Prevalence and Types of Drugs Used Among Hepatitis A Patients During Outbreaks Associated with Person-to-Person Transmission, Kentucky, Michigan, and West Virginia, 2016–2019

Background: People who use drugs are at increased risk for hepatitis A virus infection. Since 1996, the Advisory Committee on Immunization Practices has recommended hepatitis A vaccination for people who use drugs. Since 2016, the U.S. has experienced widespread hepatitis A outbreaks associated with person-to-person transmission. Purpose: To describe the prevalence of drug use, route of use, and drugs used among hepatitis A outbreak-associated patients. Methods: State outbreak and medical records were reviewed to describe the prevalence, type, and route of drug use among a random sample of 812 adult outbreak-associated hepatitis A patients from Kentucky, Michigan, and West Virginia during 2016–2019. Differences in drug-use status were analyzed by demographic and risk-factor characteristics using the χ2 test. Results: Among all patients, residents of Kentucky (55.6%), Michigan (51.1%), and West Virginia (60.1%) reported any drug use, respectively. Among patients that reported any drug use, methamphetamine was the most frequently reported drug used in Kentucky (42.3%) and West Virginia (42.1%); however, opioids were the most frequently reported drug used in Michigan (46.8%). Hepatitis A patients with documented drug use were more likely (p\u3c0.05) to be experiencing homelessness/unstable housing, have been currently or recently incarcerated, and be aged 18–39 years compared to those patients without documented drug use. Implications: Drug use was prevalent among person-to-person hepatitis A outbreak-associated patients, and more likely among younger patients and patients experiencing homelessness or incarceration. Increased hepatitis A vaccination coverage is critical to prevent similar outbreaks in the future

The role of thermal energy accommodation and atomic recombination probabilities in low pressure oxygen plasmas

International audienceSurface interaction probabilities are critical parameters that determine the behaviour of low pressure plasmas and so are crucial input parameters for plasma simulations that play a key role in determining their accuracy. However, these parameters are difficult to estimate without in situ measurements. In this work, the role of two prominent surface interaction probabilities, the atomic oxygen recombination coefficient ? O and the thermal energy accommodation coefficient ? E in determining the plasma properties of low pressure inductively coupled oxygen plasmas are investigated using two-dimensional fluid-kinetic simulations. These plasmas are the type used for semiconductor processing. It was found that ? E plays a crucial role in determining the neutral gas temperature and neutral gas density. Through this dependency, the value of ? E also determines a range of other plasma properties such as the atomic oxygen density, the plasma potential, the electron temperature, and ion bombardment energy and neutral-to-ion flux ratio at the wafer holder. The main role of ? O is in determining the atomic oxygen density and flux to the wafer holder along with the neutral-to-ion flux ratio. It was found that the plasma properties are most sensitive to each coefficient when the value of the coefficient is small causing the losses of atomic oxygen and thermal energy to be surface interaction limited rather than transport limited

Feedback Inhibition in the PhoQ/PhoP Signaling System by a Membrane Peptide

The PhoQ/PhoP signaling system responds to low magnesium and the presence of certain cationic antimicrobial peptides. It regulates genes important for growth under these conditions, as well as additional genes important for virulence in many gram-negative pathogens. PhoQ is a sensor kinase that phosphorylates and activates the transcription factor PhoP. Since feedback inhibition is a common theme in stress-response circuits, we hypothesized that some members of the PhoP regulon may play such a role in the PhoQ/PhoP pathway. We therefore screened for PhoP-regulated genes that mediate feedback in this system. We found that deletion of mgrB (yobG), which encodes a 47 amino acid peptide, results in a potent increase in PhoP-regulated transcription. In addition, over-expression of mgrB decreased transcription at both high and low concentrations of magnesium. Localization and bacterial two-hybrid studies suggest that MgrB resides in the inner-membrane and interacts directly with PhoQ. We further show that MgrB homologs from Salmonella typhimurium and Yersinia pestis also repress PhoP-regulated transcription in these organisms. In cell regulatory circuits, feedback has been associated with modulating the induction kinetics and/or the cell-to-cell variability in response to stimulus. Interestingly, we found that elimination of MgrB-mediated feedback did not have a significant effect on the kinetics of reporter protein production and did not decrease the variability in expression among cells. Our results indicate MgrB is a broadly conserved membrane peptide that is a critical mediator of negative feedback in the PhoQ/PhoP circuit. This new regulator may function as a point of control that integrates additional input signals to modulate the activity of this important signaling system