Action of household antiseptics and disinfectants against Enterococcus sp. isolated from Dilúvio stream, Rio Grande do Sul state, southern Brazil

Abstract

Located in downtown Porto Alegre, Rio Grande do Sul state, southern Brazil, the Dilúvio stream receives waste and domestic sewage inflow daily from several districts of the city. If not properly treated, such wastewater can be the source of different microorganisms like enterococci. In the present study, the activity of household disinfectants and antiseptics was tested against microorganisms isolated from such wastewater. Fifteen disinfectants and six antiseptic products were tested against 28 enterococci isolated from Dilúvio stream by the disk diffusion method. Products showing anti-enterococci activity were subjected to the minimum inhibitory concentration method, which was obtained by diluting products in 50% to 1.563% for 24 and 48 h of exposure. Of the 21 tested products, 13 disinfectants and five antiseptics showed activity against enterococci isolated from the Dilúvio stream. Although most products proved to be efficient when pure (100%), many had their antimicrobial activity efficiency reduced already in the first dilution (50%) and in the 24-h exposure time. Exposure period revealed to be an important factor for bacterial growth, since the time of permanence of compounds may influence the capacity of bacteria to grow. Our study demonstrated that most tested household disinfectants and antiseptics proved to be efficient in controlling antimicrobial-susceptible and -resistant enterococci strains isolated from the Dilúvio stream.