Biomedical subjects

B Slocombe

Publications and source records attributed to B Slocombe.

6 recordsLinked to original sources

PubMed1991

The antimicrobial activity of mupirocin--an update on resistance.

Mupirocin (pseudomonic acid A) has a novel chemical structure that is unrelated to any other known class of antibiotic, and possesses a unique mode of action. As a consequence, mupirocin lacks cross-resistance with other antibacterial agents and exhibits activity against strains of bacteria that are multiresistant. The selection in vitro of resistant variants of Staphylococcus aureus is slow, which is reflected in the low incidence of mupirocin resistance encountered in clinical practice. Pulse field gel electrophoresis studies on S. aureus highly resistant to mupirocin, have confirmed the presence of a large plasmid in the majority, but not all, of the isolates. Restriction endonuclease digests of the large plasmid DNA, and DNA hybridization studies with a non-radiolabelled probe constructed from total plasmid DNA, have shown that there were marked differences in plasmid types between isolates from different locations, but general similarities between plasmid types isolated from the same location.

DNA, Bacterial↗

PubMed1991

Activity of human extravascular temocillin concentrations simulated in an in-vitro kinetic model against beta-lactamase producing gram-negative bacilli.

An in-vitro kinetic model was used to demonstrate the bactericidal activity of concentrations of temocillin achieved in extravascular body fluids following a 1 g intravenous dosage in man. Concentrations of temocillin attainable in peripheral lymph were bactericidal for ampicillin-resistant strains of Escherichia coli, Enterobacter cloacae and Klebsiella oxytoca. Likewise, concentrations of temocillin achieved in human blister fluid following a 12-hourly dosage regimen were bactericidal for cultures of Ent. cloacae and K. oxytoca which were resistant, respectively, to simulated blister fluid concentrations of cefotaxime and aztreonam. The bactericidal activity of extravascular concentrations of temocillin against these multiresistant, Gram-negative bacteria was a reflection of the beta-lactamase-stability and good pharmacokinetic properties of temocillin.

Anti-Bacterial Agents↗

PubMed1991

Comparative activities of amoxycillin, amoxycillin/clavulanic acid and tetracycline against Chlamydia trachomatis in cell culture and in an experimental mouse pneumonitis.

The activity of amoxycillin, amoxycillin/clavulanic acid and two tetracycline antibiotics was investigated against three strains of Chlamydia trachomatis in vitro. McCoy cells were infected and single doses of antibiotic administered 24 h after infection. The percentage of infected cells was calculated at intervals up to 72 h after infection. Amoxycillin and clavulanic acid, alone and in combination, reduced the incidence of inclusion formation of all three strains. Particularly good activity was observed against the laboratory-adapted strain C. trachomatis Sa2f and a clinical isolate C. trachomatis LB1, where a progressive reduction in numbers of inclusions was observed with time. Minocycline and oxytetracycline were the most active agents tested. In an experimental animal model, mice were inoculated intranasally with C. trachomatis MoPn (ATCC VR123) which caused a fatal pneumonia within 16 days, and treated orally for four days commencing at 24 h after infection. At doses producing clinically achievable serum concentrations, amoxycillin (10 mg/kg), amoxycillin/clavulanic acid (10 + 5 mg/kg) and minocycline (5 mg/kg) all protected the mice over a 21-day period. The majority of the animals treated with clavulanic acid alone (20 mg/kg) survived the infection. Treatment with oxytetracycline was less effective, a dose of 160 mg/kg being required to protect 70% of the mice. The results indicate that amoxycillin and amoxycillin/clavulanic acid were more effective against C. trachomatis MoPn in vivo than might be predicted from in-vitro data, suggesting that amoxycillin/clavulanic acid may have potential for the treatment of polymicrobial infections involving C. trachomatis.

Amoxicillin↗

PubMed1990

Effect of low concentrations of clavulanic acid on the in-vitro activity of amoxycillin against beta-lactamase-producing Branhamella catarrhalis and Haemophilus influenzae.

Concentrations of amoxycillin/clavulanic acid achievable in the respiratory tract following oral dosage were assessed for in-vitro activity against beta-lactamase-producing strains of Branhamella catarrhalis and Haemophilus influenzae. In agar-dilution studies, 8 mg amoxycillin/l was required to inhibit 45 strains of beta-lactamase-producing B. catarrhalis, whereas all the strains were inhibited by 0.5 mg amoxycillin/l in the presence of 0.01 mg clavulanic acid/l. Similarly, 0.1 mg amoxycillin plus 0.05 mg clavulanic acid/l were bactericidal against beta-lactamase-producing strain of B. catarrhalis and prevented regrowth within 24 h. In tests against 43 beta-lactamase-producing strains of H. influenzae, concentrations of up to 128 mg amoxycillin/l were required for inhibition, whereas 32 strains (75%) were fully sensitive to amoxycillin (MIC 0.5 mg/l) in the presence of 0.12 mg clavulanic acid/l. These concentrations of amoxycillin/clavulanic acid were also bactericidal for a beta-lactamase-producing strain of H. influenzae. The study therefore showed that amoxycillin/clavulanic acid, at concentrations similar to those likely to be achieved in the respiratory tract following oral dosage, was bactericidal in vitro for beta-lactamase-producing isolates of B.catarrhalis and H. influenzae.

Amoxicillin↗

PubMed1977

Aminoglycoside-resistant enterococci.

Thirty-four recent clinical isolates of Streptococcus faecalis were tested for sensitivity to amoxycillin, benzylpenicillin, streptomycin, kanamycin, gentamicin, tobramycin, and amikacin. Amoxycillin was two- to four-fold more active than benzylpenicillin and all strains were inhibited by low concentrations of the penicillins. The aminoglycosides were less active against the enterococci than were the penicillins and a significant number of strains were insensitive or relatively insensitive to one or more of the aminoglycosides. Thus, eight (23%) strains showed a high level of resistance to streptomycin and kanamycin (MIC greater 5000 microng/ml) but were sensitive to gentamicin, tobramycin, and amikacin. In addition, two strains of Strep. faecalis, isolated at different hospitals from patients who had received topical gentamicin therapy, were relatively resistant to gentamicin (MIC250 to 500 microng/ml) and were less sensitive also to the other aminoglycosides. Bactericidal synergy was demonstrated by amoxycillin/aminoglycoside combinations against the enterococci, provided that the test strain of Strep. faecalis was sensitive to the aminoglycoside in the combination. An exception to this was the combination of amoxycillin plus amikacin which was not synergistic against kanamycin-resistant strains of Strep. faecalis although these organisms were sensitive to amikacin in the growth inhibition tests. The gentamicin-resistant strains showed variable responses to amoxycillin/aminoglycoside combinations in tests for bactericidal synergy and were generally less sensitive than typical strains of Strep. faecalis.

Aminoglycosides↗

PubMed1977

A double trial of amoxycillin in the treatment of gonorrhoea.

A double blind comparison of two regimens of amoxycillin plus probenecid in the treatment of uncomplicated anogenital gonorrhoea is reported. Forty-three (86-0%) of 50 patients treated with 1 g amoxycillin plus 1 g probenecid and followed-up for 14 days were regarded as cured, and 51 (94-4%) of 54 patients treated with 3 g amoxycillin plus 1 g probenecid were regarded as cured. Fifty-nine per cent of 69 isolates of Neisseria gonorrhoeae were sensitive to amoxycillin (minimum inhibitory concentration less than or equal to 0-05 mg/ml). Although there was no statistical difference between the results of the two regimens it is concluded that the larger dose of amoxycillin plus probenecid is required where only 60% of gonococci are sensitive to amoxycillin.

Amoxicillin↗