.

Among 585 Streptococcus pneumoniae strains isolated in 22 Croatian hospitals 21 strains (3.6%) were quinolone nonsusceptible. MICs of all quinolones were high for seven strains tested with the same serotype (23F) and mutations in gyrA, parC, and parE.