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Biomedical subjects

D S Reeves

Publications and source records attributed to D S Reeves.

At least 91 records · Page 5Linked to original sources

Pharmacokinetic aspects of antibacterial prophylaxis.

Effective prophylaxis against infection can only occur when the antibacterial achieves suitable concentrations at the site of potential infection. This review discusses how the pharmacokinetics of systemically applied prophylaxis and the factors governing the distribution of locally applied antibacterials influence the outcome of prophylactic therapy. While the choice of route of administration for systemic prophylaxis rarely poses a problem, the effective concentrations required at the site of potential infection are unclear and may possibly be less than those needed for therapy of established infection. In some tissues there may be special considerations for the access of antibacterial from the blood, although for the large majority of sites the evidence is that access occurs without difficulty and is perhaps only limited by plasma protein binding of antibacterial. Locally applied antibacterials may have difficulty in reaching their site of action but this can often be overcome by their application at very high concentrations.

Anti-Bacterial Agents↗

Absorption of oral ofloxacin after cytotoxic chemotherapy for haematological malignancy.

Ten patients with newly diagnosed haematological malignancy were given ofloxacin, 400 mg daily orally, for antibacterial prophylaxis during neutropenia. Before cytotoxic chemotherapy was given, and on three occasions between days 2-3, 5-7 and 8-10 afterwards, blood samples were taken before and 1, 2, 3, 4, 6 and 10 h after administration of ofloxacin. Serum ofloxacin concentrations were measured by HPLC. Mean (range) pharmacokinetic parameters before chemotherapy were: Cmax, 6.1 (2.7-9.1) mg/L; AUC0-2, 7.5 (1.9-11.6) mg.h/L. On days 2-3 post-chemotherapy the values were reduced to: Cmax, 5.0 (3.6-7.3) mg/L; AUC0-2, 5.8 (1.9-7.8) mg.h/L. On days 5-7 the values were: Cmax, 6.1 (4.0-10.4) mg/L; AUC0-2, 8.5 (0.8-16.8) mg.h/L, and by days 8-10 the values were: Cmax, 6.4 (3.3-12.5) mg/L; AUC0-2, 8.6 (0.8-23.1) mg.h/L. There was a statistically significant difference between Cmax pre- and Cmax two to three days post-chemotherapy (paired t-test, P = 0.05). These changes are similar to those previously reported with ciprofloxacin but less marked.

Adolescent↗

The activity of piperacillin/tazobactam against clinical isolates collected in 20 UK centres and the design of a disc test for susceptibility testing.

The in-vitro activities of piperacillin plus tazobactam at ratios of 4:1, 8:1 and 16:1 were determined against 952 non-copy clinical aerobic bacterial isolates collected from 20 UK centres. Tazobactam enhanced the activity of piperacillin against Enterobacteriaceae, Staphylococcus aureus, Haemophilus influenzae and Moraxella catarrhalis. No enhancement was noted for Pseudomonas aeruginosa, other Pseudomonas spp., streptococci and enterococci. For 95.6% of strains MICs were either the same or only one two-fold dilution different with all the three ratios of tazobactam, and for most of the remaining strains the piperacillin MIC was lowest with the highest proportion of the tazobactam (4:1). The percentage of strains which remained resistant was also lowest with the 4:1 ratio. Regression analysis of MICs versus inhibition zone size with a variety of disc strengths tested on DST agar indicated that for Enterobacteriaceae, and H. influenzae 30 +4 micrograms, and 5 +1 microgram piperacillin/tazobactam discs gave the most reliable results. However, for S. aureus no disc gave good discrimination. Zone sizes obtained on DST and Iso-Sensitest agar were similar, with 96.1% of 1450 paired tests showing agreement to within 3 mm.

Bacteria, Aerobic↗

Typing of Listeria spp. by random amplified polymorphic DNA (RAPD) analysis.

Random amplified polymorphic DNA (RAPD) analysis, a variation of the polymerase chain reaction (PCR) in which a single primer is used, was evaluated for use as a simple and reliable method with which to type Listeria spp. Representatives of six species of Listeria were studied. Five isolates of L. innocua and four isolates of L. seeligeri were all distinguishable from one another, but the four isolates of L. ivanovii tested, although distinguishable from other Listeria spp., were not differentiated. Among L. monocytogenes serovars 1/2a (eight isolates), 1/2b (eight isolates) and 4b (10 isolates), at least six, three and six RAPD patterns were observed, respectively. Fourteen neonatal cross-infection sets of L. monocytogenes isolates, shown to be indistinguishable by serotyping and phage typing, were examined with three different primers. With one primer, three of the sets were shown to consist of closely related, but distinguishable, strains. In the other 11 cases, each set of strains was indistinguishable with all three primers. These preliminary data indicate that RAPD analysis has promise as a method for typing Listeria spp.

Amino Acid Sequence↗

Mycobacterial contamination of fibreoptic bronchoscopes.

Contamination of bronchoalveolar lavage specimens by environmental mycobacteria in hospital water supplies may lead to diagnostic confusion, particularly in immunocompromised patients. Mycobacteria may become concentrated in the tubing of bronchoscope disinfecting machines. It is very difficult to eradicate these organisms once contamination has occurred.

Adult↗

Treatment of bacteriuria in pregnancy with single dose fosfomycin trometamol: a review.

Bacteriuria in pregnancy occurs in about one in 20 pregnant women and is usually initially asymptomatic. It is an important marker for acute symptomatic infection (often pyelonephritis) later in pregnancy, which occurs in about one in four bacteriurics. Several considerations surround the antibiotic treatment of the asymptomatic infection; these include a low frequency of in vitro resistance to the agent used, lack of toxicity to the foetus, a low incidence of gastrointestinal side effects, good compliance and proven efficacy. Fosfomycin trometamol seems to fit these requirements. In three controlled studies (two multicentric) 250 patients were treated with fosfomycin trometamol in a 3 g (as fosfomycin) single dose; 197 patients were given one of three other agents. Cure rates for fosfomycin trometamol were 77-94% (68-94% for other agents), which was satisfactory in an infection which is sometimes difficult to eradicate. Further studies are needed in this important but accessible group of patients. Opportunities should be taken to study more foetal outcomes and provide more data on gastro-intestinal tolerability.

Bacteriuria↗

Comparison of three methods of antibiotic prophylaxis in knee arthroplasty.

Prophylactic intravenous cefamandole nafate was administered by the systemic, systemic with probenecid (causing renal tubular blockade of antibiotic excretion), and intravenous regional routes. Bone antibiotic levels were assayed 15 minutes and 12 hours after administration, and hematoma concentrations after 8 hours. Bone concentrations after intravenous regional administration were significantly greater than systemic after 15 minutes, but were not detectable after 12 hours. Probenecid produced inhibitory concentrations in bone after 12 hours and also increased hematoma antibiotic concentrations to three times those achieved by systemic administration. Adequate prophylaxis may be possible with two rather than three doses of cefamandole if probenecid is used.

Cefamandole↗

Pharmacokinetics and metabolism of FCE 22101 following its administration as the oral pro-drug FCE 22891.

Ten healthy male volunteers who had previously received both intramuscular and intravenous doses of FCE 22101 received a single oral dose of FCE 22891, the acetoxymethyl ester and pro-drug of FCE 22101. After a lag time of 22 min, mean plasma levels of FCE 22101 rose with a T1/2 absorbance of 19 min to 2.5 mg/L at 30 min, 3.6 mg/L at 60 min and a Cmax of 4.6 mg/L at 80 min; levels then fell with a T1/2 beta of 29 min to be undetectable at 300 min. The mean area under the concentration-time curve (AUC) was 497 mg.min/L giving an absolute bioavailability for FCE 22101 of 32%. Neither FCE 22101 or its metabolites were present in any of the saliva samples collected at intervals up to 360 min after dosing. Mean urinary recoveries were FCE 22101 12% (+/- S.D. 4.6), P1 16% (+/- S.D. 9.1) and P2 3.3% (+/- S.D. 2.1). It was not possible to detect the pro-drug FCE 22891 in any of the blood or urine samples. Significant levels of the metabolite P1 were observed in blood with peak levels of 1.7 mg/L seen 130 min after dosing, 50 min later than the peak FCE 22101 levels, and giving a mean AUC of 297 mg.min/L.

Administration, Oral↗