The largest economic, population, administrative, and service production of the State of Puebla (east-central Mexico) is concentrated in the Metropolitan Area of Puebla (MAP), and its effect on the water quality of the Atoyac River is substantial. The anthropogenic contamination of the Atoyac River and its tributaries in the MAP was evaluated and characterized. For this purpose, industry types and industrial density (ID) were identified, and the physical–chemical quality of water in the urban Atoyac, Rabanillo, Zapatero Rivers, and the Covadonga and Echeverría Dams were analyzed. In addition, the cytotoxicity of water was evaluated using the biomodel Allium cepa by analyzing the mitotic index (MI) and the interphase index (II). The correlation between the physical–chemical variables of water and MI was estimated. The results included 4500 industries, among which are the construction, metallurgy, metalworking, food, and textile industries. The highest ID was found in the municipality of San Pedro Cholula. The greatest anthropogenic impact occurred in the Rabanillo River and the Echeverría Dam. Throughout the watershed, anoxic conditions were registered and 18 chemicals, most of which are toxic and carcinogenic, were detected. A Correlation analysis showed that the greatest antimitotic effect in Allium cepa was induced by turbidity, chemical oxygen demand (COD), and lead (Pb), with correlation coefficients of −0.919, p = 0.008; −0.864, p = 0.013; and −0.692; p = 0.030, respectively. It was concluded that if the population, industry, and natural resources are associated in the MAP under current conditions, the outlook, if nothing changes, is that the degradation of the water resource will be disruptive and probably unsustainable for any type of use.

The flagella of enteropathogenic Escherichia coli (EPEC) O127:H6 E2348/69 mediate adherence to host proteins and epithelial cells. What environmental and nutritional signals trigger or down-regulate flagella expression in EPEC are largely unknown. In this study, we analyzed the influence of pH, oxygen tension, cationic and anionic salts (including bile salt), carbon and nitrogen sources, and catecholamines on the expression of the flagellin gene (fliC) of E2348/69. We found that sodium bicarbonate, which has been shown to induce the expression of type III secretion effectors, down-regulated flagella expression, explaining why E2348/69 shows reduced motility and flagellation when growing in Dulbecco’s Minimal Essential Medium (DMEM). Further, growth under a 5% carbon dioxide atmosphere, in DMEM adjusted to pH 8.2, in M9 minimal medium supplemented with 80 mM glucose or sucrose, and in DMEM containing 150 mM sodium chloride, 0.1% sodium deoxycholate, or 30 µM epinephrine significantly enhanced fliC transcription to different levels in comparison to growth in DMEM alone. When EPEC was grown in the presence of HeLa cells or in supernatants of cultured HeLa cells, high levels (4-fold increase) of fliC transcription were detected in comparison to growth in DMEM alone. Our data suggest that nutritional and host signals that EPEC may encounter in the intestinal niche activate fliC expression in order to favor motility and host colonization.

Environmental, social, and economic factors are decisive for susceptibility to infectious diseases caused by opportunistic pathogens, such as Candida. Their incidence has increased significantly in recent years, mainly due to a greater number of immunocompromised people, the social and economic environment in which they develop and the current environmental crisis, climate change, which exacerbates health inequalities. Therefore, a literature review was conducted on the main social and environmental determinants of health and virulence factors as determinants of Candida spp. infection. Several studies provide valuable insights into the main predisposing determinants of Candida colonization and infection in relation to the health status of people and the virulence factors of the aetiological pathogen itself. Although there are some studies on the prevalence of Candida in different social classes, there are still few criteria to derive or claim an objective opinion on the social conditions under which this opportunistic pathogen occurs. Therefore, an overall picture that takes into account not only the intrinsic factors of the individual (human biology, health status, etc.) but also the social determinants of health, which may be related to differences in colonization and infection by different Candida species, is still lacking.

Salmonella is one of the main microorganisms that causes food-borne illnesses worldwide, although there are standard procedures to determine its presence or absence in food samples. However, these methodologies are time consuming and cumbersome, so the development of devices that rapidly and accurately determine bacteria is necessary. Various materials have been used to construct these devices. Hydrogenated amorphous silicon carbide (a-SiC:H) is one of the least studied. Therefore, in the present work, self-assembled monolayers were applied on a-SiC:H thin films to determine Salmonella Typhimurium ATCC 14028 by Fourier transform infrared spectroscopy. The detection of this microorganism was performed between 1060 and 960 cm⁻¹ corresponding to carbohydrate and phosphate groups of the bacteria. The lowest detected concentration was 10 CFU/mL. This work confirms the utility of a-SiC:H to reliably and rapidly determine Salmonella.

El municipio de Xicotepec, Puebla, es uno de los principales productores de café en México y cuenta con 978 beneficios, que arrojan sus aguas residuales a los arroyos circundantes, la mayoría sin tratamiento previo. Dichas aguas residuales contienen materia orgánica y contaminantes, que disminuyen el oxígeno disuelto, generan color y malos olores en los cuerpos de agua receptores. Este trabajo evalúa el impacto de las aguas residuales descargadas en el arroyo Nopalutla, por uno de estos beneficios húmedos de café. Se analizaron siete parámetros físicos, diez químicos y dos microbiológicos asociados a la calidad del agua, de acuerdo con la normatividad mexicana correspondiente. Se determinó que las aguas provenientes del procesamiento del café poseen características físicas y químicas, que superaron los límites permitidos en la normatividad mexicana vigente, tales como los sólidos sedimentables y los suspendidos totales, la dureza, la demanda química de oxígeno, el nitrógeno total y los fosfatos, así como la presencia de coliformes totales y fecales. Lo anterior indica un impacto negativo en la calidad del agua del arroyo Nopalutla y un riesgo a la salud de la población aledaña que la usa.