Heat-Stable Enterotoxin Secretions Assessed via ICP-MS Reveal Iron-Mediated Regulation of Virulence in CFA/I- and CS6-Expressing ETEC Isolates.

Enterotoxigenic Escherichia coli (ETEC) are a significant cause of childhood diarrhea in low-resource settings. ETEC are defined by the production of heat-stable enterotoxin (ST) and/or heat-labile enterotoxin (LT), which alter intracellular cyclic nucleotide signaling and cause the secretion of water and electrolytes into the intestinal lumen. ETEC take cues from chemicals (e.g., glycans, bile salts, and solutes) that may be liberated following enterotoxin activity to recognize entrance into the host. ETEC then alter the expression of surface adhesins called colonization factors (CFs) to attach to the intestinal epithelium, proliferate, and cause disease. Here, we used an in vivo model of oral ST intoxication to determine its impact on luminal ion concentrations via ICP-MS. We also used functional assays, including Western blots, qPCR, and toxin activity assays, to assess the impact of luminal ion flux on CF and toxin expression. Finally, we assessed ETEC strains with CFs CFA/I or CS6 in a streptomycin mouse model of ETEC colonization. ST causes rapid and significant increases in luminal chloride but significant decreases in luminal magnesium and iron. We confirmed that increased sodium chloride suppresses CFA/I production in ETEC H10407 but does not affect CS6 production in ETEC 214-4. CFA/I production in ETEC H10407 is increased when magnesium becomes limiting, although it does not affect CS6 production in ETEC 214-4. Iron restriction via deferoxamine induces CFA/I expression in ETEC H10407 but not CS6 expression in ETEC 214-4. We demonstrate that ST production is suppressed via iron restriction in H10407, 214-4, and over 50 other ETEC clinical isolates. Lastly, we demonstrate that the iron restriction of mice using oral deferoxamine pre-treatment extends the duration of ETEC H10407 (CFA/I+) fecal shedding while accelerating ETEC 214-4 (CS6+) fecal shedding. Combined, these data suggest that enterotoxins modulate luminal ion flux to influence ETEC virulence including toxin and CF production.

Effects of Ending the Use of Seclusion and Mechanical Restraint in the Pennsylvania State Hospital System, 2011-2020.

The Pennsylvania State Hospital System's use of containment procedures has been studied for >30 years. This prospective study assessed the effects of ending the use of seclusion and mechanical restraint in the system's six civil hospitals and two forensic centers from 2011 to 2020. The study examined the effect of this change on key safety measures: physical restraint, assaults, aggression, and self-injurious behavior. In total, 68,153 incidents, including 9,518 episodes of physical restraint involving 1,811 individuals, were entered into a database along with patients' demographic and diagnostic information. All data were calculated per 1,000 days to control for census changes. During the study, mechanical restraint was used 128 times and seclusion four times. Physical restraint use decreased from a high of 2.62 uses per 1,000 days in 2013 to 2.02 in 2020. The average length of time a person was held in physical restraint was reduced by 64%, from 6.6 minutes in 2011 to 2.4 minutes in 2020 (p<0.001). All safety measures improved or were unchanged. Use of unscheduled medication did not change. The hospital system safely ended the use of mechanical restraint and seclusion by using a recovery approach and by following the six core strategies for seclusion and restraint reduction.