Bactericidal polyurethane foam mattresses: Microbiological characterization and effectiveness V.S. Dagostin b , D.L. Golçalves c , C.B. Pacheco d , W.B. Almeida d , I.P. Thomé b , C.T. Pich b , M.M.S. Paula a , L. Silva a , E. Angioletto a , M.A. Fiori a, ⁎ a Departamento de Engenharia Química e de Materiais, Universidade do Extremo Sul Catarinense — UNESC, 88806-000, Criciúma, SC, Brazil b Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense — UNESC, 88806-000, Criciúma, SC, Brazil c Programa de Pós-Graduação em Biotecnologia, Universidade Federal de Santa Catarina — UFSC, Centro de Ciências Biológicas, 88040-900 — Florianópolis, SC, Brazil d Departamento de Farmácia, Universidade do Extremo Sul Catarinense — UNESC, 88806-000, Criciúma, SC, Brazil abstract article info Article history: Received 3 October 2009 Received in revised form 1 February 2010 Accepted 5 March 2010 Available online 16 March 2010 Keywords: Bactericidal polyurethane Bactericidal foam mattresses Bactericidal polymer Bactericidal materials The antimicrobial compounds 2.4.4.″-tricloro-2″ hydroxydiphenyl ether (triclosan), 5-chloro-2-methyl-4- isothiazolin-3-one (isothiazolone) and bis(2-pyridylthio)zinc 1,1′-dioxide (zinc pyrithione) were incorpo- rated into polyurethane foam matrixes. Concentrations of 0.20 wt.%, 0.50 wt.% and 1.00 wt.% of each biocide compound were used, and the infection reduction capacity was evaluated for different types of bacteria. The microbiological tests with polyurethane foams were performed with agar diffusion tests using the pour plate technique and analyzing the colony formation units (CFU) as a function of time. In preliminary tests, the micro-organisms Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella choleraesuis and Staphylococcus aureus were used. Tests in vitro showed that polyurethane foam containing zinc pyrithione gave the best performance. Genotoxicity tests were conducted to evaluate if the use of zinc pyrithione in the polyurethane causes harm to human users. Microbiological tests were also performed on the surfaces of mattresses that were produced with polyurethane foam to verify their antimicrobial properties. The significant decrease in the number of micro-organisms within the foam showed the effectiveness of the zinc pyrithione as an antimicrobial, while the genotoxicity tests demonstrated the absence of collateral effects for the users. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Hospital infections are one of the main causes of morbidity and mortality for hospitalized patients. These infections incur the largest amount of financial resources spent by hospitals and are recognized as a serious public health problem [1,2]. In Brazil, an average of 6.5% to 15.0% of all infections occurs in the hospitals, and in Europe and the USA, this rate is 10.0% [3,4]. Hospital infections may manifest during the inpatient period or after the patient is discharged [5,6]. Many hospital infections likely originate from hospital mattresses [7]. Prophylactic actions effectively minimize the hospital infections, but problems still exist, mainly in home health care. Many inpatients remain lying on a foam mattress for a great deal of time [8]. The lack of either appropriate mattress hygiene or the use of biocide agents increases the risk of acquiring an infection in a hospital. These infections can be caused by ordinary micro-organisms, including S. aureus, E. coli, P. aeruginosa, Enterobacter ssp., K. pneumoniae and C. difficile and fungi, mainly C. albicans [9–11]. Biocides with inappropriate specifications for a biocide additive can promote absences or small antimicrobial actions. The following are important specifications to consider before using biocide additives for antimicrobial polymeric production: (1) the chemical and physical compatibility of the biocide compound with the polymeric matrix, (2) the weight percentage of the biocide compounds in the polymeric matrix, (3) the response of the biocide additive to different tempera- tures conditions, (4) the condition of the machine during processing, and (5) the death capacity of the biocide additive for specific bacterial types. Many studies have investigated the development and application of materials with biocide properties. These materials could be used in special tools or as surface coatings to kill bacteria on surfaces or in the atmosphere. Studies have been conducted on bactericidal glasses [12], bactericidal polymers [13] and bactericidal polymer composites [14]. If these products have bactericidal properties, then hospital infections can be decreased, especially if these products are used in hospital foam mattresses. This research was conducted with the assumption that the implanted active principle mattresses are less susceptible to micro- organisms that are the main origin for hospital and home infections. The objective was to identify the effectiveness of various bactericidal Materials Science and Engineering C 30 (2010) 705–708 ⁎ Corresponding author. Tel./fax: + 55 48 3431 2603. E-mail address: mfi@unesc.net (M.A. Fiori). 0928-4931/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.msec.2010.03.004 Contents lists available at ScienceDirect Materials Science and Engineering C journal homepage: www.elsevier.com/locate/msec