THE FIRST ANTIBACTERIAL INFECTION PROTECTION MEDICAL GLOVE Eng Aik Hwee*, Tang Lok Si, Teh Yee Peng and David Lucas Medical R&D, Ansell Shah Alam, Malaysia Lot 16, Persiaran Perusahaan, Section 23, Shah Alam 40000, Selangor, Malaysia. Tel: +603 5541 9797 Fax: +603 5548 1207 *Corresponding author email: aikhwee.eng@ansell.com Eng obtained his Doctorate in Material Engineering from the Tokyo University of Agriculture & Technology in 1994 and was a research officer of Rubber Research Institute of Malaysia from 1994 to 2001. He joined Ansell Shah Alam in 2001 as a Module Director, and has helped in the commercialization of several new products, notably the moisturizing surgical gloves (Hydrasoft ), the antimicrobial surgical gloves (AMT TM ), and the antibacterial medical glove. He is the author or co-author of 33 journal papers, 3 books and has filed 4 patents. He was awarded the Ansell s Invention Recognition Award in 2010 and 2012. ABSTRACT Ansell s proprietary Gammex Nitrile Antibacterial is a nitrile medical glove with an antibacterial coating on the outside surface that is fast-acting in reducing and preventing further cross-contamination of a clinically relevant microbial load, upon glove contact with contaminated surfaces in the healthcare setting. The glove may, therefore, help to reduce the incidence of healthcare associated infections. In vitro testing showed that the glove was effective against both Gram positive and Gram negative bacteria in the presence of organic soils. Results from the contact-transfer test based on the Draft ASTM test method, indicated that the glove was able to reduce the transfer of bacteria when in contact with contaminated surfaces. The efficacy of the glove has also been demonstrated during a one hour wear time study under general use conditions. The shelf life of the glove was estimated by the accelerated aging methods of EN455 series and ASTM D7160, the Q 10 method, and real time aging test. In the presence of the antibacterial coating, the physical properties of the glove could meet the major international standards requirements such as ASTM, EN, and ISO. All other functional properties such as grip, ease of donning and dispensing remained unchanged. Disclaimer: The material contained in this paper has been compiled by the author and does not necessarily represent the views or opinions of Ansell Limited and its affiliates (Ansell). Further, to the extent permitted by law, any representation or warranty as to the completeness or accuracy of the contents of this paper, and any liability howsoever arising from any use of the contents of this paper, is excluded by Ansell and its officers and employees. The material contained in this paper details certain intellectual property rights which are owned by Ansell. The recipient hereby agrees that it will not use the information contained in this paper in any way so as to infringe Ansell's rights in respect of such intellectual property.
INTRODUCTION Contaminated surfaces in the healthcare settings have been reported to contribute significantly to the endemic and epidemic transmission of pathogens that could cause healthcare-associated infections. 1,2 Pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) are known to survive in the healthcare environment for hours to days. 3 The pathogen transfer from a colonized patient to contaminated surfaces, and subsequently to another patient, normally takes place via gloved hands of healthcare workers. Cleaning coupled with hand hygiene before and after direct contact with patients and their surroundings has been recommended to contain and reduce the spread of contamination. 4 However, routine cleaning by hospital personnel is frequently inadequate. 5-7 The introduction of education, checklists, and methods to evaluate the cleaning and providing feedback to relevant personnel has been found to enhance the effectiveness of cleaning and lead to a reduction in healthcare-associated infections. 8 In addition, as most of the contact transfer cases involved gloved hands, a glove with an antibacterial coating on the outside surface could play an important role in further reducing the transmission of pathogens via the gloved hands of healthcare workers. This paper describes the properties and efficacy of the Gammex Nitrile Antibacterial, a nitrile glove with an antibacterial coating on the outside surface, and its relevance in reducing the transmission of pathogens in the healthcare setting. EXPERIMENTAL The nitrile antibacterial glove was prepared by applying a proprietary coating formulation containing 0.5 to 3% of polyhexamethylene biguanide (PHMB) solution on to the exterior surface of the glove. The method has been described in details elsewhere. 9 The glove was packed in 100 pieces in a plastic packaging and sealed under reduced pressure. A control sample was produced under the same conditions without the antibacterial coating. The antibacterial properties of the glove were determined in vitro using the method described previously. 10 To demonstrate the effectiveness of the glove in reducing the microbial load during a contacttransfer, the glove was tested according to the ASTM Draft method for evaluating bacterial contact transfer with antibacterial-treated examination gloves. 11 In both methods, the log10 reductions from the initial microbial recovery levels were determined by comparing the recoveries from the antibacterial gloves with those from control gloves, without antibacterial coating. For the wear time study, the control gloves were first worn on both hands of 10 subjects and they were allowed to do their routine work in office and laboratory. After 1 hour, the fingers of one of the gloved hands touched the surface of a Tryptic Soy Agar (TSA) plate with neutralizer, while the other touched the surface of a TSA plate without neutralizer. The unused glove finger prints on both types of agar plates were also taken and all plates were incubated at 35+2 o C for 24-48hours before the colonies count was carried out. The study was then repeated using the antibacterial gloves to replace the control gloves. Other tests were carried out based on standard test methods unless otherwise specified. RESULTS AND DISCUSSION General Properties The antibacterial agent is an inherently sticky material. In addition, the antibacterial glove has been packed under reduced-pressure, which might cause blocking to the glove. Therefore, the ease of dispensing was evaluated. There was no blocking issue when the glove was dispensed piece by piece from the packaging. This is not totally unexpected as the antibacterial coating also contained anti-tack agents and lubricant in the formulation. 9 The residual powder was found to be below 0.2mg per glove, well below the maximum limit of 2mg per glove for all sizes. The grip, color, and the donning properties of the antibacterial glove were also found to be similar to those of the control glove. Tensile Properties The nitrile glove was designed to meet the different requirements of the major international standards. Unlike natural rubber, nitrile is a relatively stiffer material and an increase in the elongation at break very often leads to a significant decrease in the ultimate tensile strength. To achieve a good balance of ultimate tensile strength and elongation at break properties, the thickness of the glove was adjusted accordingly. As a result, a medium size glove with the weight of approximately 5.2g per glove was used to produce the
antibacterial glove. Table 1 shows the tensile properties of the Gammex Nitrile Antibacterial glove tested according to the major international standards. The glove could meet the unaged and aged requirements of the standards. Shelf life Study The accelerated aging study for the shelf life estimation has been conducted according to the EN455 series and ASTM D7160 procedures. The results show that the freedom from holes and physical properties of the glove could meet the maximum allowable shelf life claim of not more than 3 years. The threshold limit for the end of shelf life was set at 90% retention of the original unaged property, which is elongation at break. The shelf life for the antibacterial properties has also been estimated based on the Q 10 method and the real time aging test. As the glove is first of its kind in the market, the product shelf claim is based on the real time aging test results. Antibacterial Properties (a) The antibacterial properties of the glove have been studied using 8 clinically relevant bacterial species, of which 4 were Gram-positive and 4 Gram-negative, where the kill-rate was determined at different exposure times. The results are presented in Table 2. Of the 8 species studied, 6 were reduced by more than 4 log (i.e. 99.99%) within 1 min of exposure time, while the other 2, both are of Gram-negative, required a slightly longer exposure time to achieve the 4 log reduction. The studies demonstrated that the antibacterial coating on the glove was capable of reducing the microbial load in a short period of time. This is important because examination gloves are normally worn for a short period of time and a fast acting antibacterial property is essential in the healthcare setting for infection control purpose. (b) To further demonstrate the relevance of this glove in reducing the transmission of pathogens, a study based on the ASTM Draft method for evaluating bacterial contact transfer with antibacterial-treated examination gloves was carried out using 4 bacteria species, i.e. 2 Gram positive and 2 Gram negative. The results summarized in Table 3 clearly show that the antibacterial glove could reduce the transmission of the bacteria by at least 4 log compared to the control glove without the antibacterial coating. The residual bacteria count on the skin after the contact transfer test was also determined. The skin that was in contact with the antibacterial glove was found to have 1-2 log lower in the bacteria count than that with the control glove, implying that the lower level of the bacteria transfer by the antibacterial glove was not due to a low innoculum pick up but rather the effectiveness of the antibacterial coating in reducing the microbial load. In summary, all the surfaces, i.e. skin, glove and stainless steel coupon that were in contact with the antibacterial glove showed lower bacteria count than those in contact with the control glove. (c) The performance of the antibacterial glove was also compared with the control glove in the 1 hour wear time study described in the experimental section. The results are presented in Table 4. Before the control glove was used, it showed the presence of about 1 log of colony count when the agar plate with neutralizer was used. The count was lower when the agar plate without neutralizer was used probably because the biocides in the glove, such as accelerator, could have reduced the colony count during the incubation period. Upon wearing for 1 hour, the colony count increased significantly from 1 log to about 2 logs for the agar plate with neutralizer and 0 log to 1 log for the agar plate without neutralizer. On the other hand, the agar plates, both with and without neutralizer, for the antibacterial glove showed no significant colony count before and after the 1 hour wear time. This shows that unlike the control glove, the antibacterial glove remained substantially free from colonies even after 1 hour use in the office and laboratory environments. These results further support the effectiveness of the antibacterial glove in reducing the microbial load after contacting a contaminated surface such as a dirty hand during dispensing or any surface during use. In a recent study, 12 it has been concluded that healthcare workers could contaminate the unused non-sterile glove with skin commensals and pathogens during the glove dispensing process. This could potentially increase the risks of cross-transmission of pathogens in the healthcare setting. With the fast-acting antibacterial coating on the outside surface of the glove, this risk could be greatly reduced. CONCLUSION The antibacterial coating on the outside surface of the Gammex Nitrile Antibacterial glove has been shown to be fast-acting in reducing the bacterial load when in contact with contaminated surfaces. The efficacy of the glove in reducing bacterial load via a contact-transfer has also been demonstrated using the ASTM Draft
method. Following this method, all contaminated surfaces that were in contact with the antibacterial glove showed a significant reduction in bacteria counts. The results of the 1 hour wear time study provided further evidence that the antibacterial glove could be an effective additional infection control measure in the healthcare setting. REFERENCE 1. J.A. Otter, S. Yezli, J.A.G. Salkeld, and G.L. French. Evidence that contaminated surfaces contribute to the transmission of hospital pathogens and an overview of strategies to address contaminated surfaces in hospital settings. Am. J. Infect. Control. 2013, 41, S6-S11. 2. J.M. Boyce. Environmental contamination makes an important contribution to hospital infection. J. Hosp. Infect., 2007, 65(S2), 50-54. 3. A. Kramer, I. Scwebke, and G. Kampf How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect. Dis., 2006, 6,130, 8pp. 4. M.K. Hayden, M.J.M. Bonten, D.W. Blom, E.A. Lyle, D.A.M.C. van de Vijver, and R. Weinstein. Reduction in acquisition of vancomycin-resistant enterococcus after enforcement of routine environmental cleaning measures. Clin Infect Dis., 2006, 42,1552-1560. 5. P.C. Carling, M.F. Parry, and S.M. von Beheren. Healthcare environmental hygiene study group. Identifying opportunities to enhance environmental cleaning in 23 acute care hospitals. Infect. Control Hosp. Epidemiol., 2008, 29, 1 7. 6. E.R. Goodman, R. Platt, R. Bass, A.B. Onderdonk, D.S. Yokoe, and S.S. Huang Impact of environmental cleaning intervention on the presence of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci on surfaces in intensive care unit rooms. Infect Control Hosp Epidemiol., 2008, 29, 593 599. 7. N.L. Havill, H.L. Havill, E. Mangione, D.G. Dumigan, and J.M. Boyce. Cleanliness of portable medical equipment disinfected by nursing staff. Am J Infect Control, 2011, 39, 602 604. 8. D.J. Weber and W.A. Rutala. Understanding and preventing transmission of healthcare-associated pathogens due to the contaminated hospital environment. Infect. Control Hosp. Epidemiol., 2013, 34, 449-452. 9. A.H. Eng, L.S. Tang, W.A. Wan Ahmad, and D. Lucas. Powder-free glove with stable and fast-acting antimicrobial coating. WIPO, 2011, WO110847782011. 10. A.H. Eng, K.L. Lim, L.S. Tang, and D. Lucas World s first surgical glove with antimicrobial coating on inside surface. Proc. Inter. Latex Synth. Disper. Conf (Latex 2012), Kuala Lumpur, 2012, Paper 14. 11. ASTM Draft Standard test method for evaluating bacterial contact transfer with antibacterial-treated examination gloves. 12. K.A. Hughes, J. Cornwall, J.-C. Theis, and H.J.L. Brooks. Bacteria contamination of unused, disposible non-sterile gloves on a hospital orthopaedic ward. Aust. Med. J., 2013, 6, 331-338.
Table 1: Tensile Properties of Gammex Nitrile Antibacterial Glove Standards Conditions ance Test results /Reject Criteria ASTM Unaged *UTS 14 MPa *EB 500% Aged *UTS 14 MPa *EB 400% EN Unaged Median FAB 6N 9.8N Aged Median FAB 6N 8.9N ISO Unaged *FAB 7 N *EB 500% Aged *FAB 7 N *EB 400% JIS Unaged *UTS 15 MPa *EB 500% Aged *UTS 11 MPa *EB 450% AS/NZ Unaged *UTS 12 MPa *EB 300% *(1 accept; 2 reject); **Number of failure per 13 samples; UTS=Ultimate tensile strength; EB=Elongation at break Table 2: In Vitro kill-rate results for Gammex Nitrile Antibacterial Glove Species* ATCC Log Reduction 1min 2min 5min 10min 1) Acinetobacter baumannii (-ve) 19003 >6 >6 >6 >6 2) Enterococcus faecalis (+ve) 33186 >6 >6 >6 >5.9 3) Escherichia coli (+ve) 25922 4.4 >6 >6 >6 4) Klebsiella pneumoniae (-ve) 4352 6.0 >6 >6 5.9 5) Pseudomonas aeruginosa (-ve) 9027 0.7 1.6 3.8 4.4 6) Serratia marcescens (-ve) 14756 1.4 3.1 >6 5.9 7) Staphylococcus aureus (+ve) 6538 >6 >6 >6 >6 8) Staphylococcus epidermidis (+ve) 12228 >6 >6 >6 >6 *Tested with organic soil Table 3: Results of skin-to-surface (stainless steel) contact transfer of bacteria by gloves Species ATCC Log Reduction SS Coupon Sample Glove Enterococcus faecium VRE, MDR (+ve) 51559 >4.6 >4.6 Escherichia coli (+ve) 25922 >5.5 >5.3 Klebsiella pneumoniae (-ve) 4352 >5.0 >5.2 Staphylococcus aureus MRSA (-ve) 33591 >5.7 4.4 Note: Type of Gram staining is given in parentheses; SS coupon = stainless steel coupon
Table 4: Colony count of gloves after 1 hour use Subject No TSA agar plate colony count for control glove TSA agar plate colony count for antibacterial glove With neutralizer Without neutralizer With neutralizer Without neutralizer 0* 23 1 0 0 0* 15 3 0 0 1 209 48 0 0 2 273 95 0 0 3 150 145 0 1** 4 56 82 0 0 5 42 56 0 0 6 124 36 0 0 7 41 28 0 0 8 138 86 1 0 9 152 65 0 0 10 TNTC # 91 0 0 *Unused glove; **Outside the finger print area; # TNTC: Too numerous to count