RESUMEN
BACKGROUND: Worldwide, the emergence of multidrug-resistant gram-negative bacteria is a clinical problem. Surface disinfectant cleaners (SDCs) that are effective against these bacteria are needed for use in high risk areas around patients and on multi-touch surfaces. We determined the efficacy of several SDCs against clinically relevant bacterial species with and without common types of multidrug resistance. METHODS: Bacteria species used were ATCC strains; clinical isolates classified as antibiotic-susceptible; and multi-resistant clinical isolates from Klebsiella oxytoca, Klebsiella pneumoniae, and Serratia marcescens (all OXA-48 and KPC-2); Acinetobacter baumannii (OXA-23); Pseudomonas aeruginosa (VIM-1); and Achromobacter xylosoxidans (ATCC strain). Experiments were carried out according to EN 13727:2012 in quadruplicate under dirty conditions. The five evaluated SDCs were based on alcohol and an amphoteric substance (AAS), an oxygen-releaser (OR), surface-active substances (SAS), or surface-active-substances plus aldehydes (SASA; two formulations). Bactericidal concentrations of SDCs were determined at two different contact times. Efficacy was defined as a log10 ≥ 5 reduction in bacterial cell count. RESULTS: SDCs based on AAS, OR, and SAS were effective against all six species irrespective of the degree of multi-resistance. The SASA formulations were effective against the bacteria irrespective of degree of multi-resistance except for one of the four P. aeruginosa isolates (VIM-1). We found no general correlation between SDC efficacy and degree of antibiotic resistance. CONCLUSIONS: SDCs were generally effective against gram-negative bacteria with and without multidrug resistance. SDCs are therefore suitable for surface disinfection in the immediate proximity of patients. Single bacterial isolates, however, might have reduced susceptibility to selected biocidal agents.
Asunto(s)
Desinfectantes/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Antibacterianos/farmacología , Bacterias Gramnegativas/aislamiento & purificación , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/aislamiento & purificación , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/aislamiento & purificaciónRESUMEN
BACKGROUND: Surgical hand antiseptics often contain chlorhexidine gluconate (CHG). There are doubts that the full effect measured for these products might only be achieved after sampling because of a lack of valid neutralizing agents (NAs) in the sampling fluid. METHODS: We measured the efficacy of Avagard CHG and Hibiclens for 11 applications over 5 days according to the manufacturers' instructions. NAs were added to the sampling fluid and the dilution fluid (group 1) or to only the dilution fluid (group 2). In a third group, NAs were added to the dilution fluid only, and cream was applied after the final scrub on days 1 to 4. Neutralization was validated according to American Society for Testing and Materials International standard 1054 using Staphylococcus epidermidis. RESULTS: When NAs were not added to the sampling fluid, both products were very effective, with a mean log(10) reduction in flora of 3.32 ± 0.53 for Avagard and 3.68 ± 0.52 for Hibiclens on day 5. When NAs were included in the sampling fluid, however, the immediate efficacy was significantly lower, at 2.75 ± 0.55 and 3.14 ± 0.50, respectively. A lack of NAs in the sampling fluid resulted in overestimation of efficacy by a factor of between 0.3 and 1.1 log(10). CONCLUSION: Efficacy studies carried out without NAs in the sampling fluid for products with CHG should be critically assessed.
Asunto(s)
Clorhexidina/farmacología , Desinfectantes/farmacología , Desinfección de las Manos/métodos , Staphylococcus epidermidis/efectos de los fármacos , Staphylococcus epidermidis/aislamiento & purificación , Recuento de Colonia Microbiana , HumanosRESUMEN
The antiseptic efficacy of ethanol, isopropanol, and n-propanol at 60%, 70%, and 89.5% (all vol/vol) was analyzed after 2, 3, or 4 min of application to the forehead, back, and abdomen of 180 volunteers by the use of a standardized swab sampling method. Results of recolonization by the aerobic skin flora of the upper arms and backs of 20 volunteers were compared 72 h after treatment with 0.5%, 1%, or 2% chlorhexidine digluconate (CHG) in 89.5% n-propanol. The most effective alcohol at all skin sites was n-propanol, with a mean log(10) reduction of 1.82 after 2 min on the forehead. Efficacy against the aerobic flora of the forehead was mainly influenced by the type of alcohol (P < 0.001), followed by the concentration (P < 0.001) and the application time (P = 0.006). Ethanol and isopropanol were significantly less effective (both P < 0.001). Alcohol supplemented with 0.5% or more CHG was significantly more effective than alcohol alone in the suppression of recolonization (P < 0.05). An 89.5% solution of n-propanol was the most effective alcohol for the reduction of populations of aerobic skin flora. Its combination with CHG is appropriate whenever recolonization of the skin must be limited. Further studies are needed to determine the most effective concentration of CHG in n-propanol to provide the best protection against recolonization of the skin, e.g., for catheter site care.
Asunto(s)
Alcoholes/farmacología , Antiinfecciosos Locales/farmacología , Piel/microbiología , Adulto , Clorhexidina/análogos & derivados , Clorhexidina/farmacología , Recuento de Colonia Microbiana , Método Doble Ciego , Humanos , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
BACKGROUND: Effective neutralization of active agents is essential to obtain valid efficacy results, especially when non-volatile active agents like chlorhexidine digluconate (CHG) are tested. The aim of this study was to determine an effective and non-toxic neutralizing mixture for a propan-1-ol solution containing 2% CHG. METHODS: Experiments were carried out according to ASTM E 1054-02. The neutralization capacity was tested separately with five challenge microorganisms in suspension, and with a rayon swab carrier. Either 0.5 mL of the antiseptic solution (suspension test) or a saturated swab with the antiseptic solution (carrier test) was added to tryptic soy broth containing neutralizing agents. After the samples were mixed, aliquots were spread immediately and after 3 h of storage at 2 - 8 degrees C onto tryptic soy agar containing a neutralizing mixture. RESULTS: The neutralizer was, however, not consistently effective in the suspension test. Immediate spread yielded a valid neutralization with Staphylococcus aureus, Staphylococcus epidermidis and Corynebacterium jeikeium but not with Micrococcus luteus (p < 0.001) and Candida albicans (p < 0.001). A 3-h storage period of the neutralized active agents in suspension resulted in significant carry-over activity of CHG in addition against Staphylococcus epidermidis (p < 0.001) and Corynebacterium jeikeium (p = 0.044). In the carrier test, the neutralizing mixture was found to be effective and non toxic to all challenge microorganisms when spread immediately. However, after 3 h storage of the neutralized active agents significant carry-over activity of CHG against Micrococcus luteus (p = 0.004; Tukey HSD) was observed. CONCLUSION: Without effective neutralization in the sampling fluid, non-volatile active ingredients will continue to reduce the number of surviving microorganisms after antiseptic treatment even if the sampling fluid is kept cold straight after testing. This can result in false-positive antiseptic efficacy data. Attention should be paid during the neutralization validation process to the amount of antiseptic solution, the storage time and to the choice of appropriate and sensitive microorganisms.
Asunto(s)
Antiinfecciosos Locales/antagonistas & inhibidores , Antiinfecciosos Locales/farmacología , Técnicas Bacteriológicas/métodos , Clorhexidina/análogos & derivados , Micología/métodos , Manejo de Especímenes/métodos , Candida albicans/efectos de los fármacos , Clorhexidina/antagonistas & inhibidores , Clorhexidina/farmacología , Bacterias Grampositivas/efectos de los fármacos , Humanos , Pruebas de Sensibilidad Microbiana , Piel/microbiologíaRESUMEN
BACKGROUND: Recent data indicate that full efficacy of a hand rub preparation for hygienic hand disinfection can be achieved within 15 seconds (s). However, the efficacy test used for the European Norm (EN) 1500 samples only the fingertips. Therefore, we investigated hand coverage using sixteen different application variations. The hand rub was supplemented with a fluorescent dye, and hands were assessed under UV light by a blind test, before and after application. Fifteen non-healthcare workers were used as subjects for each application variation apart from one test which was done with a group of twenty healthcare workers. All tests apart from the reference procedure were performed using 3 mL of hand rub. The EN 1500 reference procedure, which consists of 6 specific rub-in steps performed twice with an aliquot of 3 ml each time, served as a control. In one part of this study, each of the six steps was performed from one to five times before proceeding to the next step. In another part of the study, the entire sequence of six steps was performed from one to five times. Finally, all subjects were instructed to cover both hands completely, irrespective of any specific steps ("responsible application"). Each rub-in technique was evaluated for untreated skin areas. RESULTS: The reference procedure lasted on average 75 s and resulted in 53% of subjects with at least one untreated area on the hands. Five repetitions of the rub-in steps lasted on average 37 s with 67% of subjects having incompletely treated hands. One repetition lasted on average 17 s, and all subjects had at least one untreated area. Repeating the sequence of steps lasted longer, but did not yield a better result. "Responsible application" was quite fast, lasting 25 s among non-healthcare worker subjects and 28 s among healthcare workers. It was also effective, with 53% and 55% of hands being incompletely treated. New techniques were as fast and effective as "responsible application". Large untreated areas were found only with short applications. Fingertips and palms were often covered completely. CONCLUSION: In clinical practice, hand disinfection is apparently better than practitioners of infection control often anticipate. Based on our data, a high-quality hygienic hand disinfection is not possible within 15 s. A 30 s application time can, however, be recommended for clinical practice. The currently recommended six steps of EN 1500 are not really suitable for clinical practice, because they yield comparably poor results. The most appropriate application procedure may be "responsible application", or one of the other new techniques.