Salmonella enterica in Mexico 2000-2017: epidemiology, antimicrobial resistance, and prevalence in food

In Mexico, information of Salmonella enterica cases linked to food consumption is scarce. The objective of this article was to assess how S. enterica affect public health in Mexico. To conduct this study, data on the epidemiology of nontyphoidal S. enterica (NTS), Salmonella Typhi, and Salmonella Paratyphi A collected from 2000 to 2017 through the National Epidemiological Surveillance System of Mexico (Sistema Nacional de Vigilancia Epidemiológica de Mexico [SINAVE]) were used. Geographical distribution, season, age groups, and gender were variables considered to analyze S. enterica incidence. An estimation of cases caused by S. enterica in Mexico was calculated while considering data underestimation and the proportion of foodborne diseases. Information of the prevalence of the pathogen in food and the antimicrobial resistance of isolates from food and human cases were obtained from published studies. Outbreaks of S. enterica derived from imported Mexican products in the Unites States are discussed. In 2017, the numbers of reported cases of NTS (92,013) were two and seven times higher than the reported cases of Salmonella Typhi (45,280) and Salmonella Paratyphi A (12, 458). The NTS incidence was higher in lower socioeconomic Mexican regions. The gaps in the surveillance system make it impossible to establish a reliable tendency among age groups, geographical distribution, and gender. In 2017, the estimated frequency of NTS foodborne cases was 49 times higher than that reported in SINAVE, whereas for Salmonella Typhi and Salmonella Paratyphi A it was 23 times. Fresh meat showed the highest prevalence of S. enterica, and most of their isolates had multidrug resistance. Salmonella Typhimurium was the most common serotype isolated from human cases and food. Food safety agencies in Mexico need to prioritize efforts and resources to establish guidelines to ensure the absence of S. enterica in food.