Identifying molecular mechanisms or therapeutic targets is typically based on large-scale cellular analysis that measures the abundance of mRNA or protein; however, abundance does not necessarily correlate with activity. We report a method for direct large-scale quantification of active pathways that employs a cellular array with parallel gene delivery of constructs that report pathway activity. The reporter constructs encode luciferase, whose expression is influenced by binding of transcription factors (TFs), which are the downstream targets of signaling pathways. Luciferase levels are quantified by bioluminescence imaging (BLI), which allows for rapid, noninvasive measurements. Activity profiles by BLI of 32 TFs were robust, consistent, and reproducible, and correlated with standard cell lysis techniques. The array identified five TFs with differential activity during phorbol-12-myristate-13-acetate (PMA)-induced differentiation of breast cancer cells. A system for rapid, large-scale, BLI quantification of pathway activity provides an enabling technology for mechanistic studies of cellular responses and processes.

BACKGROUND The nationally reported metric for Clostridium difficile infection (CDI) relies solely on laboratory testing, which can result in overreporting due to asymptomatic C. difficile colonization. OBJECTIVE To review the clinical scenarios of cases of healthcare facility-onset CDI (HO-CDI) and to determine the appropriateness of C. difficile testing on the basis of presence of symptomatic diarrhea in order to identify areas for improvement. DESIGN Retrospective cohort study. SETTING Northwestern Memorial Hospital, a large, tertiary academic hospital in Chicago, Illinois. PATIENTS The cohort included all patients with a positive C. difficile test result who were reported to the National Healthcare Safety Network as HO-CDI during a 1-year study period. METHODS We reviewed the clinical scenario of each HO-CDI case. On the basis of documentation and predefined criteria, appropriateness of C. difficile testing was determined; cases were deemed appropriate, inappropriate, or indeterminate. Statistical analysis was performed to compare demographic and clinical parameters among the categories of testing appropriateness. RESULTS Our facility reported 168 HO-CDI cases to NHSN during the study period. Of 168 cases, 33 (19.6%) were judged to be appropriate tests, 25 (14.8%) were considered inappropriate, and 110 (65.5%) were indeterminate. Elimination of inappropriate testing would have improved our facility's standardized infection ratio from 0.962 to 0.819. CONCLUSION Approximately 15% of HO-CDI cases were judged to be tested inappropriately. Testing only patients with clinically significant diarrhea would more accurately estimate CDI incidence, reduce unnecessary antibiotic use, and improve facilities' performance of reportable CDI metrics. Improved documentation could facilitate targeted interventions. Infect Control Hosp Epidemiol 2016;1395-1400.

We analyzed antibiotic use data from 29 southeastern US hospitals over a 5-year period to determine changes in antibiotic use after the fluoroquinolone US Food and Drug Administration (FDA) advisory update in 2016. Fluoroquinolone use declined both before and after the FDA announcement, and the use of select, alternative antibiotics increased after the announcement. Fluoroquinolones are among the 4 most commonly prescribed antibiotic classes. 1,2 Postmarketing reports of serious adverse events linked to fluoroquinolones include tendonitis, neuropathy, hypoglycemia, psychiatric side effects, and possible aortic vessel rupture, leading to safety label changes in , the US Food and Drug Administration (FDA) strengthened the "black box" warning following an initial safety announcement in May 2016, recommending avoidance of fluoroquinolones for uncomplicated infections such as acute exacerbation of chronic bronchitis, uncomplicated urinary tract infections, and acute bacterial sinusitis. 4 Concerns over safety and the association with Clostridiodes difficile infection have led inpatient antimicrobial stewardship programs (ASPs) to develop initiatives to promote avoidance of quinolones. The objective of this study was to quantify the effect of the 2016 FDA "black box" update on inpatient antibiotic use among a cohort of southeastern US hospitals.

To the Editor-Many US hospitals have recently adopted policies mandating universal masking of all staff, visitors and patients. Universal masking is particularly important in preventing transmission to and from individuals who are asymptomatic or presymptomatic for coronavirus disease 2019 (COVID-19). 1 The Centers for Disease Prevention and Control (CDC) estimates that 35% of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) cases are asymptomatic. 2 In addition, healthcare professionals (HCPs), patients, and visitors with atypical or very mild symptoms may more readily transmit SARS-CoV-2 in healthcare facilities without masking policies. 3 Risk of exposure to SARS-CoV-2 in nonclinical areas within healthcare facilities may be overlooked.The incidence of COVID-19 among HCPs decreased significantly after our health system adopted a universal masking policy. Unmasked exposure to another HCP rather than exposure to known infected patients resulted in most of the COVID-19 cases among staff after implementation of this policy. 4 We recently surveyed 50 community hospitals within the Duke Infection Control Outreach Network and found that 90% of these hospitals had also adopted universal masking policies. However, we also determined that actual compliance with universal masking policies was suboptimal, particularly among staff outside of clinical care settings, including administrative offices, shared work rooms, and break rooms. Poor compliance in these shared spaces led to known exposures in some of these hospitals, leading to employee furloughs, a substantial burden of contact tracing, and unnecessary anxiety for exposed individuals. Here, we discuss our perception and understanding of the etiology of poor compliance with universal masking policies in healthcare settings, and we discuss proposed solutions as well.

The nucleoside analogues 8-amino-adenosine and 8-chloro-adenosine have been investigated in the context of B-lineage lymphoid malignancies by our laboratories due to the selective cytotoxicity they exhibit toward multiple myeloma (MM), chronic lymphocytic leukemia (CLL), and mantle cell lymphoma (MCL) cell lines and primary cells. Encouraging pharmacokinetic and pharmacodynamic properties of 8-chloro-adenosine being documented in an ongoing Phase I trial in CLL provide additional impetus for the study of these promising drugs. In order to foster a deeper understanding of the commonalities between their mechanisms of action and gain insight into specific patient cohorts positioned to achieve maximal benefit from treatment, we devised a novel two-tiered chemoinformatic screen to identify molecular determinants of responsiveness to these compounds. This screen entailed: 1) the elucidation of gene expression patterns highly associated with the anti-tumor activity of 8-chloro-adenosine in the NCI-60 cell line panel, 2) characterization of altered transcript abundances between paired MM and MCL cell lines exhibiting differential susceptibility to 8-amino-adenosine, and 3) integration of the resulting datasets. This approach generated a signature of seven unique genes including G6PD which encodes the rate-determining enzyme of the pentose phosphate pathway (PPP), glucose-6-phosphate dehydrogenase. Bioinformatic analysis of primary cell gene expression data demonstrated that G6PD is frequently overexpressed in MM and CLL, highlighting the potential clinical implications of this finding. Utilizing the paired sensitive and resistant MM and MCL cell lines as a model system, we go on to demonstrate through loss-of-function and gain-of-function studies that elevated G6PD expression is necessary to maintain resistance to 8-amino- and 8-chloro-adenosine but insufficient to induce de novo resistance in sensitive cells. Taken together, these results indicate that G6PD activity antagonizes the cytotoxicity of 8-substituted adenosine analogues and suggests that administration of these agents to patients with B-cell malignancies exhibiting normal levels of G6PD expression may be particularly efficacious.

Background Individual hospitals may lack expertise, data resources, and educational tools to support antimicrobial stewardship programs (ASP). Methods We established a collaborative, consultative network focused on hospital ASP implementation. Services included on-site expert consultation, shared database for routine feedback and benchmarking, and educational programs. We performed a retrospective, longitudinal analysis of antimicrobial use (AU) in 17 hospitals that participated for at least 36 months during 2013–2018. ASP practice was assessed using structured interviews. Segmented regression estimated change in facility-wide AU after a 1-year assessment, planning, and intervention initiation period. Year 1 AU trend (1–12 months) and AU trend following the first year (13–42 months) were compared using relative rates (RR). Monthly AU rates were measured in days of therapy (DOT) per 1000 patient days for overall AU, specific agents, and agent groups. Results Analyzed data included over 2.5 million DOT and almost 3 million patient-days. Participating hospitals increased ASP-focused activities over time. Network-wide overall AU trends were flat during the first 12 months after network entry but decreased thereafter (RR month 42 vs month 13, 0.95, 95% confidence interval [CI]: .91–.99). Large variation was seen in hospital-specific AU. Fluoroquinolone use was stable during year 1 and then dropped significantly. Other agent groups demonstrated a nonsignificant downward trajectory after year 1. Conclusions Network hospitals increased ASP activities and demonstrated decline in AU over a 42-month period. A collaborative, consultative network is a unique model in which hospitals can access ASP implementation expertise to support long-term program growth.

Surgical site infections (SSI) are severe complications of solid organ transplant (SOT). This retrospective study assessed the epidemiology of and outcomes associated with invasive primary SSI (IP-SSI) occurring within 3 months of transplantation in adult SOT recipients at Duke University over a 5-year period (2015-2019). Among 2073 consecutive SOT recipients, 198 IP-SSI were identified. The IP-SSI rate declined over the period (14.4% in 2015 vs. 8.3% in 2019) and was higher among multi-organ compared with single-organ transplants (33.9% vs. 8.1%, p < .01). SOT recipients with IP-SSI had longer hospital stays than patients without SSI (30.0 vs. 17.0 days, p < .01). Transplant hospitalization (9.6% vs. 2.2%, p < .01), 6-month (11.6% vs. 3.3%, p < .01), and 1-year mortality (15.7% vs. 5.8%, p < .01) were higher in SOT recipients with IP-SSI than in those without. While Gram-positive bacteria were the most common pathogens, urogenital Mollicute and atypical Mycobacteria were identified as an unexpected cause of IP-SSI, particularly among lung transplant recipients. The median time to IP-SSI was 24.0 3) days, although the time to IP-SSI varied based on organ transplanted and the causative pathogen. IP-SSI is an important and potentially modifiable complication of SOT, associated with prolonged hospitalizations and reduced survival, particularly in the lung transplant population.

Antibiotic stewardship I Antibiotic use metrics I Days of therapy I Days present I Antibiotic spectrum I Antibiotic appropriateness