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Biomedical subjects

R Wise

Publications and source records attributed to R Wise.

At least 379 records · Page 21Linked to original sources

Susceptibility of clinical isolates of Campylobacter pyloridis to 11 antimicrobial agents.

The activities of 11 antimicrobial agents, including two bismuth salts, against 70 strains of Campylobacter pyloridis isolated from gastric biopsy specimens were tested. The isolates were very susceptible to penicillin (the MIC for 90% of the strains tested [MIC90] was 0.03 microgram/ml), erythromycin, cefoxitin (MIC90, 0.12 microgram/ml), gentamicin, and ciprofloxacin (MIC90, 0.25 microgram/ml). The bismuth salts and nalidixic acid had moderate activity (MIC90, 16 to 64 micrograms/ml). Twenty percent of the isolates were resistant to metronidazole (MIC, greater than 1 micrograms/ml), and all were resistant to sulfamethoxazole and trimethoprim (MIC90, greater than 256 micrograms/ml).

Anti-Bacterial Agents↗

Ceftazidime in neonatal infections.

Ninety one neonates received 108 courses of intravenous ceftazidime (25 mg/kg, 12 hourly) over a study period of 15 months. Fourteen had clinically and bacteriologically proved infections. Only one of these had resistant organisms. Four (two with group B beta haemolytic streptococcal infections, one with Escherichia coli meningitis, and one with Staphylococcal aureus septicaemia) failed to respond despite adequate treatment. Bacteriological eradication or clinical improvement, or both, were obtained in the remaining nine. Routine biochemical and haematological values were monitored and there were no side effects. High serum ceftazidime concentrations, well exceeding the minimum inhibitory concentration for most common neonatal pathogens were obtained and maintained throughout treatment. Penetration into the cerebrospinal fluid was excellent in eight of the nine cases studied. Ceftazidime has a theoretical role as a broad spectrum antibiotic suitable for neonatal use with no evident side effects. In this study, however, it was only appropriate for Gram negative infections, and was ineffective against Gram positive organisms. Ceftazidime cannot therefore be recommended as monotherapy before the results of bacteriological culture are known.

Bacterial Infections↗

The in vitro antibacterial activity of ceftriaxone in comparison with nine other antibiotics.

The results of a large three centre co-ordinated study into the in vitro susceptibility of bacterial clinical pathogens showed no significant evidence of regional variation within the U.K. towards the 10 antibiotics examined. The newer cephalosporins were highly potent and superior to other antibiotics against the Enterobacteriaceae, with ceftriaxone and cefotaxime the most potent. Against Pseudomonas aeruginosa, gentamicin was the most active, followed by ceftazidime, piperacillin and ceftriaxone; cefotetan was the least active. Staphylococcus aureus and Staphylococcus albus were most susceptible to cefuroxime and gentamicin, though most were also susceptible to ceftriaxone, cefotaxime and cefoxitin. Streptococcus (Groups A and B), Streptococcus pneumoniae and Neisseria spp. were susceptible to most agents other than gentamicin, but ceftriaxone and cefotaxime were overall the most potent. Ceftriaxone was the most active agent against Haemophilus influenzae. The newer agents were variable and relatively poor against anaerobes and only amoxycillin and piperacillin were significantly active against Streptococcus faecalis. The overall resistance level to the third generation cephalosporins was low.

Anti-Bacterial Agents↗

Pharmacokinetics and tissue penetration of temocillin.

The pharmacokinetics of intravenous (bolus) temocillin 1 g were studied in 6 healthy male volunteers, and a cantharides blister method was used to estimate tissue penetration of the antibiotic. The mean elimination half-life was 4.5 hours. Temocillin penetrated blister fluid rapidly and reached concentrations of about 50% of those in serum by 2 to 3 hours after administration. Over an 8-hour period, the serum and blister fluid concentrations exceeded the MIC90 of susceptible bacteria by 2-fold or greater, suggesting that twice or even once daily dosing with temocillin may be sufficient.

Blister↗

The pharmacokinetics and tissue penetration of norfloxacin.

The pharmacokinetics and cantharides-induced blister fluid levels of norfloxacin were studied after a single 400 mg oral dose. The mean maximum serum level was 1.45 mg/l and occurred 1.5 h after administration. The serum half-life of norfloxacin was found to be 3.5 h. After 24 h 27% of the administered dose was recovered in the urine as microbiologically active compound. High urine levels were found. Rapid blister fluid penetration occurred, the maximum level (occurring between 2-3 h) was about 1 mg/l. Thereafter the blister fluid level exceeded the serum level, both declining in parallel.

Adult↗

In-vitro activity of enoxacin (CL-919), a new quinoline derivative, compared with that of other antimicrobial agents.

The in-vitro activity of enoxacin (CI-919), a new synthetic quinoline derivative was compared with that of three other quinolines ofloxacin, norfloxacin and nalidixic acid. In addition beta-lactams and gentamicin were also included when appropriate. The MICs of enoxacin for 90% of Escherichia coli, Klebsiella spp., Enterobacter spp., Proteus spp., Providencia stuartii, Pseudomonas aeruginosa and Staphylococcus aureus were less than 4 mg/l, for Haemophilus influenzae less than 0.25 mg/l and Neisseria gonorrhoeae less than 0.03 mg/l. Bacteroides fragilis and streptococci (including Streptococcus pneumoniae) were less susceptible, MIC90 16 mg/l. Against many of the common Enterobacteriaceae enoxacin displayed a similar degree of activity as gentamicin. Gentamicin-resistant strains of common bacterial pathogens were susceptible to enoxacin as were methicillin-resistant Staph. aureus. The protein binding of enoxacin (concentration 5 mg/l) was 18%.

Anti-Bacterial Agents↗

The pharmacokinetics of orally absorbed cefuroxime compared with amoxycillin/clavulanic acid.

The pharmacokinetics of a new orally absorbed pro-drug of cefuroxime were compared with those of co-administered amoxycillin and clavulanic acid in six healthy male volunteers. Doses of 600 mg of acetoxyethyl cefuroxime and 500 mg amoxycillin plus 250 mg clavulanic acid were each administered for ten doses 8 hourly. Tissue penetration after the first dose of the antibiotic was estimated by a cantharides blister method. The faecal flora of the volunteers was studied throughout the study. The pharmacokinetics of cefuroxime and amoxycillin were very similar, peak levels of about 6.4 mg/l being found between 2 and 2.5 h after administration. The peak serum level of clavulanic acid was 4.3 mg/l at 1.25 h after administration. The serum half-lives were about 1.1 h for all three agents. No drug accumulation occurred over the four days of the study. The 0-8 h urinary recovery of cefuroxime was 30%. All three agents penetrated the blister fluid rapidly, the main peak levels being 64% of the peak serum level for cefuroxime, 72% for amoxycillin and 55% for clavulanic acid. The incidence of side effects was similar for each regimen. Three volunteers having diarrhoea after cefuroxime showed significant alterations in their bowel flora.

Adult↗

Norfloxacin--a review of pharmacology and tissue penetration.

A review of the pharmacokinetics of the highly active quinoline derivative, norfloxacin, is presented. The compound appears to be rapidly absorbed. The serum half-life is about 3 X 5 h and 30% of a given dose is recovered in the urine. Rapid penetration of an inflammatory exudate occurs. The compound is metabolized to a modest extent, probably in the liver, six metabolites being recognized. The serum half-life is prolonged in severe renal impairment. Probenecid would appear to decrease the renal elimination. The possibility of treating both urinary and tissue infections with this compound is raised.

Animals↗

A comparison of the homogeneous enzyme immunoassay and polarization fluoroimmunoassay of gentamicin.

Polarization fluoroimmunoassay (Abbott TDX) and the homogeneous enzyme immunoassay (Syva, EMIT) both allowed the rapid, accurate and precise assay of gentamicin. The presence of other antibiotics, Intralipid and gentamicin from various sources on the assay was assessed. The results obtained for both methods correlated well with the plate microbiological method (TDX correlation coefficients, spiked samples 0.98, patient samples 0.95; EMIT correlation coefficients, spiked samples 0.99, patient samples 0.94). The coefficients of variation (CV) for within assay studies were between 3.5 and 5.9% and between 5.5 and 6.2% for the TDX and EMIT procedures respectively. The CVs for the between assay studies were between 2.4 and 5.9% and from 3.2 and 14.8% for TDX and EMIT respectively. The presence of 'Intralipid' affected the two assays to differing extents but other antimicrobial agents did not. Attention is drawn to the fact that results may be influenced by standard gentamicin material obtained from different sources.

Autoanalysis↗

The pharmacokinetics and tissue penetration of ofloxacin.

The pharmacokinetics of the 4-quinolone agent, ofloxacin, were studied in six healthy volunteers, following a 600 mg oral dose. The levels of the compound were measured by a microbiological assay in serum, blister fluid and urine. The compound was rapidly absorbed, the mean maximum concentration of ofloxacin being 10.7 mg/l at 1.2 h. The mean serum elimination half-life was 7 h and 80.3% of the administered compound was recovered in the urine by 48 h. Ofloxacin penetrated the blister fluid well, the mean peak level being 5.2 mg/l at 5.3 h.

Adult↗

The pharmacokinetics and tissue penetration of enoxacin and norfloxacin.

Two new quinoline compounds, enoxacin (600 mg) and norfloxacin (400 mg) were administered consecutively to six healthy male volunteers. The levels of the two agents were measured in serum, urine and blister fluid. The mean peak serum level of enoxacin was 3.7 mg/l and attained at a mean time of 1.9 h after administration; the mean peak serum level of norfloxacin was 1.45 mg/l at a mean time of 1.5 h. The mean serum half-lives were 6.2 h for enoxacin and 3.25 h for norfloxacin. Both agents penetrated blister fluid well and reached maximum levels of 2.9 mg/l (for enoxacin) and 1.0 mg/l (for norfloxacin). The 24 h urinary recovery of enoxacin of 61% was about twice that of norfloxacin. No adverse effects of either agent were observed. The data suggest that enoxacin might be used as a once daily dose for the treatment of urinary tract infections, but twice daily for the treatment of susceptible pathogens causing systemic (as against urinary) infections.

Adult↗

In vitro activity of fludalanine combined with pentizidone compared with those of other agents.

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.

Alanine↗

Pharmacokinetics and tissue penetration of enoxacin.

The pharmacokinetics of the quinolone enoxacin were studied after a 600-mg oral dose was given to each of six male volunteers. The levels of the compound were measured in serum, blister fluid, and urine. Absorption was variable, with peak levels (mean, 3.7 micrograms/ml) being attained between 0.75 and 3.0 h (mean, 1.9 h). The serum elimination half-life was 6.2 h, and 71.6% of the drug was recovered in the urine by 48 h. Enoxacin penetrated blister fluid well, the mean percent penetration being 78.4%.

Adult↗

Pharmacokinetics of intravenously administered ciprofloxacin.

A 100-mg dose of ciprofloxacin was given as an intravenous bolus injection to each of six healthy volunteers, after which the levels of this agent were measured in serum, blister fluid, and urine. After administration, distribution of ciprofloxacin was very rapid, and the mean distribution volume was very large (177 liters). The mean terminal serum half-life was 4.0 h. The agent penetrated blister fluid rapidly, with the mean maximum level being 0.53 micrograms/ml at 30 min, after which time the blister levels exceeded those in serum. The 48-h urinary recovery of ciprofloxacin was about 80%.

Adult↗

In vitro activity of CGP 31523A, a broad-spectrum cephalosporin, in comparison with those of other agents.

The in vitro activity of CGP 31523A, a new aminothiazolyl cephalosporin, was compared with those of cefoxitin, cefuroxime, moxalactam, piperacillin, ciprofloxacin, and other beta-lactams, when appropriate, against 533 recent clinical isolates and known resistant strains of bacteria. The MICs of CGP 31523A required to inhibit 90% (MIC90S) of the members of the family Enterobacteriaceae, Neisseria gonorrhoeae, and Streptococcus pneumoniae were less than or equal to 0.25 micrograms/ml. Of Staphylococcus aureus (excluding methicillin-resistant strains) and Haemophilus influenzae, 90% were susceptible to 0.5 micrograms/ml. Pseudomonas aeruginosa and Lancefield group D streptococci were resistant to CGP 31523A (MIC90, greater than or equal to 128 micrograms/ml). The activity against Bacteroides fragilis was modest (MIC90, 32 micrograms/ml). The susceptibility of known beta-lactamase-producing strains suggested that CGP 31523A was resistant to many beta-lactamases (but not those of Bacteroides fragilis). The serum protein binding of CGP 31523A was about 73%. The primary target site of CGP 31523A in Escherichia coli appeared to be penicillin-binding protein 3.

Anti-Bacterial Agents↗