Métodos de detecção de salmonella enterica em amostras de água

Abstract

This study aimed to evaluate the frequency of Salmonella enterica in surface waters of agricultural interest in the state of Paraíba and to compare the effectiveness of the selective enrichment broths Rappaport-Vassiliadis-RV and tetrathionate-TT and selective agars (xylose lysine tergitol 4-XLT -4, bismuth sulphite-BS and enteric Hektoen-HE in the isolation of Salmonella enterica. Samples were collected from 29 points, including dams and rivers close to some agricultural activity, in 9 municipalities of the state of Paraíba during 4 consecutive months, through Moore's modified swab technique (MMS). The steps for detection of Salmonella spp. included pre-enrichment with peptone water, selective enrichment through RV and TT broths, plating on XLT-4, HE and BS selective culture media, and sowing of selected colonies on triple sugar iron agar and lysine iron agar for biochemical confirmation. The frequency of Salmonella enterica in water samples was 81.9%. The results obtained demonstrate a greater recovery of the RV broth, with 75% of the positive samples, compared to 56% of the TT. As for the selective culture media, when isolation was evaluated from a specific broth, XLT-4 resulted in the highest number of positive samples, followed by HE and BS, in both enrichment broths, with a significant difference in isolation from from TT broth, where 59 positive samples were evaluated for XLT-4 medium, 29 for HE and 26 for BS. The results of the present study demonstrate a high frequency of Salmonella enterica in surface water samples from water reservoirs in Paraíba and indicate the need to use more than one selective enrichment broth and selective agars for the isolation of the agent.