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Biomedical subjects

S W Newsom

Publications and source records attributed to S W Newsom.

At least 19 recordsLinked to original sources
PubMed1991

The clinical use of an antibiotic-bonded graft.

Attempts to produce an antibiotic-bonded prosthesis have failed owing to poor binding, drug toxicity or inadequate antimicrobial activity of the antibiotic particularly against Staphylococcus epidermidis. Rifampicin, with an ideal spectrum, but untested against slime-forming S. epidermidis has recently been shown to bind with carboxyl groups on gelatin-sealed Dacron. We therefore investigated rifampicin activity against 30 slime-forming adherent S. epidermidis colonies, isolated from 40 consecutive aortic graft recipients, and compared it with their methicillin, gentamicin, cefuroxime, tetracycline and vancomycin resistance patterns. The S. epidermidis colonies were highly sensitive to very low levels of rifampicin. Rifampicin was then bonded to gelatin-sealed Dacron aortic prostheses which were inserted in four patients at high risk of developing subsequent infection.

Aged↗
PubMed1990

Hygienic hand disinfection tests in three laboratories.

A comparative study was made in three laboratories of a test for hygienic hand disinfection. Staphylococcus aureus was applied to the fingertips of a total of 74 volunteers (49 female and 25 male) and the effect of washing with three chlorhexidine preparations and one non-medicated soap was assessed after one and five applications. Fingertip inoculation is convenient and is a realistic representation of the in-use situation. Although significant differences were obtained between log10 reductions in test organisms using the same formulation in different centres, and different periods in the same centre, the maximum differences after a single application of a preparation were small, e.g. between centres 0.39 and between periods in the same centre 0.55, and after multiple applications the maximum difference between centres was 0.42 and between periods in the same centre it was 0.51. The differences between preparations were similar in all centres. This test compares well with other similar tests and products can be placed in rank order of effectiveness. It is concluded that this test, if carried out under the controlled conditions described, is sufficiently reproducible between laboratories and repeatable within laboratories to be used as a standard test.

Chlorhexidine↗
PubMed1990

In vitro activity of ramoplanin on staphylococci.

Approximately 1000 strains of staphylococci isolated from the skin of patients before and after coronary artery by-pass surgery were speciated using the API-Staph system, and tested for susceptibility to ramoplanin and teicoplanin. In addition flucloxacillin MICs were available for 750 strains. MICs were performed by incorporating dilutions of antibiotics in 'Isosensitest' Agar (Oxoid) and applying approx 10(4) cells by a multi-point inoculator. The strains tested (numbers in brackets) included: Staph. epidermidis (352), Staph. haemolyticus (133), Staph. simulans (104), Staph aureus (69), Staph. hominis (54), Staph. warneri (39), Staph. capitis (23), Staph. saprophyticus (12), Staph. cohnii (6) and Staph. sciuri (2). The overall MICs were: ramoplanin MIC 50%: 0.5 mg/l, MIC 90%: 1 mg/l; teicoplanin MIC 50%: 2 mg/l, MIC 90%: 8 mg/l. Ramoplanin MICs of greater than 2 mg/l were only found for 17 strains from eleven patients which included: Staph. simulans (6), Staph. haemolyticus (4) and Staph. epidermidis (2). The maximum MIC however was only 8 mgl, so no strains were ramoplanin-resistant. There was no relationship between ramoplanin and flucloxacillin MICs; but despite their differing modes of action, the strains with higher ramoplanin MICs also had higher teicoplanin MICs.

Anti-Bacterial Agents↗
PubMed1989

Application of the hygienic hand-disinfection test to the gloved hand.

The Austrian Standard Hygienic Hand-Disinfection Test was adapted for comparing the effect of washing artificially contaminated hands (using Escherichia coli) with contaminated gloved hands, using liquid soap and rinsing with water. Tests showed that a single soap wash completely removed all the bacteria from the glove, and was more than 1000 times more effective on the glove than on the hand.

Escherichia coli↗
PubMed1989

Penetration of enoxacin into lung tissue.

For a study of penetration of enoxacin into lung, patients undergoing pneumonectomy were given 400 mg by mouth the night before and again approx 2 h before operation. A blood sample was taken as the lung was excised. Lung and serum enoxacin concentrations were assayed by high pressure liquid chromatography. Results from 15 patients showed that enoxacin was concentrated in the lung. Enoxacin lung concentrations were 3.2-13.1 mg/l, and ratios of lung to serum concentrations were 3-6 (mean, 4.2).

Adult↗
PubMed1988

Studies on perioperative skin flora.

Chlorhexidine in spirit is used to reduce the skin bacterial load before surgery; and recently prewashing with chlorhexidine scrub has been advocated. We describe three studies on cardio-thoracic surgical patients--particularly those having coronary artery grafts with long leg and sternal wounds. Two studies compared prewashes with chlorhexidine scrub (Hibiscrub-ICI) or soap. Study Number One (250 patients per group) was of wound infections; and Number Two (25 patients per group) was of alterations in skin flora for 10 days postoperation. Chlorhexidine scrub failed to reduce overall wound infection rates in Study 1, although leg wounds healed more quickly with less inflammation. Study Two showed that the scrub had a significant effect on skin flora that lasted at least 3 days postoperation. Study Number Three was of 100 patients (no chlorhexidine scrub) examined for methicillin-resistant coagulase-negative staphylococci (MRSE) by cultures of swabs from the leg, sternum and chest drain site before and after operation on methicillin agar. Three per cent of patients had MRSE preoperation (1 doctor) and 23% postoperation. One thousand strains were tested by agar dilution against methicillin and chlorhexidine. MRSE had a 2-8-fold increased resistance to chlorhexidine compared to a greater than 256-fold to methicillin. Thus although chlorhexidine has a marked persistent effect on skin flora, emergence of major resistance is unlikely. Use of postoperative chlorhexidine should be investigated further.

Bacteria↗
PubMed1988

What is in the surgeon's glove?

Three aspects of surgical hand hygiene have been studied: the attitude of the surgeon, the microbiology of glove changing during an operation, and the use of antiseptic-coated gloves together with different handwash routines. The survey revealed that the predominant factor in choice of agent for surgical hand hygiene was skin tolerance. The microbiological studies showed that 'closed' glove changing was to be preferred to 'open' changing, and that antiseptic-coated gloves further suppressed the skin flora, even after prolonged operations, compared to standard gloves.

Anti-Infective Agents, Local↗
PubMed1987

Hot air electric hand driers compared with paper towels for potential spread of airborne bacteria.

Hot air hand driers are increasingly used in both public areas and hospitals, but there is little literature on their bacteriology. Four units were examined by comparing the bacterial aerosols released from hands during use by sets of twelve subjects with those released by paper towels. Tests on two units also included hand imprints on agar plates for detection of residual bacteria. No significant difference between aerosols liberated by towels and driers were observed for two units, while the other two generated significantly fewer aerosols than towels. Impression plates revealed similar numbers of bacteria on the hands after drying by either method. Hot air hand driers appear safe from a bacteriological viewpoint.

Air Microbiology↗
PubMed1987

Evaluation of dishwashing machines in four hospitals.

Fifteen dishwashing machines tested in four different hospitals failed to satisfy the minimum heat treatment requirement of 82 degrees C for 2 min for satisfactory thermal disinfection. The causes of failure included design faults in the machines with lack of time temperature controls, hard water supply, inadequately treated water, improper softening and inadequate preventative maintenance.

Enterococcus faecalis↗
PubMed1987

Intraventricular vancomycin for treatment of shunt-associated ventriculitis.

Twenty episodes of shunt-associated ventriculitis caused by staphylococci or streptococci were treated with intraventricular vancomycin together with removal of the shunt and insertion of an external drain. Systemic antibiotics given concurrently included intravenous vancomycin or flucloxacillin. All the patients responded to therapy although five had re-infections and one had a relapse. Four patients were treated solely with intrathecal vancomycin. We now use intraventricular vancomycin alone for 'blind' treatment of uncomplicated shunt-associated infections when Gram-positive cocci are seen in the ventricular CSF.

Adult↗
PubMed1986

A comparative study of ciprofloxacin and trimethoprim in the treatment of urinary tract infections in geriatric patients.

A prospective, comparative clinical trial of ciprofloxacin (100 mg bd) versus trimethoprim (200 mg bd), both for five days, was carried out in 40 geriatric patients with urinary tract infection. Thirty-two could be assessed for drug efficacy, and all forty for toxicity studies. Both drugs were equally safe, and ciprofloxacin was at least as effective as trimethoprim as far as clinical response was concerned. Ciprofloxacin appeared more effective in eradication of bacteria. Antibacterial activity was found in urine and faeces up to five days after stopping ciprofloxacin therapy.

Aged↗
PubMed1985

Studies on the use of povidone-iodine with the 'hygienic hand disinfection' test.

The DGHM test for hygienic hand disinfection is based on that of Rotter et al. (1980), and compares the ability of a test agent with 60% isopropanol to reduce Escherichia coli counts on artificially contaminated fingers using 15 volunteers. The test was performed seven times--three with 10% povidone-iodine (PVP-I) scrub, three with 10% PVP-I solution and once with 5% PVP-I solution. Initial tests with PVP-I scrub ('Betadine') gave comparable results with the iso-propanol, but the latter gave an activity below that normally expected, and specified in the Austrian standard (but not in the DGHM test). A repeat test with greater attention to detail gave similar activity with the scrub, but markedly greater activity from the iso-propanol so that the PVP-I scrub failed the test. Subsequent tests with four aqueous PVP-I solutions showed that all passed the tests with activity marginally greater than that of iso-propanol. Interestingly enough, two German formulations of PVP-I solution showed almost identical activity.

1-Propanol↗
PubMed1985

Aerobiology of irradiation with the carbon dioxide laser.

The ability of a carbon dioxide laser to scatter debris and aerosolize bacteria from human skin was tested by collecting the aerosols liberated with glass impingers together with a slit sampler. Two sets of tests were done--one to detect dispersal of cells from treatment of rodent ulcers or warts, and the other on pieces of skin obtained from autopsy material, which had been injected with spores. With low power levels a few bacterial particles were collected, together with some whole cells, however, at levels greater than 750 W cm-2 all the cultures were sterile.

Aerosols↗