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Biomedical subjects

A Eley

Publications and source records attributed to A Eley.

At least 73 records · Page 4Linked to original sources
PubMed1984

Antibacterial activity of ciprofloxacin in conventional tests and in a model of bacterial cystitis.

In conventional in vitro tests and an experimental bladder model ciprofloxacin proved very active against 103 strains of enterobacteria isolated from infected urine. Nalidixic acid-resistant strains were less susceptible to ciprofloxacin than nalidixic acid-sensitive strains, and the activity of the drug was reduced under acid conditions. Nevertheless, all strains were inhibited by 4 mg/l of ciprofloxacin at pH 5.5. Streptococcus spp., Staphylococcus aureus, Pseudomonas aeruginosa and Bacteroides spp. were less susceptible than enterobacteria, although most strains were inhibited by a therapeutically achievable concentration of 2 mg/l. Under conditions simulating the treatment of bacterial cystitis, changing concentrations of ciprofloxacin well within levels achievable in urine inhibited dense bacterial cultures for periods exceeding 24 hours, and surviving bacteria did not exhibit any reduction in susceptibility.

Anti-Infective Agents, Urinary↗
PubMed1984

Variations in susceptibility to latamoxef(moxalactam) and cefoxitin within the Bacteroides fragilis group.

Conventional agar dilution MIC titrations, anaerobic turbidimetric monitoring and viable counting were used to investigate the response to latamoxef (moxalactam) and cefoxitin of four well characterized species within the Bacteroides fragilis group. MIC results indicated that Bact. fragilis and Bact. vulgatus were more susceptible to both antibiotics than were Bact. ovatus and Bact. thetaiotaomicron and that latamoxef was more active than cefoxitin. Continuous turbidimetric monitoring with parallel viable counting confirmed the greater susceptibility of Bact. fragilis and Bact. vulgatus, but also suggested that the differential in activity between latamoxef and cefoxitin was less than MIC titrations had indicated. Moreover, against the more resistant Bact. ovatus and Bact. thetaiotaomicron strains, cefoxitin actually appeared more active than latamoxef in bactericidal and bacteriolytic terms. The interpretation of these results is discussed in the light of the morphological response of the bacteria to the two antibiotics. Because species within the Bact. fragilis group appear to differ considerably in their beta-lactam antibiotic susceptibility there is a need for laboratories to test the antibiotic susceptibility of these organisms or to identify them presumptively to the species level if treatment with beta-lactam agents is contemplated.

Bacteroides fragilis↗
PubMed1983

Isoelectric focusing of beta-lactamases on cellulose acetate membranes.

Cellulose acetate membranes treated with boron trifluoride in methanol were found to provide suitable support material for isoelectric focusing of beta-lactamases; the method used is described. A linear pH gradient was obtained and the application of visible pI markers allowed the pH gradient to be monitored as focusing proceeded. beta-Lactamases extracted from antibiotic-resistant coliform organisms focused as sharp, straight bands upon visualization with nitrocefin. Results were known within two hours of applying the beta-lactamase extracts. The method allows a very economical use of expensive ampholyte and offers a quick and more simple alternative procedure for the identification of beta-lactamases than the conventional polyacrylamide gel method.

Bacterial Proteins↗
PubMed1983

Continuous opacity monitoring of the growth of bacteria under strict anaerobic conditions.

A newly designed instrument is described which generates continuous records of the opacities of six bacterial cultures growing under strict anaerobic conditions. Additions (for example, of antibacterial agents) or withdrawal of culture (for example, for viable counting) can be made at any time without breach of anaerobiosis. Use of the instrument is illustrated by growth curves obtained from small inocula of two strict anaerobes, Bacteroides asaccharolyticus and Peptostreptococcus anaerobius and by the effects on the growth curve of Bacteroides fragilis of adding various concentrations of metronidazole at different times.

Anaerobiosis↗
PubMed1982

A turbidimetric study of the responses of selected strains of Pseudomonas aeruginosa to eight antipseudomonal beta-lactam antibiotics.

Turbidimetric and morphologic responses to eight antipseudomonal beta-lactam antibiotics were compared for selected strains of Pseudomonas aeruginosa with different susceptibilities to carbenicillin. In conventional minimal inhibitory concentration tests, all of the newer antibiotics appeared more active than carbenicillin, and apalcillin and cefsulodin had the greatest overall activity. However, in turbidimetric tests the activity of apalcillin and three other N-acyl penicillins (azlocillin, mezlocillin, and piperacillin) was inferior to that of carbenicillin and the other agents. The N-acyl penicillins were also all susceptible to intrinsic pseudomonal beta-lactamase, so that dense bacterial populations inactivated these antibiotics in concentrations of greater 128 micrograms/ml during overnight incubation. Against carbenicillin-resistant strains, carbenicillin, ticarcillin, and sulbenicillin were the least active antibiotics, and cefsulodin had the best overall activity. Turbidimetric monitoring highlights the problems of interpreting the results of conventional minimal inhibitory concentration tests, particularly when large inocula are involved.

Ampicillin↗
PubMed1982

Comparative antipseudomonal activity of some newer beta-lactam agents.

The antipseudomonal activities of cefotaxime, ceftizoxime, ceftazidime, ceftriaxone, cefoperazone, and moxalactam were tested in conventional minimum inhibitory concentration titrations and according to morphological and turbidimetric criteria. Three groups of pseudomonal strains were tested: carbenicillin hypersusceptible, carbenicillin susceptible, and carbenicillin resistant. In minimum inhibitory concentration titrations, the carbenicillin-hypersusceptible strains did not differ greatly in their susceptibility to other beta-lactam agents, although moxalactam appeared to be rather less active than the other drugs. When tested against the remaining strains, ceftazidime was the most active compound, followed by cefoperazone and ceftriaxone. The turbidimetric experiments supported by microscopical observations, all of the agents induced bacterial lysis in the carbenicillin-hypersusceptible strains, but cefoperazone appeared to be less actively bacteriolytic than the rest of the antibiotics. None of the agents was able to prevent growth of the remainder of the Pseudomonas aeruginosa strains in the first few hours of drug exposure, during which time the bacteria elongated to form long filaments. However, the various agents differed in the length of time which elapsed before growth was completely halted. Judged in this way, moxalactam was the most active compound in relation to its minimum inhibitory concentration, but in comparative experiments in which the same concentration of each drug (64 microgram/ml) was used regardless of the minimum inhibitory concentration, ceftazidime appeared to be the most active antibiotic, followed by ceftriaxone and cefotaxime.

Anti-Bacterial Agents↗
PubMed1982

In vitro activity of temocillin, a new beta-lactamase-stable penicillin active against enterobacteria.

The activity of temocillin was investigated in vitro against 523 clinical isolates of enterobacteria and Pseudomonas aeruginosa. The minimum inhibitory concentration of the new compound for all ampicillin-susceptible enterobacteria and for 90% of ampicillin-resistant enterobacteria was 16 micrograms/ml or less, a concentration readily achieved in plasma. P. aeruginosa strains were uniformly resistant to temocillin. All but 3 of a separate group of 48 enterobacteria exhibiting resistance to the combination of clavulanic acid and amoxicillin were found to be inhibited by 16 micrograms or less of temocillin per ml. The new compound also displayed good activity against a group of laboratory stock cultures selected on the basis of differential resistance to presently available beta-lactam agents. Two of these strains were cefotaxime resistant.

Enterobacteriaceae↗
PubMed1981

In-vitro activity of the novel oxa-beta-lactam antibiotic moxalactam (LY 127935) against dense populations of selected Gram-negative bacilli.

The activity of moxalactam, a new beta-lactam antibiotic with a novel molecular structure, was examined against dense populations of a variety of Gram-negative bacilli. The lytic activity of moxalactam against ampicillin-sensitive strains was similar to ampicillin, but the activity was maintained against ampicillin-resistant strains, including Pseudomonas aeruginosa, irrespective of whether the ampicillin resistance was 'intrinsic' (non-enzymic) or due to beta-lactamase. Of the 18 strains tested only one, a Hafnia sp., failed to respond to moxalactam.

Ampicillin↗
PubMed1981

Activity of a new cephalosporin antibiotic, Ro 13-9904 against dense populations of selected enterobacteria.

Ro 13-9904 is a new cephalosporin antibiotic with a wide spectrum of activity similar to that of cefotaxime and some other newer beta-lactam compounds. In the present study, the response to Ro 13-9904 of 13 strains of enterobacteria, selected on the basis of differential patterns of susceptibility to beta-lactam agents, was investigated. The new cephalosporin displayed high intrinsic activity against most of the enterobacteria tested, but a group of Klebsiella and Hafnia alvei strains was identified against which Ro 13-9904 (and cefotaxime) exhibited reduced activity. Investigation of these strains revealed several different types of response to Ro 13-9904 and cefotaxime. Although such "difficult" strains represent a small minority of clinical isolates, it is likely that it is this group of strains against which the new generation of highly potent, broad-spectrum beta-lactam antibiotics will display significant differential activity.

Anti-Bacterial Agents↗
PubMed1981

In vitro activity of ceftizoxime against Bacteroides fragilis: comparison with benzylpenicillin, cephalothin, and cefoxitin.

Minimum inhibitory concentrations of ceftizoxime for seven clinical isolates of Bacteroides fragilis were found to be markedly affected by inoculum size; the very low minimum inhibitory concentration values (less than or equal to 0.25 microgram/ml) obtained in tests with most strains were not sustained when the inoculum was raised 100-fold. Benzylpenicillin and cephalothin were also affected by inoculum size, but cefoxitin was not. Antibiotic assays showed that the strains inactivated ceftizoxime and cephalothin completely, benzylpenicillin partially, and cefoxitin not at all. Morphological investigations revealed that populations of B. fragilis responded differently to each of the four beta-lactam agents during the early stages of the encounter between B. fragilis and the antibiotic. Benzylpenicillin and cefoxitin induced spheroplast formation at lower concentrations than did ceftizoxime. Cephalothin evoked a novel morphological response that was not seen with other beta-lactam agents.

Anti-Bacterial Agents↗
PubMed1980

Comparative in vitro activities of cefotaxime and ceftizoxime (FK749): new cephalosporins with exceptional potency.

Cefotaxime and its desacetoxymethyl derivative, ceftizoxime (previously known as FK749), are both extremely active against a wide spectrum of bacteria. In the present comparative study, the activity of ceftizoxime exceeded that of cefotaxime by a factor of four or more for strains of Klebsiella, Enterobacter, Providencia, Serratia, and Bacteroides; the only species for which the activity of cefotaxime exceeded that of ceftizoxime by a factor of four was Vibrio cholerae. Against other species, the activity of the two drugs was roughly comparable. Both showed outstanding activity against Haemophilus influenzae and Neisseria gonorrhoeae. Comparative turbidimetric and morphological studies revealed that ceftizoxime was able to induce spheroplast formation and rapid lysis in Escherichia coli strains at lower concentrations than cefotaxime. This difference was not found, however, when E. coli strains resistant to ampicillin by an intrinsic (nonenzymic) mechanism were tested.

Bacteria↗
PubMed1975

Lymphosarcoma of the breast.

A case of lymphosarcoma presenting as a breast tumour in a 68-year-old woman is described and the condition briefly reviewed.

Aged↗
PubMedDate not supplied

Significance of Bacteroides ureolyticus in the lower genital tract.

In a study to determine the significance of Bacteroides ureolyticus in the lower urogenital tract using a new selective and differential medium, this organism was isolated from 30.1% of asymptomatic men, 37.8% of men with genital warts, and 26.3% of men with non-gonococcal urethritis. Using the same selective medium B. ureolyticus was isolated from 49% of women attending the same genitourinary clinic with symptoms of vaginal discharge and/or pruritus vulvae, 44.1% of asymptomatic women, and 50% of asymptomatic women attending a local family planning clinic. Furthermore, this organism was isolated from 27.1% of women whose vaginal specimens isolated commensal organisms only, 43.2% with C. albicans, 59.4% with U. urealyticum, 74.4% with M. hominis, and 76.8% with G. vaginalis. On testing with the API ATB 32A test strips, 86% of the positive isolates of B. ureolyticus from the female genital tract were indistinguishable from those isolated from the male genital tract indicating that this organism is common to the lower genital tract of both sexes. These results indicate that B. ureolyticus is a commensal in the lower genital tract.

Adult↗