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Biomedical subjects

J R Babb

Publications and source records attributed to J R Babb.

At least 37 records · Page 2Linked to original sources
PubMed1991

A test procedure for evaluating surgical hand disinfection.

A technique for assessing the immediate and prolonged efficacy of surgical scrubs and alcoholic hand rubs is described. A mean baseline count is obtained from all volunteers and logarithmic reductions in resident skin flora immediately after one or more applications, and after wearing gloves for 3 h, are measured. Loose-fitting surgical gloves are used for sampling resident flora. Preparations were applied using a standard technique for 2 min, apart from one test with 70% isopropanol (IPA) in which the application time was 30 s. Two studies are described, one of which compared four chlorhexidine scrubs, and the second 70% IPA, 7.5% povidone-iodine scrub, 2% triclosan cleanser and unmedicated bar soap. In spite of their constituent similarity, the four chlorhexidine scrubs varied considerably in efficacy and user acceptability. A 2 min application of 70% IPA was the most effective treatment, and gave log10 reductions of 1.65 for immediate and 1.58 for prolonged effect. This was marginally more effective than a 30 s application, but the difference was not significant. 'Hibiscrub' was the most effective aqueous formulation and gave reductions of 1.01 for immediate effect and 1.16 for prolonged effect. The test described could be used by reference centres and manufacturers to assess the efficacy of new and existing surgical hand disinfection formulations.

Adolescent↗
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↗
PubMed1989

Bacteriological sampling of postmortem rooms.

Thirty hospital and coroners' postmortem rooms in the West Midlands were visited over two years. The design, environmental facilities, and hygienic practices were investigated and air exchange rates were measured. Microbiological samples were taken from the environment and from gloves, hands, and protective clothing of staff. Glove punctures were also recorded and a plastic isolator evaluated. Bacterial counts in the air were low and related more to the number of people in the room than to the air exchange rate. There was little evidence of the production of aerosol containing bacteria, although splashing occurred while intestines were being washed out. Surfaces often remained contaminated with Gram negative bacilli after cleaning but numbers were considerably reduced on drying. Decontamination of instruments was satisfactory. A wide range of disinfectants and concentrations was used, but none showed evidence of contamination. Gloves were heavily contaminated after use, and occasionally the hands of the wearer after removal of the gloves. Washing the hands effectively removed residual transient organisms, irrespective of the agent used. The incidence of glove punctures was higher among technicians (38%) than pathologists (12%). The plastic isolator reduced smells and limited environmental contamination but visibility and acceptability were poor. The results of the study suggest that there is little evidence of risk of infection to staff, providing basic hygienic precautions are taken, but consideration should be given to the prevention of glove punctures.

Air Microbiology↗
PubMed1988

Hand disinfection: a comparison of various agents in laboratory and ward studies.

The efficacy of 14 handwashing or disinfectant preparations was compared in laboratory tests on staff volunteers. The test organism, Escherichia coli, was applied to the fingertips and log reductions (LR) were measured following treatment with the test agent and control preparations (70% isopropanol and non-medicated bar soap). Alcoholic preparations, particularly n-propanol and isopropanol were the most effective showing LRs of 3.1-3.8. Chlorhexidine (LR 2.9) and povidone-iodine detergent preparations were significantly more effective than non-medicated soap (LR 2.1), but triclosan products were not. In addition the residual effect of several of these formulations was assessed after 10 applications by comparing the survival of E. coli on the fingertips over a 32-min period. This number of handwashes compares favourably with those recorded during an 8 h nursing shift. Chlorhexidine-detergent consistently showed the best residual activity. Alcoholic formulations showed little or no residual effect. The survival studies show that on the whole gram-positive organisms (Staphylococcus aureus and Candida albicans) survive better on the skin than Gram-negative bacilli (GNB). However, it would seem that GNB which are considered to be residents (Acinetobacter calcoaceticus and Enterobacter spp.) survive much better than many other GNB (Pseudomonas aeruginosa, E. coli and Proteus vulgaris). The Klebsiella species varied in survival times. Random sampling of ward staff hands showed that contamination with S. aureus and GNB was greater in dermatological and general wards than in an isolation unit, where handwashing or disinfection was carried out after every patient contact. No cross-infection occurred in the isolation ward during periods of study in which 70% alcohol, chlorhexidine-detergent and non-medicated soap were used.

Alcohols↗
PubMed1988

Methods of reprocessing complex medical equipment.

The choice as to which of the two gaseous processes is best suited to individual hospital needs is a difficult one. Very few items are unable to tolerate 73 degrees C (LTSF) and these few can withstand 37 degrees C or 55 degrees C (EO). Unfortunately, LTSF is a 'moist' process and sterilizers have a poor history of providing sterilization without modification, and consequently few are used. Ethylene oxide is more reliable, but environmental hazards are greater and running costs high. Both processes are time-consuming and the use of sporicidal disinfectants such as glutaraldehyde is often the only practical alternative. Before purchasing any gaseous sterilizer it is essential to consider throughput and the availability of alternative processes. It may prove sensible to share facilities or at least offer a regional facility. It is certainly not worthwhile purchasing expensive gas sterilizers for reprocessing inexpensive single-use items or for those that require disinfection only. Low temperature steam is safe, inexpensive and no special environmental provisions are necessary. It is, however, not a sterilization process. Disinfectants, hot water and steam will continue to be the only suitable methods for reprocessing items outside the hospital sterile supply department or disinfection unit. Concern over the decontamination of blood-stained instruments following use on patients with hepatitis B or HIV has led to an upsurge of interest in boilers and inexpensive bench top ovens and autoclaves. Such processes are likely to prove more effective than disinfectants but should heat treatment prove impractical then 2% glutaraldehyde or 70% alcohol may be used.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
PubMed1986

An outbreak of candidiasis in a special care baby unit: the use of a resistogram typing method.

An outbreak of candida infections involving 12 neonates in a special care baby unit is reported. An investigation of colonization of all the babies in the unit was made together with the sampling of the environment and hands of staff. Resistogram typing of isolates indicated the presence of several strains with probable cross-infection. Transmission was possibly by the hands of staff, but multiple antibiotic therapy may have played a role in the increased incidence of infection in the unit.

Candida albicans↗
PubMed1986

Evaluation of procedures for hygienic hand-disinfection: controlled parallel experiments on the Vienna test model.

Controlled parallel experiments were performed on the Vienna test model for the evaluation of procedures for hygienic hand-disinfection in three laboratories (Vienna, Mainz, Birmingham). The degerming activity of four procedures, each taking 1 min, was assessed repeatedly and compared with that of a standard disinfection procedure (ST) using isopropanol 60% (v/v). The mean log reductions (mean log RF) for each procedure were as follows: n-propanol 50% (v/v) 4.85 and 5.14 in Vienna (V) and Mainz (M) respectively, ethanol 70% (v/v) + chlorhexidine-gluconate 0.5% (w/v), 4.01 (V), 3.76 (M) and 4.00 in Birmingham (B). Washing procedures were less effective, mean log RF's of 3.19 (V), 3.49 (M) and 3.04 (B) were obtained with povidone-iodine soap, and 2.91 (V), 3.37 (M) and 3.27 (B) with a liquid phenolic soap. Analysis of variance on the data from Vienna and Mainz revealed significant differences of means not only between procedures ('preparations') but also on repeat testing. To compensate for the influence of variables such as test subjects, laboratory and day, the Vienna test model provides a method of standardization by testing a ST in parallel with the test procedure (P). Standardization of the results was obtained by pair-wise substraction, log RFPi-log RFSTi. Analysis of variance on the resulting values demonstrated that comparability of the results between laboratories and on repeat testing was achieved. The relative variation of the measurements within the laboratories ranged from 0.9 to 4.2%. As assessed by power-analysis, a disinfection procedure will be detected as significantly (P = 0.1) inferior to the standard processes in 95 of 100 experiments if it produces a mean log RF that is at least 0.55-0.65 log units smaller than that of the standard.

Austria↗
PubMed1984

Disinfection of hands and tubing of CAPD patients.

During a 3 month study the effectiveness of two methods of handwashing was assessed in a group of 31 patients undergoing continuous ambulatory peritoneal dialysis. A defined, double rinse with alcohol, prior to bag exchange, was found to be more convenient and significantly more effective than povidone-iodine alone or povidone-iodine followed by alcohol. Spraying the tubing around the bag connector with 70 per cent ethanol reduced the numbers of adherent skin organisms so reducing the likelihood of bacteria being drawn into the dialysate. Although there was no difference in the overall incidence of peritonitis in the two groups of patients studied, there was an unexpected drop in the incidence of peritonitis caused by coagulase-negative skin staphylococci. This was attributed to an overall awareness of the importance of handwashing and aseptic procedures during bag exchange. Monitoring the bacteriology of the catheter exit site may give some prior indication as to the likelihood of subsequent peritonitis especially with Staphylococcus aureus and Gram-negative bacilli.

Catheters, Indwelling↗
PubMed1984

Comparison of automated systems for the cleaning and disinfection of flexible fibreoptic endoscopes.

A comparison of four cleaning and disinfection machines is described. These varied considerably in design and function and although no single machine possessed all the preferred characteristics, cleaning and disinfection, particularly between patients, was substantially improved. Before purchasing a machine it is recommended that the user ensures that it is convenient to operate, effective in removing soil and bacteria, and adaptable to the range of fibrescopes used within the unit. Infections are often caused by Gram-negative bacilli which are particularly difficult to remove manually from moist narrow channels of the fibrescope and perfusion of all channels including the air channel, is, therefore, recommended. Thorough cleaning and disinfection will not only reduce the likelihood of infection but will also reduce channel blockages and the general deterioration of the fibrescope.

Decontamination↗
PubMed1983

A comparison of pre-operative bathing with chlorhexidine-detergent and non-medicated soap in the prevention of wound infection.

In a 60-week cross-over study on 5536 patients in 20 wards of three city hospitals (two general and one orthopaedic), pre-operative bathing with chlorhexidine-detergent failed to influence the incidence of postoperative infection, in spite of the relatively high incidence of infection with skin organisms. Of the patients bathing pre-operatively with chlorhexidine-detergent, 5.4 per cent subsequently became infected (4.0 per cent of clean wounds) and of those bathing with unmedicated soap 4.9 per cent (3.5 per cent of clean wounds). A single pre-operative bath with chlorhexidine-detergent would, therefore, appear to be of dubious value in preventing postoperative wound infection.

Baths↗
PubMed1983

Contamination of protective clothing and nurses' uniforms in an isolation ward.

Staphylococcus aureus was frequently isolated, usually in small numbers, from cotton gowns (12.6 per cent), plastic aprons (9.2 per cent) and nurses' uniforms (15 per cent). Gram-negative bacilli were infrequently isolated. Contamination of the protective clothing did not increase when used over periods of up to 11 days. Fewer organisms were recovered from the front of nurses' uniforms when plastic aprons instead of gowns were worn, but gowns provided better shoulder protection. However, no differences were observed in isolations of Staph, aureus or Gram-negative bacilli from these sites.

Cross Infection↗
PubMed1983

Evaluation of an ethylene oxide sterilizer.

Ethylene oxide gas can be used under controlled conditions to sterilize heat and moisture sensitive articles, particularly those which cannot be steam sterilized or immersed in disinfectants. The ethylene oxide process is essentially one of sterilization and all micro-organisms, including bacterial spores, are destroyed.

Equipment and Supplies, Hospital↗