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Biomedical subjects

S Selwyn

Publications and source records attributed to S Selwyn.

At least 55 records · Page 3Linked to original sources
PubMed1978

Mecillinam.

Explore the source record for details and available documents.

Amdinocillin↗
PubMed1978

Quantitative studies on competitive activities of skin bacteria growing on solid media.

Earlier quantitative investigations of antagonism between skin bacteria were based on the use of liquid cultures, but a more realistic model has now been devised, based on the use of the surfaces of solid media. Pure or mixed inocula were spread evenly over suitable agar media in Petri dishes marked out with a standard grid. Growth curves were constructed from viable counts of the surface bacteria after they had been removed from excised squares of the agar media and dispersed. The method was highly reproducible, and competitive interactions were revealed more clearly than in studies with liquid media. An antibiotic-producing strain of Staphylococcus epidermidis (S6+) readily suppressed strains of Micrococcus, Corynebacterium and Streptococcus species. However, a Staphylococcus aureus strain which was less sensitive to the antibiotic effect of S6+ interacted in a complex manner, depending on the absolute and relative size of the S6+ inoculum.

Agar↗
PubMed1977

Successful bone marrow transplant for Fanconi's anaemia.

A 15-year-old boy with Fanconi's anaemia, who required four units of blood each month, received a bone marrow graft from his 9-year-old brother, who has HLA identical and compatible on mixed lymphocyte reaction. Considerable immunosuppression was used and bacterial infection was prevented by vigorous decontamination in a Vickers-Trexler isolator. After the graft the patient's blood counts remained satisfactory for nine months, but it took six months before qualitative immune function was normal.

Adolescent↗
PubMed1977

Studies on antagonism between human skin bacteria.

Antagonism by an antibiotic-producing Staphylococcus epidermidis strain (S6+) against other bacteria was studied semi-quantitatively on solid media and quantitatively in liquid batch culture. Parallel experiments were performed with a similar but non-antibiotic producing strain (S6-). On solid media strain S6+ in the logarithmic growth phase unilaterally inhibited members of all gram-positive species tested, whereas S6- had no effect. In liquid media, more complex interactions were observed, including mutual and reversed antagonisms. The relevance of these findings to the ecology of human skin is discussed.

Anti-Bacterial Agents↗
PubMed1977

Continuous-culture studies of interactions among human skin-commensal bacteria.

Chemostat studies were made of an antibiotic-producing Staphylococcus epidermidis strain (S6+), a similar, but antibiotic non-producing S. epidermidis strain (S6-), and a sensitive indicator strain of Micrococcus sp. (M7). Pure and mixed continous cultures were investigated at low population levels (in 0-1% peptone water) and at higher levels (in 0-5% peptone water). Strain S6+ antagonised the growth of strain M7 when its colony count was maintained above 10(7-0) per ml, while strain S6- remained unaffected.

Anti-Bacterial Agents↗
PubMed1977

Evaluation of Vickers-Trexler isolator in children undergoing bone marrow transplantation.

Four children, 5 months to 15 years of age, underwent bone marrow transplantation in Vickers-Trexler isolator tents. Two grafts were elective. During 170 days of isolation no clinical infections due to exogenous micro-organisms developed despite severe immunodeficiency. The decontamination regimen and sterile procedures used, as well as the microbiological results, are described. This form of isolation in paediatric practice was found to be highly acceptable to both patients and staff.

Adolescent↗
PubMed1976

Rational choice of penicillins and cephalosporins based on parallel in-vitro and in-vivo tests.

Because of the unavailability of strictly comparable data, seven representative penicillins and the five cephalosporins currently used in Britain were evaluated in parallel, both in vitro and in vivo. Penicillin sensitive and resistant strains of Staphylococcus aureus and Proteus mirabilis were the main test organisms. Minimum bacteriocidal concentrations of cloxacillin, flucloxacillin, cephalothin, and cephazolin in serum were much higher than conventional minimum inhibitory concentrations in the absence of serum. Cephalexin and cephradine showed the smallest divergence in these values. Staph, aureus beta-lactamase caused least damage to methicillin and cephradine, whereas enzymes from Escherichia, Klebsiella, and Bacillus cereus had least effect against cephradine followed by cephalexin. In mouse protection experiments, highly protein-bound antibiotics had relatively low efficacy. Cephradine had the highest mean activity followed closely by cephaloridine and cephalexin. From the data, cephradine was the cephalosporin of choice, and firm decisions were also made about the choice of penicillins.

Animals↗