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N Brenwald

Publications and source records attributed to N Brenwald.

12 recordsLinked to original sources
PubMed1997

A reassessment of the in-vitro activity of colistin sulphomethate sodium.

The in-vitro activity of colistin sulphomethate sodium was compared with that of other commonly used antimicrobial agents against 377 recent clinical isolates of Gram-negative bacteria (including 94 strains of Pseudomonas aeruginosa from patients with cystic fibrosis) and 16 organisms with defined resistance patterns. Colistin was active against most strains of P. aeruginosa (MIC90 4 mg/L), Shigella spp. (MIC90 0.5 mg/L), Salmonella spp. (MIC90 1 mg/L), Acinetobacter spp. (MIC90 2 mg/L), Citrobacter spp. (MIC90 1 mg/L), Escherichia coli (MIC90 1 mg/L), Klebsiella spp. (MIC90 8 mg/L) and Enterobacter spp. (MIC50 1 mg/L). No useful activity was demonstrated against Providentia spp. or Serratia spp. The results show that colistin remains a useful antimicrobial agent against Gram-negative bacteria, particularly those strains which are resistant to more commonly used antibiotics.

Anti-Bacterial Agents↗
PubMed1996

In vitro activity of the tricyclic beta-lactam GV104326.

GV104326 is a novel tricyclic beta-lactam (a trinem or, formerly, tribactam). The in vitro activity of GV104326 was compared with those of cefuroxime, cefixime, amoxicillin, amoxicillin-clavulanic acid, cefpirome, and ciprofloxacin. GV104326 had in vitro activity generally similar to that of cefixime against members of the family Enterobacteriaceae (MIC at which 90% of the isolates are inhibited [MIC90], < or = 2 micrograms/ml), with cefuroxime and amoxicillin-clavulanic acid being 8- to 32-fold less active and with cefpirome being 4- to 8-fold more active against members of this family. The trinem had no activity against Pseudomonas aeruginosa or Stenotrophomonas maltophilia (MIC90, > 128 micrograms/ml) but was the most active agent against Acinetobacter calcoaceticus. GV104326 was particularly active against gram-positive cocci. Ninety percent of methicillin-susceptible Staphylococcus aureus strains were susceptible to 0.03 microgram of GV104326 per ml, making it the most active agent studied. Enterococci and Lancefield group A and B streptococci were generally equally or somewhat more susceptible to GV104326 than they were to amoxicillin. Streptococcus pneumoniae strains were highly susceptible to GV104326, and those strains which showed decreased susceptibility to penicillin were generally twofold more susceptible to the trinem than to amoxicillin. Haemophilus influenzae and Moraxella catarrhalis were highly susceptible to GV104326 (MIC90s, 0.12 and 0.03 microgram/ml, respectively). The anaerobes Clostridium perfringens, Bacteroides fragilis, and Peptostreptococcus spp. were more susceptible to the trinems (formerly tribactams) than to the other agents studied.

Amoxicillin↗
PubMed1995

The in-vitro activity of CP 99,219, a new naphthyridone antimicrobial agent: a comparison with fluoroquinolone agents.

The in-vitro activity of a new fluoroquinolone, CP 99,219 was compared with that of ciprofloxacin, DU 6859, sparfloxacin and levofloxacin. CP 99,219 showed generally similar in-vitro activity to the other compounds tested against the Enterobacteriaceae (MIC90 of all agents < 0.5 mg/L except Morganella morganii). It was found to be more active than ciprofloxacin, sparfloxacin and levofloxacin against the strains of Acinetobacter calcoaceticus tested (MIC90 1 mg/L). CP 99,219 was found to be four-fold more active against strains of Stenotrophomonas maltophilia than ciprofloxacin (MIC90 1 and 8 mg/L, respectively). Haemophilus influenzae and Neisseria spp. were highly susceptible to all the agents tested. CP 99,219 was more active than ciprofloxacin, sparfloxacin and levofloxacin against Gram-positive organisms, but less active than DU 6859. The enhanced anti-Gram-positive activity of CP 99,219 was most marked against the nine strains of methicillin-resistant Staphylococcus aureus tested. The MIC90 of CP 99,219 of these strains was 1.0 mg/L compared with 64 mg/L for ciprofloxacin. Against Bacteroides fragilis, CP 99,219 (MIC90 0.25 mg/L) and DU 6859 (MIC90 0.03 mg/L) were more active than the other quinolones. Chlamydia spp. were susceptible to < or = 0.12 mg/L of CP 99,219. Mycobacterial strains tested were less susceptible to CP 99,219 than to ciprofloxacin. The protein binding of CP 99,219 was 87.9% at 1 mg/L.

4-Quinolones↗
PubMed1995

In-vitro activity of two glycylcyclines against enterococci resistant to other agents.

Two new glycylcyclines, CL 329,998 and CL 331,002, were tested for in-vitro activity against 178 clinical strains of enterococci which were resistant to one or more of the commonly used agents (ampicillin, high level gentamicin, vancomycin and teicoplanin). Both glycylcyclines demonstrated good activity (MICs < or = 0.5 mg/L) against all isolates tested, including those strains which demonstrated multiple resistance. As resistant enterococci are increasing in importance, new agents with activity against these strains are urgently required. Glycylcyclines have in-vitro activity which suggests they may be useful agents for treatment of infections caused by these organisms.

Anti-Bacterial Agents↗
PubMed1993

The in-vitro activity of Bay y 3118, a new chlorofluoroquinolone.

The in-vitro activity of Bay y 3118, a new quinolone antimicrobial was compared with that of ciprofloxacin, sparfloxacin and three beta-lactams against 620 clinical isolates. Bay y 3118 was the most active quinolone against the majority of Enterobacteriaceae and Staphylococcus spp. The MIC90 for the members of the Enterobacteriaceae were < or = 0.12 mg/L except for Serratia spp. (1 mg/L) and in general Bay y 3118 was two-fold more active than ciprofloxacin or sparfloxacin. Strains of Pseudomonas aeruginosa were more susceptible to ciprofloxacin (MIC90 0.25 mg/L) than to Bay y 3118 (MIC90 0.5 mg/L) or sparfloxacin (MIC90 1.0 mg/L). Staphylococcus aureus was more susceptible to Bay y 3118 (MIC90 0.03 mg/L) and sparfloxacin (MIC90 0.06 mg/L) than to ciprofloxacin (MIC90 1 mg/L) and similar differences were noted for Staphylococcus saprophyticus and Staphylococcus epidermidis. Streptococcus pneumoniae was susceptible to Bay y 3118 (MIC90 0.03 mg/L) as were other streptococci. Enterococcus spp. was four-fold more susceptible to Bay y 3118 and sparfloxacin than to ciprofloxacin. All strains of Haemophilus influenzae and Moraxella spp. were inhibited by Bay y 3118 < or = 0.015 mg/L. Anaerobes were more susceptible to Bay y 3118 than to other quinolones; the MIC90 of Bay y 3118 for Bacteroides fragilis being 0.06 mg/L. Little effect was seen by increasing the inoculum from 10(4) cfu to 10(6). Bay y 3118 inhibited Chlamydia sp. at concentrations < or = 0.015 mg/L.

Anti-Bacterial Agents↗
PubMed1993

The in-vitro activity of OPC-17116, a new 5-methyl substituted quinolone.

The in-vitro activity of the new 5-methylated fluoroquinolone OPC-17116 was compared with that of other fluoroquinolines and beta-lactams against a total of 690 bacterial strains. With the exception of Klebsiella and Serratia spp., 90% of the Enterobacteriaceae were inhibited by 0.25 mg/L. OPC-17116 inhibited 90% of Serratia spp. at 8 mg/L and Klebsiella spp. at 4 mg/L. Moraxella catarrhalis and Haemophilus influenzae were highly susceptible (MIC90 < or = 0.03 mg/L). Pseudomonas aeruginosa were more susceptible to ciprofloxacin (MIC90 0.25 mg/L) than OPC-17116 (MIC90 1 mg/L). Generally, OPC-17116 was more active than ciprofloxacin against Gram-positive cocci, 90% of Staphylococcus spp. being inhibited by < or = 0.25 mg/L. OPC-17116 displayed greater activity than ciprofloxacin against Chlamydia spp. (MICs < or = 0.12 and < or = 2 mg/L, respectively).

Amoxicillin↗
PubMed1992

Resistance to desiccation and skin fatty acids in outbreak strains of methicillin-resistant Staphylococcus aureus.

Resistance to desiccation and to skin fatty acids was measured in three groups of methicillin-resistant Staphylococcus aureus (MRSA) strains and a group of control strains. Organisms from a large outbreak on a special care baby unit (SCBU), where MRSA had been isolated from staff hands but not from the environment, were significantly more sensitive to drying than strains from a burns unit where extensive environmental contamination had been demonstrated. MRSA from other wards, in the same hospital but not associated with large outbreaks, gave heterogeneous results. Fatty-acid resistance, determined by an agar dilution method, was not associated with strain origin. Some epidemic strains of MRSA were relatively sensitive to desiccation, and the abilities of such strains to spread widely on a SCBU by the hand-borne route could not be explained by enhanced resistance to skin fatty acids.

Cross Infection↗
PubMedDate not supplied

Enumeration of phagocytosed Staphylococcus aureus inside cells of the mouse macrophage cell line J774 by bioluminescence, fluorescence and viable counting techniques.

In order to quantify intracellular Staphylococcus aureus within a macrophage-like cell line by a bioluminescence technique, the mouse cell line J774 and opsonized Staphylococcus aureus were incubated together to allow phagocytosis to occur. Experiments using UV microscopy and fluorescent stained S. aureus were performed to determine an estimate of the mean intracellular bacterial numbers. For enumeration of intracellular bacteria by a bioluminescence technique, extracellular bacteria were removed by washing, the macrophages lysed mechanically and osmotically and treated with apyrase to remove somatic ATP. Bacterial cells were washed and the intracellular ATP measured by firefly luciferase bioluminescence in a luminometer. This new method of enumerating intracellular bacteria was compared to the conventional method of viable counts and found to correlate (r = 0.78). The bioluminescence assay developed was found to be a relatively rapid alternative method to the techniques currently used to enumerate intracellular bacteria and could prove advantageous in studies of intracellular killing and effects of antimicrobial agents on intracellular pathogens.

Animals↗