Attempts to control clothes-borne infection in a burn unit. I. Experimental investigations of some clothes for barrier nursing

An in vitro assessment of bacterial transfer by products used in debridement

OBJECTIVE

The aim of this in vitro study was to investigate the transfer of viable Pseudomonas aeruginosa biofilm microorganisms following treatment with debridement tools.

METHOD

The level of viable biofilm microorganisms transferred by debridement tools was compared following treatment that reflected the clinical practice of each product.

RESULTS

A significant level of microorganism transfer was seen in response to the mechanical debridement tool. Minimal transfer of microorganisms was seen when in vitro-established biofilms were treated with hydroresponsive wound dressing + polyhexamethylene biguanide (HRWD+PHMB, HydroClean plus). Less Pseudomonas aeruginosa was recovered from explants exposed to dressings compared with those exposed to debridement tools suggesting that there was less transfer of bacteria by dressings.

CONCLUSION

The reduced transfer of viable microorganisms by HRWD+PHMB may be the result of significant binding and retention of microbes by the superabsorbent polymer within the dressing, together with enhanced sequestered bacterial killing within the dressing by polymer-bound PHMB. The high levels of microbial transfer/transmission seen for debridement tools suggests that, in the clinical setting, a significant level of bacterial spread over the wound surface and/or surrounding skin by these cleansing tools is likely.

UniStatus - a cross-sectional study on the contamination of uniforms in the Danish ambulance service

Background

Patients are at risk of contracting infections due to the presence of disease-causing microorganisms that can be transmitted from the medical staff’s uniforms to the patient. The dual purpose of this study was to examine the contamination level of the uniforms worn by ambulance staff after a shift and to test the effect of washing of the uniform with and without a detergent containing acetic peroxide.

Methods

This was a cross-sectional study in which 30 ambulance staff uniforms were randomly selected for inclusion and divided into two groups. Before washing, 90 prints were performed with specific agar plates to determine bacterial contamination and to establish the prevalence of a variety of microorganisms. Group A uniforms were washed with a detergent without acetic peroxide; Group B uniforms were washed with a detergent containing acetic peroxide.

Results

Before washing, the 90 prints had an average colony-forming units (CFU) of potentially pathogenic bacteria of 68.89 per 25 cm² and a prevalence of: E. coli and Pseudomonas 0%, Bacillus cereus 27.78% (CI 95% ± 9.80), Clostridium and Enterococcus 2.22% (CI 95% ± 1.96), Staphylococcus aureus 21.11% (CI 95% ± 7.80). After washing, CFU was reduced to 3.09 (CI 95% ± 5.04) per 25 cm² in Group A and to 1.47 (CI 95% ± 4.77) per 25 cm² in Group B. The prevalence of specific bacteria in either group was 0%, except for S. aureus which had a prevalence rate of 4.40% (CI 95% ± 6.10) in Group A. The difference between the contamination degrees of the two groups was not significant in either test (p > 0.05).

Conclusion

Potentially pathogenic bacteria are detectable on ambulance staff uniforms when a shift ends. Optimal prevention of bacterial infection may be achieved by daily changing, washing at a minimum of 60 degrees Celsius and use of a detergent containing acetic peroxide.

Comparison of bacteria on new, disposable, laundered, and unlaundered hospital scrubs

BACKGROUND

As a cost-saving measure, an increasing number of hospitals allow personnel to launder their uniforms, lab coats, and operating room scrubs at home. With rising nosocomial infection rates and increasing levels of multidrug-resistant bacteria in hospital settings, uniform contamination may be an environmental factor in the spread of infection.

METHODS

We quantified the number and identity of bacteria found on swatches cut from unwashed operating room, hospital-laundered, home-laundered, new cloth, and new disposable scrubs.

RESULTS

Of the 29 unwashed hospital operating room scrub swatches analyzed, 23 (79%) were positive for some type of gram-positive cocci, with 3 (10%) of those classified as Staphylococcus aureus, and 20 (69%) were positive for coliform bacteria, 3 of which were Escherichia coli. Home-laundered scrubs had a significantly higher total bacteria count than hospital-laundered scrubs (P = .016). There was no statistical difference in the bacteria counts between hospital-laundered scrubs and unused new and disposable scrubs. In the home-laundered scrubs 44% (18/41) were positive for coliform bacteria, but no isolates were Escherichia coli.

CONCLUSIONS

Significantly higher bacteria counts were isolated from home-laundered scrubs and unwashed scrubs than from new, hospital-laundered, and disposable scrubs.

Nursing and physician attire as possible source of nosocomial infections

BACKGROUND

Uniforms worn by medical and nursing staff are not usually considered important in the transmission of microorganisms. We investigated the rate of potentially pathogenic bacteria present on uniforms worn by hospital staff, as well as the bacterial load of these microorganisms.

METHODS

Cultures were obtained from uniforms of nurses and physicians by pressing standard blood agar plates at the abdominal zone, sleeve ends, and pockets. Each participant completed a questionnaire.

RESULTS

A total of 238 samples were collected from 135 personnel, including 75 nurses (55%) and 60 physicians (45%). Of these, 79 (58%) claimed to change their uniform every day, and 104 (77%) defined the level of hygiene of their attire as fair to excellent. Potentially pathogenic bacteria were isolated from at least one site of the uniforms of 85 participants (63%) and were isolated from 119 samples (50%); 21 (14%) of the samples from nurses' gowns and 6 (6%) of the samples from physicians' gowns (P = NS) included of antibiotic-resistant bacteria.

CONCLUSION

Up to 60% of hospital staff's uniforms are colonized with potentially pathogenic bacteria, including drug-resistant organisms. It remains to be determined whether these bacteria can be transferred to patients and cause clinically relevant infection.

Aspectos de biossegurança relacionados ao uso do jaleco pelos profissionais de saúde: uma revisão da literatura

O estudo objetivou analisar a literatura publicada a respeito dos aspectos da biossegurança relacionados ao uso do jaleco pelos profissionais da saúde. Trata-se de uma revisão narrativa da literatura publicada no período de 1991 a 2008. Utilizou-se as bases de dados MEDLINE, LILACS e SciELO, sendo selecionados 22 artigos que foram agrupados para análise considerando os enfoques priorizados em: infecções cruzadas causadas por jalecos; jalecos contaminados; flora bacteriana em jalecos dos profissionais de saúde. O jaleco foi abordado como fonte de contaminação e como equipamento de proteção individual na prevenção das infecções. Portanto, são necessárias campanhas educativas no sentido de orientar os profissionais de saúde sobre o uso de jaleco.

Bacterial flora on the white coats of medical students

This study has demonstrated that the white coats of medical students are more likely to be bacteriologically contaminated at points of frequent contact, such as the sleeve and pocket. The organisms identified were principally skin commensals including Staphylococcus aureus. The cleanliness of the coat as perceived by the student was correlated with bacteriological contamination, yet despite this, a significant proportion of students only laundered their coats occassionally. This study supports the view that the students' white coat is a potential source of cross infection on the ward and its design should be modified in order to facilitate hand washing. Hospitals training medical students should consider taking on the burden of providing freshly laundered white coats for the students.

An investigation of occlusive polyester surgical clothing

The bacterial dispersion rate of people wearing operating room clothing made from several types of polyester fabric was compared to conventional cotton clothing, total-body exhaust gowns and disposable clothing. Airborne bacteria were measured in a chamber, three ultra-clean air operating rooms and a conventionally ventilated operating room. The polyester clothing was demonstrated to be much superior to conventional cotton clothing and at least as good as the total-body exhaust gowns and disposable clothing.

The dispersal of bacteria and skin scales from the body after showering and after application of a skin lotion

Application of a skin lotion to the body after showering greatly reduced the number of bacteria and skin scales dispersed from 10 men and 10 women. This effect lasted for at least 4 h when surgical clothing was worn. The use of a skin lotion to reduce bacterial dispersal could provide a simple and inexpensive alternative to an ultraclean air system or uncomfortable operating clothing during surgery requiring these procedures.

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.

Isolation efficiency and its clinical importance in patients with burns

Nine severely burned patients were submitted to reverse isolation in a mass airflow system. Their burns became colonized by Enterobacteriaceae biotypes which were not found in the patients own flora on admission. They were, therefore, probably derived from the food which was obtained from the central kitchen. These strains did not cause bacteriaemia. Suggestions to improve the isolation efficiency are made.

The evaluation of fabrics in relation to their use as protective garments in nursing and surgery. III. Wet penetration and contact transfer of particles through clothing

A method is described for comparing the resistance to penetration by aqueous fluids, under rubbing contact, of a representative series of fabrics. Untreated woven fabrics are rapidly penetrated, but some non-woven synthetic materials resist penetration for much longer and tightly woven proofed cotton fabrics for prolonged periods, even after repeated washing and sterilizing. If a wetting agent is added to water, penetration occurs more quickly, but fabrics containing natural cotton are penetrated more slowly by serum. The same fabrics were examined by a test designed to simulate transfer of dry particulate material, e.g. skin scales, through them during nursing contact. The proportionate differences observed were much greater than for air dispersal during exercise and closely resembled those obtained by a laboratory rubbing test. In particular, one of the non-woven fabrics showed much greater relative penetration when examined by these methods than the relative dispersal of skin scales through it during exercise.

Attempts to control clothes-borne infection in a burn unit, 2. Clothing routines in clinical use and the epidemiology of cross-colonization

Previous investigations have shown that cross-contamination in a burn unit is mainly clothes-borne. New barrier garments have been designed and tried experimentally. The aim of the present study was to investigate the effects of different clothing routines on cross-contamination. In a long-term study, the rates and routes of colonizations with Staphylococcus aureus, Streptococcus groups A, B, C, F, and G and Pseudomonas aeruginosa were examined. The exogenous colonization rates were, with S. aureus 77%, with Streptococcus species 52% and with Ps. aeruginosa 32%. The colonization rate with Ps. aeruginosa was higher in patients with larger burns. Patients dispersed Streptococcus and Ps. aeruginosa as well as S. aureus into the air of their rooms in considerable amounts, but dispersers were not more important as sources of cross-colonization than non-dispersers. In comparison of clothing routines, there was no difference in overall colonization rates. The newly designed barrier garment that was made from apparently particle-tight material did not reduce the transfer of bacteria from patient to patient. A less rigid routine than that previously used did not increase the risk of cross-contamination. A thorough change of barrier dress after close contact nursing delayed the first exogenous S. aureus colonization from day 6 to day 14 after admission. This routine might be recommended for clinical use. Otherwise, methods must be developed for adequate selection of materials intended for barrier garments.

An instrument for measuring bacterial penetration through fabrics used for barrier clothing

A new instrument has been designed to measure the penetration by rubbing of bacteria from cloth contaminated in the nursing of burn patients through fabrics designed for barrier garments. Most fabrics tested dry reduced the transfer of bacteria from the source cloth to about 10%, irrespective of the results of air filter tests, which agrees with mock nursing results. When the fabrics were tested against a wet surface, the transfer of bacteria rapidly reached 100% if the fabrics had a high wettability, but was slower for fabrics with a low wettability. Through closely woven waterproofed cotton, transfer was 5--25%, but increased three- to four-fold after ten launderings, in line with the water absorption. Transfer through plastic-laminated material was less than 1%. The results suggest that barrier garments should be made either of plastic or of recently waterproofed closely woven cotton at points of contact between nurse and patient where the clothes may be wetted by bacteria-containing wound secretions.

Attempts to control clothes-borne infection in a burn unit, 3. An open-roofed plastic isolator or plastic aprons to prevent contact transfer of bacteria

An open-roofed plastic isolator was built in a single patient isolation room in a burn unit. It was designed to prevent contact contamination only, as this had been shown to be the important route of cross-colonization in the unit. To exclude any possible effect on airborne transfer of bacteria, the isolator was first examined by means of an airborne particle tracer of the same size as bacteria-carrying particles. Such experiments indicated that the isolator might prevent some transfer out of but not into the isolator. This was not confirmed in simulated nursing experiments nor in a patient study, where the air counts of bacteria were practically the same inside and outside the isolator wall. Two patients only were nursed in the isolator. Both patients acquired exogenous colonizations from other patients, one with Ps. aeruginosa and the other with S. aureus. Nursing in the isolator was difficult and staff-demanding. In simulated nursing experiments, plastic aprons and gauntlets as the only protective measures against contact contamination gave as much protection to a mock patient as did the isolator. S. aureus were released from nurses' clothes more easily during work with the isolator than in open nursing with aprons and gauntlets. In conclusion, the isolator did not seem to be a realistic alternative to impermeable clothes such as plastic aprons as a means of preventing clothes-borne cross-contamination between burn patients.

A garment for use in the operating theatre: the effect upon bacterial shedding

In operating theatres the air is mainly contaminated with bacteria shed from the human skin. The emission of bacteria can be prevented by wearing clothing of impervious material, while normal cotton clothing does not decrease the shedding of bacteria. In this study shedding of viable bacteria from 20 test-persons wearing an operating theatre suit, composed of 65% polyester and 35% cotton (Diolen), was investigated in a test-chamber and compared with that when normal clothing was worn. The use of this operating-theatre suit resulted in a significant reduction (50--75%) in the number of bacteria-carrying particles in the air of the test-chamber and in an operating room when everyone present wore this suit. A combination of the suit with knee-high boots showed a further reduction in the dispersal of colony forming units. The dispersion from female subjects wearing an operating-theatre frock was significantly higher than when wearing an operating-theatre suit.

The evaluation of fabrics in relation to their use as protective garments in nursing and surgery. II. Dispersal of skin organisms in a test chamber

The effectiveness of a representative range of fabrics in restricting dispersal through them of dry skin-borne bacteria has been examined. The fabrics were tested made up into trousers which were worn by volunteers during standardized exercise in a test chamber operated within a unidirectional flow clean-air room. Under these conditions, with careful attention to sealing at ankles and waist, it was possible to estimate penetration as low as 0.3%. Penetrations as low as 1% were observed with some synthetic fabrics. These had a relatively high surface resistivity and developed significant electrostatic charges. When the observed values for penetration were compared with the results of a series of measurements and tests made on the fabrics it was clear that the correlation between these values and the other results was in every case very close for all the five woven cotton or cotton terylene fabrics but that no measurement or test was capable or predicting the behaviour of all the other materials in dispersal experiments. The inherent variability of dispersal experiments seems to be very great. With a standard deviation of the approximately log-normal distribution of the experimental values as high as about 2 times the mean, it is necessary to carry out as many as 20 replicate experiments in order to differentiate with certainty between garments with a two-fold difference in penetration.