Bacterial persisters are rare phenotypic variants that are temporarily tolerant to high concentrations of antibiotics. We have previously discovered that stationary-phase-cell subpopulations exhibiting high redox activities were less capable of producing proteins and resuming growth upon their dilution into fresh media. The redox activities of these cells were maintained by endogenous protein and RNA degradation, resulting in selfinflicted damage that transiently repressed the cellular functions targeted by antibiotics. Here, we showed that pretreatment of stationary-phase cells with an ATP synthase inhibitor, chlorpromazine hydrochloride (CPZ), significantly reduced stationary-phaseredox activities and protein degradation, and yielded cells that were more susceptible to cell death when exposed to antibiotics in fresh media. Leveraging this knowledge, we developed an assay integrating a degradable fluorescent protein system and a small library, containing FDA-approved drugs and antibiotics, to detect medically relevant drugs that potentially target persister metabolism. We identified a subset of chemical inhibitors, including polymyxin B, poly-L-lysine and phenothiazine anti-psychotic drugs, that were able to reduce the persistence phenotype in Escherichia coli. These chemical inhibitors also reduced Pseudomonas aeruginosa persistence, potentially verifying the existence of similar mechanisms in a medically relevant organism.

Abstractobjectives To determine whether medical staff at PHC level would have the time to take up additional activities such as 1-day fever camps for active VL case detection.methods This article assessed the workload of health staff of different professional categories working at health facilities in Bangladesh, India and Nepal. Data were collected from different sites in high endemic VL areas. The study population was the health staff of government health facilities at all levels. Workload indicators of staffing need (WISN) software were adopted to carry out the analysis of staff workload and their availability in the selected health facility. The WISN difference and WISN ratio for a particular health facility were calculated from actual staffing available and calculated staffing requirement.results The results showed a mixed picture of the availability of health workers. In most settings of Bangladesh and India, physicians with or without laboratory technicians would have time for active case detection. In Nepal, this would be performed by trained nurses and paramedical personnel.conclusion If all vacant posts were filled, active case detection could be performed more easily. The elimination programme can be scaled up with the current staffing levels in the endemic areas with some short training if and when necessary.keywords visceral leishmaniasis (kala-azar), active case detection, workload indicators of staffing need, Bangladesh, Nepal, India

Persistence is a transient state that poses an important health concern in cancer therapy. The mechanisms associated with persister phenotypes are highly diverse and complex, and many aspects of persister cell physiology remain to be explored. We applied a melanoma cell line and panel of chemotherapeutic agents to show that melanoma persister cells are not necessarily preexisting dormant cells; in fact, they may be induced by cancer chemotherapeutics. Our metabolomics analysis and phenotype microarray assays further demonstrated a transient upregulation in Krebs cycle metabolism in persister cells. We also verified that targeting electron transport chain activity can significantly reduce melanoma persister levels. The reported metabolic remodeling feature seems to be a conserved characteristic of melanoma persistence, as it has been observed in various melanoma persister subpopulations derived from a diverse range of chemotherapeutics. Elucidating a global metabolic mechanism that contributes to persister survival and reversible switching will ultimately foster the development of novel cancer therapeutic strategies.

Persister cells are defined as the small fraction of quiescent cells in a bulk cancer cell population that can tolerate unusually high levels of drugs. Persistence is a transient state that poses an important health concern in cancer therapy. The mechanisms associated with persister phenotypes are highly diverse and complex, and many aspects of persister cell physiology remain to be explored. We applied a melanoma cell line and panel of chemotherapeutic agents to show that melanoma persister cells are not necessarily preexisting dormant cells or stem cells; in fact, they may be induced by cancer chemotherapeutics. Our metabolomics analysis and phenotype microarray assays further demonstrated that the levels of Krebs cycle molecules are significantly lower in the melanoma persister subpopulation than in the untreated bulk cell population due to increased utilization rates in persisters. Our data indicate that this observed metabolic remodeling is transient, as the consumption rates of Krebs cycle metabolites are significantly reduced in the progenies of persisters. Given that the mitochondrial electron transport chain (ETC) is more active in the persister subpopulation than in the bulk cancer cell population, we also verified that targeting ETC activity can reduce melanoma persistence. The reported metabolic remodeling feature seems to be a conserved characteristic of melanoma persistence, as it has been observed in various melanoma persister subpopulations derived from a diverse range of chemotherapeutics. Elucidating a global metabolic mechanism that contributes to persister survival and reversible switching will ultimately foster the development of novel cancer therapeutic strategies.

A Supp. Fig. 4: Effects of osmolytes and buffers on E. coli persistence. Pre-propagated cells were diluted 1:100 fold in fresh, modified LB media with indicated osmolytes and pH buffers in baffled flasks. After growing the cultures for 24 h, the cells were diluted (1:100) to fresh, modified LB media with 5 µg/ml of OFX. At designated time points, samples were collected, washed to remove the antibiotics and plates on agar media to quantify CFUs. * indicates the statistical difference between the treatment and control groups (P<0.05).