Steel Grab Bars: Transmitters of Nosocomial Infections.
The prevalent use of steel grab bars with porous, microbe-hosting surfaces combined with unacceptably low hand-hygiene compliance rates of care-givers may result in significantly higher than expected nosocomial infection rates in healthcare facilities.
BACKGROUND:
Two million people each year become ill as the result of hospital-acquired nosocomial, infections. According to a 1992 study, nosocomial infections struck up to two million patients annually, contributed to the death of nearly 90,000 hospital patients per year, and resulted in $4.5 billion in avoidable medical expenses1. In the last two decades, the rate of nosocomial infections per 1000 patient days rose by 36%—climbing from 7.2 in 1975 to 9.8 in 19952. Of particular interest to medical administrators should be a 2003 study that utilized national data and a case-control matching method to control DRG, sex, race and comorbidity to calculate that the average excess costs attributable to the national indicator “selected infection due to medical care” are $38,656 per occurrence3.
Although CDC guidelines state that hand washing is the single most important procedure to prevent nosocomial infection, studies by Northwestern University4, Temple University5, and the Center for Disease Control and Prevention6 indicate that hospital staff hand washing compliance rates are unacceptable at the average of 40 percent. Efforts to improve hand-hygiene behavior that have focused on broad-based educational and motivational programs have had minimal sustained success. Even increasing the number of conveniently located hand washing stations does not improve the frequency of handwashing7. This suggests two things: (1) improper hand hygiene will continue to be an intractable problem, and (2) the increasing rate of infection underscores the urgent need to investigate every possible microbe incubation site and to take immediate corrective action to reduce or eliminate entirely contributory sites and/or materials.
STUDY RATIONALE
Medical facility toilet rooms in general and patient room toilet facilities in particular, are near perfect sites for the growth of health-threatening microbes which thrive in warm, wet environments that are rich in nutrients. Germs thrive where it is moist, dark, and where there is food to grow and reproduce. Mould growth in poorly ventilated bathrooms is a common occurrence8. Moreover, fecal matter can be found in a variety of places in a restroom since the flushing action of a toilet actually propels droplets containing fecal matter into the air. Contact with bathroom fixtures, especially toilets, toilet seats, tissue holders and the grab bars mounted in close proximity to the toilet, can expose humans to pathogens like E-coli, cryptosporidium, giardia, salmonella, clostridium, and shigella9. Moreover, the shared use of these facilities by staff, patients, and patient visitors results in a human traffic intersection rich in opportunities for the passing of nosocomial infections10.
All healthcare facilities’ toilet rooms have grab bars to comply with national and local building codes. Nearly 100% of those grab bars are made of 18 gauge, type 304 stainless steel and nearly all standard architectural specifications stipulate steel bars. The frequency of observed discoloration, corrosion and rust on steel grab bars in commercial establishments and healthcare facilities caused the investigators to suspect that the steel grab bars could be an underestimated site for microbial growth. A literature review revealed studies incriminating “stainless steel” in microbial growth. One study compared the effectiveness of two disinfectants to a detergent when added to the washing cycle of automatic bedpan washers. “An unexpected and potentially important finding was that polypropylene pans were much more effectively cleaned and decontaminated than their stainless steel counterparts.”11
In another study of bacterial growth on metal, small strips of stainless steel, brass, aluminum, and copper were inoculated with broths of Eschenchia coli, Staphylococcus aureus, Streptococcus group D, and Pseudomonas species. “The broths contained approximately 10,000,000 bacteria/ml, a very heavy inoculum. Then the strips were air-dried for 24 hours at room temperature, inoculated onto blood agar plates, and incubated for 24 hours at 37°C. The results were striking. The copper and brass showed little or no growth, while the aluminum and stainless steel produced a heavy growth of all microbes.”12
Based upon the evidence from other studies that stainless steel is a robust host site for microbe growth, a materials analysis regime was conducted to determine what characteristic(s) of stainless steel makes it a microbe growth site, and what alternative material(s) might be structurally anti-microbial and thus be substituted for steel in products such as grab bars.
MATERIAL TESTING METHODOLOGY:
Virtually all Grab Bars currently installed in healthcare facilities are fabricated from welded 18 Gauge, Type 304 steel and most have a smooth finish referred to as “Satin” by the manufacturers. The smooth “satin” finish is known to be slippery. Many of the bars are shot-blasted, or peened, to make the surfaces rougher with the objective of making them more slip-resistant. The investigators selected satin and peened stainless steel, nylon, and aluminum materials for testing. New unused samples of the steel and nylon grab bar products were purchased from commercial sources. It was necessary to purchase a flat bar sample of anodized aluminum since no source of aluminum grab bars was located. Each of the following specific materials was tested:
· Common satin-finish, 18 Gauge, Type 304 stainless steel grab bar material.
· Rough peened-finish 18 Gauge, Type 304 stainless steel grab bar material.
· Commercial sample of anodized aluminum.
· Polyyamide 6 Nylon grab bar material.
Each of the samples was precisely analyzed for surface roughness and porosity by PM Laboratories utilizing 500x magnification and 440 Series Precision Devices Surfometer applications per ASME B 46.1 to precisely measure porosity and depth of roughness.
PHOTOGRAPHIC TEST RESULT: SATIN FINISH STAINLESS STEEL
Fig.1. New Satin finish 18 gauge Type 304 Steel Grab Bar 500x Magnification. Surface Roughness Ra Value of 20.8 µin.
per ASME B 46.1 measured on 440 Series Precision Devices Surfometer.
Figure 1 above is the untouched photograph of the surface of the test sample Satin finish, 18 gauge Type 304 stainless steel grab bar sample under 500x magnification. The surface roughness value of 20.8 µin evidences a surface of such great porosity as to provide a medium for robust microbial incubation.
PHOTOGRAPHIC TEST RESULT: PEENED FINISH STAINLESS STEEL
Fig. 2. New 18 Gauge, Type 304 Steel Grab Bar with Shotpeened Surface, 500x Magnification. Surface Roughness Ra Value 153.9 µin measured on 440 Series Precision Devices Surfometer.
Figure 2 above is the untouched photograph of the surface of the 18 gauge Type 304 stainless steel grab bar sample with shot-peened finish under 500x magnification. The surface roughness value of 153.9 µin is 7.4 times the roughness of the satin finish steel and clearly presents an extremely robust microbial host site.
It is important to note that grab bars are installed in humid toilet, bath and shower rooms serviced by chlorine treated water which continually deteriorates the grab bar surface. The Stainless Steel Development Association (A.C.N.061 226 051) states: “In warm chloride environments, 304 is subject to pitting and crevice corrosion and to stress corrosion cracking.”13 Consequently, it is inevitable that the porosity of the stainless steel grab bars will increase over time even to the point where the corrosion and oxidation will be visible as rust.
To provide a basis for comparison for the standard steel grab bar appliance which has nearly universal usage, and to attempt to discover a more sanitary and slip resistant alternative, samples of Anodized Aluminum and Nylon materials were examined using the identical evaluation criteria.
PHOTOGRAPHIC TEST RESULT: ANNODIZED ALUMINUM
As illustrated in Figure 3 below, the sample of the Anodized Aluminum proved to be substantially less porous than the Satin Finish and Shotpeened #304 steel products.
Fig.3. Anodized Aluminum Sample 500x magnification. Surface Roughness Ra Value of 11.5 µin per ASME B 46.1 measured on 440 Series Precision Devices Surfometer.
The Anodized Aluminum sample surface roughness measurement value of 11.5 µin is 44.7% less than the surface roughness of Satin finish #304 Steel and 92.5% less than the surface roughness of the Shotpeened #304 Steel Grab bar sample. On the criteria of less porosity, better slip resistance, and better cleanability, the anodized aluminum sample is superior to both Type 304 Stainless Steel samples for grab bar applications, especially in healthcare environments.
Finally, a sample of 3mm Polyamide 6 Nylon cut from a commercially available grab bar was also evaluated for the study. Figure 4 below illustrates the test results:
PHOTOGRAPHIC TEST RESULTS: POLYAMIDE 6 NYLON
Fig.4. Nylon Plastic Bath Accessory Material at 500x magnification. Surface Roughness Ra Value of 2.6 µin per ASME B 46.1 measured on 440 Series Precision Devices Surfometer.
The Surface Roughness Measurement of 2.6 µin for the Nylon Surface is 98.3% less than the measurement for peened steel, 87.5% less that satin steel, and 77.3% less than the aluminum surface. The Nylon surface tested displayed no significant surface porosity resulting in the conclusion that it would not support the growth of nosocomial bacteria.
Grab Bar Materials Conclusions
· Type 304 Steel Grab Bars are very porous and are a robust nosocomial bacterial infection host site.
· Shotpeened Type 304 Steel Grab Bars are the most unsanitary bacterial host surfaces.
· Anodized Aluminum surfaces are significantly less porous than Type 304 Steel, but significantly more porous than Nylon.
· Nylon is a non-porous material that provides the most sanitary anti-microbial material for grab bars. It is also the most slip-resistant due to lack of porosity.
Therefore, the following factors combine to produce virtually ideal sites in healthcare facilities for the growth of pathogens: (a) low staff hand hygiene rates, (b) staff, patient, and visitor use of toilet facilities, (c) warm, humid and dark toilet room environments, and (d) porous-surfaced Type 304 stainless steel grab bars.
RECOMMENDATIONS:
(1) Intensify hand hygiene education programs.
(2) Implement special grab bar sanitizing programs.
(3) Replace Type 304 steel grab bars in existing buildings.
(4) Specify non-porous surfaced grab bars for new construction projects.
Note! Standards for grab bar strength, dimensional requirements and applications are available from:
1. The Hand Hygiene Resource Center is a project of the Saint Raphael Healthcare System and John M. Boyce, M.D. The Center’s mission is to advance the quality of patient care and reduce infection by improving hand hygiene practices in healthcare settings. http://www.handhygiene.org/
2. Weinstein, R.A. “Nosocomial Infection update.” Emerging Infectious Diseases. 1998; 4:416-420.
3. Stone PW, Larson E, Kawar LN. “A systematic audit of economic evidence linking nosocomial infections and infection control interventions: 1990-2000.” American Journal of Infection Control 2002;30:145-52.
4. Lankford MG, Zembower TR, Trick WE, Hacek DM, Noskin GA, Peterson LR. Influence of role models and hospital design on the hand hygiene of health-care workers. Emerg Infect Dis [serial online] 2003 Feb [date cited]. Available from: URL: http://www.cdc.gov/ncidod/EID/vol9no2/02-0249.htm
5. http://www.temple.edu/tuhis/washhands/section01.htm
6. http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5116a1.htm
7. Lankford MG, et. al.
8. “Pervasiveness of Mould Growth in Buildings.” http://www.cdc.gov/nceh/airpollution/mold/stachy.htm#Q2
9. McFadden, Roger. “The Usual Suspects: Microbes, Biohazards and Pathogens” Coastwide Laboratiories, Wilsonville, OR. http://coastwidelabs.com/Technical%20Articles/biohazards.pdf.
10. Black, J.G. (1996). Microbiology. Principles and Applications. Third Edition. Prentice Hall. Upper Saddle River, New Jersey. p.438. "Theoretically, nosocomial infections can be transmitted by all modes of transmission that occur in the community. However, direct person-to-person transmission between an infected patient, staff member, or visitor and noninfected patients; indirect transmission through equipment, supplies, and hospital procedures; and transmission through air are most common in hospitals."
11. Block C, Baron O, Bogokowski B, Amit P, Rubenstein E. ”An in-use evaluation of decontamination of polypropylene versus steel bedpans.” Department of Clinical Microbiology, Chaim Sheba Medical Centre, Tel Hashomer, Israel.
12. Kuhn, Phyllis
J. Ph.D. “Doorknobs: A Source of Nosocomial
Infection?” Hamat Medical Center. Erie, PA Medical Economics Company,
Inc. 1983.
13. Australian Stainless Steel Development Association. http://www.assda.asn.au “This grade is not designed for applications where sensitization corrosion could be expected. In warm chloride environments, 304 is subject to pitting and crevice corrosion and to stress corrosion cracking . . .”
More informtion about anti-mocrobial Nylon Grab Bars can be fournd on the following websites:
http://www.assistivehardware.com/
http://www.safeaccesssystems.com/