Vázquez-Quiñones Carlos Ramón, Rincón-Guevara Monica, Natividad-Bonifacio Iván, Vázquez-Salinas Carlos, González-Márquez Humberto
Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Iztapalapa, CDMX, Mexico.
Laboratorio Divisional de Espectrometría de Masas, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Iztapalapa, CDMX, Mexico.
Access Microbiol. 2025 Jul 28;7(7). doi: 10.1099/acmi.0.000957.v3. eCollection 2025.
Diarrhoeal diseases remain a significant global health challenge, particularly in developing regions such as Africa, Asia and Latin America, where they are a leading cause of child mortality. Contaminated food, including raw or undercooked vegetables, is a major transmission route for diarrhoeal pathogens such as norovirus, , non-typhoid and pathogenic . This study aimed to assess the prevalence of enterotoxigenic (ETEC), a key diarrhoeal pathogen, in fresh produce and prepared salads in Mexico City. A total of 128 samples, including prepared salads (lettuce, carrots and tomatoes) and unprocessed coriander and lettuce, were analysed over 2 years using protocols from the Bacteriological Analytical Manual and the Official Mexican Standard (NOM) SSA 210. Genotyping was performed to detect ETEC-specific virulence genes encoding heat-stable and heat-labile enterotoxins ( and ), respectively. ETEC was identified in 9.9% of the total samples, representing 51.56% of the confirmed isolates. Contamination rates varied by food type, with coriander showing the highest prevalence (78.78%), followed by lettuce (9.09%) and prepared salads from La Vicentina Market (9.09%) and La Purísima Market (3.03%). Genotyping revealed that 12.12% of the ETEC-positive samples carried both and genes, while 33.3 and 54.6% carried only the or gene, respectively. In lettuce samples, 9.09% were positive for ETEC, with 3.03% carrying the gene, 3.03% the gene and 3.03% both genes. Similarly, in coriander, 21.21% were positive for the gene, 51.51% for the gene and 6.06% for both genes. These findings highlight the widespread presence of ETEC in fresh produce sold in Mexico City, posing a significant public health risk, particularly given the increasing consumption of raw vegetables. The study provides the first reported data on ETEC contamination ratios in Mexico City, emphasizing the urgent need for improved food safety measures, including better hygiene practices during production, handling and preparation of fresh produce. This research underscores the importance of ongoing surveillance and preventive strategies to mitigate the risk of foodborne diarrhoeal diseases in urban populations.
腹泻病仍然是一项重大的全球卫生挑战，在非洲、亚洲和拉丁美洲等发展中地区尤为如此，腹泻病是这些地区儿童死亡的主要原因。受污染的食物，包括生的或未煮熟的蔬菜，是诺如病毒、非伤寒沙门氏菌和致病性大肠杆菌等腹泻病原体的主要传播途径。本研究旨在评估墨西哥城新鲜农产品和预制沙拉中关键腹泻病原体产肠毒素大肠杆菌（ETEC）的流行情况。在两年时间里，共分析了128个样本，包括预制沙拉（生菜、胡萝卜和西红柿）以及未加工的香菜和生菜，分析采用了《细菌学分析手册》和墨西哥官方标准（NOM）SSA 210中的方案。进行基因分型以检测分别编码耐热和不耐热肠毒素（ST和LT）的ETEC特异性毒力基因。在所有样本中，9.9%检测出ETEC，占已确认分离株的51.56%。污染率因食物类型而异，香菜的污染率最高（78.78%），其次是生菜（9.09%）以及来自拉维森蒂纳市场（9.09%）和拉普里西马市场（3.03%）的预制沙拉。基因分型显示，12.12%的ETEC阳性样本同时携带ST和LT基因，而分别有33.3%和54.6%的样本仅携带ST或LT基因。在生菜样本中，9.09%的样本ETEC呈阳性，其中3.03%携带ST基因，3.03%携带LT基因，3.03%同时携带这两种基因。同样，在香菜样本中，21.21%的样本ST基因呈阳性，51.51%的样本LT基因呈阳性，6.06%的样本两种基因均呈阳性。这些发现凸显了ETEC在墨西哥城销售的新鲜农产品中广泛存在，构成了重大的公共卫生风险，特别是考虑到生蔬菜的消费量不断增加。该研究提供了墨西哥城ETEC污染率的首次报告数据，强调迫切需要改进食品安全措施，包括在新鲜农产品生产、处理和制备过程中加强卫生操作。这项研究强调了持续监测和预防策略对于降低城市人口食源性腹泻病风险的重要性。
