Departamento de Ecología y Gestión Ambiental, Centro Universitario Regional Este, Universidad de La República, 20000, Maldonado, Uruguay.
Laboratorio de Ecología Microbiana Acuática, Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, 11600, Montevideo, Uruguay.
Environ Monit Assess. 2024 Oct 17;196(11):1067. doi: 10.1007/s10661-024-13256-z.
For decades, the risk of exposure to infectious diseases in recreational beaches has been evaluated through the quantification of fecal indicator bacteria in water samples using culture methods. The analyses of sand samples have recently been developed as a complement to the monitoring of recreational waters in beach quality assessments. The growing use of molecular techniques for environmental monitoring allows for the rapid detection of pathogenic genes, thus providing more accurate information regarding the health risk of exposure to contaminated sand. The aim of this work was to determine the relationship between the fecal indicators abundance in water and sand and the presence of Shiga toxin-producer Escherichia coli (STEC) in sand by analyzing samples from touristic beaches using culture-dependent (fecal coliforms assay) and culture-independent (real-time PCR of stx1, stx2, and eae genes) techniques. We found a high concentration of coliform bacteria in water and sand in several beaches in eastern Uruguay, with different levels of sanitation networks and levels of urbanization. The presence of STEC virulence genes (mainly stx1) was confirmed in 8 out of 20 sand samples. The recreational use of sandy beaches may imply a risk to the health of its users, especially near streams and creek outflows, thus highlighting the need of monitoring sand bacteriological quality and pathogens using molecular tools.
几十年来，人们一直通过使用培养方法定量分析水样中的粪便指示细菌来评估休闲海滩接触传染病的风险。最近，沙样分析已作为海滩水质评估中休闲水域监测的补充方法得到发展。分子技术在环境监测中的广泛应用使得能够快速检测致病基因，从而更准确地提供有关接触受污染沙的健康风险的信息。本研究旨在通过分析乌拉圭东部旅游海滩的水样，使用依赖培养（粪大肠菌群检测）和非依赖培养（stx1、stx2 和 eae 基因实时 PCR）技术，确定水样和沙样中粪便指示生物丰度与沙样中产志贺毒素大肠杆菌（STEC）的存在之间的关系。我们发现乌拉圭东部几个海滩的水和沙中含有高浓度的大肠菌群，这些海滩的卫生网络和城市化程度不同。在 20 个沙样中，有 8 个确认存在 STEC 毒力基因（主要是 stx1）。休闲使用沙滩可能会对使用者的健康构成威胁，特别是在溪流和小溪出水口附近，因此强调了使用分子工具监测沙滩细菌质量和病原体的必要性。
